Updated by the Progyny Clinical Team — November 2025.
Conversations about health can sometimes focus solely on weight, which may feel challenging or overwhelming — especially if recommendations don’t consider your relationship with food, your body, or your mental health.
Weight is one factor that can affect fertility, but conditions such as polycystic ovarian syndrome (PCOS) can also play a role. This article explores how weight connects to fertility and shares holistic tips for nutrition and fitness.
Why weight matters for fertility
Weight can be a sensitive topic, but it’s important to address it as part of overall health. Maintaining a healthy weight can help support your fertility and reduce certain health risks.
Excess weight or obesity can increase the likelihood of conditions such as type 2 diabetes, high blood pressure, heart disease, and stroke. Being underweight can also affect your health by disrupting your menstrual cycle and making it more difficult to conceive. During pregnancy, being underweight may increase the risk of premature delivery and other complications. It can also raise your risk of osteoporosis and cardiovascular issues later in life.
For those trying to conceive, both excess and low body weight can affect hormones, menstrual cycles, and pregnancy outcomes.
Understanding body mass index (BMI) and fertility
BMI is a tool that compares weight and height to estimate body fat. Many providers use it to help assess health risks.
- Underweight: BMI less than 18.5
- Normal weight: BMI between 18.5 and 24.9
- Overweight: BMI between 25 and 29.9
- Obesity: BMI of 30 or greater
A provider may use BMI to assess risks such as heart disease, sleep apnea, and type 2 diabetes. For those trying to get pregnant, BMI can also provide insight into potential risks during pregnancy, such as miscarriage or irregular ovulation.
Many factors can influence BMI, including age, sex, and ethnicity. Conditions such as PCOS and thyroid disorders can also affect both fertility and weight. For example, PCOS can increase the body’s resistance to insulin, leading to higher insulin levels and contributing to weight gain. It also increases the amount of male hormones (androgens), which also contribute to insulin resistance, as well as irregular periods and infertility.
Because healthy weight looks different for everyone, talk with your provider if you’re concerned about your BMI or its impact on fertility.
Risks of being overweight or underweight for people with ovaries
Ovulatory dysfunction
Ovulation — the release of an egg each month — typically occurs in menstrual cycles lasting 21 to 35 days. Cycles outside this range can suggest ovulatory dysfunction, which happens when hormonal signals between the brain and ovaries are disrupted.
- Higher estrogen levels: Excess body fat can increase estrogen production, which may interfere with ovulation.
- Decreased gonadotropin-releasing hormone: Being underweight can reduce gonadotropin-releasing hormone levels, leading to low production of follicle-stimulating hormone and luteinizing hormone. Without enough of these hormones, ovarian follicles can’t mature properly, which may lead to irregular or absent ovulation.
High-risk pregnancy
According to the American College of Obstetricians and Gynecologists:
- Underweight individuals have a higher risk of preterm labor, preterm birth, and delivering a baby who is underweight.
- Overweight individuals have a higher risk of miscarriage, fetal loss after 20 weeks of pregnancy, high blood pressure, preeclampsia, and gestational diabetes. Excess weight can also increase the risk of birth defects, such as heart and neural tube defects, and preterm birth.
Risks of excess weight for people with testes
- Hormone imbalance: Excess weight can raise body temperature, especially around the scrotum, which may lower testosterone and increase estrogen levels.
- Abnormal sperm production: Hormone changes can affect sperm count and movement, reducing fertilization rates.
Nutrition and exercise for healthy weight maintenance
A balanced diet and regular exercise support both fertility and overall well-being. The American Society for Reproductive Medicine recommends focusing on:
- Plant-based proteins
- Whole grains
- Fruits and vegetables
- Healthy fats, such as those from avocados and olive oil
Limiting trans fats and added sugars can also help manage weight and blood sugar. Studies show that an anti-inflammatory approach supports reproductive health. While the Mediterranean diet is a great example, every type of cuisine can have an anti-inflammatory approach applied to it.
If meal planning feels overwhelming, consider meeting with a registered dietitian or nutritionist. They can help you create a plan that fits your goals and preferences.
Physical activity is another important part of maintaining a healthy weight. Experts recommend moderate exercise — such as brisk walking, swimming, or yoga — for about 30 minutes a day, most days of the week. Intense activity can sometimes affect menstrual cycles, so talk with your provider about what level of exercise is right for you.
People with testes also benefit from regular physical activity. Cardiovascular and strength-training exercises can improve testosterone levels and sperm quality.
If you’ve made healthy changes to your nutrition and movement routine but are still facing challenges, talk with your provider. They can help identify factors that may affect your weight or fertility.
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Disclaimer: The information provided by Progyny is for educational purposes only and is not medical advice. Always consult a qualified healthcare provider for medical guidance. Conversations about health can sometimes focus solely on weight, which may feel challenging or overwhelming — especially if recommendations don’t consider your relationship with food, your body, or your mental health.