Study examines which birth control pills are safest for women with high BMI

Women with high body mass index (BMI) who use the combined oestrogen/progestogen pill have a 24 times higher risk of life-threatening blood clots, according to a new study from Italy.

It has been found that the risk is 12 times higher in overweight women. The results are from women of childbearing age.

The combined birth control pill contains a synthetic version of estrogen, a hormone that can cause venous thromboembolism (VTE). The condition reduces blood flow to organs and can potentially trigger heart attacks or strokes.

Lead author Professor Giuseppe Rosano from IRCCS San Raffaele Pisana in Rome said: “It is well known that both obesity and estrogen-containing contraceptives are risk factors for VTE. Despite this, overweight women continue to receive these drugs.”

“The scientific evidence suggests that obesity and combined oral contraceptives have a synergistic effect on VTE risk and this should be considered in prescribing decisions.”

He advised them to use the “mini-pill” – which only contains chemicals that mimic the hormone progestin – or other methods. Both prevent pregnancy.

Women who have had breast cancer, previously had blood clots, or have a family history are already excluded from the combined pill. “Progestogen-only products, including pills, IUDs or implants, are a safer alternative to the combined pill in overweight women,” Rosano said.

The study appears in European Heart Journal (EHJ). The article is based on a review of the latest evidence.

The researchers found that the likelihood of developing blood clots is almost double and two and a half times higher, respectively. However, the risk increased by a factor of 12 and 24 in users of the combined pill compared to non-users with a normal BMI.

“This article highlights the latest evidence on the independent effects of obesity and contraceptives, as well as their synergistic effects on VTE risk, and provides clinical recommendations,” Rosano said.

She said that “VTE refers to a blood clot in a vein and includes two life-threatening conditions – deep vein thrombosis and pulmonary embolism.”

The World Health Organization (WHO) estimates that the global prevalence of obesity nearly tripled between 1975 and 2016, with one in seven women being obese. VTE risk increases progressively with BMI—more than double in obese women. The greatest impact occurs in the under-40s, which increases fivefold.

Rosano said, “The particularly high risk in overweight women under 40 is important because many are at that age looking for contraception.” Overall, the combined pill is associated with a three to seven-fold increase in the chance of VTE. There is no link between the minipill and blood clots.

“Obese women using birth control are vulnerable to VTE and should take steps to limit their other predisposing factors to cardiovascular disease — for example, by quitting smoking and increasing physical activity,” Rosano said.

Pharmaceutical company executives have been accused of holding back the launch of a breakthrough pill in the UK that could transform birth control.

The drug Slynd only contains progestin, causes fewer side effects and is more effective than the mini-pill. It can be used at any time during a 24-hour period. Others need to be taken within a short window of time each day.

The revolutionary tablet has been widely available in America and Australia since 2019 and received its UK approval from the Medicines and Healthcare Products Regulatory Agency in March last year. However, manufacturer Exeltis doesn’t expect it to be available in the UK until at least next year.

The financial regulator NICE (National Institute for Health and Care Excellence) must approve prescriptions through the UK National Health Service.

Produced in collaboration with SWNS talker.

This story was provided to Newsweek by Zenger News.