THE ASSOCIATION BETWEEN PRENATAL STRESS AND INFANT BIRTH-WEIGHT AND GESTATIONAL-AGE AT BIRTH - A PROSPECTIVE INVESTIGATION

OBJECTIVE: The aim was to test a model of the influence of maternal pr enatal psychosocial stress on birth outcomes after controlling for bio medical risk. STUDY DESIGN: In a prospective study a sociodemographica lly homogeneous sample of 90 women was assessed during the third trime ster with standard, reliable questionnaires that measured episodic and chronic stress, strain (response to stress), and pregnancy-related an xiety. Birth outcomes included infant birth weight, gestational age at birth, and intrapartum complications. Parity and biomedical (antepart um) risk was also coded. Bivariate and multivariate analyses were perf ormed after controlling for the effects of biomedical risk factors. RE SULTS: Independent of biomedical risk, each unit increase of prenatal life event stress (from a possible sample range of 14.7 units) was ass ociated with a 55.03 gm decrease in infant birth weight and with a sig nificant increase in the likelihood of low birth weight (odds ratio 1. 32), and each unit increase of prenatal pregnancy anxiety (from a poss ible sample range of 5 units) was associated with a 3-day decrease in gestational age at birth. CONCLUSION: Independent of biomedical risk, maternal prenatal stress factors are significantly associated with inf ant birth weight and with gestational age at birth.