The Janus face of maternal serum relaxin: a facilitator of birth, might it also induce preterm birth?

Abstract

Objective: Preterm birth is a major cause of neonatal morbidity and mortality in the developed world. In order to better understand the pathophysiological pathway of this condition, the role of genetic factors and/or inflammation-associated molecules, as well as of socioeconomic parameters, is therefore under intense investigation. The purpose of this review study was to examine the potential role of maternal serum relaxin levels in the etiology of preterm birth.

Methods: Electronic databases (Pubmed, Embase, Cochrane Library) were searched for previously published research studies that investigated the biological role of relaxin and the mechanisms in which this hormone is involved during pregnancy and labor.

Results: It is evident that while relaxin is an essential endometrial/decidual angiogentic factor playing a vital role in maternal accommodation of pregnancy, elevated levels of this hormone could well be associated with preterm birth.

Conclusions: There are strong indications that maternal serum hyperrelaxinemia correlates with an increased risk of preterm birth.

Keywords: Genetics; hormones; inflammation; preterm delivery; relaxin.