Q: What are the odds of pregnancy and having a baby in couples with unexplained infertility?

A: The term unexplained infertility applies to couples with no

obvious reason for infertility. The most commonly reported figures are between 10-20% of infertile couples. Unexplained infertility is diagnosed when standard tests show no problems: the woman has no ovulation problems, the sperm count is OK, and the fallopian tubes are open.

The likelihood of a diagnosis of unexplained infertility is increased substantially in women 35 and over - and greatly increased in women over 38. The reason for this is that there are more likely to be egg-quality problems as women age. Since we do not have a "standard category" called egg-factor infertility, these couples sometimes get lumped into the "unexplained" infertility category. One study showed that for couples with unexplained infertility of over three years' duration, the cumulative conception rate after 24 months of attempting conception without any treatment was 28%. This number was found to be reduced by 10% for each year that the woman is over 31.