Obesity can cause infertility

Obesity is becoming an increasingly common cause for infertility. A recent talk by registered dietician Ria Catsicas has highlighted how infertility and PCOS (Polycystic Ovary Syndrome) are believed to be directly associated with obesity. DietDoc reports back.


A study showed that approximately 34% of young women (average age of 23 years) who struggle to fall pregnant due to infertility issues are also obese. When it comes to amenorrhoea (lack of menstruation and ovulation), 45% of women are obese. Researchers such as Zain and Norman (2008), have said that, "Obesity contributes to anovulation and menstrual irregularities, reduced conception rate and a reduced response to fertility treatment. It also increases miscarriage and contributes to maternal and perinatal complications".

In other words, not only does obesity make it much more difficult to conceive, but it also exposes both the mother and the infant to all manner of risks before and after birth.

Catsicas (2013) pointed out that in addition to the above, obese women who underwent fertility treatments were less likely to achieve success with in vitro fertilisation (IVF), ICSI (an in vitro fertilisation method where a single sperm is injected directly into the egg cell) or  GIFT (removing the egg cells from a woman’s body, mixing them with sperm, and then placing them directly into the Fallopian tubes).


Fat that is deposited in a woman’s abdomen is known to produce male hormones called androgens which in turn prevent follicular maturation and contribute to anovulation.
It has also been found that leptin, a hormone that plays an important role in regulating energy intake (appetite) and metabolism, is also involved in the hormonal derangements associated with obesity (Catsicas, 2013).


Despite the dire scenario that obesity creates in the female body, a moderate loss of weight of only 5% of body weight can already turn the situation around.

The following positive results were obtained with female subjects who lost 5% of their body weight:

On average, the women
  • lost 11% of their abdominal fat 
  • reduced their waist circumference measurements by 4 cm
  • increased their insulin sensitivity by an amazing 71%
  • improved the hormonal environment in their bodies
  • restored their regular menstruation and ovulation
  • improved their pregnancy rates
(Zain & Norman, 2008)
In real terms a woman who weighs 100kg would need to lose 5kg to achieve the above mentioned turn-around in her reproductive capacity and her chances of falling pregnant. This kind of modest weight loss should be within reach of most women who long to fall pregnant and have children of their own.

Zain and Norman (2008) emphasise that, "treatment of obesity itself should be the initial aim in obese infertile women before embarking on ovulation-inducing drugs or assisted reproductive techniques". These authors also point out that a change of lifestyle, diet and exercise remains the simplest (and probably the most effective) solution to infertility associated with obesity.

How successful are lifestyle modification programmes?

However, Catsicas (2013), stressed that lifestyle intervention studies conducted with female patients suffering from PCOS (95% of women attending fertility clinics have PCOS), were associated with high dropout rates of up to 38%.

These disappointing statistics are influenced by the hormone disruptions that characterise PCOS. Women with PCOS tend to gain weight rapidly because of insulin resistance which has an anabolic effect, combined with an increased appetite and a tendency to crave high glycaemic index (GI) starches (sweets, white bread, cakes, etc) caused by the androgens their bodies are producing.

In addition, psychological factors play an important role. Obese women with PCOS tend to feed their depressed and negative moods with high-fat, high-GI foods, thus making the situation even worse.

Finally such patients tend not to feel satiated because their ghrelin levels are also disturbed.

All these factors affect the chances that an obese woman suffering from PCOS will manage to lose 5% of her weight so that she can improve her chances of falling pregnant.

What should such a programme consist of?

Lifestyle modification programmes, therefore, must make provision for the above mentioned complications and should include:
  • A nutrition intervention such as a balanced, low-GI, low-fat diet
  • An increase in physical activity provided by an exercise programme which should preferably be monitored in a gym or by an organisation such as Run/Walk for Life
  • Medication such as glucophage which has been found to be just as successful in treating PCOS, as the use of female hormones
  • Behavioural modification to change the patient’s approach to life and help her address some of her fears, anxieties and negative habits

It is evident that such a lifestyle intervention programme needs to be presented and monitored by a team of experts which should include a dietician, a medical doctor and a clinical psychologist as well as gym instructors or biokineticists.
Most women who yearn for a baby will probably be aghast and believe that they will not be able to afford the costs of such a team effort, but on the other hand if one compares the costs of any of the assisted fertilisation methods mentioned at the beginning of this article, against the costs of consulting some or all of these lifestyle modification programme team members, then patients may be surprised by how much cheaper the latter approach can be.

And in the long run, the lifestyle approach, when it results in successful weight loss of 5% or more, will probably lead to success whereas without the change in lifestyle and the modest weight loss, obese women may spend vast amounts of money on fertilisation methods to no avail.

So if you are longing to fall pregnant or struggle with PCOS, give lifestyle modification a chance and take the first step by consulting a registered dietitian.
(References: Catsicas R (2013). The nutrition and fertility fit. Paper presented at: Nutritional Solutions CNE, Johannesburg 11 April 2013; Zain MM, Norman RJ (2008). Impact of obesity on female fertility and fertility treatment. Womens Health (Lond Engl), 4(2):183-94.)

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