Weight loss surgery was linked to more regular periods and fewer polyendocrine metabolic ovarian syndrome (PMOS) symptoms in women aged 18 to 45 living with obesity in a recent study.

The researchers recommend that women undergoing the procedure have access to preconception care and reproductive counselling to support their reproductive health.

Researchers at the University of Surrey analysed data over 24 months from 84 women who underwent bariatric surgery and 18 women living with obesity who did not have surgery.

Of those who underwent surgery, 49 had gastric bypass procedures and 35 had gastric sleeve surgery.

Women who underwent metabolic bariatric surgery lost more than 30kg on average at 12 and 24 months after the procedure.

Among women with polycystic ovaries, the condition persisted in only 10 per cent after 24 months.

Women also reported a resolution of clinical hirsutism, or excess body hair, by 12 months.

Women who had previously experienced irregular periods reported more regular menstrual cycles after surgery.

Professor Martin Whyte, co-author of the study and professor of metabolic medicine at the University of Surrey, said: “A large proportion of those undergoing bariatric surgery are women of reproductive age, who may be planning a pregnancy in the coming years.

“So much remains unknown about the impact of this type of surgery on women who are planning to have children.

“This raises the question of when the ideal time after surgery is to conceive.”

Women have a higher prevalence of obesity than men, with 57 per cent of women in the UK classified as overweight and 27 per cent living with obesity, which can affect fertility and the health of an unborn baby.

The researchers said 17 women had healthy pregnancies following surgery.

Although this was not specifically examined in the study, no difference in birth weight was observed between babies conceived within or after the first year.

Dr Kathryn Hart, co-author of the study and associate professor in nutrition and dietetics at the University of Surrey, said: “What we have found is that bariatric surgery positively affects the reproductive health of women living with obesity and can improve the likelihood of them having a healthy pregnancy after surgery.

“Dysregulated hormone levels, irregular periods and conditions such as polycystic ovaries are affected by obesity.

“By reducing this, what we have seen is that it can lead to improvements without the need for medication.

“We would suggest that clinicians consider medical intervention for obesity to treat irregularities in the menstrual cycle and issues with fertility.”

The Scottish government has launched a national review into whether NHS IVF access should be extended to single women.

The review will also consider whether wider access should be offered to couples who have children from previous relationships.

Health secretary Angela Constance said: “Access to NHS IVF treatment should be fair, timely and reflect the way people’s lives and families look today.”

Most single women are not currently eligible for NHS IVF treatment in Scotland.

Campaigners have welcomed the review.

Katie Rollings of Fertility Action said: “It’s an essential and long-awaited decision that will impact a huge number of people who are struggling to grow their families.

She said there is “no evidence” that having two parents rather than one determines whether a child will thrive.

She added: “What matters is whether a child is loved, safe, supported and has stable, positive relationships around them.”

Figures from the Human Fertilisation and Embryology Authority show Scotland is the only UK nation where NHS-funded IVF cycles outnumber privately funded cycles.

In 2024, more than 6,000 cycles of fertility treatment were carried out among more than 4,000 patients in Scotland. Both figures were slightly lower than the record highs recorded in 2022.

The past 20 years have also seen a rise in the number of same-sex female couples and single women receiving fertility treatment.

In 2024, 625 IVF cycles were carried out for women in same-sex couples in Scotland, with more than one third funded by the NHS.

There were 330 cycles involving single women, of which 50 were NHS-funded.

In England, single women can access IVF through the NHS, although eligibility varies according to the local health trust’s policy.

Current Scottish rules state that couples are eligible if they have been living in a stable relationship for two years and neither partner has been sterilised.

Couples where one partner already has a child can be eligible, but those where both partners have children from previous relationships are not.

Eligibility rules also require a body mass index above 18.5 and below 30, and state that couples must not smoke, drink alcohol or take drugs during treatment. The mother must be under 42.

The Scottish government said the review would also examine consistency of access to fertility preservation, including during cancer treatment, as well as reducing waiting times for donor eggs and sperm.

Same-sex female couples already have access to NHS IVF, but they can face long waits for donor eggs or sperm, as can heterosexual couples who require donor treatment.

The National Fertility Group will lead the review and make “costed, demand-modelled recommendations”, which are due to be published by early summer 2027.

The group will include fertility experts from Scotland’s four NHS-assisted conception units in Glasgow, Edinburgh, Aberdeen and Dundee.

Prof Sarah Martins Da Silva, an NHS consultant and chair of fertility medicine at Dundee University, said there were questions to be answered in a resource-stretched NHS.

“As a fertility specialist I’m never going to be disappointed if the criteria is widened,” she said.

“But with single people, as an NHS clinician looking at the competing demands we have, I’d ask the question about whether being single is a health condition that needs to be funded.”

Da Silva said NHS waiting lists were full of couples who require donated eggs or sperm because of medical conditions including cancer and could face longer waits.

“It’s slightly a disservice to them,” she said.

“There would need to be a real investment and resource without making everybody wait an extraordinary long time.

“With the current financial environment we work in, if you’re talking about new money, where would that come from?”

She said she would welcome changes that encouraged more people to donate eggs or sperm and questioned whether arguments about children needing two parents were necessarily relevant to the debate.

“On the one hand bringing up a child is quite an expensive process, and if you don’t have that support, it can be very difficult.

“But on the other hand, many people start off as a couple and divorce.”

Da Silva also welcomed plans for the review to consider eligibility for couples who already have children, describing the move as “fantastic”.