Placental Thickness – an alternative to biparietal diameter for assessment of gestational age in cases of unknown last menstrual period: a cross-sectional observational study

Abstract

Objective. The objective of this study was to evaluate the relationship of placental thickness with biparietal diameter (BPD) which can be used for assessment of gestational age in women with unknown last menstrual period.Materials and Methods. This was a cross-sectional observational study conducted at antenatal outpatient department of a tertiary center hospital among second and third trimester pregnant women of age 18-35 years with singleton live fetus. All women were subjected to ultrasonography for measurement of placental thickness (measured at the level of umbilical cord insertion) and BPD of fetus.Results. 200 pregnant women were recruited (Mean age -24.5 years). Both biparietal diameter and placental thickness increases with gestational age. Mean placental thickness show strong positive correlation with BPD (r=0.930 and p-value <0.0001). Further, subgroup analysis showed BPD and placental thickness to have significant correlation at all gestational age groups with significantly strong positive correlation from 13-33 week of gestation.Conclusions. Placental thickness is positively correlated with BPD and can be used as a marker for gestational age in pregnant women.