Umbilical cord insertion into the lower segment of the uterus at 11 to 13 weeks' gestation is associated with maternal serum PAPP-A.

Objectives: To evaluate whether the location of the placental cord insertion (CI) at 11 to 13 weeks' gestation affects the maternal serum pregnancy-associated plasma protein-A (PAPP-A).

Methods: Cohort study was conducted in patients who underwent the first trimester screening including nuchal translucency and blood test. We additionally documented the CI site. The thickness of the placenta under the CI and the minimum distance on the uterine wall between the internal cervical os and the CI (Dis) were measured. The subjects were divided into two groups. Below the tenth percentile in multiples of median (MoM) of Dis were defined as cases in which CI was located on the lower uterine segment (low CI) and the others were defined as controls.

Results: A total of 117 subjects were analyzed. The thickness of the placenta (r = 0.237, p = 0.010) and Dis (r = 0.243, p = 0.008) was correlated with the crown-rump length (CRL). The maternal serum PAPP-A MoM in the low CI group was lower than in controls (0.76 ± 0.34 vs 1.16 ± 0.55; p = 0.009), whereas the other ultrasonographic measurements and maternal demographics were not different between the two groups.

Conclusion: CI on the lower segment of the uterus is associated with low maternal serum PAPP-A MoM levels.