The Ministry of Health in Brazil has declared an emergency, urging women in the northeast section of the country not to become pregnant after an outbreak of microcephaly, babies born with an untreatable brain condition.

‘There have been more than 2,400 cases this year​ compared with 147 cases in 2014, according to a report issued by the European Centre for Disease Prevention and Control’, reported CNN.

‘It’s a very personal decision, but at this moment of uncertainty, if families can put off their pregnancy plans, that’s what we’re recommending,’ Angela Rocha, the pediatric infectologist at Oswaldo Cruz Hospital in Brazil.

The rare congenital condition is associated with incomplete brain development, and affected infants are born with shrunken skulls.

The World Health Organisation reports the most affected areas of Brazil are the states of Pernambuco and Paraíba. Additional cases have been detected in Rio de Janeiro and Sao Paulo, sparking concern ahead of the 2016 Summer Olympics to be held in August at Rio de Janeiro. ​The WHO has not confirmed a cause for the epidemic. However, CNN reports that doctors speculate the condition began to spike with the appearance of the mosquito-borne Zika virus in Brazil, which is characterized by a mild fever, rash and headaches.

Microcephaly is untreatable, according to the WHO. Brazilian health officials urge health officials in the area to report any cases of the condition.