Stress and anxiety can be toxic to kids right from the start. A mother’s stress is her baby’s stress, and too much stress is a bad thing for the developing fetus. Prenatal stress can be a significant factor in reduced brain development, memory, and cognition. (Huizink, Mulder & Buitelaar, 2004) High levels of stress during pregnancy can also result in an alteration of immune regulation in the fetus. (Wadhwa, Sandman & Garite, 2001) “Prenatal stress can change the brain forever,” argues Tallie Baram, a neurologist with the University of California, Irvine. “Stress changes how genes are expressed throughout life.” (Boyd, 11-20-08)
Of course, there are many things that can cause stress, such as financial problems, depression, or other adverse life events. But of particular concern is the stress induced by physical abuse, domestic violence or other conflict. Such stress increases the risk for low birth weight, poor immune regulation, and a generally less-healthy baby. (Boy & Salihu, 2004) Another side effect of too much stress is that it increases the likelihood that the mother will engage in other behaviors that pose a risk to her developing baby, such as smoking, drinking, or using drugs. (Martin et al., 2001; Martin, Beaumont & Kupper, 2003; Parker, McFarlane & Soeken, 1994)
Stress is also commonly intertwined with depression, and the physiological environment brought about by depression can also cause problems. One study showed that women with significant depressive symptoms were nearly twice as likely to deliver a preterm baby. (Rubin, 10-23-08) A mother’s overall mood can also alter the developmental temperament of her baby. (see the basic temperaments described in chapter 6) “Temperament is not only genetically determined,” says Catherine Monk, a Columbia University psychologist. “It is constructed throughout early development and, in part, in utero exposure to the mother’s mood.” (Laber-Warren, 2009) One study examining children of depression found that the number of months of maternal depression they experienced in the womb was one of the best predictors of preschool children’s baseline cortisol stress levels. (Dawson, 1999; More on the effects of depression during pregnancy can be found in our chapter on Parental Depression)
Numerous studies have found a link between prenatal stress and poor outcomes later on. Infants whose pregnant mothers developed posttraumatic stress disorder after the September 11 terrorist attacks were found to be more easily upset by loud noises and unfamiliar people. In another study of thousands of women in England, those who ranked in the top 15% for anxiety during pregnancy had children with double the rate of emotional and behavioral problems at 10-years-old. Subjecting pregnant monkeys to loud car-horn blasts at unpredictable intervals over just a 10-minute period per day for one-quarter of their pregnancy induced enough stress that their infants had a hippocampus that was 10% smaller at 3-years-old, and these monkeys also showed other impairments. (LaberWarren, 2009) In perhaps one of the more troubling examples, a study known as “project ice storm” surveyed nearly 150 expectant mothers who spent up to 40 days without power in Quebec during a 1998 ice storm. In 2008 researchers released the results of the study, which showed that the added stress the mothers endured appeared to have had “significant effects (on their children)…in every area of development that we have examined.” For example the children whose mothers endured extra stress in the womb had lower-than-average IQ’s and language skills at age 5. (Carmichael, 2-23-09)
Factors That Determine If Prenatal Stress Will Harm The Baby
All of these things, however, shouldn’t stress parents out too much (irony intended). Such findings must be taken with a grain of salt. As with all things, the key to health lies in balance, so it’s not as if a baby will be ruined should their parent endure a stressful event or two. Research has shown that some stress can even be beneficial. “Just as challenges can bring out the best in adults, prenatal stress seems to benefit children sometimes,” notes Emily Laber-Warren (2009). “Two-year-olds whose mothers were moderately anxious or depressed during pregnancy performed better than average on reasoning and coordination tasks such as solving puzzles, stacking blocks, and manipulating small objects.” This doesn’t mean you should aim for stress during pregnancy, but don’t panic if some should occur. What’s most harmful is chronic stress that subjects a baby to continuous elevated stress hormones.
What happens after birth is just as important. Research by Catherine Monk and her colleagues has shown that 4-month-old infants who showed elevated stress hormones in their saliva had mothers who were anxious and/or depressed both before the birth and afterwards. When moms were caring and attuned to their babies, the infants’ cortisol levels were normal, even if they were subjected to elevated stress during the pregnancy. Nurturing and mental stimulation can reverse the effects of a compromised pregnancy. Once again, the proper care and comforting is capable of eroding past negative experiences. As noted by Marla Weinstock-Rosin, a psychopharmacologist at Hebrew University in Jerusalem, “You can look at it as though the system has been primed. But if nothing else bad happens and everything is calm, it may well be all right.” (Laber-Warren, 2009)