Weight and Its Impact on Fertility and Pregnancy

Your chances of getting pregnant are based on many variables, such as your age, frequency of intercourse, and the time within your monthly cycle. Certain lifestyle factors can also play a substantial role in fertility and pregnancy, including weight.

Being slightly overweight or underweight typically does not have a significant effect on your ability to conceive. However, having a body mass index (BMI) outside the ‘normal’ range (above 25 or below 19) can cause hormone imbalances that affect menstrual cycles and prevent ovulation.

It’s also important to look at other factors that can impact weight, such as muscle weight. For example, a muscular physique can put you on the higher end of the BMI scale even though you may have minimal body fat.

Being Overweight and Its Effect on Fertility

Most estrogens, including estradiol which controls the menstrual cycle, are produced in the ovaries. Estrogen is also produced by fat cells meaning the more fat you carry, the more estrogen you produce. If you are a healthy weight, you are likely producing a normal amount of estrogen.

However, if you are overweight, your body may be producing excess estrogen. Excess estrogen in the body can cause numerous symptoms, including hot flashes, headaches, night sweats, and vaginal dryness. It can also affect fertility by preventing ovulation. In fact, studies have shown 30 to 47 percent of obese women (with BMIs ranging from 35 to 40) suffer from irregular periods. Irregular periods make it difficult to pinpoint when you are ovulating, which can reduce your chances of becoming pregnant.

Even if you are overweight and have regular menstrual cycles, you may still struggle with infertility. Women who are overweight or obese have a higher risk of developing hormonal and endocrine conditions, such as PCOS and insulin resistance, which can reduce fertility. Overweight women who do become pregnant are also at a higher risk for miscarriage, diabetes, preeclampsia, and birth defects.

If you are trying to conceive, you can improve your chances of conception by losing weight and leading a healthier lifestyle. Studies have shown that losing as little as 5 percent of your body weight can substantially improve your chances of becoming pregnant. The same notion can be said about improved fertility in men who lose weight.

Being Underweight and Its Effect on Fertility

Body fat plays a significant role in reproduction. Some women with low BMIs (generally 18.5 or below) may experience fertility problems. In fact, approximately 12 percent of infertility cases are caused by having a low BMI or being underweight. Women who are underweight often experience irregular periods which can cause irregular or sometimes even non-existent ovulation.

A simple solution to increasing your odds of pregnancy is to gain weight. Remember that you want to gain fat, not muscle, as estrogen is produced by fat. Even if you have regular menstrual bleeding, you may still develop fertility problems. Many times underweight women experience cycles that are anovulatory, which means that bleeding may still occur but ovulation does not. The ideal BMI for women trying to conceive is between 20 and 25.

Reaching a Healthy Weight for Fertility

If you’re having difficulty getting pregnant, you may be wondering if your weight is to blame. On the BMI scale, women less than 18.5 are considered underweight and between 18.5 and 24.9 are considered a healthy weight. Women between 25.0 and 29.9 are considered overweight, and 30.0 or more are considered obese.

If you fall outside the ‘healthy’ weight on the BMI scale, consider altering your diet. Eliminate “bad” or high-calorie foods and beverages, such as caffeine, alcohol, trans fat, processed sugar, and overly-processed foods. Introduce whole grains, fresh fruits and vegetables, and healthy fats into your diet. Not only will you acquire more energy and work your way towards a healthier weight, but you’ll also be more likely to conceive and progress through a complication-free pregnancy.