Relaxin-2 connecting peptide (pro-RLX2) levels in second trimester serum samples to predict preeclampsia.

Objectives: Preeclampsia is a serious complication of pregnancy, threatening fetal and maternal health. The aim of our study is to examine the association between preeclampsia and the connecting peptide of the pregnancy hormone relaxin (pro-RLX2) as a potential new biochemical marker.

Study Design: This is a nested case/control study derived from the cohort of pregnancies delivering at Women & Infants Hospital. Cases were identified at a clinic or by hospital codes, and individually confirmed by record review. Stored samples were available from 'integrated' Down syndrome screening. Results were expressed as multiples of the median (MoM).

Main Outcome Measures: Preeclampsia was classified as early/severe, late/severe, or mild based on professional guidelines.

Results: Fifty-one cases were each matched with five control pregnancies. Population distribution parameters were derived for cases and controls. As shown previously, discrimination between cases and controls (applying MoM analysis) was possible for PlGF (0.576, p < .05), inhibin A (1.45, p < .05) and endoglin (1.278, p < .05). No association with preeclampsia was found for pro-RLX2. However, pro-RLX2 correlates with Inhibin A and Endoglin.

Conclusions: Endoglin, Inhibin A and PlGF are highly predictive of preeclampsia. Quantification of pro-RLX2 is not able to predict preeclampsia. Nevertheless, the potential involvement of relaxin 2/pro-RLX2 in the pathophysiology of preeclampsia requires further study.