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The menopause and breastfeeding

I’m seeing increasing numbers of questions form mums in the perimenopause who are still breastfeeding. Maybe they delivered later or maybe they have been feeding to term or maybe lots of other reasons. I remember asking for blood tests to check my hormone levels because I just couldnt think clearly anymore and my memory was poor which wasnt ideal as I was just becoming an independent pharmacist prescriber! My levels had indeed dropped and I went on to HRT. This may not be everyone’s choice or be suitable for them

I have spent many hours this year looking for guidance on HRT and breastfeeding and failed to find any studies or conclusive data. Everything is anecdotal at the moment but I hope this information helps.

One vital piece of information – please keep checking your breasts for lumps .HRT can slightly increase the risk of breast cancer. If you’ve had breast cancer you’ll usually be advised not to take HRT. The increased risk is low: there are around 5 extra cases of breast cancer in every 1,000 women who take combined HRT for 5 years. The risk increases the longer you take it, and the older you are.

Risk of breast cancer BNF June 2024 https://bnf.nice.org.uk/treatment-summaries/sex-hormones/

All types of systemic (oral or transdermal) HRT treatment increase the risk of breast cancer after 1 year of use. This risk is higher for combined oestrogen-progestogen HRT (particularly for continuous HRT preparations where both oestrogen and progestogen are taken throughout each month) than for oestrogen-only HRT, but is irrespective of the type of oestrogen or progestogen. Longer duration of HRT use (but not the age at which HRT is started) further increases risk.

Although the risk of breast cancer is lower after stopping HRT than it is during current use, the excess risk persists for more than 10 years after stopping compared with women who have never used HRT. Vaginal preparations containing low doses of oestrogen to treat local symptoms are not thought to be associated with an effect on breast cancer risk.

The MHRA advises discussing the updated information on the risk of breast cancer with women who use or are considering starting HRT, at their next routine appointment. 

There are also risks of endometrial cancer, ovarian cancer, thromboembolism, stroke and coronary vascular disease.

As usual please message me on wendy@breastfeeding-and-medication.co.uk if you have a question

PDF of factsheet available:


The Menopause And Breastfeeding

There remains no conclusive research on the passage of HRT medication into breastmilk. It appears anecdotally that there is less impact on milk supply from using transdermal preparations than oral medication. There remains the possibility of reduction in lactation due to the oestrogen contact inhibiting prolactin. Anecdotally HRT at standard dose of less than 2mg has been used by breastfeeding women without impact on the nursling or supply. There is no research on higher doses or use outside of licence application.

For use of vaginal oestrogen see https://breastfeeding-and-medication.co.uk/fact-sheet/breastfeeding-and-oestrogen-cream-or-pessary

I typed “menopause and breastfeeding” into a well-known search engine and what came up first was “It is most likely that you are suffering from menopausal-like symptoms due to breastfeeding. After childbirth and during breastfeeding, women’s oestrogen levels can drop to lower levels than usual. These low levels of oestrogen can cause symptoms that mimic menopause.”

Whilst in a paper published in 2020 Langton et al found that after studying 100,000 women ages 25 to 42 years in the Nurses’ Health Study II (an analysis funded by the National Institutes of Health) “Women who breastfed their infants exclusively for seven to 12 months may have a significantly lower risk of early menopause than their peers who breastfed their infants for less than a month”.  The study also suggests that pregnancy can reduce the risk of early menopause.”

As many women now give birth later than in the past, due to changes in work and finance, and feed until they and their nursling choose to stop, questions that I have received from mothers exhibiting signs of early menopause have increased substantially. Most women begin the menopause between 45 and 55 years of age.

There is also a group who have experienced premature ovarian failure which may be hereditary. There is a further group who have had their uterus and ovaries removed surgically for a variety of reasons.

Premature ovarian insufficiency (POI)

This affects about one in a hundred women under 40 in the UK. It occurs when the ovaries no longer produce normal amounts of estrogen and therefore may not produce eggs. This means that periods will become irregular or stop altogether, with symptoms of the menopause. Many women have POI without actually realising it. Any mother under the age of 40 and having irregular periods (or if they have even stopped completely) should be talk to their doctor about having further tests. No woman is too young to be menopausal. Unlike the normal menopause when the ovaries stop working completely, in POI ovarian function can be intermittent, occasionally resulting in a period, ovulation or even pregnancy. This intermittent return of ovarian function means that 5–10% of women with POI will conceive spontaneously.


The period leading up to the menopause, when hormone production decreases symptoms may start to be experienced is defined as the perimenopause. The period is rather ill defined and may vary dramatically between women. It usually suggested as beginning with irregular menstruation. There may be changes to flow with periods becoming heavier or lighter. For others it may be defined by mood swings or changes in mental function. Each person has a different awareness of their own bodies. This is the period in which most calls about breastfeeding appear to originate with a request to begin hormone replacement therapy.


The menopause is defined as an absence of menstruation for over a year. Not all symptoms will be experienced by all women, we are all different.

Typical menopausal symptoms, include:

  • hot flushes
  • night sweats
  • vaginal dryness and discomfort during sex
  • difficulty sleeping
  • low mood or anxiety
  • reduced sex drive (libido)
  • problems with memory and concentration

However, Newson diagram shows that the menopause may affect any part of the body with a wide variety of symptoms

Reproduced from Newson, Menopause: All you need to know in one concise manual

Interestingly when Newson surveyed approximately 2,920 women about their experiences of care around the menopause. The majority of respondents had visited their usual GP:

  • 66% said they were offered antidepressants rather than HRT
  • 20% said they had been referred to a hospital for appointments and/or investigations e.g., migraine clinics, scans or heart tests with symptoms likely to be related to their perimenopause/menopause.

This suggests that medical understanding of perimenopausal symptoms may be poorly understood and probably more so if the women is breastfeeding as well, particularly outside of the perceived “normal” timeframe.

Post menopause

This is defined as the remainder of a women’s life which can present with an increased risk of osteoporosis although the risk is lowered in women who have breastfed (https://www.unicef.org.uk/babyfriendly/news-and-research/baby-friendly-research/maternal-health-research/maternal-health-research-bone-density/).

HRT and Breastfeeding

HRT contains oestrogen and sometimes a progesterone e.g., norethisterone, not that dissimilar to that in the combined oral contraceptive which can be used in breastfeeding. The ethinylestradiol content of COCs range from 20–40 micrograms whilst that in HRT products contain 1 – 2 milligrams of estradiol (there are 1000 micrograms in a milligram).

However, Hale says “Although small amounts of Conjugated estrogens may pass into breastmilk, the effects of estrogens on the infant appear minimal. Early postpartum use of estrogens may reduce volume of milk produced and the protein content, but it is variable and depends on dose and the individual.”

“Conjugated estrogens comprise more than 90% of the total estrogen content of human milk and plasma (McGarrigle) Estriol glucosiduronates were the predominant oestrogen metabolites (63%) in plasma”

His conclusion is that low levels pass into milk confirmed in a query to the InfantRisk forum (https://www.infantrisk.com/forum/forum/medications-and-breastfeeding-mothers/medications-and-mothers-milk/339-hormone-replacement-therapy )

Martindale (39th Ed) states that estradiol has been detected in breastmilk after the use of pessaries containing estradiol 50 or 100mg (Nilsson 1978) and that the American Academy of Pediatrics (2001) considers that it is compatible with breastfeeding

Pharmacokinetics of HRT (Taken from Hale)

Conjugated estrogens:  Milk plasma ratio 0.08, Plasma Protein Binding 98%


  • American Academy of Pediatrics Committee on Drugs. Transfer of drugs and other chemicals into human milk. Pediatrics. 2001 Sep;108(3):776-89.
  • Chollet, J. A., G. Carter, et al. (2009). “Efficacy and safety of vaginal estriol and progesterone in postmenopausal women with atrophic vaginitis.” Menopause 16(5): 978-983.
  • Hale TW Medications and Mothers Milk online access
  • Langton CR, Whitcomb BW, Purdue-Smithe AC, et al. Association of Parity and Breastfeeding With Risk of Early Natural Menopause. JAMA Netw Open. 2020;3(1): e1919615)
  • Martindale The Complete Drug Reference 39 Ed. Pharmaceutical Press
  • McGarrigle HH, Lachelin GC. Oestrone, oestradiol and oestriol glucosiduronates and sulphates in human puerperal plasma and milk. J Steroid Biochem. 1983May;18(5):607-11.
  • Newson, Dr Louise. Menopause: All you need to know in one concise manual. Kindle
  • Nilsson S, Nygren KG, Johansson ED. Transfer of estradiol to human milk. Am J Obstet Gynecol. 1978 Nov 15;132(6):653-7

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