2.3 Problems and Solutions

The early days of prenatal life place the developing person on a path toward health and success—or not. Fortunately, resilience is apparent from the beginning; healthy newborns are the norm, not the exception.

From the moment of conception to the days and months after birth, many biological and psychological factors protect each new life. We now look at specific problems that may occur and how to prevent or minimize them. Always remember dynamic systems—every hazard is affected by dozens of factors. As one scientist stresses, “genes and their products almost never act alone, but in networks with other genes and proteins and in the context of the environment” (Chakravarti, 2011).

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Abnormal Genes and Chromosomes

Perhaps half of all zygotes have serious abnormalities of their chromosomes or genes. Most of them never grow or implant—an early example of the protection built into nature. However, some newborns with serious genetic problems survive and live close to a normal life—especially if protective factors are present (Nadeau & Dudley, 2011).

Chromosomal MiscountsAbout once in every 200 births, an infant is born with 45, 47, or even 48 or 49 chromosomes instead of the usual 46. Each of these produces a recognizable syndrome, a cluster of distinct characteristics that occur together. The variable that most often correlates with an odd number of chromosomes is the age of the mother, presumably because her ova become increasingly fragile by midlife. The father’s age is also relevant, again probably because his gametes become less robust with age (Brenner et al., 2009).

The most common extra-chromosome condition that results in a surviving child is Down syndrome, also called trisomy-21 because the person has three (tri) copies of chromosome 21. No individual with Down syndrome is identical to another, but most have specific observable characteristics—a thick tongue, round face, slanted eyes, distinctive body proportions. Many also have hearing problems, heart abnormalities, muscle weakness, and short stature. They are usually slower to develop intellectually, especially in language, and they reach their maximum intellectual potential at about age 15 (Rondal, 2010). Some are severely intellectually disabled; others are of average or above-average intelligence. That extra chromosome affects the person throughout his or her life, but family context, educational efforts, and possibly medication can improve the person’s prognosis (Kuehn, 2011).

Another common problem occurs at the 23rd pair of chromosomes. Not every person has two, and only two, sex chromosomes. About 1 in every 500 infants is born with only one sex chromosome (no Y) or with three or more (not just two) (Hamerton & Evans, 2005). Such children have many challenges, especially in sexual maturation and fertility. The specifics depend on the particular configuration as well as on other genetic factors (Mazzocco & Ross, 2007).

An Artist in the Making Daniel, seen here painting a brightly coloured picture on a big canvas has trisomy-21. He attends the only school in Chile where children with and without special needs share classrooms.
REUTERS/CLAUDIA DAUT

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Gene DisordersEveryone is a carrier of genes or alleles that could produce serious diseases or disabilities in the next generation. Given that most disorders are polygenic and that the mapping of the human genome is recent, the exact impact of each allele is not yet known (Couzin-Frankel, 2011a). It is likely that common complex disorders arise from an accumulation of genetic defects in many genes (Chakravarti, 2011). Although most disorders result from many genes, single-gene disorders have been studied for decades. Our accumulated knowledge of them can help us understand more complex disorders.

Most of the 7000 known single-gene disorders are dominant and easy to identify as such: Half the offspring of parents with a dominant disorder will also have the disorder (in other words, it will be expressed in their phenotype) and half will escape the gene, and hence the disorder, completely.

If the condition is fatal in childhood, it will, of course, never be transmitted. Thus, all common dominant disorders either begin in adulthood (Huntington disease and early-onset Alzheimer disease, for instance) or have relatively mild symptoms.

One disorder once thought to be dominant is Tourette syndrome, which may make a person have uncontrollable tics and explosive verbal outbursts. But most people with Tourette syndrome have milder symptoms, such as an occasional twitch or a controllable impulse to speak inappropriately. Recent research finds a complex inheritance: probably multiple genes and epigenetic factors rather than a single dominant gene (Woods et al., 2007).

The number of recessive disorders is probably in the millions, most of them rare. For example, Canadian writer Ian Brown’s son Walker was born with a genetic disorder so rare it occurs only once in every 300 000 births. The resulting syndrome creates very serious developmental difficulties. The Boy in the Moon, Brown’s 2009 account of Walker’s birth and development, gives a moving description of what it is like to live with (and to love) a child who is severely disabled:

Tonight I wake up in the dark to a steady, motorized noise. Something wrong with the water heater. Nnngah. Pause. Nnngah. Nnngah.

But it’s not the water heater. It’s my boy, Walker, grunting as he punches himself in the head, again and again.

He has done this since before he was two. He was born with an impossibly rare genetic mutation, cardiofaciocutaneous syndrome, a technical name for a mash of symptoms. He is globally delayed and can’t speak, so I never know what’s wrong. No one does. There are just over a hundred people with CFC around the world. The disorder turns up randomly, a misfire that has no certain cause or roots; doctors call it an orphan syndrome because it seems to come from nowhere.

[Brown, 2009]

Other recessive conditions are much more common, including cystic fibrosis, thalassemia, and sickle-cell anemia. About 1 in 12 North Americans is a carrier for one of them. The reason these three are common is that carriers are protected from lethal diseases. For example, carriers of the sickle-cell trait are unlikely to die of malaria, a deadly killer in central Africa. As a result, over the centuries, African carriers were more likely than non-carriers to survive. Similarly, the single cystic fibrosis gene is more common among people whose ancestors came from northern Europe because carriers of that gene may have been protected against cholera. Prenatal and even preconception tests can detect many disorders (see TABLE 2.5).

Table : TABLE 2.5 Methods of Prenatal and Preconception Testing*
Method Description Risks, Concerns, and Indications
Preconception blood tests Test for nutrients (especially iron); for diseases (syphilis, HIV, herpes, hepatitis B); for carrier status (cystic fibrosis, sickle-cell anemia, Tay-Sachs disease, thalassemia, etc.). Might require postponement of pregnancy for counselling, treatment.
Pre-implantation testing After in vitro fertilization, one cell is removed from each zygote at the four- or eight-cell stage and analyzed. Not entirely accurate; requires in vitro fertilization and rapid assessment, delaying implantation. Used when couples are at high risk of known, testable disorders.
Tests for pregnancy-associated plasma protein A (PAPPA) and human chorionic gonadotropin Blood tests are usually done at about 11 weeks to indicate levels of these substances. Low levels correlate with chromosomal miscounts and slow prenatal growth, but falsepositive or false-negative results can occur.
Alpha-fetoprotein assay Blood is tested for alpha-fetoprotein (AFP) level, often combined with other blood tests and repeat sonogram. High AFP indicates neural-tube defects or multiple embryos; low AFP indicates Down syndrome. Normal levels change weekly; accurate conception dating required.
Sonogram (ultrasound) High-frequency sound waves produce a “picture” of the fetus, often done several times, from 6 to 38 weeks. Detects many problems, anticipates complications. Reveals head or body malformations, excess brain fluid, Down syndrome (via fetal neck measurement), and several diseases. Estimates fetal age and growth, reveals multiple fetuses and placental position. No known risks, unlike the X-rays that it has replaced.
Chorionic villus sampling (CVS) A sample of the chorion (part of the placenta) obtained (via sonogram and syringe) at 10 weeks and analyzed. Cells of placenta are genetically identical to fetal cells, so CVS indicates genetic conditions. Can cause spontaneous abortion (rare).
Amniocentesis Some fluid inside the placenta is withdrawn (via sonogram and syringe) at 16 weeks; cells cultured and analyzed. Can cause spontaneous abortion (rare). Detects abnormalities later in pregnancy than other tests but is very accurate.
*Many newer tests are experimental, soon to be offered to the general public. Therefore, this list is partial, to illustrate that many tests are used at various times during pregnancy to indicate possible problems.

Teratogens

Possible problems can occur after conception as well, because many toxic substances, illnesses, and experiences can harm a fetus. Every week scientists discover an unexpected teratogen, which is anything—drugs, viruses, pollutants, malnutrition, stress, and more—that increases the risk of prenatal abnormalities. Many abnormalities can be avoided, many potential teratogens do no harm, and much damage can be remedied.

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Some teratogens cause no physical defects but affect the brain, making a child hyperactive or antisocial, or resulting in the child having a learning disability. These are behavioural teratogens. About 20 percent of all children have difficulties that could be connected to behavioural teratogens, although the link is not straightforward: The cascade is murky, in part because the impact of the environment varies (Bell & Robinson, 2011).

One of my students described her little brother as follows:

I was nine years old when my mother announced she was pregnant. I was the one who was most excited.…My mother was a heavy smoker, Colt 45 beer drinker.…I asked, “Why are you doing it?” She said, “I don’t know.”

During this time I was in the fifth grade and we saw a film about birth defects. My biggest fear was that my mother was going to give birth to an infant with fetal alcohol syndrome (FAS)… My baby brother was born right on schedule. The doctors claimed a healthy newborn… Once I heard healthy, I thought everything was going to be fine. I was wrong, then again I was just a child.…My baby brother never showed any interest in toys…he just cannot get the right words out of his mouth…he has no common sense. …

[J., personal communication]

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My student wrote: “Why hurt those who cannot defend themselves?” J. blames her mother for drinking beer, although genes, postnatal experiences, and the lack of information and services that could have prevented harm (for instance, some drug rehab programs do not accept pregnant women) may have contributed to her brother’s lack of “common sense.” Just as every teratogen can be mitigated by other circumstances, every one can be made worse. An understanding of risk is crucial.

Risk Analysis

Risk analysis discerns which chances are worth taking and how risks are minimized. Let’s pick an easy example: Crossing the street is a risk, yet it would be worse to avoid all street crossing. Knowing this, we cross carefully, looking both ways.

Although all teratogens increase the risk of harm, none always causes damage. The impact of teratogens depends on the interplay of many factors, both destructive and protective, an example of the dynamic-systems perspective.

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The Critical TimeOne crucial factor in the effect of a teratogen is timing—the age of the developing embryo or fetus when it is exposed to the teratogen (Sadler, 2012). Some teratogens cause damage only during a critical period (see Chapter 1) (see Figure 2.9).

FIGURE 2.9 Critical Periods in Human Development The most serious damage from teratogens (green bars) is likely to occur early in prenatal development. However, significant damage (purple bars) to many vital parts of the body can occur during the last months of pregnancy as well. Behavioural teratogens also affect the fetus throughout development.

Obstetricians recommend that before pregnancy occurs, women should avoid drugs (especially alcohol), supplement a balanced diet with extra folic acid and iron, and update their immunizations. Indeed, preconception health is at least as important as health during pregnancy.

In recent years, Canadian women have been more active and aware of the importance of preconception health as a strategy to optimize a healthy birth. Through public awareness campaigns, discussions with health care providers, and preconception classes, expectant mothers and fathers have gained the knowledge, skills, motivation, opportunity, access, and supportive environments that make it easier to engage in healthy behaviours (McGreary, 2007). (See Figure 2.10 for examples of changes in prenatal health behaviours.)

FIGURE 2.10 For the Sake of the Baby According to one study in Ontario, there were significant changes in prenatal health behaviours between 2002 and 2008. Specifically, when compared to their last pregnancy, women were more likely to consult their health care provider about improving their health, quit/cut down on their smoking, and/or begin taking folic acid. In fact, many of these behaviour changes began even before conception (Best Start Resource Centre, 2009).

The first days and weeks after conception (the germinal and embryonic periods) are critical for body formation, but the entire fetal period is a sensitive time for brain development. Further, preterm birth is a risk factor that is affected by nutrition and drugs throughout pregnancy.

Timing may be important even before conception. When pregnancy occurs soon after a previous pregnancy, risk increases, perhaps because a woman’s body may need time to recover from birth. For example, second-born children are twice as likely to be autistic if they are born within a year of the first-born child than if they are born several years later (Cheslack-Postava et al., 2011). Mothers who are under age 16 or over age 40 have higher rates of genetic, prenatal, and birth complications.

The critical and sensitive period concepts are helpful in understanding cerebral palsy (difficulties with movement control resulting from brain damage), which was once thought to be caused solely by birth procedures (excessive medication, slow breech birth, or use of forceps to pull the fetal head through the birth canal). We now know that cerebral palsy results from genetic vulnerability, teratogens, and maternal infection (J. R. Mann et al., 2009), and not only insufficient oxygen to the fetal brain at birth.

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A lack of oxygen is anoxia, which often occurs for a second or two during birth, indicated by a slower fetal heart rate. To prevent prolonged anoxia, the fetal heart rate is monitored during labour. Avoiding anoxia is also the reason that two of the five Apgar ratings indicate oxygen level. How long anoxia can continue without harming the brain depends on genes, birth weight, gestational age (preterm newborns are more vulnerable), drugs (either taken by the mother before birth or given during birth), and many other factors. Insufficient oxygen may begin long before birth. Thus, anoxia is part of a cascade that may cause cerebral palsy or other problems. Inadequate oxygen during pregnancy is a serious condition, which is why listening to the fetal heartbeat is part of every prenatal visit.

How Much is Too Much?A second factor affecting the harm from any teratogen is the dose and/or frequency of exposure. Some teratogens have a threshold effect; they are virtually harmless until exposure reaches a certain level, at which point they “cross the threshold” and become damaging. This threshold is not a fixed boundary: Dose, timing, frequency, and other teratogens affect when the threshold is crossed (O’Leary et al., 2010).

Thresholds are difficult to set because one teratogen may increase the harm from another. Consider alcohol. Early in pregnancy, an embryo exposed to heavy drinking can develop fetal alcohol syndrome (FAS), which distorts the facial features (especially the eyes, ears, and upper lip). Later in pregnancy, alcohol is a behavioural teratogen, the cause of fetal alcohol effects (FAE), leading to hyperactivity, poor concentration, impaired spatial reasoning, and slow learning (Niccols, 2007; Streissguth & Connor, 2001). Health Canada (2005) estimates that the Canada-wide rate for FAS is 1 to 3 per every 1000 live births; for FAE, the Canadian rate is 30 per 1000. These rates are much higher for some First Nations and Inuit communities. Together, FAS and FAE are the leading causes of preventable birth defects in Canada. However, some pregnant women drink alcohol with no evident harm to the fetus. FAS is more apparent when women are poorly nourished and cigarette smokers (Abel, 2009). If occasional drinking during pregnancy always caused FAS, almost everyone born in Europe before 1980 would be affected. As for FAE, hyperactivity and slow learning are so common that FAE cannot be blamed for every case.

Currently, Health Canada advises all Canadian women who are pregnant or even thinking of becoming pregnant to avoid taking any alcohol whatsoever: “STOP drinking alcohol now if you are planning to become pregnant” (Health Canada, 2005). By contrast, women in the United Kingdom receive conflicting advice about drinking an occasional glass of wine (Raymond et al., 2009), and French women are told to abstain, but many have not heard that message (Toutain, 2010). Total abstinence requires that all women who might become pregnant avoid a legal substance that most adults use routinely. Wise? Probably. Necessary? Maybe not.

ESPECIALLY FOR Judges and Juries How much protection, if any, should the legal system provide for fetuses? Should alcoholic women who are pregnant be jailed to prevent them from drinking? What about people who enable them to drink, such as their partners, their parents, bar owners, bartenders?

Genetic VulnerabilityGenes are a third factor that influences every aspect of conception, pregnancy, and birth. Consider what happens when a woman carrying dizygotic twins drinks alcohol, for example. The alcohol in the mother’s blood stream reaches the placenta and then the embryos via the umbilical cord. Thus, the twins’ blood alcohol levels are equal. However, one twin may be more severely affected than the other because their alleles for the enzyme that metabolizes alcohol may differ.

Genetic vulnerability is a particular example of differential susceptibility, as described in Chapter 1. Genetic protections or hazards are suspected for many birth defects (Sadler, 2012). A protective factor seems to be the X chromosome; male fetuses (only one X) are more vulnerable to teratogens than females (XX) (Lewis & Kestler, 2012).

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Since fathers provide 23 chromosomes, they are as likely as mothers to provide genetic protection or vulnerability. Maternal genes have an additional role: They affect a mother’s body and thus the environment of the womb. One maternal allele results in low levels of folic acid during pregnancy. Via the umbilical cord, this can produce neural-tube defects—either spina bifida, in which the tail of the spine is not enclosed properly (in healthy embryos, enclosure occurs at about week 7), or anencephaly, when part of the brain is missing.

Neural-tube defects are more common in certain ethnic groups (Irish, English, and Egyptian) than in others. For these groups, folic acid supplements before pregnancy are strongly recommended. Although the allele that causes low folic acid in women is rare among Asians and Africans, it is still beneficial for pregnant women of these backgrounds to take supplemental folic acid as it is not harmful.

In 1998, both Canada and the United States created laws that required folic acid to be added to packaged cereal products such as white flour, enriched pasta, and cornmeal. The aim of these measures is to protect every woman, even if she does not expect to become pregnant. A Canadian study found that the rate of neural-tube defects in Canada dropped by 46 percent since these laws were enacted, which means that as many as 170 fewer babies a year are growing up with conditions such as spina bifida (De Wals et al., 2007).

Applying the ResearchRisk analysis cannot precisely predict the results of genetic vulnerability, teratogenic exposure, or birth complications in individual cases. However, much is known about what individuals and society can do to reduce the risks. TABLE 2.6 lists some teratogens and their possible effects, as well as preventive measures.

Table : TABLE 2.6 Teratogens: Effects of Exposure and Prevention of Damage*
Teratogens Effects of Exposure on Fetus Measures for Preventing Damage
Diseases
Rubella (German measles) In embryonic period, causes blindness and deafness; in first and second trimesters, causes brain damage. Get immunized before becoming pregnant.
Toxoplasmosis Brain damage, loss of vision, intellectual disabilities. Avoid eating undercooked meat and handling cat feces, garden dirt during pregnancy.
Measles, chicken pox, influenza May impair brain functioning. Get immunized before getting pregnant; avoid infected people during pregnancy.
Syphilis Baby is born with syphilis, which, untreated, leads to brain and bone damage and eventual death. Early prenatal diagnosis and treatment with antibiotics.
AIDS Baby may catch the virus. Without treatment, illness and death are likely during childhood. Prenatal drugs and Caesarean birth make AIDS transmission rare.
Other sexually transmitted infections, including gonorrhea and chlamydia Not usually harmful during pregnancy but may cause blindness and infections if transmitted during birth. Early diagnosis and treatment; if necessary, Caesarean section, treatment of newborn.
Infections, including infections of urinary tract, gums, and teeth May cause premature labour, which increases vulnerability to brain damage. Get infection treated, preferably before becoming pregnant.
Pollutants
Lead, mercury, PCBs (polychlorinated biphenyls); dioxin; and some pesticides, herbicides, and cleaning compounds May cause spontaneous abortion, preterm labour, and brain damage. Most common substances are harmless in small doses, but pregnant women should avoid regular and direct exposure, such as drinking well water, eating unwashed fruits or vegetables, using chemical compounds, and eating fish from polluted waters.
Radiation
Massive or repeated exposure to radiation, as in medical X-rays In the embryonic period, may cause abnormally small head (microcephaly) and intellectual disabilities; in the fetal period, suspected but not proven to cause brain damage. Exposure to background radiation, as from power plants, is usually too low to have an effect. Get sonograms, not X-rays, during pregnancy; pregnant women who work directly with radiation need special protection or temporary assignment to another job.
Social and Behavioural Factors
Very high stress Early in pregnancy, may cause cleft lip or cleft palate, spontaneous abortion, or preterm labour. Get adequate relaxation, rest, and sleep; reduce hours of employment; get help with housework and child care.
Malnutrition When severe, may interfere with conception, implantation, normal fetal development, and full-term birth. Eat a balanced diet (with adequate vitamins and minerals, including, especially, folic acid, iron, and vitamin A); achieve normal weight before getting pregnant, then gain 10–15 kg during pregnancy.
Excessive, exhausting exercise Can affect fetal development when it interferes with pregnant woman’s sleep, digestion, or nutrition. Get regular, moderate exercise.
Medicinal Drugs
Lithium
Tetracycline
Retinoic acid
Streptomycin
ACE inhibitors
Phenobarbital
Thalidomide
Can cause heart abnormalities.
Can harm teeth.
Can cause limb deformities.
Can cause deafness.
Can harm digestive organs.
Can affect brain development.
Can stop ear and limb formation.
Avoid all medicines, whether prescription or over-the-counter, during pregnancy unless they are approved by a medical professional who knows about the pregnancy and is aware of the most recent research.
Psychoactive Drugs
Caffeine Normal use poses no problem. Avoid excessive use: Drink no more than three cups a day of beverages containing caffeine (coffee, tea, cola drinks, hot chocolate).
Alcohol May cause fetal alcohol syndrome (FAS) or fetal alcohol effects (FAE). Stop or severely limit alcohol consumption during pregnancy; especially dangerous are three or more drinks a day or four or more drinks on one occasion.
Tobacco Reduces birth weight, increases risk of malformations of limbs and urinary tract, and may affect the baby’s lungs. Stop smoking before becoming pregnant; if already pregnant, stop smoking immediately.
Marijuana Heavy exposure may affect the central nervous system; when smoked, may hinder fetal growth. Avoid or strictly limit marijuana consumption.
Heroin Slows fetal growth and may cause premature labour; newborns with heroin in their bloodstream require medical treatment to prevent the pain and convulsions of withdrawal. Get treated for heroin addiction before becoming pregnant; if already pregnant, gradual withdrawal on methadone is better than continued use of heroin.
Cocaine May cause slow fetal growth, premature labour, and learning problems in the first years of life. Stop using cocaine before pregnancy; babies of cocaine-using mothers may need special medical and educational attention in their first years of life.
Inhaled solvents (glue or aerosol) May cause abnormally small head, crossed eyes, and other indications of brain damage. Stop sniffing inhalants before becoming pregnant; be aware that serious damage can occur before a woman knows she is pregnant.
Sources: Gupta, 2011; Mann & Andrews, 2007; O’Rahilly & Müller, 2001; Reece & Hobbins, 2007; Sadler, 2012; Shepard & Lemire, 2004.
* The field of toxicology advances daily. Research on new substances begins with their effects on nonhuman species, which provides suggestive (though not conclusive) evidence. This table is a primer; it is no substitute for careful consultation with a professional who knows the recent research.

Remember that the outcomes vary. Many fetuses are exposed with no evident harm. The opposite occurs as well: About 20 percent of all serious defects occur for reasons unknown. Women are advised to maintain good nutrition and avoid teratogens, especially drugs and chemicals (pesticides, cleaning fluids, and many cosmetics contain teratogenic chemicals). Some medications are necessary (e.g., for women who have epilepsy, diabetes, severe depression) and should be continued, but caution should begin before pregnancy is confirmed.

Sadly, the cascade of teratogens is most likely to begin with women who are already vulnerable. For example, cigarette smokers are more often drinkers (as was J.’s mother); those whose jobs involve chemicals and pesticides are more often malnourished; low-SES women are more likely to give birth early, and they are less likely to get prenatal care and be admitted to modern hospitals (Ahmed & Jaakkola, 2007; A. S. Bryant et al., 2010; Hougaard & Hansen, 2007).

The benefits of early prenatal care are many: Women can be told which substances to avoid, they can learn what to eat and what to do, and they may be diagnosed and treated for some conditions (syphilis and HIV among them) that harm the fetus only if early treatment does not occur. As noted earlier, prenatal tests (of blood, urine, and fetal heart rate, as well as ultrasound) and even preconception tests can identify many disorders (see TABLE 2.5). When complications (such as twins, gestational diabetes, infections) arise, early recognition increases the chance of a healthy birth.

One obvious effect of early prenatal care is that the risk of low birth weight is reduced. As you will now see, an underweight newborn is vulnerable in dozens of ways. Indeed, the United States’ rate of infant death is higher than many other nations largely because of more underweight babies. In Canada, the rate of infant death is also higher than for many industrialized countries, but the reasons for this are complex, as you will see in the feature A View from Science: Why Are Infant Mortality Rates in Canada So High?.

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Low Birth Weight

Some newborns, especially preterm babies, are small and immature. With modern hospital care, tiny infants usually survive, but it would be better for everyone—mother, father, baby, and society—if all newborns were in the womb for at least 35 weeks and weighed more than 2500 grams.

Low birth weight (LBW) is defined by the World Health Organization as weight under 2500 grams. LBW babies are further grouped into very low birth weight (VLBW), under 1500 grams, and extremely low birth weight (ELBW), under 1000 grams.

Recently, some researchers have examined the issue of birth weight by taking ethnicity into consideration. One Canadian study noted that babies of immigrant mothers from regions of the world other than Europe and North America are often smaller than those of domestically born mothers. Some of these smaller babies run the risk of being classified LBW and subjected to unnecessary tests and hospitalizations when actually they are a normal weight for newborns from their world region. The researchers concluded that “birthweight curves [standards] need to be modified for newborns of immigrant mothers originating from non-European/Western nations” (Ray et al., 2012).

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Doing Great Survival is uncertain for extremely low birth weight newborns, such as Owen (shown here) and his twin brother, Oliver. However, Owen and Oliver’s chances are excellent, partly because they are receiving specialized care at the neonatal intensive care unit (NICU) at Mount Sinai Hospital in Toronto. Medical advances, such as those at Mount Sinai Hospital, have led to decreased mortality rates of at-risk babies.
LUCAS OLENIUK/TORONTO STAR VIA GETTY IMAGES

Maternal BehaviourFetal weight normally doubles in the last three months of a full term pregnancy, with 900 grams of that gain occurring in the final three weeks. Thus, a baby born preterm (three or more weeks early; no longer called premature) is usually LBW.

Preterm birth correlates with many of the teratogens already mentioned, an example of the cascade that leads to newborns with evident problems. The prenatal environment itself may cause early labour as well. Indeed, when the environment of the womb is harmful, as when multiple fetuses reduce nourishment to each individual fetus, hormones can precipitate labour.

Early birth is only one cause of low birth weight. Some fetuses gain weight slowly throughout pregnancy and are small for gestational age (SGA) (also called small-for-dates). For example, a full-term baby weighing only 2500 grams and a 30-week-old fetus weighing 1000 grams are both SGA. The former is one gram shy of LBW and the latter, if born, is ELBW and SGA. Maternal or fetal illness might cause SGA, but maternal drug use before and during pregnancy is the most common underlying cause. Every psychoactive drug slows fetal growth; tobacco is implicated in 25 percent of all LBW births worldwide.

Another common reason for slow fetal growth is maternal malnutrition. Women who begin pregnancy underweight, who eat poorly during pregnancy, or who gain less than 1.3 kilograms per month in the final six months are likely to have an underweight infant. Malnutrition (not age) is the primary reason teenagers often have small babies. Unfortunately, many of the risk factors just mentioned—underweight, undernutrition, underage, and smoking—tend to occur together.

Fathers and Significant OthersThe causes just mentioned of low birth weight focus on the pregnant woman: If she takes drugs or is undernourished, her fetus suffers. Conversely, if she take cares to nourish herself, to not take drugs, and to avoid exhaustion, she can help protect the baby’s prenatal health. However, the more we learn about birth problems, the more important fathers—and grandmothers, neighbours, and communities—are discovered to be. As an editorial in a journal for obstetricians explains: “Fathers’ attitudes regarding the pregnancy, fathers’ behaviours during the prenatal period, and the relationship between fathers and mothers…may indirectly influence risk for adverse birth outcomes” (Misra et al., 2010).

Much Canadian research over the last two decades bears out the idea that fathers have strong impacts on the health and well-being of their newborn babies. For example, a team of researchers from Ottawa examined the links between paternal age and adverse birth outcomes (Chen et al., 2007). They found that, compared with fathers in their 20s or older than 40, teenage fathers were more likely to have children who experienced preterm birth, low birth weight, low Apgar scores, and neonatal mortality.

Although there are no clear reasons why teenage fathers might contribute to an increased rate of negative birth outcomes, the researchers speculated about several causes. First, biology itself might play a role, since younger men tend to have more immature sperm, which lead to “abnormal placentation,” or difficulties in implanting properly in the nourishing environment of the placenta.

Second, socioeconomic factors may have an influence, since teenage fathers often come from economically disadvantaged families and have less education than older fathers. Parents from disadvantaged backgrounds are less likely to make use of prenatal care services, which leads to a greater risk of poor birth outcomes. Also the social dynamics between teenage parents may have negative consequences for newborns, since men of this age tend to be more prone to violence and have fewer financial resources to support their spouses than older men have.

Finally, lifestyle factors can play a role, because drinking, smoking, and the use of illegal drugs, which are all more common with teenage fathers, can lead to adverse birth outcomes (Chen et al., 2007).

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Consequences of Low Birth WeightEarly death is the most obvious hazard of low birth weight. But problems do not end with survival. When compared with newborns conceived at the same time but born later, very low-birth-weight infants are later to smile, hold a bottle, walk, and talk.

As months go by, cognitive, visual, and hearing impairments emerge. High-risk newborns are more likely to cry more, pay attention less, disobey, and experience language delays as they get older (Aarnoudse-Moens et al., 2009; Spinillo et al., 2009).

Longitudinal research studies find that, compared with the average child in middle childhood, formerly SGA children have smaller brain volume, and those who were preterm have lower IQs (van Soelen et al., 2010). Even in adulthood, risks persist: Adults who were LBW are more likely to have heart disease and diabetes.

However, remember that risk analysis gives odds, not certainties—and remember that many factors (including the genes and prenatal care already described and caregiving explained in the following chapters) affect each child. Although low birth weight is a risk to be avoided if possible, some tiny newborns, by age 4 years, are normal in brain development and in every other way (Claas et al., 2011; Spittle et al., 2009).

Comparing NationsThe low-birth-weight rate in Canada is about 6 percent. This rate is higher than that of some northern European nations, such as Sweden, which has an LBW rate of 4 percent, and lower than that of countries such as the United States, which has an LBW rate of about 8 percent. In several South Asian nations, including India, more than 20 percent of infants weigh less than 2500 grams (see Figure 2.11).

FIGURE 2.11 Getting Better Some public health experts consider the rate of low birth weight to be indicative of national health, since both are affected by the same causes. If that is true, the world is getting healthier, since the LBW world average was 28 percent in 2009 but is now 16 percent. When all nations are included, 47 report LBW at 6 per 100 or lower, which suggests that many nations (including Canada and the United States) could improve.

What factors other than being born preterm may affect the baby’s birth weight? Historically, personal factors such as smoking, alcohol and drug use, poor nutrition before and during pregnancy, and high stress have put a mother at risk for a low birth weight baby. Key environmental factors have been poverty, single or teenage parenthood, and living with a violent partner.

Lending a Hand Fathers-to-be play an important role in expectant mothers’ and babies’ well-being. With the support of her partner, this mother-to-be is likely to eat well, avoid drugs, and rest when she is tired.
DIGITALSKILLET/GETTY IMAGES

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However, according to a 2009 report from Vital Signs Canada (VSC), some factors that have historically contributed to low birth weight are declining across the country, including smoking among pregnant women and incidence of teenage pregnancy (VSC, 2009). Other factors, such as the increasing number of older women (aged 35–49) who are giving birth, the increased use of assisted reproductive technologies and Caesarean sections, and greater numbers of multiple births, all contributed to a 17 percent increase in low-birth-weight babies over the 10-year period from 1995–2004 (VSC, 2009).

As for the United States, the Department of Agriculture found an increase in food insecurity (measured by skipped meals, use of food stamps, and outright hunger) in the past decade. Food insecurity directly affects LBW, and it also increases chronic illness, which itself correlates with LBW (Seligman & Schillinger, 2010). In 2008, about 15 percent of U.S. households were considered food insecure, with rates higher among women in their prime reproductive years than among middle-aged women or men of any age. These rates increased with the economic recession of 2008–2010; if food insecurity is one explanation for LBW rates, rates of LBW will continue to increase.

Worldwide, far fewer low-birth-weight babies are born now than 20 years ago, and neonatal deaths have been reduced by one-third as a result (Rajaratnam et al., 2010). Some nations, China and Chile among them, have shown dramatic improvement. In 1970 about half of Chinese newborns were LBW; recent estimates put that number at 4 percent (UNICEF, 2012). By contrast, in other nations, notably in sub-Saharan Africa, the LBW rate is steady or rising because global warming, AIDS, food shortages, wars, and other problems affect pregnancy.

A VIEW FROM SCIENCE

Why Are Infant Mortality Rates So High in Canada?

The infant mortality rate (IMR) is defined as the number of deaths that occur before a child’s first birthday per 1000 live births. Tracking this rate is important because it acts as an indicator of children’s health and well-being in a particular society over time. It also provides a standard we can use to judge the effectiveness of a country’s health system as a whole. As the Organisation of Economic Cooperation and Development (OECD) noted in a 2009 report, “the infant mortality rate…reflects the economic and social conditions for the health of mothers and newborns, as well as the effectiveness of health systems” (p. 246).

Given the importance of the IMR, the question becomes how well is Canada performing compared with other nations? Apparently rather poorly, according to the OECD report just mentioned. In ranking 17 industrialized nations, the OECD placed Canada second to last, with an IMR of 5.1, ahead of only the United States (see Figure 2.12). This result led the Conference Board of Canada to call Canada’s IMR “shockingly high for a country at Canada’s level of socioeconomic development” André Lalonde, vicepresident of the Society of Obstetricians and Gynaecologists of Canada, lamented, “We’re losing our reputation. We have fallen way behind” (Priest, 2010).

FIGURE 2.12 Poor Grade for Canada In its report on infant mortality, the Conference Board of Canada assigned Canada a grade of “C” for its relatively high infant mortality rate compared with other industrialized countries. Twelve of the 17 listed countries had rates below 4, while Canada’s was 5.1. What could be some reasons for such a wealthy country having a relatively high rate of infant mortality?

Thanks to medical advances, between 1960 and 1980 Canada’s IMR did drop significantly, from 27 deaths per 1000 live births to 10. After 1980, the rate continued to improve but not in as dramatic a fashion. After 2000, it stabilized to between 5.5 and 5.0 but stubbornly resisted all attempts to push it below the 5.0 mark. Nonetheless, since the 1960s, many other industrialized countries have improved at greater speed and have achieved lower rates. For example, Japan’s 2009 IMR was 2.6, just about half that of Canada’s.

To some extent, relatively high IMR in Canada may stem from the way “live birth” is defined across nations. For instance, Canadian officials define a live birth as a newborn that takes a breath or shows other signs of life (Statistics Canada, 2011a). In contrast, both France and the Netherlands define a live birth as a baby who meets the minimal weight of 2500 grams or 22 weeks gestation (EURO-PERISTAT et al., 2008). Plainly, a baby who meets the European standards has a better chance of surviving than one who was born before 22 weeks gestation or who weighed less than 2500 grams but still managed to draw a breath after delivery.

Other researchers have suggested that the higher Canadian rates are due in part to the prevalence of new technologies for delivering preterm or VLBW babies (Milan, 2011). Thus, many more babies are given a greater chance of living who may have been stillborn in years past. Since they are so fragile, however, a number of them die in infancy. New fertility programs also lead to multiple births, and since these babies tend to be born preterm, they are at a higher risk of early death (Conference Board of Canada, 2012).

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Researchers also recognize that there are important environmental or socioeconomic factors that contribute to Canada’s high IMR. These include the growing gap between rich and poor and high rates of child poverty and teen pregnancies (Warick, 2010; Raphael, 2010). Another factor that can have an effect is isolation, as with remote villages in rural regions where quality health care can be difficult to access and where poor water quality and substandard housing are persistent concerns.

All of these environmental factors have particular relevance for Aboriginal peoples in Canada. According to most researchers, the IMR among First Nations is twice as high as that for the general population, while the rate for Inuit communities is three to four times higher (Smylie et al., 2010). Federal government initiatives to lower the IMR, especially in Aboriginal communities, include the Maternal Child Health Program, the Canada Prenatal Nutrition Program, Aboriginal Head Start, and Early Childhood Development programs (Native Women’s Association of Canada, 2012).

Thanks in part to these and other initiatives, in 2009 Canada’s IMR finally cracked the 5.0 barrier and registered at 4.9. However, by current measure, Canada’s IMR is still significantly higher than that of most other industrialized countries.

KEY points

  • Zygotes with abnormal chromosomes and genes are common: Most are spontaneously aborted early after conception. Survivors (e.g., those with Down syndrome) benefit from good care.
  • Although hundreds of teratogens can harm the fetus, many future babies are protected by genes, timing (late), dose (small), and frequency (rare).
  • Fathers, future grandparents, and cultures reduce risks, making sure expectant mothers are well fed, rested, and drug-free.
  • Newborns born early and small for gestational age are at risk for many problems, at birth and throughout the life span.
  • Infant mortality rates in Canada are considered high when compared with rates in other countries.

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