Lifespan Development. Tara L. Kuther

Illness

      Depending on the type and when it occurs, an illness experienced by the mother during pregnancy can have devastating consequences for the developing fetus. For example, rubella (German measles) prior to the 11th week of pregnancy can cause a variety of defects, including blindness, deafness, heart defects, and brain damage, but after the first trimester, adverse consequences become less likely (Bouthry et al., 2014). Other illnesses have varying effects on the fetus. For example, chicken pox can produce birth defects affecting the arms, legs, eyes, and brain; mumps can increase the risk of miscarriage (Mehta, 2016; Webster et al., 2018). In addition to posing risks to development, some sexually transmitted infections (STIs), such as syphilis, can be transmitted to the fetus during pregnancy (Tsimis & Sheffield, 2017). Others, such as gonorrhea, genital herpes, and human immunodeficiency virus (HIV), can be transmitted as the child passes through the birth canal during birth or through bodily fluids after birth. Since some diseases, such as mumps and rubella, can be prevented with vaccinations, it is important for women who are considering becoming pregnant to discuss their immunization status with their health care provider.

      Some illnesses with teratogenic effects, such as the mosquito-borne Zika virus, are not well understood. Children born to women infected with the Zika virus are at greater risk of microencephaly, reduced head size (Prakalapakorn, Meaney-Delman, Honein, & Rasmussen, 2017). They may also show a pattern of defects now known as congenital Zika syndrome, which includes severe microcephaly characterized by partial skull collapse, damage to the back of the eye, and body deformities, including joints and muscles with restricted range of motion (Centers for Disease Control and Prevention, 2017c; D. L. Moore, 2017).

      Environmental Hazards

      Prenatal exposure to chemicals, radiation, air pollution, and extremes of heat and humidity can impair development. Infants prenatally exposed to heavy metals, such as lead and mercury, whether through ingestion or inhalation, score lower on tests of cognitive ability and intelligence, as well as have higher rates of childhood illness (Sadler, 2015; Vigeh, Yokoyama, Matsukawa, Shinohara, & Ohtani, 2014; Xie et al., 2013). Exposure to radiation can cause genetic mutations. Infants born to mothers pregnant during the atomic bomb explosions in Hiroshima and Nagasaki and after the nuclear power accident at Chernobyl displayed many physical deformities, mutations, and intellectual deficits. Prenatal exposure to radiation is associated with Down syndrome, reduced head circumference, intellectual disability, reduced intelligence scores and school performance, and heightened risk for cancer (Chang, Lasley, Das, Mendonca, & Dynlacht, 2014). About 85% of the world’s birth defects occur in developing countries, supporting the role of context in influencing prenatal development directly via environmental hazards but also indirectly through the opportunities and resources for education, health, and financial support (Weinhold, 2009).

      In April 2011, an earthquake and tsunami severly crippled a Japanese nuclear reactor. Hiromi Kobayashi, who was eight months pregnant, was tested for possible nuclear radiation exposure at an evacuation center.

      Reuters/Kim Kyung Hoon

      Parental Characteristics and Behaviors

      Teratogens—and the avoidance of them—are, of course, not the only determinants of how healthy a baby will be. A pregnant woman’s characteristics, such as her age and her behavior during pregnancy, including nutrition and emotional well-being, also influence prenatal outcomes.

      Nutrition

      Nutrition plays a role in prenatal development both before and after conception. The quality of men’s and women’s diets influences the health of the sperm and egg (Sinclair & Watkins, 2013). Most women need to consume 2,200 to 2,900 calories per day to sustain a pregnancy (Kaiser, Allen, & American Dietetic Association, 2008). Yet about 41 million people in the United States (about 12% of households) reported food insecurity in 2016 (U.S. Department of Agriculture, 2017). That is, at least sometimes they lacked access to enough food for an active healthy lifestyle for all members of the household. About 795 million people of the 7.3 billion people in the world, or one in nine, suffer from chronic undernourishment, almost all of whom live in developing countries (World Hunger Education Service, 2017). Fetal malnutrition is associated with increased susceptibility to complex diseases in postnatal life (Chmurzynska, 2010). Dietary supplements can reduce many of the problems caused by maternal malnourishment, and infants who are malnourished can overcome some of the negative effects if they are raised in enriched environments. However, most children who are malnourished before birth remain malnourished; few have the opportunity to be raised in enriched environments after birth.

      Good nutrition is important for a healthy pregnancy.

      iStock/becon

      Some deficits resulting from an inadequate diet cannot be remedied. For example, inadequate consumption of folic acid (a B vitamin) very early in pregnancy can result in the formation of neural tube defects stemming from the failure of the neural tube to close. Spina bifida occurs when the lower part of the neural tube fails to close and spinal nerves begin to grow outside of the vertebrae, often resulting in paralysis. Surgery must be performed before or shortly after birth, but lost capacities cannot be restored (Adzick, 2013). Spina bifida is often accompanied by malformations in brain development and impaired cognitive development (Donnan et al., 2017). Another neural tube defect, anencephaly, occurs when the top part of the neural tube fails to close and all or part of the brain fails to develop, resulting in death shortly after birth. As researchers have learned and disseminated the knowledge that folic acid helps prevent these defects, the frequency of neural tube defects has declined to about 1 in 1,000 births (Viswanathan et al., 2017; Williams et al., 2015). However, in a national study of U.S. mothers, only 24% consumed the recommended dose of folic acid during pregnancy (Tinker, Cogswell, Devine, & Berry, 2010).

      Some stress during pregnancy is normal, but exposure to chronic and severe stress during pregnancy poses risks including low birthweight, premature birth, and a longer postpartum hospital stay.

      iStock/monkeybusinessimages

      Emotional well-being

      Although stress is inherently part of almost everyone’s life, exposure to chronic and severe stress during pregnancy poses risks, including low birthweight, premature birth, and a longer postpartum hospital stay (Field, 2011; Schetter & Tanner, 2012). Maternal stress influences prenatal development because stress hormones cross the placenta, raising the fetus’s heart rate and activity level. Long-term exposure to stress hormones in utero is associated with higher levels of stress hormones in newborns (Kapoor, Lubach, Ziegler, & Coe, 2016). As a result, the newborn may be more irritable and active than a low-stress infant and may have difficulties in sleep, digestion, and self-regulation (Davis, Glynn, Waffarn, & Sandman, 2011; Kingston, Tough, & Whitfield, 2012). Later in childhood, he or she may have symptoms of anxiety, attention-deficit hyperactivity disorder, and aggression (Glover, 2011). Prenatal stress may also have epigenetic effects on development, influencing stress responses throughout the lifespan (Van den Bergh et al., 2017). Stress in the home may make it difficult for parents to respond with warmth and sensitivity to an irritable infant (Crnic & Ross, 2017). Social support can mitigate the effects of stress on pregnancy and infant care (Feldman, Dunkel-Schetter, Sandman, & Wadhwa, 2000; Ghosh, Wilhelm, Dunkel-Schetter, Lombardi, & Ritz, 2010).

      Maternal age