The association between preeclampsia and placental disruption induced by chorionic villous sampling

The objectives of this study were (1) to evaluate if the elevation of maternal serum alpha-feto protein (MSAFP) and pregnancy-associated placental protein-A (PAPP-A) in the maternal blood after chorionic villous sampling (CVS) is associated with a higher preeclampsia (PE) rate and (2) to verify the clinical utility of the analytes elevation for predicting PE.

A prospective study on 106 subjects who underwent CVS was performed. At the time of CVS, two blood samples were obtained for MSAFP and PAPP-A dosage, the first just before the procedure, and the second one 30 min after the procedure. Cases with abnormal karyotype, major anomalies or preterm delivery were subsequently excluded. The ratio between the two samples was calculated as Sigma (MSAFP or PAPP-A post-CVS/MSAFP or PAPP-A pre-CVS) and it was related to subsequent occurrence of PE.

The rate of PE was 5.7% (6/106). Both MSAFP and PAPP-A levels were higher after than before CVS (median ratio = 8.33 and 1.08, respectively). Cases developing PE had significantly higher MSAFP ratio (11.6 vs 7.4, p-value = 0.04) and PAPP-A ratio (1.13 vs 1.08, p-value = 0.009) than those who did not develop PE. Receiver operating characteristic curve analysis showed that PAPP-A ratio was a better predictor of subsequent PE than MSAFP ratio: at a fixed false positive rate of 10%, the detection rates for MSAFP and PAPP-A ratios were 33 and 50%, respectively.

The elevation of MSAFP and PAPP-A observed with CVS is associated with increased risk of subsequent PE. The ability of such increases to predict PE appears to be modest.