Hypertension during pregnancy in Africa and infants' health. A cohort study in an urban setting

Abstract

The objective of the study was to assess the prevalence of unclassified hypertension during pregnancy and its consequences on infant's health in an African urban setting: Pikine, a suburb of Dakar, Senegal. A cross-sectional study of a random sample of pregnant women and a prospective study, from the inclusion to seven days after delivery, were performed. 886 women attending the prenatal centers were included in the cross-sectional study. 471 pregnant women were included in the follow-up study. The prevalence of DBP > or = 120 mmHg was 0.7%; 5.7% of the women had DBP > or = 95 mmHg. Longitudinal data were available for 425 deliveries. Two spontaneous abortions, 25 stillbirths, and 12 deaths during the early neonatal period were recorded. Among babies living at birth, the percentage of LBW (> or = 2500 g) was 8.5%. The percentages of adverse outcome of pregnancy (death and/or low birth weight) was associated with mothers' diastolic BP: < 85 mmHg: 13%; 85 to 89: 16%; 90 to 94: 9%; DBP > or = 95: 32%, (p < 0.01). Using 95 mmHg as a cutpoint, the relative risk of adverse outcome associated with a DBP > or = 95 mmHg was 2.5 (CI 95%: 1.4-4.3). This risk was significantly increased among women who reported difficult living conditions. Eight percent of the adverse outcomes of pregnancy, 10% of the low birth weights and 8% of the perinatal mortality were found to be associated with DBP > or 95 mmHg.

PIP: Epidemiologists conducted a cross-sectional study of 886 pregnant women attending 3 prenatal centers in Dakar-Pikine, Senegal, during the rainy season (April-June 1987) and the dry season (December 1987-January 1988) and a follow-up study of 471 of these women to measure the prevalence of high blood pressure and to determine which blood pressure level should define hypertension. A diastolic blood pressure (DBP) of at least 95 mmHg was a risk factor for poor pregnancy outcome (death and/or low birth weight [LBW] =or 2500 gm) among these women. Specifically, women whose DBP was at or greater than 95 mmHg were more likely to experience an adverse pregnancy outcome at birth and at 7 days postpartum than those whose DBP was lower than 95 mmHg (32.4% vs. 13.1% and 34.3% vs. 15.8%, respectively; p .01). 5.7% of the 886 women had hypertension based on this criterion. Seasonality did not affect pregnancy or birth outcomes. There were 2 spontaneous abortions, 25 stillbirths, and 12 early neonatal deaths. 8.5% of the live-born infants had a LBW (or= 2500 gm). A DBP at or greater than 95 mmHg increased the risk of poor pregnancy outcome by 3.4 (adjusted odds ratio [AOR]) (relative risk [RR] = 2.5) and the risk of low birth weight by 3.3 (RR = 3.1). Hypertension increased the risk of early neonatal mortality by 3.1. Women who had difficult living conditions had a significantly higher risk of adverse outcome linked to a DBP equal to or greater than 95 mmHg. For example, 55.6% and 62.5% of women who had no help to perform daily activities and had hypertension suffered adverse outcome at delivery and 7 days postpartum compared to 14.7% and 17.6% of those who did not have hypertension (RR = 3.8 and 3.5, respectively; p = .01). DBP at or greater than 95 mmHg was associated with 8% of adverse pregnancy outcomes, 10% of LBWs, and 8% of perinatal deaths.