Semaglutide, pregnancy and birth control
The label says to stop at least 2 months before trying to conceive, because semaglutide has a long half-life. It also lists the two hormones in a combined pill among the drugs whose levels it did not meaningfully change.1
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If you are trying to conceive
The label puts an interval on this, and it is longer than people expect:
Because of the potential for fetal harm, discontinue WEGOVY in patients at least 2 months before they plan to become pregnant to account for the long half-life of semaglutide.
Two months is a pharmacology number rather than a caution: semaglutide leaves the body slowly, so stopping the week before would leave drug in circulation. The instruction is addressed to prescribers, which is who decides how and when to stop.
If a pregnancy happens while you are taking it
The label separates the weight use from the liver one, and it is blunt about the first:
Weight loss offers no benefit to a pregnant patient and may cause fetal harm. When a pregnancy is recognized, advise the pregnant patient of the risk to a fetus. Discontinue WEGOVY in pregnant patients who are using it for weight reduction.
Behind that sit two other facts the label states. Animal reproduction studies found embryofetal mortality, structural abnormalities and altered growth at clinically relevant exposures in rats. And human data, from pharmacovigilance and from trials, are insufficient to establish a drug-associated risk of major birth defects, miscarriage or adverse outcomes. Insufficient is not the same as reassuring, and the label does not offer it as reassurance.1
For the liver indication, which is WEGOVY’s third approved use, the label takes a different line, saying WEGOVY should be used in pregnancy only if the potential benefit justifies the potential risk. There is also a pregnancy exposure registry, which the label names with a phone number and a website for patients and clinicians to contact.
Does it interfere with the pill?
This is the question that gets answered badly most often, usually by reasoning from what the label says about delayed gastric emptying to a conclusion nobody measured. The label measured it. Its clinical pharmacology section lists the drugs studied alongside semaglutide and puts the two hormones in a combined oral contraceptive among them:
No clinically significant differences in the pharmacokinetics of the following drugs were observed when used concomitantly with semaglutide: lisinopril, S-warfarin, R-warfarin, metformin, digoxin, ethinyl estradiol, levonorgestrel, furosemide or rosuvastatin.
Ethinyl estradiol and levonorgestrel are the estrogen and the progestin in a combined pill. The label’s own summary of the interaction question says the same thing in plainer words: in clinical pharmacology trials with semaglutide 1 mg once weekly injection, semaglutide did not affect the absorption of orally administered medications.1
Two limits on that, both from the same label. It is a pharmacokinetic result about drug levels, not a contraceptive-failure study. And it does not carry over to every form: in a drug interaction study with the semaglutide tablet, levothyroxine exposure was increased 33%. The label’s instruction for oral medicines taken alongside is to monitor their effects.1
Questions
How long before pregnancy should I stop semaglutide?
The label says at least 2 months before a patient plans to become pregnant, and gives the reason as the long half-life of semaglutide. That interval is an instruction to prescribers, so it is the number to take to yours rather than to act on alone.
Does semaglutide make birth control pills less effective?
The label reports no clinically significant differences in the pharmacokinetics of ethinyl estradiol or levonorgestrel alongside semaglutide, and says the injection did not affect the absorption of orally administered medications in its pharmacology trials. That is a measurement of drug levels rather than a study of contraceptive failure.
What if I am already pregnant?
The label tells prescribers to discontinue it in pregnant patients using it for weight reduction, and says weight loss offers no benefit to a pregnant patient and may cause fetal harm. It is a same-day phone call to the person who prescribed it, not a decision to make from a web page.
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Sources
A reference, not medical advice, and not a substitute for your prescriber or pharmacist. If you think you are having a medical emergency, call your local emergency number.