Objective
To examine the relationship between second trimester maternal serum biomarkers and the development of early- and late-onset severe preeclampsia in euploid pregnancies.
Study Design
Included were 136,139 pregnancies participating in second trimester prenatal screening through the California Prenatal Screening Program with live births in 2006 through 2008. We identified severe preeclampsia diagnoses from hospital discharge records. We used log binomial regression to examine the association between abnormal second trimester maternal serum biomarkers and the development of severe preeclampsia.
Results
Approximately 0.9% of all women (n= 1,208) in our sample developed severe preeclampsia; 329 before 34 weeks gestation and 879 at or after 34 weeks. High levels of alpha fetoprotein (AFP), human gonadotropin (hCG) and inhibin (INH) (multiple of the median (MoM) ≥ 95th percentile), and low estriol (uE3) (MoM ≤ 5th percentile), were associated with severe preeclampsia (RRs 2.5 – 11.7). Biomarkers were more predictive of early-onset severe preeclampsia (RRs 3.8 – 11.7). One in 9.5 pregnancies with combined high AFP, INH and low uE3 developed severe early-onset preeclampsia compared to one in 680.5 pregnancies without any abnormal biomarkers.
Conclusions
The risk of developing severe preeclampsia increases for women with high second trimester AFP, hCG, INH and/or low uE3; this is especially true for early-onset severe preeclampsia. When abnormal biomarkers co-occur, risk dramatically increases. Although the screening value of second trimester biomarkers is low, abnormal biomarkers, especially when occurring in combination, appear to indicate placental dysfunction associated with the development of severe preeclampsia.