Preterm births, especially those prior to 32 weeks' gestation, heavily contribute to infant problems and death. Preterm births are consistently highest among socially disadvantaged women, leading many to wonder whether these women's greater exposure to social stressors may prompt shorter pregnancies.
A new study, supported by the Agency for Healthcare Research and Quality (HS06930), suggests that one social stressor in particular, loss of a mother or sister during pregnancy, does seem to prompt shorter pregnancies among poor black women. Gail A. Barbosa, Sc.D., R.N., of the Medical University of South Carolina, and her colleagues found that low-income pregnant women who lost a mother or sister during pregnancy delivered their babies on average 4.6 weeks earlier than other women in the study. Women who experienced the death of other significant family members or close friends did not have shorter pregnancies.
Other factors related to shorter gestational age included pregnancy complications, inadequate use of prenatal care, smoking, no Medicaid insurance, and use of street drugs. No variation in length of pregnancy was found among women with different levels of emotional support, number of children, age-adjusted education, or alcohol use. Heightened levels of stress or total number of stressful life events were not associated with earlier deliveries.
Stressful life events are thought to initiate preterm labor and birth, either directly through hormonal responses that end in increased uterine irritability and premature contractions or indirectly via unhealthy coping behaviors, such as ignoring prenatal care. Stress also may diminish the capabilities of the immune system in preventing complications associated with early delivery. Yet surprisingly, the women in this study who reported a high number of life stressors did not report more smoking, drug use, or experience more complications of pregnancy. These findings are based on interviews with 472 black women from three public prenatal clinics, which addressed stressful life events, availability of emotional support, and health habits, as well as pregnancy and birth data collected from a clinical database.
See "The association of life events to gestational age at delivery among low-income, urban, African American women," by Dr. Barbosa, in the Journal of Perinatology 20, pp. 438-442, 2000.