As confirmed by ISTAT, in Italy, and in many Western countries, women now tend to decide to have children in the second part of their reproductive years. This can obviously be explained both by social factors and personal choices, and by economic reasons. Italian women generally have children at an age considered more advanced than almost all other European women. According to the latest ISTAT data, the average age at childbirth in Italy has risen to 31.8 years. Moreover, in 2017 there were 464,000 births, a new historic low, 2% fewer than in 2016, when there were 473,000.
Age therefore represents one of the first causes of a woman's inability to conceive. Women should be aware that fertile age has its own decline as the years pass. And it is very important to know that the decrease in fertility occurs before the onset of menopause. Women's fertility in fact already begins to decline after age 30, undergoing a significant drop after age 35 (50%) and a more drastic one after age 40.
The age factor is today the most important and frequent cause of female infertility. This is because the oocytes of women over 40 may show a higher percentage of genetic abnormalities, and at the moment of fertilization this can give rise to embryos with alterations. The ISS (Istituto Superiore di Sanità) states that natural selection eliminates most embryos with abnormalities, causing a high rate of spontaneous miscarriage in women over 40; indeed, at this age the rate of spontaneous miscarriage is around 34%, compared to around 18% for women between 30 and 39.
The age factor has a lesser impact on the organ that will carry the pregnancy, the uterus, although some statistical data have shown a correlation between maternal age and a higher incidence of placenta previa, difficulties during labor, and benign uterine conditions such as endometrial polyps and uterine fibroids.
The causes of female infertility can also be attributed to an endocrine factor: a woman of reproductive age is subject to physiological hormonal fluctuations that occur periodically, regulating the menstrual cycle and, as a result, reproductive capacity. Some diseases or syndromes, such as polycystic ovary syndrome (PCOS), thyroid disorders, or a reduced ovarian reserve, can cause alterations in the menstrual cycle, up to and including anovulation (absence of ovulation).
Female infertility can also be significantly affected by an abnormality in the morphology and function of the fallopian tubes. The most common and frequent damage to the tubes can be caused by pelvic infections, past surgeries, or pathogens such as gonorrhea and Chlamydia, a sexually transmitted bacterium.
A well known condition, affecting around 10% of women of reproductive age, is endometriosis, which can be considered one of the leading causes of female infertility today, significantly affecting a woman's life in other aspects of her daily life as well.
Some morphological or functional abnormalities of the cervix can make it difficult for sperm to travel up toward the tubes, and thus cause difficulty conceiving, although the cervical factor in infertility is much debated.
Finally, among the many other factors that can affect female infertility are certain systemic diseases (such as diabetes mellitus, thyroid disorders, and others), nutritional factors, exposure to toxic substances, exposure to heavy metals, and lifestyle habits such as smoking, alcohol abuse, drugs, and, not least, stress.
It is very important to know that infertility can develop following a cancer diagnosis, due to the administration of anticancer drugs. According to recent studies, in fact, after a cancer diagnosis the reproductive rate is generally lower than average. For this reason, reproductive counseling is recommended before starting any chemotherapy or radiotherapy treatment, as advised by all oncology institutes in recent years. This applies to women, but naturally to men as well.