Anti-Obesity Medication

Anti-Obesity Medication, Contraceptives, and Pregnancy

October 23, 2024

Studies have consistently shown that women who are overweight or obese have difficulty becoming pregnant. Once pregnant, the risk of complications, such as hypertensive disorders of pregnancy, gestational diabetes, acute liver injury, emergency cesarean delivery, and stillbirth, can increase(1).  The use of anti-obesity medication in a woman of childbearing age requires a close collaboration between the medical weight loss specialist, the Ob/gyn, and the woman.  All the anti-obesity medications have the potential to cause problems with the pregnancy and birth defects(2).  Each woman of childbearing age is encouraged to have a conversation with their Ob/gyn regarding their desire to use weight loss medication and birth control options.

Injectable Anti-Obesity Medications

There has been a marked increase in the use of injectable anti-obesity medications such as Semaglutide (WegovyTM) and Tirzepatide (ZepboundTM). These medications provide significantly better weight loss results compared to other weight loss medications(1). There have been reports of unintended pregnancies in women taking Zepbound and using oral contraceptive medication.  The cause is partially attributable to slowed emptying of the stomach, leading to decreased absorption of oral birth control pills(2).  Studies have also shown a decrease in the amount of oral birth control medication in the bloodstream of women taking Wegovy. While this is useful information, the study indicated that the diminished amount of birth control medication in the blood was not significant and didn’t result in an increased rate of unintended pregnancies compared to other birth control medications(3).  While this may sound like a woman taking Wegovy can continue taking oral birth control medication, it is recommended that a woman receiving Wegovy should use a mechanical barrier. 

What should a woman do in order to minimize the chance of having an unintended pregnancy while taking injectable medications?

The recommendations in the instructions for use from the drug manufacturers state that a woman should be switched to a mechanical form of birth control. Intrauterine device (IUD), implantable birth controls under the skin, and/or use of condoms represent options for mechanical birth control. The decision to use an alternative form of birth control must be made in concert with the obstetrician. The good news for women trying to get pregnant is that once a woman loses weight, she is more likely to conceive and have a healthier pregnancy and baby. Keep in mind that it is recommended that a woman should stop taking any anti-obesity medication at least 8 weeks (2 months) prior to attempting to get pregnant. Make sure to communicate this to your obstetrician and weight loss physician since some of the medications must be tapered (reduced) slowly and shouldn’t be stopped suddenly.

References

  • Curr Obstet Gynecol Rep . 2023 June ; 12(2): 138–146. doi:10.1007/s13669-023-00350-1.
  • Journal of the American Pharmacists Association 64 (2024) 204e211 The impact of tirzepatide and glucagon-like peptide 1 receptor agonists on oral hormonal contraception The impact of tirzepatide and glucagon-like peptide 1 receptor agonists on oral hormonal contraception
  • The Journal of Clinical Pharmacology 2015, 55(5) 497–504.  Semaglutide, a Once-Weekly Human GLP-1 Analog, Does Not Reduce the Bioavailability of the Combined Oral Contraceptive, Ethinylestradiol/Levonorgestrel.
Anti-Obesity Medication
Leon Katz

ABOUT THE AUTHOR

Dr. Leon Katz MD, FACS, FASMBS, is a bariatrician specializing in non-surgical, medically supervised weight loss. He focuses on patients seeking alternatives to surgery and those needing care after bariatric procedures. Dr. Katz was recently the director of a major medical weight loss program. With extensive experience in establishing successful weight management programs, he now concentrates exclusively on non-surgical weight loss solutions. Dr. Katz is a Diplomate of the American Board of Obesity Medicine and Fellow of American College of Surgeons. Dr. Katz currently practices at Dr. Leon Katz Medical Weight Loss Center.