Dr. Uchendu

Dr. (Mrs.) Florence Ngozi Uchendu, a Public Health Nutritionist, Nutritional Epidemiologist and Lecturer at the Department of Public Health, Faculty of Health Sciences, National Open University of Nigeria, Jabi, Abuja, has stated that weight gain can lead to infertility in couples.

Dr. Uchendu who disclosed this in this interview with BusinessHallmark’s FAVOUR ALILU, noted that weight gain can influence the amount of estrogen produced in your body, and healthy body weight has a higher probability of producing an appropriate amount of estrogen than overweight or obese body.


There have be suggestions that being overweight causes infertility. Is this really the case?

Yes, weight gain is one of the causes of infertility in couples. Infertility has been generally defined as failure to conceive after 12 or more months of attempts of natural fertilization. According to World Health Organisation (WHO), 50-80 million women are facing the challenges of infertility.Other studies have reported the global prevalence of infertility in couples as 8–12 %. Institutional-based prevalence of infertility has been reported in some parts of Nigeria as follows: 4.0 % (Ilorin, North central), 15.4 % (Abakaliki, South east), and 48.1 % (Oshogbo, South west) and 15.7 % in North West Nigeria

Weight gain can either be overweight or obesity. WHO classifies weight gain using an indicator called Body Mass Index (BMI). BMI is used to access nutritional status. Your BMI is an indirect measure of your body fat. It is calculated by dividing your weight (in kilograms) by your height squared (in meters). You are said to be underweight if your BMI is below 18.5 kg/m2; normal weight (18.5 to 24.9 kg/m2); overweight (25 to 29.9kg/m2) and obese (30 kg/m2 and above). Weight gain (being overweight or obese) has negative effect on fertility among couples.

On the flip side, could being underweight also affect fertility?

Yes, being underweight, overweight or obese can affect a couple’s fertility. Overweight and obesity are defined as excessive fat accumulation in the body which is not healthy and is linked to many non-communicable diseases including infertility. Studies have shown that being underweight can reduce a woman’s fertility by causing hormonal imbalances that affect ovulation and the chances of getting pregnant. It has also been reported that underweight women are more likely to take more than a year to get pregnant compared to women in the normal or healthy weight range (18.5 to 24.9 kg/m2).

Underweight might result in deficiency of essential nutrients required for egg development and this can decrease hormones in the ovaries. According to the American Society for Reproductive Medicine (ASRM), obesity is the cause of fertility struggles in 6.0 % of women who have never been pregnant before. Obesity affects infertility by changing the way a woman’s body stores sex hormones. The process has been explained as follows: fat cells convert a male hormone known as androstenedione into a female hormone called estrone. The estrone in turn affects the metabolism of the part of the brain that regulates ovarian and testicular function and this can cause reproductive dysfunction. Obesity is also associated with polycystic ovary syndrome (PCOS), a common cause of low fertility or infertility.

Weight gain can influence the amount of estrogen produced in your body. Ovaries and adipose tissue (fat cells) produce estrogen. A healthy body weight has a higher probability of producing an appropriate amount of estrogen than overweight or obese body because your adipose tissue produces excess estrogen than is required which causes hormonal imbalance. Overweight and obese women have higher levels of a hormone called leptin which is produced in fatty tissue. This can also disrupt the hormone balance and lead to reduced fertility. The quantity and distribution of body fat affect the menstrual cycle through a range of hormonal mechanisms. The right amount of body fat is needed for a successful conception.

Extra fat in obesity increases insulin levels, which causes the ovaries to produce too much testosterone and too much testosterone causes the ovaries to stop releasing eggs. It has also been reported that women with a higher BMI do not respond very well to assisted-fertility treatments such as vitro fertilization. Being overweight and obese result to type 2 diabetes which also increases the risk of insulin resistance by having excess glucose in the blood system. The presence of excess sugar in the blood induces the pancreas to release excess insulin. Having a high level of insulin in your blood can cause metabolic disturbances that can affect ovulation.

Also, being underweight causes the ovaries to make less estrogen which can negatively influence ovulation because at ovulation, increased levels of estrogen are needed in order to release the egg from its follicle. It has been reported that being significantly underweight can affect hormone production and inhibit normal ovulation while being underweight can stop menstruation.Obesity can also cause infertility in men. In men, obesity has been associated with lower testosterone, impaired sperm quality and higher rate of erectile dysfunction.

A study found that a decrease in testosterone was associated with an increase in BMI. Men with a waist size of more than 40 inches were more likely to have erectile dysfunction. A waist size of more than 40 inches has been reported to be the strongest single predictor of developing symptoms of testosterone deficiency. Reports have it that obese men are more likely to have low or non-existent sperm counts. Reasons why this happen is because obesity can elevate body temperatures especially around the scrotum and can also lead to hormonal imbalances. Obese men are more likely to have higher estrogen levels, combined with lower levels of sperm-producing hormones like inhibin b and androgen which can negatively affect the sperm count, sperm concentration and the sperm’s ability to swim well.

We understand that overweight women take longer time to conceive…?

Yes, that is true. A study reported that women who gained weight in adulthood took longer period to conceive compared with women with steady, normal healthy weights (18.5 to 24.9 kg/m2). This is also applicable to men. Men and women who carry extra weight might take longer time to conceive. Underweight women also have this challenge. Like I mentioned above, studies have shown that underweight women are more likely to take longer time to conceive compared to women in the normal or healthy weight range (18.5 to 24.9 kg/m2). This is because all the problems associated with obesity and infertility discussed above might certainly delay conception in obese couples even though they might be some exceptions.

A study published in the journal Obstetrics and Gynecology, found that changes in body weight of women participants after age 18 affected their ability to get pregnant. For every 5-kilogram (or 11-pound) increase in their body weight after age 18, it took them 5 percent longer to get pregnant. Those who were underweight (under 18.5 kg/m2) also experienced a 25 % longer time to conceive than those whose weight was in the normal range.

What is the ideal weight for conception?

The ideal weight for conception depends on an individual’s height and this is taken into consideration by the BMI. Having a healthy weight does not guarantee fertility. However, your weight can influence your baby-making abilities. The normal or healthy weight range according to BMI is 18.5 to 24.9 kg/m2.

What’s the effect of being overweight on the overall health condition of the pregnancy of the baby?

Overweight and obesity reduces fertility and the chances of having a healthy baby. Obese baby might lead to difficulty during birth. Obesity and excess weight gain during pregnancy is associated with a number of pregnancy-related complications such as increased risk of miscarriage, high blood pressure, pre-eclampsia, gestational diabetes, infection, blood clotting, induced labour, caesarean birth, preterm and stillbirth. Babies born to very overweight mothers have an increased risk of childhood and adult obesity and other long-term health problems.

According to the American College of Obstetricians and Gynecologists, babies born to obese women are at increased risk of having birth defects such as heart defects and neural tube defects. Another study reported that overweight and obese women have miscarriages at a higher rate than other women.

What is your advice to overweight couples?

If you are overweight or obese you try weight loss programmes to help you loseweight before getting pregnant. A healthy weight before conception increases the chance of the baby being healthy at birth and into adulthood. Even during pregnancy, maintaining a healthy weight is very important for mother and baby’s health

For men, it is advised that they be in a healthy weight status at least three months before conception because it can improve the chance of conception. This is because sperm take about three months to develop and being in the healthy weight range during this period can help to develop healthy sperm. A healthy diet and moderate exercise might increase sperm count and improve sperm motility.