Secondary infertility is generally defined as the inability of a couple to conceive after a year of unprotected and appropriately timed intercourse when one or both partners have previously conceived children. Both male and female factors may be involved and in about one-quarter of the cases the cause is multi-factorial.
The most prevalent cause of secondary infertility may be age. Much has been written about aging and women’s fertility. Women are born with all of the oocytes they will ever have and female fertility peaks in the mid-twenties to mid-thirties. Menopause, of course, occurs when there are no more oocytes. The decrease in fertility by 35 years of age is marked. By age 40 the spontaneous pregnancy rate is significantly lowered and at age 45 the chances of natural conception with unprotected and well timed intercourse are, at best, approximately 6% per cycle. Older oocytes (eggs) have been around longer and have been exposed to more environmental factors which may contribute to a decrease in egg quality.
Single gene mutations may be responsible for spontaneous interruption of early pregnancies therefore it is not surprising that along with the decrease in natural pregnancy rate comes an age related increase in spontaneous abortion (miscarriage) rate. When one also considers that many spontaneous abortions occur before a woman even knows that she is pregnant it is easy to see why female age is a significant factor in the etiology of secondary infertility. Less has been written about male age and fertility. Men, after all, normally go on producing new sperm throughout their adult life. Newer studies, however, have shown a decrease in both the quality and quantity of sperm produced by older men. Thus paternal age is no longer an insignificant factor to consider.
One factor that occasionally contributes to the creation of a secondarily infertile couple is the introduction of a “new partner”. A female or male who has previously successfully conceived may become secondarily infertile with a new partner. Successful conception relies upon the production of healthy sperm and oocytes that meet and fuse in a supportive environment. Interruption of any step along this complex pathway may result in infertility. In women, tubal blockage and abdominal adhesions are responsible about one third of the time for the diagnosis of infertility, ovulatory issues (anovulation, premature ovarian failure, ovulation irregularities) are responsible about 25% of the time though this, as previously mentioned, increases significantly with age and uterine factors (including endometriosis, a condition where uterine tissues are located outside of the uterus) are thought to be a contributing factor in approximately 30% of. Once again, it is important to remember that there may be multiple etiologies in the same couple and that many of these etiologies may develop after the first successful conception. In men, acquired defects in spermatogenesis, blockage in the semen delivery system and impotence are the primary contributing factors to infertility. Some of the causes of these problems are relatively reversible and easy to correct others less so.
Proper weight and good nutrition are important. Obesity interferes with ovulation as does excessively low body fat percentages. Tobacco use leads to decreased fertility via several different mechanisms. The use of alcohol and recreational drugs can not only decrease the quality of gametes (oocytes and sperm) but also impair judgement leading one into situations where other fertility challenging issues may arise.
Multiple sexual partners increase the risk for sexually transmitted infections (STI’s). STI’s may cause decreases in fertility due to inflammation and scarring in the reproductive tract (pelvic inflammatory disease in women, epidydimitis in men). Some STI’s have a relatively silent presentation. All suspicious signs or symptoms (pelvic pain, abnormal discharge, pain or burning on urination) should be promptly evaluated by the appropriate health care professional. Stress has definitely been shown to increase infertility rates; conversely faith, hope, prayer and support groups have all been shown to increase fertility rates.
