For thousands of women in Latin American countries, the joy of pregnancy has given way to fear. Maternity wards across the region are full of women waiting anxiously for ultrasound scans that will indicate whether the child they are carrying has a shrunken head and damaged brain, as a result of a condition called microcephaly.

Shocking images of babies with birth defects have made many women think twice about getting pregnant. Some women face a dilemma, pitting their religious beliefs about abortion against the risk that their babies could be born with abnormally small heads and a short life expectancy.

The virus has been reported in more than 30 countries, most of them in the Americas. So far, only Brazil has seen a sharp rise in microcephaly cases suspected of being linked to the mosquito-borne Zika virus.

The US Centers for Disease Control and Prevention (CDC) has advised pregnant women to avoid travel to areas with an active Zika outbreak. The American Red Cross has asked blood donors who have traveled to Zika virus outbreak areas such as Mexico, the Caribbean or Central and South America to wait at least 28 days before donating.

Some Latin American governments have advised women to delay having children. El Salvador recommended women not get pregnant for two years.

The Zika outbreak has triggered debate on liberalising abortion in the region, where many countries have strict laws. A group of researchers, activists and lawyers plan to petition Brazil's Supreme Court to allow abortions for women who have the virus, bypassing an increasingly conservative Congress where Evangelical lawmakers are backing a bill to restrict abortion, even in cases of rape.

Public health experts believe Zika will lead to an increase in illegal abortions. An estimated one million are already carried out every year in Brazil. Botched procedures in clandestine clinics using sharp tools, over-the-counter medicines and no sterilisation are already a major cause of deaths.

Brazil's government says women who want to get pregnant should discuss the risks with their doctors, but has stopped short of telling them to delay. Instead, it plans to hand out insect repellent to tens of thousands of low-income pregnant women and is stepping up an offensive to eradicate the mosquito, with the help of the army.

Zika is spread by the Aedes aegypti mosquito, which breeds in stagnant water. While anyone can be bitten by Aedes, public health experts agree that the poor are more vulnerable because they often lack amenities that help diminish the risk, such as air conditioning and window screens. Test kits for the virus are only effective in the first week of infection and only available at private clinics at a cost of 900 reais (£157), out of the reach of many women.

World Health Organisation officials say there is no scientific proof that Zika stunts the development of the foetus, causing microcephaly, but it is strongly suspected.