Most specialists define infertility based on the age of the woman. At Poma Fertility, we define infertility as a failure to have a baby after 12 months of trying if the woman is less than 35 years old and after 6 months of trying if the woman is older than 35.
Because a woman is less likely to become pregnant as she ages, testing and treatment is started earlier when the woman reaches 35. The age of the man is less important in this context because men remain essentially fertile throughout their lives.
For reproductive endocrinologists it is valuable to specifically ask our patients about the number of months they have been trying to get pregnant. This information can be used to establish whether the couple has had enough opportunities to conceive. This question can sometimes be difficult for couples to answer accurately if they have not been closely monitoring all their ovulation cycles. It is important to know how often the woman ovulates and if intercourse is being times to coincide with the fertile period of her cycle.
To explain the math, look at the curve for 20%/month, which is the probability for young women.
- Assume that 100 woman begin attempting pregnancy, after 1 month 20 of the 100 women would be pregnant.
- In the second month, 80 women remain and 20% or 16 of them conceive.
- Cumulatively, then 20 in the first month and 16 in the second month then equals 36% after 2 months are pregnant.
- The math then continues so that after 12 months, 93 of 100 women will be pregnant if every month 20% conceive.
The incidence of infertility in the US is about 6-9% after 12 months of attempts. In addition, patients with unexplained infertility who do not undergo treatment have about a 66% probability of pregnancy after six years, equivalent to 1.5%/month fertility.
The probability is less than 1% pregnancy will not be attained after 18-24 months of trying. In these cases, there is usually some significant problem and it is not just a timing issue or simple fix.