Fertility and Obesity
Obesity can disrupt hormonal balance, affecting ovulation in women and lowering sperm quality in men. These changes often make it harder to conceive naturally.
The Hidden Dangers of Excess Weight
Obesity has a significant but often under-recognised impact on fertility in both women and men. It affects hormonal regulation, ovulation, and sperm health, and is associated with lower success rates in natural conception and assisted reproductive treatments. At the Obesity Unit in Johannesburg, we work closely with individuals and couples who are struggling to conceive and suspect that weight may be part of the challenge. The good news is that targeted, medically supervised weight loss can restore hormonal balance, improve reproductive outcomes, and increase the chances of a healthy pregnancy.
How Obesity Affects Female Fertility
Excess body fat disrupts the delicate hormonal interplay required for normal ovulation. In women, this can lead to:
- Irregular menstrual cycles
- Anovulation (failure to release an egg during the cycle)
- Insulin resistance and elevated androgen levels, which impair fertility
- Increased risk of miscarriage and pregnancy complications such as pre-eclampsia and gestational diabetes
Furthermore, women with obesity are less likely to respond well to fertility treatments such as ovulation induction and in vitro fertilisation (IVF), and may require higher doses of medication with lower success rates.
How Obesity Affects Male Fertility
While often overlooked, obesity can also impair male reproductive function. In men, excess weight has been linked to:
- Lower testosterone levels and elevated oestrogen
- Reduced sperm count, motility, and morphology
- Erectile dysfunction and reduced libido
- Increased oxidative stress, which can damage sperm DNA
Together, these factors contribute to decreased fertility potential and may complicate a couple’s efforts to conceive naturally or through assisted methods.
Fertility and Bariatric Surgery
For individuals with a BMI ≥ 35 with associated health conditions, or BMI ≥ 40, bariatric surgery is a proven and effective intervention. Studies show that weight loss after bariatric procedures such as gastric bypass or sleeve gastrectomy can restore ovulatory cycles, improve insulin sensitivity, and significantly improve fertility outcomes in women. In men, weight loss can enhance testosterone levels and improve overall sperm parameters.
We work collaboratively with fertility clinics and gynaecologists to ensure that our patients receive comprehensive care. Whether you are preparing for IVF, addressing PCOS, or hoping to conceive naturally, the Obesity Unit can guide your weight loss safely and effectively.
When to Seek Help
You should consider a consultation if:
- You have been diagnosed with PCOS, irregular cycles, or insulin resistance
- You are planning fertility treatment and have a BMI over 30
- You are looking for a safer pregnancy with fewer complications
Even modest weight loss – as little as 5–10% of your current body weight – can make a measurable difference in fertility and pregnancy outcomes.
At the Obesity Unit, we offer a multidisciplinary, personalised approach tailored to your goals. Our team includes bariatric surgeons, endocrinologists, dietitians, and wellness professionals who understand the complex relationship between weight and reproductive health.
