Comparative sonographic evaluation of placental thickness in pregnancy-induced hypertension and normotensive pregnant women in the University of Calabar Teaching Hospital, Calabar, Nigeria

Abstract

Objectives: The human placenta is the nourishing reservoir for the sustenance of the fetus and synthesizes a growth-stimulating hormone to enhance proper growth and maturation. The size or thickness of the placenta enlarges as the pregnancy progresses in age to attain a favorable state which can cope with the increasing fetal demands. Placental thickness (PT) is a reflector of fetal well-being, and it is related to fetal weight making it necessary to assess the influence of pregnancy-induced hypertension (PIH), a common pathology in pregnancy, on the placental size or thickness. The main objective of this research is to compare and evaluate the PT and fetal weight in PIH and normotensive pregnant women. Material and Methods: The study was a prospective cross-sectional case-controlled study done in the Radiology Department of the University of Calabar Teaching Hospital. During a 12 months study period, 200 singleton pregnant women (consisting of 100 pregnancy-induced hypertensives and 100 normotensive pregnant women) of between 20 and 40 weeks of gestation were enrolled in this study. The two groups were gestational age-matched. The PT was measured trans-abdominally using an ultrasound scan. Pearson’s correlation analysis was used to establish the degree of relationship between PT and other fetal anthropometric and maternal parameters. Results: PT was significantly lower in pregnancy-induced hypertensives than in the controls (28.95 ± 5.71 mm vs. 32.31 ± 5.47 mm, P = 0.000). There was a significant negative correlation between the PT and the degree of proteinuria (P = 0.011). Conversely, a significant positive correlation existed between PT and estimated gestational age (P = 0.000) and also estimated fetal weight (EFW) (P = 0.000), in both groups. This same relationship was observed between the body mass index and PT (P = 0.007) as well as the EFW (P = 0.002) in the control group. The mean EFW in pregnancy-induced hypertensives (2.23 ± 1.07 kg) was higher than in the controls (2.13 ± 1.03 kg), but the difference was not significant (P = 0.505). Conclusion: There was a reduction in the PT in PIH, which may be due to the appearance of proteinuria when the blood pressure was elevated. However, we did not observe the expected reduction in the EFW due to a reduction in PT, which usually results from proteinuria.