COMPARISON OF PLACENTAL THICKNESS AND AMNIOTIC FLUID INDEX IN HYPERTENSIVE VERSUS NORMOTENSIVE MOTHERS

Abstract

Background:

Maternal hypertensive disorders, including gestational hypertension and preeclampsia, are major contributors to adverse perinatal outcomes. These conditions are known to cause placental dysfunction, potentially altering its morphology and impacting the amniotic fluid volume. Sonographic assessment of placental thickness and the Amniotic Fluid Index (AFI) can serve as crucial indicators of fetal well-being in these high-risk pregnancies.

Objective:

This study aimed to compare placental thickness and amniotic fluid index between normotensive and hypertensive pregnant women and to explore the association between maternal blood pressure status and these sonographic parameters.

Methodology:

A comparative cross-sectional study was conducted at District Head Quarter (DHQ) Hospital Rajan Pur, Punjab, Pakistan over four months. A total of 100 pregnant women with singleton pregnancies between 28-40 weeks of gestation were enrolled and divided into two groups: Group A (n=50, hypertensive) and Group B (n=50, normotensive), matched for gestational age. Exclusion criteria included multiple pregnancies, diabetes mellitus, other systemic illnesses, placental anomalies, and fetal congenital anomalies. Placental thickness and AFI were measured for all participants using an ALOKA PROSOUND SSD ultrasound machine with a convex probe (3.5-10 MHz). Data on maternal demographics, blood pressure, and fetal heart rate were also collected.

Results:

The study population comprised 37% young mothers (<25 years), 35% middle-aged (25-34 years), and 28% of advanced maternal age (≥35 years). Among hypertensive mothers, 23% had gestational hypertension, 17% had preeclampsia, and 10% had chronic hypertension. Placental thickness distribution across all participants was 54% normal (30-40 mm), 33% thick (>40 mm), and 13% thin (<30 mm). A significant association was found between blood pressure status and placental thickness: among normotensive women, 52% had thick placentas, while hypertensive women predominantly had normal thickness (66%) and a higher proportion of thin placentas (20% vs. 6% in normotensives). Regarding AFI, 76% of all participants had a normal index (8-18 cm), while 24% had oligohydramnios (<8 cm). This was heavily skewed in the hypertensive group, where 44% had oligohydramnios compared to only 4% in the normotensive group. Most fetuses (94%) had a normal heart rate (120-160 bpm).

Conclusion:

Hypertensive disorders in pregnancy are significantly associated with altered placental morphology and reduced amniotic fluid. The higher prevalence of thin placentas and oligohydramnios in hypertensive mothers suggests underlying placental insufficiency. Sonographic evaluation of placental thickness and AFI are valuable tools for monitoring fetuses in hypertensive pregnancies and can help in anticipating adverse perinatal outcomes.