Overweight and obesity: an obstacle in the way of becoming parents?
It’s a reality that overweight and obesity are increasingly more common in developed countries. These conditions are also associated with many health issues.
Obesity is the result of the interaction of several factors, mainly those of genetic, metabolic, environmental, cultural and socioeconomic origin.
How do we measure the degree of obesity in medicine?
The most commonly used tool is the body mass index (BMI), which we can calculate by dividing an individual’s weight (in kilograms) by their height (in metres) squared.
A person is considered to be overweight when their BMI falls between 25 and 29.9, and they will be diagnosed with obesity if their BMI is equal to or greater than 30.
Obesity and likelihood of pregnancy
There is a relationship between fertility and obesity, and for this reason many women and couples who are overweight come to fertility clinics for help getting pregnant. Obesity is the direct cause of numerous conditions that can negatively impact a couple’s chances of conceiving.
Women with obesity are two to three times less likely to fall pregnant naturally.
This statistic may be explained by problems with ovulation: the female may not ovulate correctly or, she might be ovulating but her eggs are not good quality, thus resulting in potential problems with the embryo.
Apart from ovulation, obesity can also have an impact on the endometrial lining of the uterus: this is the most important uterine layer as it’s the place where embryo implantation will occur.
Obesity and changes in endocrine functioning
The most important changes in endocrine functioning that occur as a result of obesity are the rise in basal insulin levels and insulin resistance, both of which lead to menstrual cycle and ovulatory abnormalities.
On the other hand, oestrogen is the sex hormone produced in females, mainly in the reproductive organs, and it is produced by fat cells.
Thus, women with obesity will have higher levels of oestrogens which can trigger an imbalance in the female hormonal axis due to an excess of this hormone.
Polycystic ovarian syndrome and how it relates to obesity
Polycystic ovarian syndrome (PCOS) affects between 12% and 21% of females of childbearing age and is the most common cause of anovulation and in turn, infertility.
Typically (but not always), patients with PCOS are overweight and also have irregular menstrual cycles.
The Rotterdam Criteria are used to diagnose PCOS and require at least two of the following characteristics to be present: oligo or anovulation; clinical and/or biochemical evidence of hyperandrogenism (such as acne and hirsutism), and evidence of polycystic ovaries found on an ultrasound.
The symptoms of PCOS may improve if the female reduces her body weight by 5% to 10%.
How does obesity affect assisted reproduction treatment?
So what is the first piece of advice a professional will give you?
To lose weight. A lower body weight will be beneficial to both achieving a pregnancy as well as preventing complications later on.
During assisted reproduction treatment, females with obesity require higher doses of gonadotropins as their bodies are more resistant to them; this in turn results in a less favourable ovarian response. The higher a patient’s weight, the greater the dosage of gonadotropins she’ll need, thus resulting in longer treatment times and a more costly cycle due to the amount of medication ultimately needed.
Additionally, obesity is associated with a greater incidence of miscarriage and complications during pregnancy, delivery and the post‑partum period.
During pregnancy, women who are obese have a higher likelihood of developing gestational diabetes, arterial hypertension, pre‑eclampsia and are also more likely to require a Caesarean section delivery, among other complications.
There are studies which have found that children born to mothers with obesity are at a higher risk for developing health problems later in life such as cardiovascular diseases, metabolic syndrome, Type II Diabetes and obesity.
Obesity and fertility: it’s not something that only affects females
Men also matter ‑and a lot‑, when it comes to the field of assisted reproduction; the male plays an important role in the couple’s overall estimated success rates and results.
When we talk about being overweight, males with obesity have also been found to present fertility-related issues such as problems with sperm count and motility: there are studies which have shown that sperm concentration in the semen of obese males is 10% to 20% lower than in males with a normal body weight.
In addition, obesity in males has also been associated with hormone abnormalities such as declining testosterone levels as well as lower levels of other hormones that are important when it comes to reproduction.
Everything explained in this article make it necessary to advise couples hoping to become parents to strive for a healthy weight before trying to conceive, regardless of whether they try to achieve a pregnancy naturally or through the help of assisted reproduction techniques.
A low‑calorie diet and exercise, together with the proper psychological support and a multidisciplinary approach, is the main piece of advice we give to all patients with obesity and who want to become parents.
Do you have other questions? Contact us and ask! We’ll be happy to help you!