We know that it’s important to optimize metabolic health and weight before pregnancy. The Obesity Canada Clinical Practice Guidelines recommend that women with obesity enter pregnancy at a lower BMI, to reduce health risks to both mom and developing baby. GLP1 medications [semaglutide (Ozempic/Wegovy), tirzepatide (Mounjaro/Zepbound), liraglutide (Victoza/Saxenda), dulaglutide (Trulicity)] are now in common use in women of reproductive age, to improve weight and/or control blood sugars in diabetes. GLP1 medications need to be stopped 1-2 months before pregnancy attempts (exact duration varies by medication per the product monographs), because we do not have safety data on GLP1 in pregnancy, and weight loss during pregnancy is not recommended.

Here’s the conundrum: Every study ever done of any GLP1 medication (and any weight loss med for that matter) tells us that weight is regained when GLP1 medications are stopped. So, after stopping GLP1 medication to plan a pregnancy, weight is likely to go up before the woman gets pregnant and possibly during the pregnancy. We know that excessive weight gain during pregnancy is associated with health risks to mom and baby. So with higher risk of health issues related to obesity before pregnancy, and higher risk of health issues related to weight gain in pregnancy, does the balance rest in favor or against using GLP1s before pregnancy?

The data on this question are conflicting. A recent study published in JAMA looked at 448 women in a database at one American center who had taken a GLP1 between 3 years before and 90 days after getting pregnant. Compared to 1344 matched women who hadn’t taken a GLP1 during that time frame, women who had taken GLP1s had 3.3kg greater weight gain in pregnancy, a 32% higher risk of excessive weight gain in pregnancy, a slightly higher percentile baby birth weight (58.4% vs 54.8%), and 34% higher risk of preterm delivery, 30% higher risk of gestational diabetes, and 29% higher risk of hypertensive (high blood pressure) disorders of pregnancy, but no higher risk of small or large babies or C-section. One other study also found a higher risk of excessive weight gain in pregnancy in women who used GLP1s up to a year before pregnancy vs those who had not, but this and another study found a lower risk of hypertensive disorders of pregnancy. Other data have suggested a lower risk of gestational diabetes, preterm delivery, and C-section.

An important limitation in the current data is that they compare women who haven’t used GLP1 to women of similar BMI who have – but we don’t know the BMI or the health of the women before they started GLP1 in the first place. In other words, these data are not capturing the health/weight benefits that the women have achieved with their GLP1 use. What we need are data comparing women who used vs didn’t use GLP1 , according to BMI and health before the GLP1 ever started.

Sometimes, women accidentally get pregnant while still taking GLP1s. Reassuringly, no association between accidental use of GLP1 around the time of pregnancy and birth defects has so far been found.

Where does this leave women who are taking GLP1s to optimize health before pregnancy? Given that weight and health benefits of GLP1 start to regress when the GLP1 is stopped, increased support and health surveillance (monitoring with clinical assessments and lab work) for these women before and during pregnancy is likely important.


Where does this leave women who are thinking about taking GLP1s to optimize health before pregnancy? We don’t know where the balance of health benefit (improving weight and metabolic health), vs pontetial risk (of weight regain and regression of health benefits after stopping treatment) pans out. Included on the benefit side, some women with elevated weight and polycystic ovary syndrome (PCOS) may have infertility related to their PCOS, and may improve their fertility with weight loss. As weight loss is very difficult for the vast majority of people to achieve with lifestyle changes alone, these women may need a weight loss medication to achieve improvement in their PCOS and weight to a place where they can get pregnant (but still needing to stop GLP1 before pregnancy attempts, as above). Bariatric surgery prior to pregnancy planning may be an appropriate option for a small minority of women, but this comes with its own host of planning, potential risks, and very close monitoring needs (see the Obesity Canada Clinical Practice Guidelines for more on this). Bariatric surgery requires planning years in advance of family planning, and in most places has long wait times and very limited access. For women taking GLP1 medications for diabetes control, other options exist for prepregnancy treatment (eg metformin, insulin), but these do not come with the holistic benefits of weight loss, and in fact, insulin promotes weight gain.

BOTTOM LINE: The decision to take GLP1 medication prior to pregnancy attempts should be individualized and discussed thoroughly between the person and their doctor. Until we have better data comparing pregnancy health and outcomes in women who took GLP1 before pregnancy vs those who did not, comparing their health and weight before GLP1 was started, we don’t have clear information to tell us where the balance of health benefit vs risk pans out. Some women may need the help of weight management medication to help them achieve improvement in PCOS to be able to get pregnant in the first place. GLP1 medications must be stopped prior to pregnancy attempts, as we do not have safety data in conception/pregnancy, and weight loss during pregnancy is not recommended. For any women who accidentally become pregnant on GLP1 medication, systematic collection of data on pregnancy and long term outcomes is important. This blog is not personalized medical advice; be sure to discuss your individual health situation with your doctor and health care team.

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