OC 19.03: PAPP ‐A at 5–11 weeks' gestation and the prediction of pregnancy outcome

Pregnancy-associated plasma protein A (PAPP-A) is a biochemical marker currently used as part of combined first trimester screening. A low PAPP-A at 11−13 weeks' gestation is predictive of miscarriage and late adverse pregnancy outcomes. We aimed to determine whether PAPP-A measured at 5−11 weeks would be predictive of early pregnancy loss. Women attending our early pregnancy assessment service at 5-11 weeks with symptoms of miscarriage were asked to participate. Those with sonographic evidence of a failed pregnancy were excluded. Maternal serum PAPP-A was quantified and levels were analysed in relation to pregnancy outcome. 94 women were recruited at a median of 7 + 3 days. Four women were subsequently excluded (2 congenital anomalies and 2 lost to follow-up). 80 (89%) women had ultrasound evidence of a live intrauterine pregnancy. All 13 pregnancies ending in first trimester miscarriage had a raw PAPP-A level of <0.06IU/L. Using a PAPP-A cut-off of ≤0.06IU/L would detect early pregnancy loss with a sensitivity of 100% (95% CI 73−100%) and a specificity of 68% (95% CI 56−77%). Final pregnancy outcome data was available for 87 (97%) women with 13 late adverse outcomes. In those ongoing pregnancies with an early PAPP-A level of ≤0.06IU/L there was a trend towards increased risk of late adverse obstetric outcomes (OR 2.4; 95% CI 0.7−8.1). PAPP-A at 5−11 weeks could be used to predict ongoing risk of miscarriage. Greater numbers of women are required to determine if risk of other adverse outcomes can be predicted from this early gestation.