Lifespan Development. Tara L. Kuther

2004). These protective cultural factors interact with strong social support networks and informal systems of health care among Latino women, in which women tend to take responsibility for the health needs of those beyond their nuclear households. Mothers benefit from the support of other family members such as sisters, aunts, and other extended family. In this way, knowledge about health is passed down from generation to generation. There is a strong tradition of women helping other women in the community, and warm interpersonal relationships, known as personalismo, are highly valued (Fracasso & Busch-Rossnagel, 1992; McGlade et al., 2004).

      Brain and Biological Influences on Development

      Pregnancy and the Maternal Brain

      Pregnancy is associated with neurological changes especially in the areas of the brain responsible for social cognition.

      John Bavosi/Science Source

      The developing embryo and fetus receive a great deal of research attention, but what does pregnancy mean for mothers’ development? Women’s bodies undergo a radical transformation during pregnancy. For example, the hormone progesterone increases up to 15-fold and is accompanied by a flood of estrogen that is greater than the lifelong exposure prior to pregnancy. Research has shown that hormonal shifts are associated with brain changes during puberty as well as later in life. Do the hormonal changes with pregnancy influence women’s brain structure? Animal research suggests that pregnancy is accompanied by neurological changes, including changes in neural receptors, neuron generation, and gene expression, that are long-lasting (Kinsley & Amory-Meyer, 2011). It is likely that pregnancy is also associated with neural changes in humans, but there is little research to date (Hillerer, Jacobs, Fischer, & Aigner, 2014).

      In a recent groundbreaking study, Elseine Hoekzema and colleagues (2017) conducted brain scans of women who were attempting to become pregnant for the first time as well as their partners. Women who became pregnant were scanned again after giving birth and at least 2 years later. The fathers and women who had not become pregnant were also assessed. The new mothers experienced reductions in the brain’s gray matter, signifying increased neural efficiency in regions of the brain involved in social cognition, specifically, theory of mind, which enables us to sense another person’s emotions and perspective (Schurz, Radua, Aichhorn, Richlan, & Perner, 2014). Theory of mind underlies a mother’s ability to interpret her infant’s mental states and is important for secure parent–infant attachment and for the development of the child’s own social cognitive functions (Meins, Fernyhough, Fradley, & Tuckey, 2001). The changes in gray matter volume predicted mothers’ attachment to their infants in the postpartum period, as indicated by mothers’ increased neural activity in response to viewing photos of their infant compared with other infants. Other research suggests that pregnancy is associated with the enhanced ability to recognize faces, especially those displaying emotions (Pearson, Lightman, & Evans, 2009). Gestational alterations in the brain structures that are implicated in social processes may offer an adaptive advantage to mothers by facilitating their ability to recognize the needs of their children and to promote mother–infant bonding.

      Moreover, similar to findings with animals (Kinsley & Amory-Meyer, 2011), Hoekzema and colleagues observed that the neural changes that accompanied pregnancy were long lasting, persisting 2 years after birth. The pregnancy-related neurological changes were so marked and predictable that all of the women could be classified as having undergone pregnancy or not on the basis of the volume changes in gray matter. Notably, fathers did not show a change in gray matter volume, suggesting that the neural effects of pregnancy are biological in nature rather than associated with the contextual changes that occur with the transition to parenthood.

      What Do You Think?

      What adaptive purpose might pregnancy-related neurological changes serve?

      Although these cultural factors are thought to underlie the positive birth outcomes seen in Latino women, they appear to erode as Latino women acculturate to American society. The birth advantage has been found to decline in subsequent American-born generations. Recent findings have called the existence of the Latino paradox into question, as some samples have illustrated that the negative effects of socioeconomic disadvantage cannot be easily ameliorated by cultural supports (Hoggatt, Flores, Solorio, Wilhelm, & Ritz, 2012; Sanchez-Vaznaugh et al., 2016).

      Our discussion thus far has emphasized fetal development; however, expectant mothers also experience radical physical changes during pregnancy. In addition to changes in body weight and shape, pregnancy is accompanied by changes in brain structure and function, as discussed in the Brain and Biological Influences on Development feature.

      Thinking in Context 3.1

      Petra noticed that her abdomen has not grown much since she became pregnant 3 months ago. She concluded that the fetus must not undergo significant development early in pregnancy. How would you respond to Petra?

      Environmental Influences on Prenatal Development

      As described, prenatal development unfolds along a programmed path. However, sometimes environmental factors can hinder prenatal development. A teratogen is an agent that causes damage to prenatal development, such as a disease, drug, or other environmental factor, producing a birth defect. The field of teratology attempts to find the causes of birth defects so that they may be avoided. Health care providers help pregnant women and those who intend to become pregnant to be aware of teratogens and avoid them, as much as possible, to maximize the likelihood of having a healthy baby.

      Principles of Teratology

      There are many ways in which teratogens may affect prenatal development, but it is not always easy to predict the harm caused by teratogens. Generally, the effects of exposure to teratogens on prenatal development vary depending on the following principles (K. S. Moore & Persaud, 2016; Sadler, 2015).

       Critical Periods. There are critical periods during prenatal development in which an embryo is more susceptible to damage from exposure to teratogens. The extent to which exposure to a teratogen disrupts prenatal development depends on the stage of prenatal development when exposure occurs. Generally, sensitivity to teratogens begins at about 3 weeks after conception (Webster et al., 2018). Structural defects occur when the embryo is exposed to a teratogen while that part of the body is developing. As shown in Figure 3.6, each organ of the body has a sensitive period in development during which it is most susceptible to damage from teratogens such as drugs, alcohol, and environmental contaminants. Once a body part is fully formed, it is less likely to be harmed by exposure to teratogens; however, some body parts, like the brain, remain vulnerable throughout pregnancy.

       Dose. The amount of exposure (i.e., dose level) to a teratogen influences its effects. Generally, the greater the dose, the more damage to development. However, teratogens also differ in their strength. Some teratogens, like alcohol, display a powerful dose–response relationship so that larger doses, or heavier and more frequent drinking, result in greater damage (Muggli et al., 2017).

       Individual Differences. Individuals vary in their susceptibility to particular teratogens based on the genetic makeup of both the organism and mother, as well as the quality of the prenatal environment.

       Complicated Effects. Different teratogens can cause the same birth defect, and a variety of birth defects can result from the same teratogen. Also, some teratogens have subtle effects that result in developmental delays that are not obvious at birth. For example, infants exposed prenatally to as little as an ounce of alcohol a day may display no obvious physical deformities at birth but later, as children, may demonstrate cognitive delays (Charness, Riley, & Sowell, 2016). Other teratogens display sleeper effects—effects that are not visible until many years later. For example, infants