Observational Study
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Jan 6, 2021; 9(1): 91-101
Published online Jan 6, 2021. doi: 10.12998/wjcc.v9.i1.91
Role of relaxin in diastasis of the pubic symphysis peripartum
Yan Wang, Yong-Qiang Li, Mei-Rong Tian, Nan Wang, Zun-Cheng Zheng
Yan Wang, Rehabilitation Medicine, Taian City Central Hospital, Taian 271000, Shandong Province, China
Yong-Qiang Li, Department of Otolaryngology, Taian City Central Hospital, Taian 271000, Shandong Province, China
Mei-Rong Tian, Department of Obstetrics, Taian City Central Hospital, Taian 271000, Shandong Province, China
Nan Wang, Rehabilitation Centre, Qingdao Fuwai Cardiovascular Hospital, Qingdao 266034, Shandong Province, China
Zun-Cheng Zheng, Department of Rehabilitation, Taian City Central Hospital, Taian 271000, Shandong Province, China
Author contributions: Zheng ZC designed the study, supervised the study performance, and revised the manuscript; Wang Y developed the project and participated in the acquisition, analysis, and interpretation of the data; Li YQ, Tian MR and Wang N analyzed the data, drafted the manuscript, and critically revised the manuscript for intellectual content.
Supported by The Science and Technology Development Plan of Taian, No. 2018NS0203.
Institutional review board statement: The study protocol was reviewed and approved by the Ethics Committee of Taian City Central Hospital.
Informed consent statement: All study participants, or their legal guardians, provided informed written consent prior to study enrollment.
Conflict-of-interest statement: There are no conflicts of interest to report.
Data sharing statement: No additional data are available.
STROBE statement: The authors have read the STROBE Statement—checklist of items, and the manuscript was prepared and revised according to the STROBE Statement—checklist of items.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Zun-Cheng Zheng, MAMS, Chief Doctor, Director, Professor, Department of Rehabilitation, Taian City Central Hospital, No. 29 Longtan Road, Taian 271000, Shandong Province, China. zhengzc1965@126.com
Received: June 15, 2020
Peer-review started: June 15, 2020
First decision: September 13, 2020
Revised: October 10, 2020
Accepted: November 13, 2020
Article in press: November 13, 2020
Published online: January 6, 2021
Processing time: 200 Days and 5.5 Hours
Abstract
BACKGROUND

Separation of the pubic symphysis can occur during the peripartum period. Relaxin (RLX) is a hormone primarily secreted by the corpus luteum that can mediate hemodynamic changes during pregnancy as well as loosen the pelvic ligaments. However, it is unknown whether RLX is associated with peripartum pubic symphysis separation and if the association is affected by other factors.

AIM

To study the association between RLX and peripartum pubic symphysis separation and evaluate other factors that might affect this association.

METHODS

We performed a cross-sectional study of pregnant women between April 2019 and January 2020. Baseline demographic characteristics, including gestational age, weight, neonatal weight, delivery mode and duration of the first and second stages of labor, were recorded. The clinical symptoms were used as a screening index during pregnancy, and the patients with pubic symphysis and inguinal pain were examined by color Doppler ultrasonography to determine whether there was pubic symphysis separation. Serum RLX concentrations were evaluated 1 d after delivery using an enzyme-linked immunosorbent assay, and pubic symphysis separation was diagnosed based on postpartum X-ray examination. We used an independent-sample t test to analyze the association between serum RLX levels and peripartum pubic symphysis separation. Multivariate regression analysis was used to evaluate whether the association between RLX and peripartum pubic symphysis separation was confounded by other factors, and the association between RLX and the severity of pubic symphysis separation was also assessed. We used Pearson correlation analysis to determine the factors related to RLX levels as well as the correlation between the degree of pubic symphysis separation and activities of daily living (ADL) and pain.

RESULTS

A total of 54 women were enrolled in the study, with 15 exhibiting (observational group) and 39 not exhibiting (control group) peripartum pubic symphysis separation. There were no statistically significant differences in terms of maternal age, gestational age, pre-pregnancy weight, weight gain during pregnancy, delivery modes, or duration of the first or second stages of labor between the 2 groups. We did, however, note a statistically significant difference in serum RLX concentrations and neonatal weight between the observational and control groups (122.3 ± 0.7 µg/mL vs 170.4 ± 42.3 µg/mL, P < 0.05; 3676.000 ± 521.725 g vs 3379.487 ± 402.420 g, P < 0.05, respectively). Multivariate regression analyses showed that serum RLX level [odds ratio (OR): 1.022) and neonatal weight (OR: 1.002) were associated with pubic symphysis separation peripartum. The degree of separation of the pubic symphysis was negatively correlated with ADL and positively correlated with pain. There was no statistically significant association between serum RLX levels and the severity of pubic symphysis separation after adjusting for confounding factors.

CONCLUSION

Serum RLX levels and neonatal weight were associated with the occurrence, but not the severity, of peripartum pubic symphysis separation.

Keywords: Pregnancy; Pubic symphysis separation; Relaxin; Neonatal weight; Cross-sectional study; Activities of daily living

Core Tip: Peripartum separation of the pubic symphysis is not a frequent pregnancy complication, but it can cause chronic pelvic pain and difficult ambulation. Furthermore, it limits activities of daily living (ADL). We performed a cross-sectional study and identified an association between postpartum serum relaxin (RLX) levels and neonatal weight with peripartum separation of the pubic symphysis. The degree of separation of the pubic symphysis was positively correlated with the degree of pain and was negatively correlated with ADL. Serum RLX levels and neonatal weight may be used to identify women at a high risk of pubic symphysis separation peripartum.