Unexplained Infertility

What is unexplained infertility?

Unexplained infertility is diagnosed when a couple has not conceived after 12 months of regular unprotected intercourse (or 6 months if the woman is 35 or older), but the standard fertility tests are normal. It accounts for roughly one in four to one in three couples with infertility. "Unexplained" does not mean there is no reason; it means the cause cannot be identified with routine tests. Possible hidden factors include subtle problems with egg quality, fertilisation, embryo development, tubal function or implantation.

Symptoms and signs

By definition, there are no specific symptoms. Periods are usually regular, and both partners are generally healthy. The main sign is that pregnancy has not occurred despite trying.

Causes and risk factors

• Age-related decline in egg quality, which standard tests cannot measure
• Mild endometriosis that is not visible on ultrasound
• Problems with egg pick-up by the fallopian tube despite open tubes
• Subtle sperm problems, such as DNA damage, not shown on a routine semen analysis
• Fertilisation or embryo development problems
• Implantation factors in the womb lining
• Lifestyle factors such as smoking, obesity, stress and timing of intercourse

How it is diagnosed

Unexplained infertility is a diagnosis of exclusion. Before it is made, a complete evaluation should include:

• Confirmation of ovulation, by cycle history, mid-luteal progesterone or follicle tracking
• Tests of ovarian reserve: AMH and antral follicle count
• Tubal patency testing with HSG, sonosalpingography or laparoscopy
• Pelvic ultrasound to check the uterus and ovaries
• Semen analysis using WHO 2021 reference values
• Thyroid function and prolactin where indicated

Treatment options

Expectant management

Younger couples who have been trying for a short time may be advised to keep trying naturally for a period, with attention to timing and lifestyle, because many conceive without treatment.

Ovarian stimulation with IUI

ESHRE recommends IUI with ovarian stimulation, using tablets such as letrozole or clomiphene or low-dose injections, as a first-line treatment for unexplained infertility. It is usually tried for three to six cycles, with careful monitoring to reduce the risk of twins.

IVF

IVF is recommended if IUI has not worked, if the woman is older or if the couple has been trying for several years. IVF can also reveal hidden problems, such as poor fertilisation, that were not detectable before. ICSI is not routinely needed for unexplained infertility unless there is a specific reason.

Lifestyle

Not smoking, limiting alcohol, maintaining a healthy weight and managing stress support fertility for both partners.

Chances of pregnancy

The outlook for unexplained infertility is often reasonable. Many couples conceive naturally or with IUI, and IVF offers good chances for others. The most important factors are the woman's age and the duration of infertility. Iswarya Fertility reports IVF success of about 75 percent for women under 35, but individual chances vary and cannot be guaranteed.

When to see a fertility specialist

See a specialist after 12 months of trying if the woman is under 35, after 6 months if she is 35 to 39, and straight away if she is 40 or older. Iswarya Fertility has 91+ centres, with EMI options from ₹9,999 per month for eligible treatments.