Placental thickness (PT) plays an important role when the menstrual age is not known. The present study was undertaken to first calculate the PT at level of insertion of umbilical cord and correlate it with gestational age and fetal weight, thereby establishing a nomogram for PT at different gestations.
Method: A total of 100 antenatal women from 11 to 40 weeks of gestation with singleton pregnancy and with no other obstetric or medical high risk factor were included in the study. A detailed history was taken from all the patients. Basic antenatal investigations, clinical and ultrasonography examination were done.
Results: The maximum (37%) patients were >30 weeks of gestation. 36% were between 20 to 30 weeks of gestation and 27% were between 12- 20 weeks of gestation. The mean PT was directly proportional to the advancing gestational age and had linear correlation with gestational age from 11 to 40 weeks. It was observed that the mean PT was 14mm at 12 weeks of gestation and proportionately increased and was 35mm at 40 weeks of gestation. The mean PT was 25.50±6.52mm and the mean estimated fetal weight was 1275.75±982.29gm. Thus, the significant positive correlation was found between PT and estimated fetal birth weight, (p value 0.000).
Conclusion: The linear correlation and statistical compatibility of placental thickness in estimation of gestational age makes it an alternate parameter for gestational age and fetal weight estimation.