Second trimester maternal serum biomarkers and the risk of cerebral palsy.

AIMS: To investigate whether second trimester maternal serum screening (2TMSS) biomarkers are associated with cerebral palsy (CP) and identify CP characteristics associated with abnormal biomarker levels.

METHOD: In this retrospective case-control data linkage study, we linked mothers of 129 singleton CP cases from a population register to their 2TMSS records and selected 10 singleton pregnancy controls per case (n = 1290). We compared mean and abnormal levels of alpha-fetoprotein (AFP), beta subunit of human chorionic gonadotrophin (β-hCG), unconjugated estriol (uE3), and inhibin between cases and controls and within CP subgroups.

RESULTS

Compared to control pregnancies, CP pregnancies had higher mean levels of AFP (1.10 vs. 1.01 multiple of the population median [MoM], p = 0.01) and inhibin (1.10 vs. 0.98 MoM, p ≤ 0.01). CP pregnancies were 2.5 times more likely to be associated with high levels of AFP (OR 2.52 [95% confidence interval [CI] 1.30, 4.65]; p < 0.01) and 2.6 times for inhibin (OR 2.63 [95% CI 1.37, 4.77]; p < 0.01), and 6.8 times when AFP and inhibin were both elevated (OR 6.75 [95% CI 2.41, 18.94]; p < 0.01). In CP cases, high AFP and high inhibin levels were associated with preterm birth and low birthweight.

INTERPRETATION: Abnormal second-trimester biomarker levels suggest abnormal placentation plays a role in the causal pathway of some CP cases.