Obesity affects both female and male fertility, making it harder to conceive. Obesity is classed as having a body mass index (BMI) of ≥30kg/m2. Use a BMI calculator like this one https://www.heartfoundation.org.au/bmi-calculator to find out your BMI.

Having obesity does not mean you can’t or shouldn’t conceive, however there are additional considerations when trying to conceive.

For Women

  • Hormonal Imbalances: Obesity can disrupt the hypothalamic-pituitary-ovarian axis, leading to irregular ovulation or anovulation (failure to ovulate).
  • Research shows that women with Class 3 Obesity (Severe Obesity BMI >40kg/m2) are 60% less likely to conceive within one year compared with women in the normal weight range (BMI 18.5-24.9kg/m2).
  • Women with a Class 3 obesity have a 5-fold higher risk of preeclampsia and gestational diabetes compared to women with normal BMI.
  • The risk of stillbirth is elevated in women with obesity, particularly in those with severe obesity.

For Men

  • Sperm Quality: Obesity is associated with reduced sperm count, motility, and morphology due to hormonal disturbances (e.g., lower testosterone and higher oestrogen levels).
  • Oxidative Stress: Excess fat tissue can increase oxidative stress, damaging sperm DNA.

What to do about it?

Research shows that achieving weight loss before pregnancy is a key goal for women with severe obesity to improve the chance of conception and improve health outcomes for both mother and baby, during and after pregnancy. Even a modest weight loss of 5–10% of total body weight can boost fertility and reduce pregnancy-related risks.

Weight loss recommendations depend on many factors, such as how much excess weight is held, weight history, medical history, social history, diet quality, and health goals. This is why it’s important to have an assessment by an accredited practising dietitian to receive personalised advice and support. It is important that weight loss if conducted in a healthy and sustainable to way to avoid nutritional deficiencies or complications of poorly planned rapid weight loss.

3x Ways to start today:

  1. Increase vegetable intake, aim to have a good serving of vegetables twice per day, every day.
  2. Reduce calories from drinks by swapping out soft drink, energy drinks, flavoured milks, and alcohol for water. Aim for 2L of water and sip on it through the day. Take out alcohol completely if already trying to conceive or hoping to conceive within 3 months.
  3. Reduce takeaways, cook more at home, use meal delivery services like LiteNeasy or hello fresh for portion control and reducing burden of grocery and meal preparation.

Whether you’re already on your journey of trying to conceive or if you haven’t yet started, it is never too early or too late to see a dietitian for nutritional advice and support. Strategies should be tailored to your needs and preferences so reach out today to get started on a healthier fertility and pregnancy journey and learn how to give your baby the best nutrition even before conception.

Get in touch with your local Sports & Spinal team today and see how Dietitian and Multidisciplinary team can help you.