Decreased PAPP-A is associated with preeclampsia, premature delivery and small for gestational age infants but not with placental abruption

Objective: To investigate links between first trimester Down's syndrome screening markers and adverse pregnancy outcomes; preeclampsia (PE), small for gestational age (SGA), preterm delivery (PD) and placental abruption (PA) in spontaneous, chromosomally normal pregnancies.

Study design: Cohort study in a university hospital. Data during pregnancy were routinely collected from a total study population of 2844 pregnant women between 2005 and 2007. Four study groups were pregnancies with PE (N=175), PA (N=17), PD (N=213) and SGA (N=275) plus a reference group with normal outcome (N=2164). The median MOMs of maternal serum concentrations of pregnancy associated plasma protein A (PAPP-A) and free beta human chorionic gonadotropin (fβ-hCG) were compared using two-tailed pooled t-tests, continuous variables were compared using Student's two-way t-tests, and Chi-square tests were used to analyse dichotomous variables. Fisher's exact test was used when there were fewer than five units in any of the classes.

Results: The median MOM of maternal serum PAPP-A was significantly lower in women with PE, PD and SGA (0.79, 0.80 and 0.79 MOM, respectively) than in the reference group (0.99 MOM) (p<0.01). The median MOM of maternal serum fβ-hCG was also significantly lower in the SGA group (0.90 MOM) and in the PE and PD groups (0.86 and 0.92 MOM) than in the reference group (0.99 MOM, p=0.02). There was no detectable difference between the biochemical markers in the PA group and the reference group. No statistical difference was found between NT MOMs in the reference and study groups.

Conclusion: The concentrations of first trimester screening (FTS) serum markers were lower in pregnancies where PE, PD and SGA occurred. In the latter two cases, there was an inverse association between incidence and PAPP-A and fβ-hCG values. However, the development of PA during pregnancy could not be predicted from biochemical marker concentrations. The mechanism behind PA is probably less dependent on the placenta than on the decidua.