Relationship between first-trimester serum placental protein-13 and maternal characteristics, placental Doppler studies and pregnancy outcome.

OBJECTIVE

To examine potential correlations between maternal serum placental protein-13 (PP-13) and first trimester maternal and placental factors, and to evaluate the association of this marker with adverse pregnancy outcome.

METHODS

Serum samples from prospectively enrolled patients between 11 and 13 weeks and 6 days were analyzed for PP-13 using an ELISA assay. The relationships between maternal serum PP-13 levels and gestational age, maternal age, ethnicity, parity, smoking status, body mass index (BMI), mean arterial blood pressure, uterine and umbilical artery Doppler parameters were examined. The association between first-trimester PP-13 levels and subsequent pre-eclampsia and delivery of a small for gestational age (SGA) neonate was also investigated, after excluding patients who received aspirin.

RESULTS

In 908 patients, PP-13 levels ranged from 8.0 to 537.5 pg/mL. A significant negative correlation was identified between PP13 and BMI (Spearman rho -0.20, P<0.0001). Smoking significantly decreased PP-13 (P<0.01). No relationship was identified with the other parameters. In a subgroup of 668 low-risk patients who did not receive aspirin, PP-13 levels were not associated with development of pre-eclampsia, SGA or the combination of them.

CONCLUSION

First-trimester PP-13 levels are significantly correlated with BMI and smoking. These correlations appear independent of uterine and umbilical artery resistance. In low risk patients, PP-13 levels fail to predict the risk for pre-eclampsia or SGA.