High BMI and Pregnancy: Does Being Overweight Cause Ovulation Disorders and Recurrent Miscarriage?

Many couples who have fertility problems may not know that their BMI is one of the most important factors affecting their chances of pregnancy. Science believes that obesity can have a huge effect on reproductive health. Body fat isn’t just an energy store. It also acts as an endocrine organ that produces sex hormones, like estrogen. Moreover, too much fat can cause insulin resistance, which may interfere with mother’s hormonal balance. These changes can lead to irregular ovulation, poor egg quality, and a less receptive uterine lining.

In this article, we have explained how BMI and pregnancy are related, what the normal weight range for pregnancy is, how obesity affects IVF and ICSI, and the best fertility treatments for overweight women. If you have questions about your hormone test results or fertility treatment options, the Raadina Health team can help you. Contact us via this link.

 What Is Abdominal Fat & How Does It Affect Your Hormones?

Fat stored around the abdomen and internal organs is known as “abdominal fat” or “visceral fat”. Compared with subcutaneous fat, visceral fat is more metabolically active. According to the Cleveland Clinic, abdominal fat can cause insulin resistance, chronic inflammation, and changes in female reproductive hormones. In other words, it can change the balance between sex hormones and increase estrogen levels in the female body.

It can also negatively affect ovulation and increase the risk of PCOS. That’s why most specialists believe that belly fat affects fertility more than excess weight in other parts of the body.

Who Is Called Overweight?

Doctors usually use the body mass index to determine whether a person is underweight, at a healthy weight, overweight, or obese. BMI is calculated by dividing body weight (in kilograms) by the square of height (in meters). A BMI chart shows a person’s weight status:

According to WHO, women with a BMI above 30 are at higher risk of fertility problems, such as gestational diabetes, high blood pressure during pregnancy, and other complications. However, BMI doesn’t tell the whole story. Waist size, abdominal fat, and overall metabolic health should also be taken into account.

Doctors should also consider the difference between overall obesity and abdominal fat. General obesity means having excess body fat throughout the body, while abdominal obesity means having extra fat around the abdomen and internal organs. A larger waist size can increase the risk of infertility even in women with normal BMI. In fact, abdominal fat can affect fertility more than excess weight alone. 

How Does Obesity Affect Female Fertility?

Body weight can affect almost every stage of pregnancy, from follicle development to embryo implantation. These changes usually happen gradually, and you may not notice any symptoms for years. Let’s see the effects of obesity on 4 fertility-related factors:

1) On Ovulation and the Menstrual Cycle 

Obesity can affect FSH and LH, and make it harder for follicles to develop normally. As a result, women may experience:

• No ovulation (anovulation)
• Long menstrual cycles
• Irregular periods
• A higher chance of delayed ovulation
• In severe cases, complete loss of ovulation

2) On Reproductive Hormones

Fat tissue increases the level of estrogen in the body. High estrogen levels confuse the brain. So it sends wrong signals to the ovaries and doesn’t let them work properly. Insulin resistance is also more common in people with obesity, and this can increase the level of male hormones in females.

3) on Egg Quality

Excess weight can also cause chronic inflammation, oxidative stress, and insulin resistance. All these problems make it harder for the ovaries to produce mature, high-quality egg follicles. Some obese women also suffer from mitochondrial diseases. It means that their egg cells don’t have enough energy to divide and form a healthy embryo. Plus, excess weight can increase oxidative damage to the eggs’ DNA.

4) On Uterus and Embryo Implantation

Based on the Mayo Clinic’s studies, obesity causes metabolic problems, such as hypertension, dyslipidemia, and diabetes. These issues:

• Reduce the chances of a successful pregnancy.
• Change the endometrium.
• Cause chronic tissue inflammation.
• Affect blood flow to the uterus.
• Prevent embryo implantation.

Read more: مطالب مرتبط

Pre-Pregnancy Tests for Overweight Women

Overweight women should take both hormonal and ovarian reserve tests before trying to conceive. These tests include AMH, FSH, LH, prolactin, and other reproductive hormones. In addition to blood tests, the doctor should examine their uterus, ovaries, and fallopian tubes via ultrasound. To be more specific, the following pre-pregnancy tests are necessary for obese women:

• Transvaginal ultrasound to check the ovaries.
• Assessing the endometrial thickness.
• Ultrasound to find ovarian cysts.
• Checking for uterine fibroids or polyps.
• Checking health conditions related to obesity, such as diabetes or prediabetes, high blood pressure, nonalcoholic fatty liver disease (NAFLD), abnormal blood lipids (dyslipidemia), and thyroid disorders.

Obesity and PCOS: Are They Related?

Obesity worsens PCOS symptoms and makes its treatment even more challenging. According to the Endocrine Society, around 40–80% of women with PCOS are overweight (BMI over 25–29.9) or obese (BMI over 30). Although obesity itself does not cause PCOS, it can make its symptoms worse.

This hormonal imbalance can make ovulation less regular and make it harder to get pregnant. Therefore, if women with PCOS lose even 3-5 kg, they may experience more regular ovulation and improve their chances of pregnancy. If fertility problems continue despite lifestyle changes and medical treatment, assisted reproductive methods may be considered, including options such as IVF in Iran.

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Can Obesity Lead to IVF and ICSI Failure?

According to ESHRE, obesity reduces the ovaries' response to ovulation induction drugs used during IVF and ICSI. As a result, the patient may need a higher dose of medication, and her chance of having a healthy baby is reduced.

Excess weight can also negatively affect the uterus, embryo implantation, and the successful transfer of the embryo into the uterus. That’s why fertility specialists recommend reaching a healthy BMI before undergoing IVF.

Does Obesity Affect Baby’s Health and Pregnancy?

Yes. Obesity can affect egg quality, the baby’s health, and how pregnancy proceeds. According to research by ACOG, women with obesity have a higher risk of miscarriage (especially during the first trimester), gestational diabetes, hypertension, preterm birth, and having a baby with a high birth weight.

What Is the Best Weight Range for Pregnancy?

There is no best weight range for pregnancy. A healthy pre-pregnancy weight depends on several factors, including your height, body composition, overall health, and BMI. In general, a BMI between 18.5 and 24.9 is within the normal range. The following table can give you a better idea of a healthy weight before pregnancy. 

How Much Weight Should You Lose before Pregnancy?

The good news is that even losing 5% to 10% of your current weight can improve your ovulation, hormonal balance, and infertility treatments. For example, if you weigh 90 kg, losing just 5–10 kg will have a positive effect on your reproductive health and chances of getting pregnant.

Read more: مطالب مرتبط

When Should You Lose Weight Before Pregnancy or IVF?

It’s better to lose weight several months before trying to conceive or undergoing IVF. When you lose weight gradually over 3 to 6 months, the body has more time to adjust, and the results are more likely to last. Eating too few calories daily can also interfere with your menstrual cycles and reproductive health.

For overweight women planning to undergo IVF, the specialists usually recommend losing weight before starting treatment. The amount of weight they should lose depends on their overall health, BMI, age, fertility condition, and treatment plan.

8 Tips to Lose Weight Before Pregnancy

A healthy diet, regular physical activity, and positive lifestyle changes are all you need to prepare your body for pregnancy. The following 8 tips can help you during your weight loss jorney:

1. Eat more vegetables, fruits, whole grains, and lean protein.
2. Avoid sugary drinks, fast food, and processed foods.
3. Control portion sizes and avoid overeating.
4. Do at least 150 minutes of moderate physical activity per week.
5. Get at least 7 hours of sleep per day.
6. Manage stress and anxiety.
7. Stop smoking and using tobacco products.
8. Avoid alcoholic beverages.

Does Rapid Weight Loss Make It Harder to Get Pregnant?

Yes. Very low-calorie diets and losing weight rapidly can disrupt the hormonal balance and cause irregular or missed periods. Not getting enough nutrients can affect ovulation and egg quality just as much as obesity.

A Real Story

Samira, a 29-year-old woman, says she decided to lose weight while trying to conceive, so she started a very strict diet. She lost around 15 kg in three months. At first, she was very happy with the results, but gradually her periods became irregular, and eventually she missed two periods in a row.

She visited her gynecologist because she was having difficulty getting pregnant. The doctor examined her and explained that the rapid weight loss had disrupted her reproductive hormones and reduced her chances of conception. The doctor recommended that she first lose weight gradually through a balanced diet and lifestyle changes, then try to conceive.

Fortunately, three months later, she became pregnant after changing her lifestyle and taking the supplements recommended by her doctor. She is now the mother of a three-year-old daughter.

Does Weight Loss Surgery Improve Female Fertility?

Women with severe obesity who couldn’t lose weight with diet and exercise can consider weight-loss surgery (AKA bariatric surgery and metabolic surgery). According to ACOG and ASMBS, patients should wait at least 12 to 18 months after bariatric surgery before trying to conceive. This gives your body enough time to adjust to the new weight and recover from nutritional deficiencies during the rapid weight-loss period.

Are Weight-Loss Medications Safe Before Pregnancy?

If you are planning to get pregnant, it is recommended to stop weight-loss medications weeks or months before trying to conceive. There is not enough evidence about the safety of many of these medications, so they should not be used during pregnancy unless your doctor prescribes them.

When Should You See a Fertility Specialist?

If you are 35 or older and have not become pregnant after six months of trying, you should consult a gynecologist or fertility specialist. If you are under 35, you need to see a specialist after 12 months of trying without success. However, you shouldn’t wait six months or a year if you already have fertility issues, like irregular periods, a history of miscarriage, PCOS, or an underlying medical condition. In other words, it may be better to see a doctor as soon as you decide to have a baby.

Choosing the best doctor, fertility center, and labs can be confusing for many TTC couples. Luckily, the experienced Raadina Health team is ready to help them. We will review your medical records for free and explain the treatment costs to you clearly. Plus, our team can arrange your appointments with doctors and labs. From your first appointment to pregnancy and delivery, Raadina is there to support you every step of the way.

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The Final Words

Excess fat, especially around the abdomen, can cause insulin resistance, hormonal imbalances, and chronic inflammation. These problems can affect the uterus and ovulation, and make fertility treatment more challenging. However, even losing just 5% - 10% of weight can improve reproductive health and increase the treatment’s success rate.

Get a free consultation, precise treatment planning, dedicated support, and a personalized medical travel roadmap. Contact the experts at Iran health agency today.

FAQs

Are all obese women infertile?

No. Many obese women have healthy pregnancies and successful deliveries. The issue is that being overweight can make it harder to conceive naturally and make the fertility problems more challenging.

Can you get pregnant with a large waist size?

Having a large belly does not mean that you cannot become pregnant. However, if your large waist size is due to visceral fat, it may interfere with ovulation and reduce your chances of getting pregnant.

Does belly fat cause infertility?

Belly fat can make it harder to conceive, but it doesn’t mean you’ll definitely have fertility problems. Other factors, including age, hormone status, ovulation, and underlying medical conditions, also play an important role.

I weigh 80 kg. Should I be worried about my fertility?

Not necessarily. A person's weight alone cannot determine whether they are infertile or not. Weight should be assessed alongside other factors such as BMI, waist size, age, overall health, etc.

How much extra weight will affect my fertility?

Even a few extra pounds can affect fertility in some women. In general, women with a BMI over 25 are at higher risk.

What is the pregnancy rate if you are overweight?

The answer to this question is a bit hard because it depends on various factors such as age, the underlying cause of infertility, metabolic health, ovulation, and other reproductive factors.

Can obesity cause miscarriage?

Obesity does not necessarily cause miscarriage on its own, but it can increase the risk. Losing weight and treating underlying health conditions before conception can reduce some of these risks.

Can losing weight improve ovulation?

Yes. For many women, losing 5-10% of weight means better hormonal balance and more regular ovulation. It can also improve their metabolic health and egg quality.

Can women with PCOS get pregnant after losing weight?

In many cases, yes. Losing weight can reduce insulin sensitivity and improve ovulation in women with PCOS. As a result, their bodies respond to fertility medications better.