Understanding the Link & Improving Your Chances Obesity and Fertility
Hearing that your weight could be holding up your family plans can feel confronting. You’re not alone—more than 60 % of Australian adults live with overweight or obesity, and many eventually achieve pregnancy with the right support. Here’s what science tells us, and the steps that make the most significant difference.
How excess weight affects fertility in women
| Factor | Why it matters |
|---|---|
| Hormone imbalance | Higher insulin and androgen levels can switch off regular ovulation. |
| Egg quality | Inflammation and oxidative stress may damage egg DNA. |
| Uterine lining | The endometrium becomes less receptive, reducing the odds of implantation. |
| Pregnancy risks | Rates of gestational diabetes, high blood pressure and caesarean birth are higher. |
In men
- Extra body-fat converts testosterone to oestrogen, lowering sperm production.
- Scrotal heat rises, reducing motility and increasing DNA damage.
- Erectile difficulties are more common.
Small losses, significant gains
Losing 5–10 % of starting weight often:
- Restarts regular periods
- Improves sperm count and movement
- Lifts success rates for IUI and IVF
- Lowers pregnancy complications once you conceive
You don’t have to reach a textbook BMI—steady, achievable progress is what counts.
Practical first steps
| Action | Benefit |
|---|---|
| Balanced plate – half vegetables, quarter lean protein, quarter whole-grain carbs | More fibre, slower blood-sugar rise, lasting satiety |
| 150 min exercise/week – brisk walking, cycling, swimming | Burns calories, improves insulin sensitivity, boosts mood |
| 7–8 hours of sleep | Poor sleep raises hunger hormones and cravings |
| Stress reduction – mindfulness, yoga, counselling | High cortisol can stall weight loss and affect ovulation |
| Professional team – dietitian, exercise physiologist, psychologist | People with structured support lose more weight and keep it off |
Medical Options
- Weight-loss medication – helpful for some, but most drugs need to be stopped before IVF or natural conception; your doctor will guide timing.
- Bariatric surgery is considered when BMI > 35 kg/m² with health issues. Pregnancy is usually delayed 12 months so that weight and nutrition stabilise. Egg or embryo freezing may be discussed beforehand.
Partnering for success & emotional wellbeing
Tackling weight together—meal planning, walking after dinner, and celebrating non-scale wins—keeps motivation high and strengthens your relationship. Don’t hesitate to seek counselling; fertility and weight challenges can be emotionally draining.
Timeline: when to get help
| Situation | Recommended action |
|---|---|
| < 6 months trying, both partners < 35 yrs | Start a healthy-weight plan, keep trying |
| 6–12 months trying or female partner ≥ 35 yrs | Book a joint fertility assessment |
| Any time | Seek advice sooner if periods are absent, BMI > 40, known sperm issues or chronic illness |
For male-factor detail, see Male Infertility Guide; for menstrual-cycle issues, see Irregular Periods & Fertility.
Frequently Asked Questions
Does losing weight guarantee pregnancy?
There’s no guarantee, but a healthier weight can improve natural conception and IVF outcomes.
How quickly should I lose weight?
A steady 0.5–1 kg per week is safest and more sustainable.
Do both partners need to slim down?
Yes—sperm quality and embryo potential improve when the male partner reaches a healthier weight, too.
Can I keep exercising during fertility treatment?
Moderate activity, such as walking or swimming, is encouraged unless your specialist advises otherwise.
Are meal-replacement shakes safe while trying to conceive (TTC)?
Short-term use can jump-start weight loss, but transition to whole foods before conception.
Is weight-loss surgery bad for fertility?
Fertility usually improves after surgery once weight stabilises and vitamin levels are corrected.
Taking the next step
Dr Simon Nothman offers integrated weight management and fertility care in Bondi Junction, the Sydney CBD, and via secure telehealth.
Book a consultation or call (02) 8357 1747 to start your personalised plan.
This article provides general information and is not a substitute for medical advice. Always consult a qualified health professional for care specific to your situation.
Published 24 April 2025 • Dr Simon Nothman