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The impact of maternal obesity on in vivo uterine contractile activity during parturition in the rat

Muir, Ronan; Khan, Raheela; Shmygol, Anatoly; Quenby, Siobhan; Elmes, Matthew


Ronan Muir

Professor of Cellular Physiology

Anatoly Shmygol

Siobhan Quenby


Maternal obesity is associated with increased risk of prolonged and dysfunctional labour and emergency caesarean section. To elucidate the mechanisms behind the associated uterine dystocia, a translational animal model is required. Our previous work identified that exposure to a high fat, high cholesterol (HFHC) diet to induce
obesity down-regulates uterine contractile associated protein expression and causes asynchronous contractions ex-vivo. This study aims to investigate the impact of maternal obesity on uterine contractile function in-vivo using intra-uterine telemetry
surgery. Virgin female Wistar rats were fed either a control (CON, n=6) or HFHC (n=6) diet for 6 weeks prior to conception, and throughout pregnancy. On day 9 of gestation, a pressure-sensitive catheter was surgically implanted aseptically within the gravid
uterus. Following 5 days recovery, intra-uterine pressure (IUP) was recorded continuously until delivery of the 5th pup (day 22). HFHC induced obesity led to a significant 1.5-fold increase in IUP (P=0.026) and 5-fold increase in frequency of contractions (P=0.013) relative to CON. Determination of the time of labour onset identified that HFHC rats IUP (P=0.046) increased significantly 8 hours prior to 5th pup
delivery, which contrasts to CON with no significant increase. Myometrial contractile frequency in HFHC rats significantly increased 12 hours prior to delivery of the 5th pup (P=0.023) compared to only 3 hours in CON, providing evidence that labour in HFHC rats was prolonged by 9 hours. In conclusion, we have established a translational rat model that will allow us to unravel the mechanism behind uterine dystocia associated with maternal obesity.


Muir, R., Khan, R., Shmygol, A., Quenby, S., & Elmes, M. (2023). The impact of maternal obesity on in vivo uterine contractile activity during parturition in the rat. Physiological Reports, 11, Article e15610.

Journal Article Type Article
Acceptance Date Jan 21, 2023
Online Publication Date Mar 2, 2023
Publication Date 2023-03
Deposit Date Feb 8, 2023
Publicly Available Date Mar 2, 2023
Journal Physiological Reports
Electronic ISSN 2051-817X
Publisher Wiley
Peer Reviewed Peer Reviewed
Volume 11
Article Number e15610
Keywords Dysfunctional labor, dystocia, in vivo myometrial contractile activity, labor, maternal obesity, myometrial contractile function, parturition, telemetry surgery
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The impact of maternal obesity on in vivo uterine contractile activity during parturition in the rat (1.5 Mb)


Copyright Statement
© 2023 The Authors. Physiological Reports published by Wiley Periodicals LLC on behalf of The Physiological Society and the American Physiological Society.<br /> <br /> This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

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