Читать книгу Child Development From Infancy to Adolescence - Laura E. Levine - Страница 234

There are a number of different sources of stress that a pregnant woman might experience. She might be stressed at the prospect of going through the pregnancy, labor, and delivery, or the transition to becoming a parent, which we discuss more fully later in this chapter. She also experiences the day-to-day stress anyone might have and may have some challenging or even traumatic life events during her pregnancy.

Maternal stress. Pregnancy brings with it some unique stresses, but excessive stress from any source can affect the fetus because stress hormones cross through the placenta. What are some things a pregnant woman could do to manage her level of stress?

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Whenever we are under stress, our body produces stress hormones, and one of those hormones, cortisol, can pass through the placenta. In animal studies, maternal stress has been associated with changes in the structure and function of the brain (Buss, Entringer, Swanson, & Wadhwa, 2012). In studies of human mothers, high levels of maternal stress hormones during a pregnancy have been associated with lower birth weight and a slower growth rate in the fetus, and with temperamental difficulties in infants (Wadhwa, 2005). The exact effects depend on the nature, timing, and duration of exposure, but several studies have found that it is maternal stress early in the prenatal period that has a greater impact on fetal growth, length of gestation, infant reactivity to stress, and cognitive development (Davis, Glynn, Waffarn, & Sandman, 2011; Davis & Sandman, 2010; Wadhwa, 2005). Although excessive stress may be harmful, there also is a potentially beneficial effect of an appropriate amount of stress during a pregnancy. The stress inoculation hypothesis suggests that exposure to manageable amounts helps prepare the individual prenatally for challenges that occur after birth (Buss et al., 2012).