The efficiency of first-trimester serum analytes and maternal characteristics in predicting fetal growth disorders

Objective: To evaluate the association between first-trimester serum analytes, pregnancy-associated plasma protein A and free beta-human chorionic gonadotropin, and fetal growth disorders, and to determine whether a prediction model for these growth disorders can be developed. Study Design: Retrospective cohort study of patients seen for first-trimester aneuploidy screening. Pregnancy-associated plasma protein A and free beta-human chorionic gonadotropin multiples of the median were evaluated for association with small- and large-for-gestational-age infants in combination with maternal characteristics. Univariate and backward stepwise logistic regression analyses were performed and the area under the receiver-operator curves used to determine the best prediction models. Results: Neither pregnancy-associated plasma protein A nor free beta-human chorionic gonadotropin levels were associated with an increased risk of large-for-gestational-age infants. For small-for-gestational-age infants, the final model included black race, free beta-human chorionic gonadotropin multiples of the median >90th percentile, and pregnancy-associated plasma protein A multiples of the median <5th percentile as significant predictors (area under the curve = 0.58). Conclusion: Low pregnancy-associated plasma protein A and high free beta-human chorionic gonadotropin levels are associated with a small-for-gestational-age growth pattern; however, additional factors to improve the prediction model are needed.