A very important and underrated topic in the public debate surrounding injectable weight loss drugs is the increased pregnancy rates in young women with obesity and amenorrhea (or menstrual irregularities) after using GLP-1 agonists such as semaglutide (Ozempic/Wegovy) and tirzepatide (Mounjaro/Zepbound).
Why is this happening?
Hormonal function & obesity:
Obesity affects the hypothalamus-pituitary-ovary (HPO axis), causing:
Amenorrhea or infrequent cycle
Infertility, due to ovulation that does not occur
With weight loss, the hormonal environment changes:
Ovulation is restored
The cycle becomes normal (sometimes abruptly)
The woman becomes fertile again, often without expecting it
These drugs enhance this condition:
Significant weight is lost in a short time
Insulin resistance is regulated (especially in PCOS – polycystic ovary syndrome)
So, fertility returns without warning
What does it mean in practice?
Many young obese women with amenorrhea get pregnant “by accident” once their periods return due to medication – because they didn’t expect to “get pregnant again”.
Clinical data:
There is a growing body of clinical trial and retrospective analysis reports
Companies have started to issue warnings:
Use contraception during and for at least 1–2 months after stopping
GLP-1 agonists are contraindicated in pregnancy – there is no safety
What to emphasize as a healthcare professional:
“You can get pregnant again, even if you have had chronic amenorrhea”
“Your body is changing – and your fertility often returns silently”
“It is important to have contraception if you do not want pregnancy”
“Talk to a gynecologist/endocrinologist before starting or stopping”