BRASILIA (Reuters) - The number of confirmed and suspected cases of microcephaly in Brazil associated with the Zika virus remained stable at 4,908 in the week through April 23, just one case more than a week earlier, the Health Ministry said on Tuesday.

Of these, the number of confirmed cases climbed to 1,198 from 1,168 a week earlier, but suspected ones under investigation continued to decline to 3,710 from 3,741 a week ago.

Cases that have been ruled out rose to 2,320 in the week through April 23, from 2,241 a week earlier, the ministry said.

Brazil considered most of the cases of babies born with abnormally small heads to be related to Zika, though the link between the virus and the birth defects has not been scientifically established.

Brazil has registered 91,387 likely cases of the Zika virus from February until April 2, the health ministry said earlier on Tuesday, in its first national report on the epidemic.

The country's populous southeast, which includes Olympic city Rio de Janeiro, registered the most diagnoses of any region, with 35,505 likely cases.

(Reporting by Brad Haynes and Anthony Boadle; Editing by Bernard Orr)