Sono-elastographic evaluation of Placenta and Its Correlation with Placental Thickness and Uterine Artery Doppler Parameters

Abstract

Introduction: Placenta is the supplier of nutrients to the developing fetus. Placental health is directly related to the fetal health. The placental thickness and elasticity have direct impact on the fetal birth weight and wellbeing. There are not many studies in India, correlating the placental elasticity with fetal birth weight and wellbeing. Aim: To correlate the placental thickness, mean uterine artery Pulsatility Index (PI), placental stiffness, gestational weight and birth weight in controls, gestational diabetes and pregnancyinduced hypertensive patients. Materials and Methods: This exploratory correlative study was performed on 222 pregnant women in the third trimester of pregnancy. The patients in the third trimester, referred to obstetric ultrasonography from January 2017 to June 2018 were included in the study. The thickness of the placenta was measured at the umbilical cord insertion site. Sono-elastography was performed at the centre, superior and inferior ends of the placenta and the average stiffness was recorded. The average gestational age was estimated using standard sonographic techniques. The average gestational age, placental thickness, stiffness on sono-elastography, mean uterine artery pulsatility index and association with gestational diabetes/pregnancyinduced hypertension were correlated and analysed. Results: The placental thickness ranged between 27-34 mm in the pregnancy-induced hypertension group with mean of 30.36 mm and standard deviation of 1.868. The thickness ranged between 33-51 mm with a mean of 40.75 mm and standard deviation of 4.181 in patients with gestational diabetes. The Pulsatility Index of the uterine arteries ranged between 1.6- 2.2 in pregnancy-induced hypertensive patients with a mean of 1.824. In gestational diabetes patients, the uterine artery Pulsatility Index ranged between 0.6-1.1 with a mean of 0.866. The placental stiffness was significantly higher in pregnancyinduced hypertension group with the mean stiffness being 7.233 and standard deviation of 0.7025 as against the stiffness of 2.906 kpa with standard deviation of 0.2923 in controls and 2.838 with standard deviation of 0.3424 in gestational diabetes patients. All the babies with maternal pregnancyinduced hypertension had low birth weight than the controls and the babies of gestational diabetes patients had higher birth weight. Conclusion: The placentae in patients with gestational diabetes are larger with larger foetuses. The stiffness of the placenta is not affected by gestational diabetes. The placenta and fetus are smaller in pregnancy-induced hypertensive patients. Stiffness of the placenta is increased in pregnancy-induced hypertension. The placental stiffness can be used as an additional prognostic parameter in the outcome of pregnancy-induced hypertension. The higher the stiffness, more are the chances of intrauterine growth restriction and small fetus.

Keywords

• gestational diabetes
• placental stiffness
• placental thickness
• pregnancy-induced hypertension