People who live in areas where the Zika virus is spreading are now recommended by the World Health Organization to delay pregnancies, The New York Times reports. That's to avoid having babies with birth defects like microcephaly, a condition that causes babies to be born with abnormally small heads.

The new WHO guidelines are directed at millions of people in Latin America and the Caribbean, including Puerto Rico, where the first Zika-related death was reported in April. For people who visit countries where the virus is circulating, the WHO recommends couples to wait at least eight weeks before trying to conceive. Puerto Rico’s health secretary has already been advising couples to delay pregnancies. And health officials in other countries where Zika is circulating, like Colombia and El Salvador, are urging women to avoid pregnancies.

In April, the CDC officially linked Zika and microcephaly

Some infectious disease specialists argue that delaying pregnancies is the only safe way to avoid giving birth to babies with brain damage, since no vaccine for Zika currently exists. But critics say that the government shouldn't have a say on when women and their partners decide to conceive. Others insist that it's unrealistic to ask women not to get pregnant, recognizing that many often don't have a choice — especially in areas with restrictions on abortion.

The Zika virus, which is carried by the yellow fever mosquito and can be transmitted through sex, was officially connected to microcephaly in April by the CDC. Last month, for the first time, scientists observed that the virus crosses the placenta when infecting babies, causing developmental disorders.