What is the medical definition of infertility?
The definition of infertility varies depending upon the situation. The American Society for Reproductive Medicine (ASRM) defines infertility as follows: “Infertility is a disease, defined by
the failure to achieve a successful pregnancy after 12 months or more of appropriate, timed unprotected intercourse or therapeutic donor insemination.” (Practice Committee ASRM)
The Committee goes on to suggest that: “Earlier evaluation and treatment may be justified based on medical history and physical findings and is warranted after 6 months for women over age 35 years. Recurrent pregnancy loss is a disease distinct from infertility, defined by two or more failed pregnancies.”
However, some countries use 2 years as the limit before defining infertility. Much of the significance of the definition lies in when to start evaluation for infertility and when do insurance benefits start. In Illinois with the “Family Building Act”, infertility is a covered benefit but the State uses the ASRM definition of infertility. This means that some people seeking treatment for infertility will not qualify because they have not had unprotected intercourse, such as same-sex couples or single people. The definition is derived from studies evaluating the time to conception for fertile women. A number of women who had children are asked how long it took then to conceive. They data are summarized, and many studies show that 65% of the women who conceived with a pregnancy where the pregnancy results in the birth of a child at term, achieved this pregnancy within 3 months and 85% did so within 6 months. This was independent of age, so a fertile 40 year will conceive within the same timeframe as a fertile 20 year. Its just that there are fewer fertile 40-year-old women. The diagnosis then becomes one of predicting the chance of conception given the length of unprotected intercourse. So the definition of infertility is actually based upon the probability of conception given how long a person has been experiencing unprotected intercourse.
How does female fertility vary decade by decade?
Women do not make oocytes (eggs) after 5months gestation while still inside their mother. They make about 6- 7 million oocytes but by the time they are born they are down to 2 -3 million. By the time a woman is 20 she has about 300k- 400K oocytes. Each month, no matter what else she may be doping, such as taking oral contraceptives, a woman recruits about 1000 oocytes from the resting pool. Over the next 5 – 6 months, the ovary develops the oocytes that were recruited, such that by the end of 5 and ½ months only one oocyte remains; the one selected to be released at ovulation. The other 999 are literally killed off by the ovary through a programmed cell death. So obviously if a woman is not making oocytes and she is using a large number each month, she will eventually run out of oocytes. That results in menopause, which for Caucasian females, occurs in 50% of women by the age of 51. Underappreciated is the fact that there are really two groups of oocytes; one group is structurally normal and can create an embryo with the correct number of chromosomes which can result in the birth of a child. The other pool consists of damaged oocytes and they will never produce an embryo that will result in the birth of a child. The ovary has a nasty tendency to use the normal eggs first. Thus, as a woman ages she not only has fewer oocytes remaining, but more and more of those that remain are damaged and will not product a child. For Caucasian females it has been estimated that by age 41, 50% of the women will be functionally sterile.
When is peak fertility for women?
The peak fertility for woman is in her late teens and 20’s. This make sense from an evolutionary standpoint. Consider that the human body evolved in primitive societies and the core has not changed. The average life-expectancy for a woman in a primitive society was 27 years old. So, nature did not have to deal with reproduction in a woman in her 30’s and 40’s.
At what age can male fertility issues start to appear?
This is a very controversial topic primarily because people use the semen analysis as a way to determine fertility in men. However, many studies show that there seems to be no actual limit as to the effect of age on male reproduction. Some studies have suggested that miscarriage rates are higher in men over the age of 55, but other studies have not confirmed this. Other factors such as erectile dysfunction and general system disease can reduce male fertility but the actual ability to reproduce seems to be largely unaffected by age.
How can you increase your chances of becoming pregnant in your 20s/30s/40s?
The most obvious way is to have intercourse. Maintaining a normal body weight and avoiding smoking can help. However, the issue of when to have intercourse often arises. If a woman has regular cycles, then subtract 14 days from the cycles length and have intercourse every other day for 3 times around this day of the cycle. So for example, if a woman has regular 28 day cycles (day one of menses to the next day one of menses) then she will ovulate roughly at day 14 of her cycle with day one being the first day she considers the cycle to have started. Having intercourse on days 13-15-17 or 12- 14- 16 will result in the same pregnancy rate as more aggressive efforts, such as intercourse every day or the use of home ovulation predictor devices. A person can have intercourse more frequently and this will not reduce the chance of concept. The use of a basal body temperature chart (BBT) is unnecessary for woman with regular cycles. For those women without regular cycles, they should consult their gynecologist so that they can use fertility medications to enhance their chances for conception and reduce their risk of miscarriage. Irregular cycles are those where the length is > 35 days or < 25 days, or where there is no consistent cycle length.
If women are concerned about their fertility, what tests are available to help them determine if they may need medical intervention? There are a multitude of tests but one thing to keep in mind is that for 20% of those couples experiencing infertility, there is more than one cause. The three areas that need to be screened with testing are male factor (semen analysis), female anatomy ( US with tubal patency testing), and oocytes ( hormone tests such as AMH, day 3 FSH,LH, E2 , TSH , prolactin, Vit D, [potentially DHEA-S, Testosterone free and total, and fasting glucose with perhaps a glucose tolerance test of Hb A1C]) Of primary importance is to NOT start fertility medications ( ex. Clomid) without a complete screening of oocytes and semen. For young women with regular cycles and infertility, the most common reason for infertility is male factor. Treating the female with clomid for male factor delays the appropriate form of treatment. As with all medical treatment, the choice to treat and the type of treatment need to be diagnosis – driven. Nothing is more important than this concept.
What are the most common infertility options on the market? That depends upon the diagnosis.
Are there any new advancements in fertility treatments women should know about? The treatment of infertility is highly commercialized, and people need to be wary of new forms of treatment that promise high success rates. There are things that are being studied and perhaps will result in ways to improve pregnancy rates. For example, the use of Big Data to develop more accurate prediction models, individualized to the patient, are being developed. Stem cell research that could one day restore the oocyte pool is making strides but is a number of years away. If this is ever perfected, it will treat age related infertility but will also treat menopause. Bioinformatics is studying the genetics of infertility and this may help identify people with genetic risk factors that would help determine potential treatments. Work is alson being done on issues with the uterus and implantation.