Comparison of Fetal Biometry in Pregnancies with Anterior and Posterior Placental Locations

Since the invention of ultrasound, it has become the most popular and widespread method in obstetric care to establish fetal gestational age (GA), to monitor the growth and to predict the adverse pregnancy outcome. Nowadays, the information of placental details (location, size, volume, morphology) has become the greatest interest to the obstetrician. Assessment of in utero placenta by ultrasound along with other fetal biometry can provide more details regarding current pregnancy. The importance of examining the placenta cannot be overlooked as it plays the central role in supporting fetal growth, also maternal wellbeing. Whether there are any differences among the different physiological positions of the placenta are still smoky. In this study, we compared anterior and posterior placental pregnancy of 13 -40 weeks intending to determine whether there are any variations in fetal biometry between these two and we also compared maternal age between two placental positions to find out if there is any relation of placental attachment variation with maternal age. A total of 427 pregnancies were in the range of 13-40 weeks. Among them, in 40 pregnancies, the placentas were formed in locations other than anterior or posterior (low lying position or completely fundal or lateral position). We excluded those pregnancies. Only anterior and posterior placental pregnancies were analyzed in this study. As a result of the above exclusion criteria, we could include a total of 387 pregnancies in our final analysis among them 188 pregnancies were anterior placental, and 199 pregnancies were posterior placental. As the anterior and posterior placental locations are more common in our study group, we compared fetal presentation, fetal HR, fetal biometry (BPD, FL, EFW), AFI, maternal age between the pregnancies of these two placental locations. In the case of anterior placental pregnancies, the fetal presentations were cephalic in 78.7% cases, breach in 11.2% cases, unstable in 9.04% cases and transverse in 1.06% cases. On the other hand, in pregnancies of posterior placenta fetal presentations were cephalic in 82.4% cases, breech in 14.6% cases, unstable in 2.5% cases and transverse in 0.5% cases. In this observational study, several parameters (BPD, FL, EFW, AFI, fetal presentation, HR, and maternal age) were compared between pregnancies of anterior placenta and pregnancies of the posterior placenta. In the case of all the parameters, no significant differences were found between the two groups except in some measurements of a few gestational age groups. But overall, when the measurements of 13-40 weeks of each parameter in two different groups were compared, there were no significant differences between them. In summary, this study results suggest that advanced maternal age is not one of the predisposing factors of having either anterior or posterior placenta and there is no significant difference in fetal presentation, fetal biometry, or fetal biophysical profile between anterior or posterior placental pregnancy.