The Impact of Weight on Fertility

Being at a healthy weight is important for so many reasons, one of which is fertility. If you're trying to conceive and you or your partner is over or underweight, it may be harder to conceive. Before you start trying to conceive, it’s a good idea to consult your doctor about your general health and, if necessary, work on a plan to reach and maintain a healthy weight following the specific diet (check out the review at Slender Series).

Being overweight and its effect on fertility

Being overweight (having a BMI of 25 or more) can interfere with a woman’s fertility by affecting her body’s production of hormones. Having more fat results in producing more estrogen, which in term can interfere with ovulation. In addition, obesity has been linked to a couple of fertility-related problems, including endocrine disorder and poly-cystic ovary syndrome. In total, women who are obese have a significantly harder time conceiving, and being overweight can also undermine fertility. For men, being overweight can reduce testosterone levels and result in lower sperm quality.

Being underweight and its effect on fertility

Being underweight (having a BMI under 18.5) can also be a problem for fertility. Like being overweight, being underweight can lead to imbalanced hormone production. Women who are underweight are also frequently not getting sufficient nutrients. This can lead to irregular ovulation or even stop ovulation from happening altogether. When underweight women do become pregnant, a lack of nutrients can cause risks for their pregnancies. Being underweight is also a problem for men. It often leads to a low sperm count, which makes fertilization more difficult. For both men and women, therefore, it’s important to work towards a healthy weight before trying to conceive. This will not only help you to get pregnant, it will help you to have a healthy pregnancy and live long, healthy lives while raising a family. MORE ABOUT CONCEIVE PLUS If you have just started trying to get pregnant or have been trying for a while, Conceive Plus® can help increase your chances of conception naturally! Recommended by doctors, pharmacists and fertility clinics in more than 60 countries, this is the fertility friendly lubricant approved by the FDA and a prescription is not required.

Frequently Asked Questions

Can being overweight stop me getting pregnant?

Yes, being overweight can make it harder to conceive. According to the NHS, having a BMI of 25 or above can affect hormone production and interfere with ovulation, making it more difficult to become pregnant naturally. Women with obesity may also be at higher risk of conditions like polycystic ovary syndrome (PCOS), which can further impact fertility.

What BMI do I need for NHS fertility treatment?

Most Clinical Commissioning Groups (CCGs) require women to have a BMI between 19 and 30 to qualify for NHS-funded fertility treatment, though this can vary by area. NICE guidelines recommend that women with a BMI over 30 should be supported to lose weight before starting assisted reproduction. It's worth checking with your local Integrated Care Board (ICB) for specific criteria in your region.

Does my partner's weight affect our chances of conceiving?

Yes, weight affects male fertility too. Men who are overweight may have lower testosterone levels and reduced sperm quality, whilst being underweight can lead to a lower sperm count. The NHS recommends that both partners aim for a healthy weight when trying to conceive to maximise your chances.

Will losing weight help me get pregnant faster?

Reaching a healthy weight can significantly improve your chances of conception. Research sho

ws that even losing 5-10% of body weight can help restore regular ovulation and improve hormone balance. Your GP can refer you to weight management services if you need support, and this may also help you meet the criteria for NHS fertility treatment if needed.

Can being too thin cause fertility problems?

Yes, being underweight with a BMI under 18.5 can disrupt hormone production and lead to irregular periods or stop ovulation altogether. The NHS advises that women who are underweight may also lack essential nutrients needed for a healthy pregnancy. If you're struggling to gain weight, speak to your GP who can check for underlying conditions and refer you to a dietitian.

How long should I try to conceive before seeing my GP about weight and fertility?

The NHS recommends seeing your GP if you haven't conceived after 12 months of regular unprotected sex, or after 6 months if you're over 35. However, if you know your BMI is outside the healthy range of 18.5-24.9, it's worth speaking to your doctor sooner. Around 1 in 7 UK couples experience fertility issues, and addressing weight concerns early can help improve your chances.

What support is available on the NHS to help me reach a healthy weight before TTC?

Your GP can refer you to NHS weight management programmes, which may include dietitian appointments, exercise programmes, or group support sessions. Some areas also offer specialist preconception clinics for women with weight-related fertility concerns. These services are free and can help you reach a healthy weight safely before trying to conceive.