2D-ultrasound and endocrinologic evaluation of placentation in early pregnancy and its relationship to fetal birthweight in normal pregnancies and pre-eclampsia

Objectives

To study the relationships between 2D ultrasound measurements of placentation and maternal serum (MS) levels of PAPP-A, inhibin A and fβhCG in early pregnancy and subsequent fetal growth in pregnancies with a normal and abnormal outcome.

Study design

Prospective population-based cohort study of 301 pregnancies with a normal outcome, 18 with a pregnancy complicated by pre-term delivery (PTD) and 14 with subsequent pre-eclampsia (PE).

Main outcome measures

Basal placental surface area, placental thickness, ellipsivity and volume; MS PAPP-A and fβhCG at 11–13 + 6 weeks, MS inhibin A at 15–22 weeks and birthweight centile at delivery.

Results

In the normal group, the basal surface area showed a significantly (P < 0.001) positive correlation with placental thickness and placental ellipsivity. With the exception of placental ellipsivity, all other placental ultrasound parameters were significantly related with birthweight centile. Inhibin A showed a significant (P < 0.005) correlation with birthweight centiles. The basal plate surface area and MS PAPP-A were significantly (P < 0.01 and P < 0.001, respectively) lower and MS inhibin A significantly (P < 0.01) higher in PE than in controls. No changes were found in pregnancies complicated by PTD.

Conclusion

The basal plate surface area at 11–14 weeks reflects indirectly normal and abnormal placentation and development of the definitive placenta. Combined with MS PAPP-A and/or inhibin A levels this parameter could be useful in identifying from the end of the first trimester, pregnancies subsequently complicated with PE.