The most commonly accepted definition of the term infertility is the lack of pregnancy (regardless of cause) after 1 year of unprotected intercourse. Infertility affects approximately 15-20% of couples of reproductive age. Its prevalence has been stable during the past 50 years, although a shift in etiology and in the age of the patient population has occurred. In particular the presence of premature ovarian failure (PFO) is increasing recently. Women appear less fertile at age 40 than before.
Fertility is influenced by the moral attitudes of US society, in which sexual liberation and promiscuity have increased during the last 40 years, and by changing priorities among women. In developed countries, where family planning and professional career development are practiced, some women postpone childbearing until after age 30-40 years. Improvements in fertility treatment have made it possible for many patients with severe male-factor infertility to have a family. These new and advanced technologies include in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), and other related procedures in Assisted Reproductive Technologies (ART).
Fertility is defined as the capacity to reproduce or the state of being fertile. This term should be differentiated from fecundability, which is the probability of achieving a pregnancy each month, and fecundity, which is the ability to achieve a live birth within one menstrual cycle. The fecundability rate in the general population is rather constant and is approximately 0.22/mo (Maruani, 1983). The estimated fecundity rate is 0.15-0.18/mo, representing a cumulative pregnancy rate of 90%/y (Trussell, 1985).
The reproduction process requires the interaction and integrity of the female and male reproductive tracts, which allows for (1) the release of a normal preovulatory oocyte, (2) the production of adequate spermatozoa, (3) the normal transport of the gametes to the ampullary portion of the fallopian tubes (where fertilization occurs), and (4) the subsequent transport of the cleaving embryo up to the endometrial cavity for its normal implantation and further development.
The origin of infertility is similarly due to male or female factors; the causes are multiple. Female factors account for 32% of infertility. Male factors account for 18.8% of infertility. Male and female factors combined cause 18.5% of fertility. The etiology is unknown in 11.1%, and other causes are identified in 5.6%.
Those with an unknown etiology can also be categorized as a normal infertile couple (NIC), indicating that all findings from standard tests used to evaluate the patients are normal. In NICs, the actual cause for infertility cannot be detected because it may be at the oocyte/sperm level or it may be due to the quality of the embryo or to any disruption at the implantation site level. In the future, ascribing the mutation or the absence of a specific gene as the cause of infertility may be possible in this patient population.
Other etiologic factors have been associated with an increased risk of infertility. These include pelvic inflammatory disease (PID); endometriosis; environmental and occupational factors; toxic effects related to tobacco, marijuana, or other drugs; exercise; inadequate diet associated with extreme weight loss or gain; and advanced age.
Il Prof. Giorlandinoi dirige il centro di eccellenza di diagnosi e terapia della sterilità di coppia presso Altamedica Main Center Roma.