Causes of infertility

Infertility can be caused by many different things. For 1 in 4 couples, a cause cannot be identified.

Infertility is commonly caused by problems with ovulation (the monthly release of an egg from the ovaries).

Some problems stop an egg being released at all, while others prevent an egg being released during some cycles but not others.

Ovulation problems can be a result of:

polycystic ovary syndrome (PCOS),
thyroid problems – both an overactive thyroid gland and an underactive thyroid gland can prevent ovulation,
premature ovarian failure – where the ovaries stop working before the age of 40.

Pelvic surgery can damage and scar the fallopian tubes, which link the ovaries to the womb.

Cervical surgery can also sometimes cause scarring or shorten the neck of the womb (the cervix).

When you’re ovulating, mucus in your cervix becomes thinner so sperm can swim through it more easily. If there’s a problem with the mucus,...