Serum relaxin levels are reduced in pregnant women with a history of recurrent miscarriage, and correlate with maternal uterine artery Doppler indices in first trimester
Received 12 February 2009; received in revised form 22 May 2009; accepted 21 July 2009. published online 12 August 2009.
Abstract
Objectives
Defective implantation is a mechanism for recurrent pregnancy loss (RPL). We sought to determine whether the serum expression of human relaxin-2 (RLX) is impaired in women with a history of RPL.
Study design
Employing a prospective case-controlled design we studied 20 pregnant women with a history of RPL and 20 age-matched women with no history of RPL (NRPL). We measured serum relaxin-2 levels by ELISA at 6–8, 10–12, 20, and 34 weeks gestation and in cord blood, and maternal uterine artery Doppler resistance index (RI) at ≥10 weeks gestation.
Results
Relaxin rose to a peak at 12 weeks, and gradually declined towards term. At all gestations, women with a history of RPL had lower RLX levels than women without. At 10–12 weeks gestation, uterine artery RI correlated with serum RLX for both RPL and NRPL. In the NRPL group at 10–12 weeks the presence of a notched waveform was associated with higher RLX levels than the absence of a notch (mean 2.1ng/ml vs. 1.3ng/ml, P<0.05) and also at 20 weeks (2.1ng/ml vs. 0.95ng/ml, P<0.05) but no such difference was seen in the RPL group. Umbilical venous RLX was 4-fold higher in the RPL group than the NRPL group.
Conclusion
Women with a history of RPL demonstrate attenuated levels of serum RLX across all pregnancy trimesters. How dysregulated RLX metabolism may contribute to adverse pregnancy outcome in RPL requires further investigation.
Section of Endocrinology and Reproduction, Academic Unit of Reproductive and Developmental Medicine, The University of Sheffield, 4th Floor, Jessop Wing, Tree Root Walk, Sheffield S10 2SF, UK
ABSTRACT