Sonological Evaluation of gestational Age by Placental Thickness

Abstract

Background: Ultrasound is a non-invasive procedure used routinely in antenatal check up. gestational age is essential to manage pregnancies in regard to terminating pregnancy, managing high risk pregnancies, elective induction of labour & elective caesarean sections. Many fetal parameters are used sonographically to date pregnancy which includes fetal bi-parietal diameter (BPD), head circumference (HC), femur length (FL) and abdominal circumference (AC) and along with that placental thickness measured at umbilical cord insertion site can also be used as a new parameter for estimating gestational age. Present study was undertaken to evaluate the relationship between placental thickness and gestational age of the fetus and also to assess the growth pattern of placenta with advancing gestational age. Aims and Objectives: Estimation of gestational age of fetus by measuring placental thickness at umbilical cord insertion site Methods: This is a prospective study, conducted in King George hospital, Department of Radiodiagnosis. A total of 100 pregnant women were selected between the gestational ages from 14 weeks to 40 weeks who do not have any maternal or fetal complications The Placental thickness (PT) is measured by e-saote ultrasound machine with a curvilinear probe 3.5 MHz. Mean value of placental thickness along with the standard deviation (SD) value and 95% confidence interval were calculated for each gestational age between 14 weeks to 40 weeks. Pearson's correlation analysis and linear regression analysis was done quantifying the relationship between the gestational age in weeks and the placental thickness in millimetres Results: Placental thicknessis gradually increased from 14 to 36 weeks which almost correlates with the gestational age in weeks and the placental thickness with gestational age from 37-40 weeks falls marginally. Interpretation: Linear and direct relationship of placental thickness with gestational age is noticed from 14-36weeks After 37 weeks of period of gestation, placental thickness with gestational age falls marginally. Conclusions: Placental thickness can also be used as an estimate for gestational age from 14-36 weeks.