GLP-1’s & Fertility: Do weight loss medications affect fertility?

Many people struggling with fertility look for new and promising treatment options, and may have heard that GLP-1 medications like Ozempic® or Wegovy® can improve fertility. Recently, several people on social media have credited GLP-1 medications like Ozempic and Wegovy (also known as semaglutide) or GIP/GLP-1 medications such as Mounjaro® and Zepbound® (also known as tirzepatide) with their surprise pregnancies despite previous challenges with infertility. Read on to learn how GLP-1 and GIP/GLP-1 medications impact fertility.

Understanding GLP-1 agonists and their role in metabolism

GLP-1 and GLP-1/GIP agonists are medications used to treat type 2 diabetes and obesity. To understand how these medications work, we need to look at a few important hormones in our body: GLP-1, GIP, and insulin.

GLP-1 (glucagon-like peptide-1) is a hormone naturally made by our bodies that helps regulate blood sugar (glucose) levels. It is secreted by cells in the intestines in response to meals and triggers insulin to be released from the pancreas (more on insulin below). GLP-1 also reduces glucose production in the liver. These effects help lower blood sugar levels which is why it is used to treat type 2 diabetes. GLP-1 also acts on the brain to decrease appetite and cravings and slows stomach emptying (making one feel fuller for longer) which can lead to weight loss. Ozempic, Wegovy, and Saxenda(R) are medications that mimic the GLP-1 hormone. Both Ozempic and Wegovy have the same active ingredient (semaglutide) but Ozempic is FDA-approved for type 2 diabetes and Wegovy is FDA-approved for weight loss.* Saxenda contains the active ingredient liraglutide and is FDA-approved for weight loss.*

Zepbound and Mounjaro work by mimicking GLP-1 as well as glucose-dependent insulinotropic polypeptide (GIP), another hormone that is naturally found in the body. GIP affects the metabolism of lipids (fat) and glucose (sugar), improves insulin sensitivity, and increases the effects of GLP-1, which helps with weight loss. They both have the same active ingredient (tirzepatide) but Mounjaro is FDA-approved for type 2 diabetes and Zepbound is FDA-approved for weight loss.*

Insulin is a hormone made by the pancreas, and one of its functions is to lower blood sugar (glucose). When we eat, our food gets broken down into glucose which enters our bloodstream. Insulin then tells cells to take glucose out of the blood so it can be used as energy. When there are high levels of glucose, more insulin is made. Over time, the body can become resistant to insulin, and as a result, blood glucose increases because the cells are not taking it out of the bloodstream efficiently. Insulin resistance can also lead to hormonal dysregulation which has the downstream effect of reducing fertility.

Improvement in blood sugar and lowering insulin resistance can improve ovulation (the release of an egg by the ovaries) both by increasing ovulation itself and by making it occur more regularly, which in turn increases fertility. We’ll talk more about ovulation below. In short, having excess body weight can contribute to developing insulin resistance, and weight loss can improve insulin sensitivity. In the next section we’ll dive deeper into the connection between obesity and fertility.

The connection between obesity, PCOS, and fertility

The connection between obesity and infertility is complex. There are several ways in which obesity can affect fertility:

• Obesity is commonly associated with PCOS which is one of the leading causes of infertility.
• The hormonal dysregulation that occurs in the setting of obesity affects the hypothalamus-pituitary-ovarian (HPO) axis, a network of hormones that are involved in fertility. For example, the monthly cycle of hormonal fluctuations that lead to one having a period.
• The inflammation associated with obesity can directly affect the reproductive organs thereby reducing fertility.
• Obesity can affect endometrial cells and directly affect embryo implantation, which can contribute to miscarriages and abnormal embryo growth.

Polycystic Ovarian Syndrome (PCOS) is a medical condition that affects 5-10% of women. It is not known at this time if weight gain is a cause of PCOS or a consequence of the condition. That being said, excess weight also contributes to worsening insulin resistance and can negatively impact fertility.

PCOS is also characterized by excessive levels of androgens (male hormones) which can affect ovulation leading to irregular periods and infertility. To understand this, it helps to review the basics of the female reproductive system. Ovulation is when an egg is released by the ovaries into the fallopian tubes. If that egg becomes fertilized (i.e. sperm unites with the egg) it will develop into an embryo and eventually a baby. If it is not fertilized, then there is a cascade of  hormonal changes leading to a woman having a period. A period is when the lining of the uterus is shed so that it can be built up again as it prepares for the next egg to be released. Therefore, in PCOS the hormonal imbalance (i.e. excess androgen hormones) effectively causes the egg to not be released when it normally should (i.e. no or irregular ovulation), and if the egg is not released, a woman cannot get pregnant.

How GLP-1’s can help with weight management

GLP-1 medications like Ozempic, Wegovy, Mounjaro, and Zepbound help improve type 2 diabetes and hormone levels which can improve ovulation and fertility. In addition, GLP-1 medication's ability to reduce hunger and cravings and increase satiety makes them very effective in helping people with obesity and PCOS to lose weight, which can also improve hormone levels and fertility. Because GLP-1 medications work on the brain to reduce cravings and hunger, people using these medications are less likely to overeat, eat smaller portions, and be more likely to choose healthier food options, all of which support weight loss. It has been confirmed that more regular ovulation and increased regular menstrual cycles improve fertility and the chances of successfully conceiving. Furthermore, the improved blood sugar levels and insulin sensitivity increase the likelihood of a successful pregnancy.

Specific considerations for using semaglutide in women trying to conceive

It is important for women using Ozempic or Wegovy (which both contain the active ingredient semaglutide) to do so under the guidance of medical supervision, particularly when planning a pregnancy. It is recommended that patients stop these medications for at least 8 weeks prior to becoming pregnant due to concerns for fetal harm, and these medications are contraindicated during pregnancy. This is because GLP-1 medications given to pregnant animals lead to fetal birth defects and even death, and because of the long half-life of the medications it takes a while for the medication to get out of the body completely. Those interested in improving fertility through the use of GLP-1 medications should work with an experienced medical clinician and discuss their family planning goals in advance.

Achieving better fertility outcomes with comprehensive care

Fertility can be improved with a holistic and comprehensive approach that includes healthy nutrition, physical activity, and lifestyle changes to support weight loss. If appropriate, the use of medication to support weight loss may be recommended while an individual is not actively trying to conceive but working to lose weight to improve fertility. Working with a team of healthcare professionals, such as expert clinicians and Registered Dietitians, can provide support in one’s weight loss journey and it is important that any weight loss program is tailored to each unique individual’s goals.

Boosting your fertility journey with Form Health

Obesity and PCOS can impact fertility and weight loss is an important tool to help address these conditions. GLP-1 medications can potentially be a helpful tool by increasing insulin sensitivity and promoting weight loss. However, these medications must be used in combination with healthy nutrition and lifestyle modifications and under a medically supervised treatment plan in appropriate patients. Form Health is a virtual obesity medicine practice where, under the supervision of board-certified obesity medicine doctors and Registered Dietitians, we help create the weight loss plan to support your weight and fertility goals.

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*In patients with BMI 30+ or 27+ with a weight related medical condition (e.g. diabetes, high blood pressure, high cholesterol) and used in combination with a low calorie eating pattern and increased physical activity.