Stress During Pregnancy Affects General Intellectual and Language Functioning in Human Toddlers

Abstract

Prenatal maternal stress has been shown to impair functioning in nonhuman primate offspring. Little is known about the effects of prenatal stress on intellectual and language development in humans because it is difficult to identify sufficiently large samples of pregnant women who have been exposed to an independent stressor. We took advantage of a natural disaster (January 1998 ice storm in Québec, Canada) to determine the effect of the objective severity of pregnant women's stress exposure on general intellectual and language development of their children. Bayley Mental Development Index (MDI) scores and parentreported language abilities of 58 toddlers of mothers who were exposed to varying levels of prenatal stress were obtained at 2 y of age. The hierarchical multiple regression analyses indicated that the toddlers' birth weight and age at testing accounted for 12.0% and 14.8% of the variance in the Bayley MDI scores and in productive language abilities, respectively. More importantly, the level of prenatal stress exposure accounted for an additional 11.4% and 12.1% of the variance in the toddlers' Bayley MDI and productive language abilities and uniquely accounted for 17.3% of the variance of their receptive language abilities. The more severe the level of prenatal stress exposure, the poorer the toddlers' abilities. The level of prenatal stress exposure accounted for a significant proportion of the variance in the three dependent variables above and beyond that already accounted for by non-ice storm-related factors. We suspect that high levels of prenatal stress exposure, particularly early in the pregnancy, may negatively affect the brain development of the fetus, reflected in the lower general intellectual and language abilities in the toddlers. The effects of prenatal maternal stress (PNMS) on offspring abilities have been examined extensively in nonhuman primates in well-controlled studies. In general, increases in PNMS are related to elevated levels of inhibited behavior and decreases in cognitive and neuromotor functioning (1, 2). For example, both chronic stress during pregnancy (1) and 2 wk of ACTH administration at midgestation (2) predict poorer attention during infancy. Moreover, mild prenatal maternal stress is associated with delayed object permanence (3). In human populations, maternal anxiety (4) and moderate to severe life events (5, 6) during pregnancy increase the risk of obstetric complications such as preeclampsia, fetal distress, preterm birth, and low birth weight and predict an increase in neonatal crying (7), acute health problems during the first year (8), and behavioral and/or emotional problems at 4 y of age (9). Moreover, Apgar scores at 5 min were 2 SD lower in newborns of anxious mothers (4), indicating birth trauma. In terms of cognitive functioning in humans, PNMS has been linked to poorer performance. For example, a study of the long-term effects of PNMS associated with a major earthquake demonstrated that 18-y-olds who were exposed prenatally had signif- Received February ...

Prenatal exposure to a natural disaster increases risk for obesity in 5½-year-old children

“…Exposure was sufficient to have an impact on infant growth and development-higher levels of objective PNMS were associated with shorter infant length at birth (25)-and we postulated that it might also affect development at later ages. For example, increasing objective PNMS predicted poorer cognitive and linguistic functioning at 2 and 5½ years of age, all else being equal (28,29), and fingerprint asymmetry (27), which reflects disruptions in fetal development during gestation weeks 14-22. Results from the present study suggest that objective PNMS increases obesity risk at age 5½ (OR = 1.37-1.43) and that these effects are independent of size at birth and several maternal characteristics, including size (height or BMI), which is a major predictor of childhood obesity (36). Models differ in other risk factor trends, likely reflecting small sample size and the small number of children with obesity (nine in model 1, seven in model 2).…”

“…Shortly after the storm, we assessed levels of objective exposure and subjective distress dimensions of PNMS among women who were pregnant during the storm or who conceived within the following 3 months, when levels of stress hormones could still be elevated. We have since analyzed a number of physical, behavioral, and developmental measures among their children (25)(26)(27)(28)(29). Project Ice Storm differs in several important ways from other studies of PNMS among humans.…”

Women's response to fetal choroid plexus cysts detected by prenatal ultrasound

“…36 Perhaps most concerning was the degree to which women expressed either transient or persistent feelings of heightened pregnancy burden and stress as well as decreased attachment to the fetus. Both are cause for concern, given that psychological distress during pregnancy has been associated with a range of deleterious outcomes [37][38][39] and prenatal psychological attachment to the fetus has important implications for subsequent maternal attachment to and interaction with the child. 40 Consistent with our other studies of fetal development, women who participate as volunteers tend to be relatively highly educated.…”

Cortisol and anxiety response to a relaxing intervention on pregnant women awaiting amniocentesis

“…Women with high antenatal anxiety or stress are more likely to have premature and low birth weight babies (Copper et al, 1996;Wadhwa et al, 1993Wadhwa et al, , 1998Field et al, 2003). Prenatal maternal stress is also suspect of affecting infant development and promoting a range of adverse temperamental effects (O'Connor et al, 2002(O'Connor et al, , 2003Field et al, 2003;Huizink et al, 2004;Laplante et al, 2004;Van den Bergh et al, 2005;Talge et al, 2007;Glover et al, 2010). The most widely exploited hypothesis for the underlying mechanisms states that the fetus is exposed to an excess of maternally derived glucocorticoids when the latter are raised at times of stress.…”