CORRELATION OF PLACENTAL THICKNESS WITH GESTATIONAL AGE IN SECOND AND THIRD TRIMESTER OF PREGNANCY USING ULTRASONOGRAPHY

Objectives: The objective of the study was to evaluate correlation between ultrasound-measured placental thickness and gestational age in singleton pregnancies beyond 12 weeks’ gestation. Methods: A cross-sectional observational study was conducted at a tertiary care center over 2 years, involving 120 pregnant women beyond 12 weeks of gestation with singleton pregnancies. Gestational age was first assessed using standard fetal biometric parameters. Placental thickness was measured at the level of the umbilical cord insertion using grayscale ultrasound. It was measured perpendicular to the chorionic and basal plates. Placental location and abnormalities were also recorded. Data analysis was performed using the Statistical Package for the Social Sciences version 23.0. Pearson’s correlation coefficient was used to evaluate the relationship between placental thickness and gestational age. For statistical purposes, a p<0.05 is considered as statistically significant. Results: Most placentas were anteriorly located (46.67%), and the majority had normal morphology (84.17%). There was a strong and statistically significant positive correlation between placental thickness and gestational age from 12 to 37 weeks of gestation in singleton pregnancies. In the 12–24 week group (n=58), r=0.9623 (p<0.0001), and in the 25–37 week group (n=59), r=0.9892 (p<0.00001). Beyond 38 weeks (n=3), placental thickness showed a slight decline, and the correlation was negative (r=−0.7384, p=0.083). However, this correlation was not found to be statistically significant. Conclusion: Placental thickness correlated positively with gestational age from 12 to 37 weeks. Its utility as a marker for gestational age estimation diminishes beyond 38 weeks. Therefore, placental thickness can be used as reliable adjunct to fetal biometry for GA estimation during the second and third trimesters.