Obesity Causes Infertility

weight measurement

There are several possible causes why a woman may be unable to have a baby. Did you know that “obesity” is one of them?

In addition, there are people who invite infertility through an unreasonable diet. In this article, we will take a look at the relationship between infertility and obesity, such as how much fat causes it difficult to become pregnant? why obesity and diet are related to infertility, and points of caution when an obese person is pregnant.

What is the effect of obesity on infertility?

What we will tackle first is how much “obesity” causes infertility. The number of women who believe that they are fat is increasing because of recent trends which consider thin as beautiful. But women’s obesity is when the BMI, which is the index of obesity, is 25 or more. If you are 160cm (5’3″), you are considered overweight if you weigh between 142 lbs to 164 lbs (between 25 to 29.9 BMI), and obese if you weigh more than 164 lbs.

How to calculate BMI: weight kg ÷ (height m × height m)

It is said that BMI related to infertility is 25 or more, and it tends to be difficult to become pregnant as the number increases. The main reasons why obesity may cause infertility are as follows:

Insulin resistance

For obese persons, the action of insulin on sugar in the blood that keeps blood glucose constant is sometimes less effective. Inadequate insulin action in the ovary or uterus may hamper the development of eggs or cause implantation impairment.


If you have insulin resistance, insulin is over-secreted to suppress the rise of blood glucose, which leads to “hyperinsulinemia” which chronically increases insulin blood level. This can cause ovulation disorders.

Decrease of adiponectin

As visceral fat increases, the amount of secretion of good protein adiponectin secreted from adipocytes decreases, ovarian skin may become thicker, eggs may not grow well, and ovulation may be difficult.

Ovulation is suppressed

The female hormone estrogen, which promotes ovulation, is made not only in the ovary but also in adipose tissue. Therefore, when fat increases and hormonal excess is present, secretion from the ovary is suppressed, and the function of the uterus and ovary may deteriorate.

Polycystic ovary syndrome (PCOS)

When there is excessive secretion of insulin or disturbance of hormonal balance occurs, it may develop into “polycystic ovary syndrome” so that even if eggs grow in the ovary they are not ovulated.

Besides this, it is said that it is possible that nutrition does not reach the ovaries and uterus due to deterioration of blood flow caused by obesity, which may lead to infertility.

The standard BMI for females is 18.5 or more and less than 25. Data on women whose BMI is around 22 are the most likely to become pregnant. Therefore, first of all know your own BMI. If you are obese and would like to have a baby, it is recommended to first lower the BMI figure.

Keep your diet on track

Because it may happen that the efficacy of hormonal agents used for infertility treatment does not appear well on obese people, there are times when you are recommended to diet before beginning treatment. Many examples have shown that fertility increased and natural pregnancy was obtained by lowering the numerical value of BMI, and if obesity is the cause of infertility, the diet leads to improving infertility.

However, sudden weight loss and a wrong diet also cause new problems, and even if you have lost weight, it may be difficult to become pregnant.

Causes of infertility due to rapid weight loss or wrong diet

Improvement of living and eating habits can create a balance inside the body and increase the chances of getting pregnant, so it is important to reduce the weight while keeping in mind to maintain a nutrient-balanced diet so that no burden is imposed on the body. Be careful of the potential causes of infertility below:

  • Nutritional deficiency due to biased dietary restriction
  • Disturbance of hormonal balance due to rapid weight loss
  • Stopping pregnancy function by trying to suppress energy consumption
  • Stress due to unreasonable diet
  • Coldness due to body fat reduction


As mentioned above, obesity itself is not the cause of infertility, but the possibility of infertility is increasing due to the symptoms caused by obesity.

Some women do get pregnant and give birth even if their BMI is 25 or more, and it cannot be said that a woman cannot get pregnant simply because she is fat. However, since obesity tends to cause various troubles during pregnancy and childbirth, you cannot disregard the fact that a healthy diet has merit on both the mother and baby.

Even if the major cause of infertility is not obesity, there is a high possibility that the effect of treatment will differ between an obese and non-obese body. So it is better to have infertility treatment after lowering the numerical value of BMI.

Causes of infertility are various, there are cases where several causes overlap. Improvement of obesity leads to clearing one cause, to find out the direction of pregnancy.

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