Ultrasonographic measurement of placental thickness and its correlation with gestational age – a cross-sectional ultrasonographic study.

Introduction: Determination of placental size is a part of the overall assessment of intrauterine environment. Placental growth can be estimated by either measuring the thickness or estimating its volume. Placental thickness is directly related to the gestational age of the foetus till certain weeks of pregnancy. Thus, thickness can be used to determine the gestational age rather than using the BPD,AC,HC and FL. Objectives: The purpose of the present study was to determine the normal range of placental thickness in our population in third trimester of pregnancy and its correlation with gestational age of the foetus. Methods:100 cases were recruited for the study who came for routine antenatal checkup to Department of Obstetrics and Gynecology at Queen Marry’s Hospital, King George’s Medical University, Lucknow. Subjects who had any obstetrical, gynecological, medical and surgical illnesses were excluded. Placental thickness was measured at the level of umbilical cord insertion by two dimensional ultrasonography. Result: Mean thickness of the placenta was 3.90±1.1cm which increased till 38 weeks of gestation, thereafter decreased. Discussion: It may give an indication of the amount of substances (nutrients, gases) that is exchanged between the foetus and the mother. Thin placenta may be due to intrauterine growth retardation, placental infarction and pregnancy with essential hypertention and pre-eclampsia. The thinnest placenta was 1cm in thickness and thickest placenta was 7.5cm in thickness and these were not associated with any maternal or fetal complications.