Weight, fertility and getting pregnant: Here’s what matters.

Conception is a miraculous thing, involving a complicated sequence of human anatomy, hormones and perfect timing. Our bodies and overall health play a tremendous role in that delicate dance, so it shouldn’t come as a surprise that a person’s weight, high or low, can impact fertility.

Anyone struggling to conceive should consider their overall health, including their diet, nutrition and weight, as part of their self-guided treatment plan. That said, there is a lot of misinformation out there about fertility diets, supplements and lifestyle choices, so we’re taking a look at what the science actually says. After all, knowledge is power.

What is a healthy weight for getting pregnant?

While there is not one ideal healthy weight for each person, being underweight or overweight can negatively affect hormones involved in reproduction.

How to determine a healthy weight? There are a number of factors that go into this calculation including age, muscle mass, height, etc. But a common rough estimate is to utilize the body mass index (BMI).

BMI takes into account a person’s weight relative to height.

• Underweight: a BMI of less than 18.5.
• Ideal: a BMI of between 18.5 and 24.9.
• Overweight: a BMI of between 25 and 29.9.
• Obese: a BMI over 30.

BMI calculator

While BMI is an easy way to calculate an ideal weight, it should not be the only measure as it does not take into account muscle mass, body fat, nutrition or other factors that contribute to a healthy body.

Both diet and physical activity play a critical role in getting to or maintaining a healthy body. In turn, a healthy body makes it easier to conceive and makes for a healthy pregnancy after conception.

Anyone worried about their fertility and weight or body composition should discuss their concerns with a nutritionist or a doctor, including one of our fertility specialists.

Link between being underweight and infertility

Some women may experience ovulation problems when their BMI is too high or too low. In fact, if weight is too low, they may stop menstruating altogether.

Needless to say, this has a detrimental effect on reproduction. In fact, in one study of nearly 17,000 women, researchers found a clear link between healthy lifestyle (weight, nutrition and exercise) and a reduction in ovulation-based infertility.

In men, research suggests that being underweight can influence sex drive and potentially reducing sperm quality.

Gaining healthy body weight can regulate hormones and improve the chances of conceiving.

Link between overweight, obesity and infertility

Research suggests that being overweight and obesity can cause infertility in men and women. For instance, up to 47% of obese women have irregular menstrual cycles. These irregularities increase as weight increases. In men, studies suggest that the higher a man’s BMI, the more likely he is to have a low sperm count.

Moreover, research suggests that excess weight not only affects the ability to conceive naturally but also the success rates for in vitro fertilization (IVF) and other fertility treatments, as much as 30%. Losing as little as 5% body weight results in stabilized ovulation for 60% of women.

Excess weight can also create other health complications that can cause infertility, such as hypertension or worsened manifestations of polycystic ovary syndrome (PCOS). The latter condition often involves high levels of insulin and male hormones, which impair ovulation, a critical hormone for getting pregnant.

Fortunately, losing weight can make it easier to conceive and make fertility treatments more effective.

For anyone overweight, most doctors will recommend incorporating dietary changes and exercise. For those with a BMI above 50, doctors may recommend weight loss surgery.

Diet pills for weight loss, supplements and fertility

A word of caution on using diet pills or appetite suppressants for weight loss when trying to get pregnant.

Nutrition plays a key role in fertility, and there is plenty of research into how antioxidants, Omega-3’s and other key vitamins can aid conception or pregnancy. However, the same can’t be said for diet pills and supplements.

In fact, the opposite may be true. Some diet pills have serious side effects, such as increasing heart rate or blood pressure, which may hurt the chances of getting pregnant or having a healthy pregnancy.

The truth is, that we don’t know the full extent of their harm. So while maintaining a healthy weight can aid fertility, it is better to achieve that weight via proper nutrition and exercise strategies.

As a general rule, avoid any supplements or stimulants that aren’t approved for pregnancy. If unsure, speak to a doctor before use.

Final thoughts on weight loss (or gain) and fertility

Sometimes addressing fertility challenges starts with a healthy lifestyle. Whether someone has a low BMI or a high BMI, there are steps they can take to improve their health and fertility.

Moreover, weight is just one issue that can make it difficult to conceive. A fertility specialists can help diagnose and treat the underlying conditions that are compromising your ability to conceive.