The vaginal muscles undergo a stretch up to 3x their original resting length during a vaginal delivery (1). This is a truly amazing physical feat and a testament to the power of the natural physiology of the pelvic floor. No other muscle in the body could do this without injury.
The body is actively changing the structure of the pelvic floor musculature during pregnancy in preparation to stretch. The resting length of the muscles increase during pregnancy by increasing the amount of sarcomeres the pelvic floor muscles have (2).
What does this mean? Sarcomeres are the basic unit of a muscle that allows it to contract and relax. Think of them like the links in chain. During pregnancy, the body is adding more links, sarcomeres, to make the chain longer (2). This does not happen in any other muscle in the body.
While these changes are necessary for pregnancy and birth, the postpartum pelvic floor has to readapt to its non pregnant resting length. These changes also don’t account for a 300% change in musculature. If we think of this from an orthopedic standpoint, the tissue and muscles need time to heal. So how long does this take?
Tissue Healing Times
It takes between 4 and 12 weeks postpartum, depending on the muscle, for the resting muscle length and the amount of sarcomeres to return to pre-pregnancy levels (2). However, muscle length is not the only factor that is healing.
Healing times can be changed by vaginal tearing or other birth related injuries, overall health and wellbeing, and genetic make-up of your individual tissue. These numbers can be used as a guide but every body heals on different timelines.
Return of Strength
There is a 15% and 7% reduction in overall pelvic floor muscle strength at 6 months and 12 months postpartum respectively (3). Pelvic floor strength recovery is a part of healing and it takes time. Pelvic floor weakness could impact a person in many different ways. Someone might not even notice a change while others may feel pelvic heaviness, experience leakage, or have decreased strength of orgasm.
Whether you are having symptoms or not, seeing a pelvic floor physical therapist could help you stay on the right track to recovery.
Vaginal Resting Pressure
Vaginal resting pressure is measured by how much pressure the vaginal walls are putting on an air-filled balloon inserted into the vagina at rest. In non-research world, this would be how much pressure your vaginal wall is putting onto a toy or a penis. There is a 21% and 20% reduction in vaginal resting pressure at 6 months and 12 months postpartum respectively (3). This might make your vagina feel different postpartum during penetration and your partner might notice a difference as well. This is part of healing.
I want to reiterate that that pelvic floor is a powerhouse of the body. It is doing what the rest of the body cannot. But the pelvic floor also needs time to heal from pregnancy and birth and there are often unrealistic expectation of new mamas to return to “normal” by their 6 weeks OB follow-up. Yes, healing continually is occurring once you become postpartum, but some of this healing is still occurring one year postpartum. If there is any bit of question in your healing journey, get help, talk to your OB, go see a pelvic floor physical therapist, so you could make sure you are on the right track. You got this mama, heal well!
Sources:
- Ashton-Miller, J.A., DeLancey, J.O.L. (2021). Mechanisms of Pelvic Floor Trauma During Vaginal Delivery. In: Santoro, G.A., Wieczorek, A.P., Sultan, A.H. (eds) Pelvic Floor Disorders. Springer, Cham. https://doi.org/10.1007/978-3-030-40862-6_12
- Alperin M, Lawley DM, Esparza MC, Lieber RL. Pregnancy-induced adaptations in the intrinsic structure of rat pelvic floor muscles. Am J Obstet Gynecol. 2015 Aug;213(2):191.e1-7. doi: 10.1016/ j.ajog.2015.05.012. Epub 2015 May 13. PMID: 25979618; PMCID: PMC4757427.
- . Bø K, Næss K, Stær-Jensen J, Siafarikas F, Ellström Engh M, Hilde G. Recovery of pelvic floor muscle strength and endurance 6 and 12 months postpartum in primiparous women-a prospective cohort study. Int Urogynecol J. 2022 Dec;33(12):3455-3464. doi: 10.1007/s00192-022-05334-y. Epub 2022 Sep 1. PMID: 36048249; PMCID: PMC9666345.
DISCLAIMER: THIS ARTICLE DOES NOT PROVIDE MEDICAL ADVICE The information, including but not limited to, text, graphics, images and other material contained on this article are for informational purposes only. No material on this site is intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of your physician or other qualified health care provider with any questions you may have regarding a medical condition or treatment and before undertaking a new health care regimen, and never disregard professional medical advice or delay in seeking it because of something you have read on this website. All Content Copyright Ariel Zablocki
