Late pregnancy associated plasma protein A levels decrease in preterm labor

The purpose of the present study is to evaluate late, 'at admission', Pregnancy-associated plasma protein-A (PAPP-A) levels as a predictor of preterm birth in women with complaints of preterm labor or preterm painful contractions.

Prospective cohort study of singleton gestations, 23-37 weeks, and symptoms of preterm labor. Primary end point was delivery < 37 weeks. Predictive PAPP-A values were calculated both for preterm delivery and threatened preterm delivery on receiver operator curve.

In all, 41 women (38.3%) delivered before 37 weeks (Group 1); 32 women (30.7%) had symptoms of preterm labor but did not deliver preterm (Group 2); 31 women (29.7%) delivered term (Group 3, control). Mean PAPP-A levels in preterm-labor and its matched control were 33.4 ± 19.9 and 52.5 ± 25.4 mIU/ml, respectively, and difference was statistically significant (p = 0.003). Mean PAPP-A level in threatened preterm labor group was 47.6 ± 25.3 mIU/ml and difference was significant compared to preterm-labor, but not significant compared to control group (p = 0.028 and p = 0.74, respectively).

Late PAPP-A levels decreased in preterm labor, levels < 29.8 mIU/ml was associated with increased risk for preterm birth, supporting active management whereas cutoff value of 33.6 mIU/ml is useful for discrimination of preterm birth from threatened preterm birth reaching to term.