Unexplained or idiopathic infertility is a condition defined by a lack of obvious cause behind a couple's or individual's infertility. Unexplained infertility can only be diagnosed after both partners have been completely evaluated with common fertility issues being ruled out. Unexplained infertility accounts for about 15–30% of all infertility cases.
Unexplained infertility — also referred to as idiopathic infertility in medical settings — is when tests, lab results, and other findings are unable to find a cause for a couple's inability to get pregnant. Although it's hard to say exactly what percentage of infertility cases are unexplained, some research suggests that approximately 30% of infertility cases have unknown causes.
When a couple is trying to get pregnant, there are two factors at play: female factor — the health of the eggs and female reproductive system — and male factor, the health of the sperm and male reproductive system.
If a person with testes is experiencing poor semen parameters (low sperm count, motility, morphology, or genetic health) or has sexual dysfunction that makes conception difficult, that’s considered male-factor infertility. Typically, doctors will try to find the cause of the issue. This may be hormonal imbalances, an infection or inflammatory condition, a genetic disease, or exposure to harmful environmental or lifestyle factors that negatively impact sperm production.
When a couple is unable to become pregnant after 12 months or trying (or six months if over the age of 35), it is usually recommended that they see a fertility doctor. A fertility evaluation is completed along with standard tests for both partners, including a semen analysis, blood tests to evaluate hormone levels, and imaging tests (such as an ultrasound).
If all evaluations and testing come back normal, but you’re still unable to get pregnant on your own, you may be diagnosed with unexplained infertility.
Unexplained infertility can be disheartening, but this diagnosis doesn't mean having a biological child is impossible. Couples with unexplained infertility can try fertility medications and procedures like intrauterine insemination (IUI) and in vitro fertilization (IVF), which can improve pregnancy rates.