1. What is obesity?
  2. Does obesity influence the menstrual cycle and fertility?
  3. Obesity and Polycystic Ovary Syndrome

What is obesity?

Obesity is a syndrome characterised by an excessive and abnormal increase in body weight, with an excessive formation of body fat in the tissues. There are two types of obesity:

  • Android obesity: characterised by the distribution of the body’s extra fat primarily around the neck, shoulders and over the upper abdominal region of the body.
  • Gynoid obesity: characterised by the distribution of the body’s extra fat in the lower parts of the body (thighs, glutes, lower abdominal region) and by a poor development of muscles, frequent in women.

Does obesity influence the menstrual cycle and fertility?

The physiological mechanisms related to gender, in particular the effects of hormones, play a significant role in feminine obesity. The impact of being overweight and especially of obesity has alarmingly increased in female population of childbearing potential. Recent studies have shown that overweight women are affected by disorders of the menstrual cycle. This confirms the fact that excess weight has plays an important role in those mechanisms involved with infertility. In fact, obese women can be affected by those complications related to obesity like diabetes, arterial hypertension, stroke and arteriosclerosis but can also be affected by problems of the reproductive system. Much more than women of healthy weight, obese women are frequently affected by amenorrhea that is the absence of menstrual cycle. The analysis of the hormonal profile of obese women has shown that obesity and excessive weight in general are often associated to infertility because women are in a state of hypogonadotrophic hypogonadism, which means that there is an alteration of the hypothalamus-hypophysis-ovary axis that regulates the menstrual cycle through the synthesis of gonadotropins like FSH and LH.

In addition, obesity also modifies the levels of insulin produced by the pancreas, causing an overproduction of androgens, which, correlated to an increase in the production of oestrogens, impacts on the menstrual cycle causing disorders, reduction of ovulation and therefore low levels of fertility. Last but not least, fat deposits in the ovaries can interfere with follicular and embryonic development in case of pregnancy.

Obesity and Polycystic Ovary Syndrome

The most widespread problem of obese women is the Polycystic Ovary Syndrome (PCOS), which is characterised by hyperandrogenemia, ovulation absence, hirsutism, acne and altered morphology of the ovaries. Obesity amplifies the hyperandrogenemia of PCOS, thus impacting on the fertility rate and on anovulatory cycles.

Pregnancy rate for obese women treated for infertility is lower than for women of healthy weight and even after fertility treatments, the risk of miscarriage is very high.

Obesity is an important risk factor related to a series of gynaecological diseases. It is therefore important, especially for young adolescents, to set prevention strategies that allow the normalization of body weight for obese or overweight adolescents because this can increase the chances of recovery of the menstrual cycle and of ovulation.