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The relationship between weight and fertility

Did you know that being overweight can affect your chances of becoming pregnant? Significant excess weight can have a negative impact on fertility in women and there is also an increase in the risk of health problems for your baby.

Each person’s ‘healthy weight’ is different, but there are certain markers you can use to determine whether you are outside of the healthy range. The body mass index (BMI) calculator is useful to give an idea of whether you are overweight, underweight or healthy by taking into account your weight, height, gender and age.1

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Elevated oestrogen

One of the reasons being overweight or obese can affect fertility is due to an over-production of oestrogen.

An overweight or obese person has more fat cells than someone at a healthy weight. Fat cells produce oestrogen2 which means that in overweight people, levels of oestrogen can become elevated. This extra oestrogen can throw off the hormonal balance in the body that regulate the reproductive system, and lead to reduced or irregular ovulation and periods.3 Having irregular ovulation means it can take longer and be more problematic to become pregnant.

Insulin resistance

Another factor of excess weight which can affect fertility is insulin resistance, which can upset the body's delicate balance of female hormones.

Insulin is made in the pancreas and helps the body process glucose from the bloodstream into energy. Insulin resistance is when the cells of the body do not respond to insulin and can’t absorb glucose from the blood.4 When this happens, the pancreas produces too much insulin which can cause the testosterone levels to rise in the body. Too much testosterone can negatively impact your fertility by reducing ovulation. Some people’s bodies can become resistant to insulin as a result of certain health conditions but it’s usually associated with obesity.5

Lose weight safely to boost fertility

Losing weight could be the change you need to help you conceive.6 A sensible approach to losing weight means no crash diets, faddy eating plans or unsustainable exercise routines. Make small, realistic changes instead, such as exercising for 30 minutes each day. Diet is very important, so try to cut down or eliminate fried and greasy foods, fizzy drinks and processed foods. Instead, cook at home as much as possible and eat a wide variety of fruits, vegetables, leafy greens dairy products and whole grains. Handpicked content: How to lose weight healthily and keep it off

See your GP if you are having trouble becoming pregnant and are concerned.

Advice is for information only and should not replace medical care. Please consult a doctor or healthcare professional before trying any remedies.
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1. [Online] https://www.nhs.uk/Tools/Pages/Healthyweightcalculator.aspx.
2. [Online] https://www.ncbi.nlm.nih.gov/pubmed/11511861.
3. [Online] https://www.nhs.uk/conditions/stopped-or-missed-periods/.
4. [Online] https://www.diabetes.co.uk/insulin-resistance.html.
5. [Online] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3018970/.
6. [Online] https://www.ncbi.nlm.nih.gov/pubmed/26351959.

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