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. 2025 Jan;51(1):e16190.
doi: 10.1111/jog.16190.

Relationship between relaxin-2 levels in serum and mode of conception in twin gestations: A prospective cohort study

Angela Silvano  1 , Oumaima Ammar  1 , Astrid Parenti  2 , Noemi Strambi  1 , Viola Seravalli  1 , Daniele Bani  3 , Mariarosaria Di Tommaso  1
Affiliations

Relationship between relaxin-2 levels in serum and mode of conception in twin gestations: A prospective cohort study

Angela Silvano et al. J Obstet Gynaecol Res. 2025 Jan.

Abstract

Aim: Relaxin is a peptide hormone commonly associated with pregnancy when it is thought to play a role in modulating various physiological processes to optimize maternal-fetal adaptation. In twin pregnancies these adaptive requirements are higher than in singleton pregnancies, therefore it is important to understand how circulating relaxin behaves in such conditions. This prospective cohort study aims to determine the serum relaxin-2 levels throughout gestation in twin pregnancies and to investigate its association with the mode of conception.

Methods: Blood samples were collected during each trimester of gestation from 26 women with twin pregnancies obtained through spontaneous conception (SC, n = 18) or assisted reproductive technologies, specifically through intracytoplasmic sperm injection (ART, n = 8). Serum relaxin-2 levels were measured by a highly sensitive ELISA method.

Results: The results indicated that serum relaxin-2 level peaks in the first trimester (491.05 ± 207.41 pg/mL), then decreases in the second trimester (446.27 ± 180.4 pg/mL; p < 0.057) and in the third trimester (422.19 ± 194.30 pg/mL; p < 0.025). Interestingly, the serum relaxin-2 level was higher in the spontaneous conception group with respect to the assisted reproductive technologies group (p < 0.001), when measured at each trimester of gestation. In addition, the multivariate regression analysis showed that only the assisted reproductive technologies had a significant impact on serum levels of relaxin-2 (p < 0.001), and no significant association was found with other women's clinical and demographic characteristics.

Conclusions: These findings extend the current knowledge about the pattern of circulating relaxin-2 throughout gestation in twin pregnancies, providing a sensitive measurement of serum relaxin-2 levels and a description of its putative physiological roles in humans.

Keywords: assisted reproductive technologies; maternal and neonatal outcomes; relaxin; spontaneous conception; twin pregnancies.

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Conflict of interest statement

The authors declare that they have no conflicts of interest.

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References

    1. Hisaw FL. Experimental relaxation of the pubic ligament of the Guinea pig. Proc Soc Exp Biol Med. 1926;23:661–663.
    1. Fevold HL, Hisaw FL, Meyer RK. The relaxative hormone of the corpus luteum. Its purification and concentration. J Am Chem Soc. 1930;52:3340–3348.
    1. Schwabe C, Büllesbach EE. Relaxin: structure, functions, promises and nonevolution. FASEB. 1994;8:1152–1160. - PubMed
    1. Sherwood OD. Relaxin's physiological roles and other diverse actions. Endocr Rev. 2004;25:205–234. - PubMed
    1. Bathgate RA, Samuel CS, Burazin TC, Gundlach AL, Tregear GW. Relaxin: new peptides, receptors and novel actions. Trends Endocrinol Metab. 2003;2003(14):207–213. - PubMed