Genitourinary Syndrome of Lactation: how breastfeeding can impact vaginal and urinary health

Authored by Jessica Childs, Intimate Health Specialist at Pelvic Relief.

Genitourinary Syndrome of Lactation (GSL) describes the collection of genital and urinary symptoms that can be experienced by postpartum mothers if they choose to breastfeed. It is a new term, formalised in 2025, and one that hopefully shines the light on some of these changes, and helps women get the best symptom management tools for this period.

Breastfeeding is amazing if its something that a Mother can and chooses to do. During this time however, a woman's hormones can be impacted in a way that may lead to a variety of genial and urinary symptoms, such as dryness, soreness, painful sex, increased urinary urgency or frequency, or UTIs that keep coming back. These symptoms aren't just normal postpartum discomfort. They're linked to low oestrogen during breastfeeding.

Below I cover what symptoms GSL covers, why it happens, and what it can mean for your microbiome, your urinary tract and the health of your tissues, and most importantly, what management options are available.

What is GSL?

GSL describes the genital and urinary symptoms that can happen while breastfeeding because of hormonal changes. It was put forward by sexual medicine researchers at Weill Cornell Medicine in a 2024 review in Sexual Medicine Reviews (1). The symptoms include:

• Vaginal dryness
• Thinning of the vaginal and vulval tissues (atrophy)
• Pain during sex (dyspareunia)
• Urinary symptoms, such as urgency, burning or recurrent UTIs
• Changes in sexual desire and function

If this list sounds like the menopause, that's no coincidence. The same hormone (reduced oestrogen) is behind both. GSL is really a 'temporary dip' into some of the symptoms that may appear again in menopause.

Why does breastfeeding affect these tissues?

To make milk, your body produces high levels of prolactin. Prolactin suppresses the ovaries' production of oestrogen and androgens such as testosterone. For as long as a woman breastfeeds, her body can be in a somewhat low-oestrogen state similar to the menopause (1).

Oestrogen is very protective for the genital and urinary tissues. It helps to:

• Keep the vaginal walls thick, elastic and lubricated
• Support the tissue of the vulva and urethra
• Maintain blood flow and collagen
• Feed the protective Lactobacillus bacteria that keep the vagina acidic and free from infection causing microbes.

The vagina, vulva, urethra and bladder all have oestrogen receptors, which is why the effects reach beyond the vagina (1).

How common is GSL?

GSL is common, yet its not discussed often or openly, so its something that most people will not be aware of. A 2025 systematic review of 65 studies in Obstetrics & Gynecology found that, among breastfeeding women (2):

• About 64% had vaginal atrophy and about 54% had vaginal dryness
• Pain during sex affected around 60% at 3 months postpartum, falling to about 40% at 6 months and 29% at 12 months
• Breastfeeding women were around 2.3 times more likely to have vaginal atrophy than women who weren't breastfeeding (3)

The impact of GSL on the vaginal microbiome

A healthy vaginal microbiome is typically dominated by Lactobacillus. These bacteria produce lactic acid, which keeps the vagina acidic and makes it harder for the bacteria linked to BV, UTIs, and yeasts, to take hold. Oestrogen supports this by encouraging the vaginal lining to store glycogen, which feeds the lactobacilli.

• A longitudinal study that followed women through childbirth found that delivery, whether vaginal or caesarean, was associated with inflammation in the vagina and a loss of Lactobacillus dominance. A year after birth, the chance of having returned to a Lactobacillus-dominant microbiome was only about 49% (4)
• A UK study found the postpartum vaginal microbiome shifts markedly towards fewer Lactobacillus species and more diversity (5)

Lactation is thought to prolong this low-oestrogen window. When lactobacilli are depleted, the vagina becomes less acidic. This can increase one's risk of BV, thrush and recurrent UTIs, and it can make an already thinned lining more easily irritated.

The impact of GSL on tissue integrity

When levels of oestrogen stay low:

• The vaginal and vulval lining thins and becomes less elastic. Women are more likely to feel sore, tear or bleed during sex or when using tampons, dilators or during a smear test.
• Natural lubrication drops. Dryness and friction can cause micro-tears and irritation
• Healing may be slower. Oestrogen helps to grow the cells involved in tissue repair, and research suggests it supports wound healing and collagen production (6). This may be impactful in cases of perineal tear or episiotomy
• Support tissues may be affected. Collagen is part of what holds pelvic tissues in place, and it's proposed that lower collagen contributes to postpartum urinary incontinence and prolapse (6)

The impact of GSL on the urinary tract

The female urethra is short, around 4cm, so bacteria have a short journey to the bladder. It's also oestrogen-sensitive. With lower oestrogen, the urethral lining can thin, and with fewer protective lactobacilli, bacteria such as E. coli are more able to colonise the vaginal area, and be more prevalent in the urethra and bladder. Researchers describe lactation-related hypoestrogenism as contributing to burning on weeing and recurrent UTIs (1).

GSL management options

Moisturisers and lubricants. A vaginal moisturiser used regularly helps restore moisture to the tissue, and a lubricant reduces friction during sex. Choose pH-balanced products without glycerin, parabens, propylene glycol or fragrance, as these can irritate delicate tissue and upset the vaginal microbiome. Our guide to choosing a lubricant and moisturiser may be helpful.

Vaginal oestrogen. A low-dose, local treatment that replenishes oestrogen in the vaginal tissues can be really beneficial. A 2026 systematic review found topical vaginal oestrogens appear safe and well tolerated postpartum (7). If you are struggling with any of the symptoms mentioned, speak with your Doctor about temporary use of vaginal oestrogen.

Pelvic floor physiotherapy. Pelvic health physiotherapists can help with pelvic floor strength and relaxation, painful sex, scar tissue and bladder symptoms. We recommend POGP certified Physiotherapists.

Probiotics for the vaginal microbiome. Lactobacillus depends on oestrogen, and its numbers can fall during lactation, which raises the risk of imbalances. A probiotic containing vaginal Lactobacillus strains may be considered as temporary support for the vaginal microbiome. Ultimate V is an oral probiotic that contains four vaginal Lactobacillus species plus biotin. This can be taken daily during breastfeeding to support the microbiome of the vagina. Ultimate UT contains D mannose in addition to the lactobacillus, and is designed to support the health of the bladder.

Find out what's going on with your microbiome. If you have recurrent thrush, BV-type symptoms or UTIs, a vaginal microbiome test can show which bacteria and yeasts are present and in what amounts, to support re balancing efforts.

What healthcare professionals can do

If you work with postpartum women, a few simple steps can make a big difference:

• Ask specific questions about genitourinary symptoms, such as dryness, pain with sex, burning, urgency and leaking. Many women won't bring them up unprompted.
• Validate that symptoms can be hormonal and treatable. They aren't just something to put up with
• Consider referral pathways, including the GP, physiotherapy, pelvic health services and gynaecology

When to speak to a professional

Please speak to your GP, midwife, health visitor or a pelvic health physiotherapist if you have:

• Pain during sex that isn't improving
• Burning, bleeding or tearing of the skin
• UTI symptoms, especially if they keep coming back
• Leaking urine, or a feeling of heaviness or bulging in the vagina
• Any symptoms that are affecting your day-to-day life or your relationships

We hope you find this article helpful. This article is for general information and isn't a substitute for medical advice. If you're concerned about your symptoms, please speak to a healthcare professional.

References

1. Perelmuter S, Burns R, Shearer K, et al. Genitourinary syndrome of lactation: a new perspective on postpartum and lactation-related genitourinary symptoms. Sex Med Rev. 2024;12(3):279–287. doi:10.1093/sxmrev/qeae034
2. Perelmuter S, Stokes C, Chapalamadugu M, et al. Postpartum and lactation-related genitourinary symptoms: a systematic review. Obstet Gynecol. 2025;146(1):59–72. https://journals.lww.com/greenjournal/abstract/10.1097/aog.0000000000005940
3. Medscape. Lactation triggers menopause-like symptoms in newly recognized syndrome. 23 May 2025 (reporting the findings of reference 2). https://www.medscape.com/viewarticle/lactation-triggers-menopause-symptoms-newly-recognized-2025a1000d1o
4. A longitudinal study of the vaginal ecosystem before and after childbirth. PubMed Central: PMC10338445. https://pmc.ncbi.nlm.nih.gov/articles/PMC10338445
5. MacIntyre DA, et al. The vaginal microbiome during pregnancy and the postpartum period in a European population. Sci Rep. 2015;5:8988. https://link.springer.com/article/10.1038/srep08988
6. Oetken C. Attention moms: breastfeeding and genitourinary symptoms are connected. Pelvic Health and Rehabilitation Center blog. 2025. https://pelvicpainrehab.com/blog/attention-moms-breast-feeding-genitourinary-symptoms-are-connected/
7. Waheed A, Taithongchai A, Robinson D. The use of topical vaginal estrogens in postpartum women: a systematic review. Acta Obstet Gynecol Scand. 2026;105(7):1405–1410. https://pubmed.ncbi.nlm.nih.gov/42077139/
8. Kelly L. Postpartum vulvar biology beyond atrophy: a 5-axis mechanistic review of genitourinary syndrome of lactation. Sex Med Rev. 2026;14(3):qeag076. doi:10.1093/sxmrev/qeag076
9. Contemporary OB/GYN. Sara Perelmuter on genitourinary syndrome of lactation in the postpartum period. 2026. https://www.contemporaryobgyn.net/view/sara-perelmuter-on-genitourinary-syndrome-of-lactation-in-the-postpartum-period