weighing scale

13 August 2020

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How can weight affect fertility?

 Dr Robert Lahoud

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Dr Robert Lahoud

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When women and couples who are experiencing difficulties with conception are overweight, they have generally already heard or read the advice that being overweight reduces their chance of falling pregnant. Seeing other women who have an equal or even greater problem with their weight, who have conceived successfully and are happily pushing their strollers down the street, only adds to the frustration and disappointment they are already feeling.

So how much of an impact does weight really have on conception and pregnancy, and for those who are struggling with their weight, can we help put this into perspective - successful conception and a safe pregnancy is certainly still possible.

How does weight impact my chances of having a baby?

Weight is an important consideration for both women and men in the preconception period. If you’re significantly overweight or underweight this can cause your body to produce more or less of the hormones that regulate ovulation in women and disrupt sperm production in men.
Weight gain in some women can be an indicator of a hormonal imbalance caused by a condition known as Polycystic Ovarian Syndrome (PCOS) - affecting both your ability to lose weight and disrupt regular ovulation.  However not all women with PCOS are overweight.
Men who are significantly overweight generally have poorer sperm quality than those within a healthy weight range. Often, when a man is extremely overweight he will also have a reduced sex drive and erectile difficulties.

How do I know if I’m a healthy weight?

A common measure of weight is the Body Mass Index (BMI) which provides an index of your weight range in relation to your height. A healthy BMI is considered to be between 18.5 and 25.

Having a very high BMI (greater than 35) may decrease fertility rates in some circumstances and may also increase the risk of pregnancy related complications such as miscarriage, gestational diabetes and hypertension. As fertility specialists we understand that for many individuals BMI is not easy to change. However, as you can see from the effects, it is good to do as much as you can to improve your health.

The end result of a healthy lifestyle may not always be weight loss. Muscle build up (which is encouraged) can increase body weight. Striving to lose weight by following extreme diets is not sustainable and may be detrimental to a healthy pregnancy. Hence the focus should be on lifestyle modification not specifically weight loss. This philosophy equally applies to couples with normal BMIs – focus on general health and fitness, not just weight.

PCOS and Infertility

Polycystic Ovarian Syndrome (PCOS) is a hormonal condition that affects up to one in five women of reproductive age and can impact your ability to lose weight and ovulate. I see many women with PCOS where the condition causes insulin resistance, predisposing them to fat deposition and weight gain. This weight gain then contributes to increasing insulin levels, creating a self-perpetuating cycle.

The common symptoms of PCOS include:

  • Acne
  • Increased hair growth
  • Irregular or infrequent periods
  • Infertility
  • Weight gain and difficulty losing weight

How can we help women with PCOS have a baby?

Not all women with PCOS experience difficulty conceiving, although for those struggling there are ways we can manage the condition to help you conceive and go on to have a healthy pregnancy.

In addition to positive lifestyle changes through diet and exercise, medication such as Metformin, which is also used in the management of diabetes, can lower insulin levels to support weight loss.

If you are diagnosed as having PCOS and require additional support to induce ovulation, a simple fertility treatment such as Ovulation Induction (using medication such as Clomiphene and Letrozole) can help. If you do not respond to these oral medications, injectable medication (FSH injections) may be required.
For a small number of women with PCOS who don’t respond or respond excessively to ovulation inducing medication, we may recommend in-vitro fertilisation (IVF).

What if we are experiencing trouble becoming pregnant?

If you’re experiencing a delay in falling pregnant, a fertility specialist can help by offering a comprehensive medical assessment including understanding your medical history and conducting further tests. For the female, this might include an ultrasound scan to determine if a condition such as PCOS may be affecting your ability to conceive.  If you are diagnosed with PCOS there are dedicated PCOS clinics that can help you manage non -fertility related symptoms.
As fertility specialists, we want to help as many couples as possible have their families, both successfully and safely. That includes providing you with empathetic support and medical care to enable you to reach your end goal of a healthy baby. 
Find out more: IVFAustralia,  Queensland Fertility Group,  Melbourne IVFTasIVFVirtus Fertility Centre (Singapore)

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