(Reuters) -Infertility is an overlooked public health challenge and affordable treatment should be available within national health systems, the ​World Health Organization said on Friday in its first guideline on ‌the topic.

Infertility is estimated to affect more than 1 in 6 people of reproductive age at some ‌point in their lives, the WHO said. But access to care is severely limited, and differs greatly from country to country.

It is also often paid for out-of-pocket, leading to catastrophic financial expenditure, the U.N. health ⁠agency added. In some ‌countries, a single round of in vitro fertilisation, or IVF, can cost twice as much as the average annual household ‍income, the WHO said.

“Infertility is one of the most overlooked public health challenges of our time and a major equity issue globally,” said Dr. Tedros Adhanom ​Ghebreyesus, WHO director-general, in a statement.

Millions of men and ‌women face the condition alone, he said, forced to choose between having children and financial security, or pushed towards cheaper but unproven treatment options.

The WHO defines infertility as the failure to achieve a pregnancy after 12 months or more of regular unprotected sexual intercourse.

Treatment is not just about IVF, but about all the ⁠steps those in primary healthcare can take to ​help couples or individuals have a child, ​including guidance on lifestyle interventions like stopping smoking, the WHO said.

The guideline includes 40 recommendations for countries with the aim of ‍making fertility care safer,⁠ fairer and more affordable for all, WHO said, focusing on male, female and unexplained infertility.

Alongside these steps, the WHO ⁠said better education on factors affecting fertility, such as age, was also important, alongside ‌support for those facing stigma and the stress of treatment.

(‌Reporting by Jennifer RigbyEditing by Bill Berkrot)