Could weight-loss drugs increase fertility?

On social media, an increasing number of people, including those who have struggled with fertility in the past, are reporting unplanned pregnancies while on popular weight-loss drugs like Ozempic and Wegovy.

"I thought I couldn't have any more kids," said Torria Leggett, a 40-year-old woman who has been trying for another child since her first was born in 2018. Leggett initially took Ozempic in 2022 before switching to another weight-loss drug, Mounjaro. "The weight loss, that’s likely what jump-started it. I couldn't believe it."

According to health experts, being overweight or obese can negatively impact periods, ovulation, and the implantation of immature eggs. "Women living with obesity are more likely to have problems in conceiving, to suffer miscarriage, and are less likely to deliver live infants," Nerys Astbury, a senior researcher in diet and obesity at the University of Oxford's Nuffield Department of Primary Health Care Sciences, said.

As patients lose weight, they may experience changes to their hormonal and insulin levels that increase their fertility, making it easier for them to get pregnant.

"Many high BMI patients do not ovulate, some have polycystic ovary syndrome (PCOS), and many just don't ovulate regularly," said Jamie Grifo, program director at the NYU Langone Fertility Center and chief executive physician at Inception Fertility. "With the weight loss from these drugs, many women who are anovulatory start to have regular ovulation and menses, which takes them from a low fertility situation to a more normal fertile state."

Some health experts have also suggested that weight-loss drugs could impact the effectiveness of birth control. Because weight-loss drugs slow digestion, they can affect how food and medication are absorbed in the body.

"This causes oral birth control pills to not be absorbed consistently, especially each time the dose of GLP-1/ GIP+ GLP-1 agonists are stepped up," Neha Lalani, a board-certified endocrinologist with a private practice at Bluebonnet Diabetes & Endocrinology in Texas, said. "This is resulting in failure of oral birth control pills."

According to Lalani, she recommends people use alternative methods of birth control while on weight-loss medications.

More research is needed on how these drugs impact pregnancy

According to the Washington Post, there is not much data on how Ozempic and other similar drugs affect people who are currently pregnant or want to become pregnant, since they were excluded from early clinical trials of the medications.

Currently, FDA recommends people stop taking Ozempic and Wegovy at least two months before getting pregnant due to risks of miscarriage and birth defects. Animal studies have shown that rats, rabbits, and monkeys who were treated with the drug had higher rates of miscarriage. Their offspring were also smaller and had more birth defects than what would normally be expected.

To better understand the potential side effects of weight-loss drugs, FDA asked Novo Nordisk, which manufactures Ozempic and Wegovy, to set up a registry to collect data on individuals who became pregnant while taking the drugs. Eli Lilly, which manufactures Mounjaro, said it plans to set up a similar registry.

In addition to the registry, FDA said Novo Nordisk is also required to do another pregnancy study using either insurance claims or electronic medical records.

So far, some people who originally got pregnant while on weight-loss drugs have reported experiencing intense side effects after stopping the medications. Some of these side effects include severe hunger pangs, weight gain, and blood sugar swings.

"I was a human garbage can. And I didn't want sweets or anything. I wanted real food, like meats, cheese, and other rich protein, which was completely different from my first pregnancy," said Amanda Brierley, a 42-year-old woman who initially took semaglutide, the active ingredient in Ozempic, to treat insulin resistance from PCOS. "I was like a caveman. I couldn't stop. It was crazy."

According to fertility and bariatric experts, it's not clear if pregnancy is worsening side effects of stopping a weight-loss drug or if hormonal changes associated with pregnancy are amplifying these symptoms.

"Do weight-loss medications suppress some pregnancy symptoms that then return more intensely when a person gets off of them? Or does pregnancy worsen withdrawal symptoms?" said Allison Rodgers, an ob/gyn and reproductive endocrinologist at Fertility Centers of Illinois. "It's really hard to tease out."

Manijeh Kamyar, a maternal-fetal medicine specialist and ob/gyn in Las Vegas, Nevada, said that there’s  not enough information on how weight-loss drugs affect pregnant people and those of childbearing age.

"Research in this area needs to be expedited and physicians really need to do their due diligence in counseling patients that we do not have this data," Kamyar said.

"My recommendation is: While you're on this treatment — if your doctor has decided it's the best for you — you should definitely be on some type of birth control," she added. "Because if you accidentally get pregnant while on this, I don’t know what that's going to mean for your pregnancy… I cannot guarantee the safety of this medication in pregnancy."

Advisory Board's weight-related resources:

To help you address the growing use of weight management drugs, Advisory Board offers several resources:

This expert insight outlines the five biggest questions about weight management drugs and their answers. Similarly, this expert insight addresses what headlines get wrong about weight management drugs and what healthcare leaders should know instead.

Radio Advisory's Rachel Woods has also covered GLP-1 drugs on the podcast, discussing the potential future of these drugs and how they could help — or hurt — health systems' finances. This expert insight on the five catalysts that will impact the future of obesity care and this research on three potential pathways for the future of obesity care are also useful resources.

Our weight management and obesity care resource library can also help leaders understand the current care landscape, manage innovations, and prepare for transformations in care. (Muller, Bloomberg, 4/18; Reed, Axios, 4/18; Camero, USA Today, 4/17; Schimelpfening, Healthline, 3/26; Klein, Washington Post, 4/5; Pawlowski, TODAY, 4/24; Hignett, Forbes, 4/24)