SAO PAULO - The birth rate in Brazil has fallen by its fastest rate in nearly three decades after the Zika and microcephaly crisis of 2016.

Brazil's statistics agency says on Tuesday there were 2.79 million births in 2016, a 5 per cent decrease from the year prior.

The birth rate fell by 10 per cent in the northeastern state of Pernambuco, where the Zika crisis hit particularly hard.

The Zika virus is spread primarily through mosquito bites and causes babies to be born with abnormally small heads and other severe brain defects.

Analysts from the Institute of Geography and Statistics believe the country's long economic crisis also contributed to the decrease.