The five boys and one girl, each weighing between 0.9kg and 1.4kg, were born on Saturday night to 29-year-old Karoline Byler.

Five of the babies, who were born more than two months early, were listed in stable condition, while the medical team was still trying to stabilise one of the boys.

'The babies are still developing,' said Dr Roberto Sosa of All Children's Hospital. 'We are just trying to do what Mother Nature would do. We are cautiously optimistic that everything will turn out all right.'

Mr Ben Byler, the father, described the births as 'amazing'.

The boys were named Brady Christopher, Eli Benjamin, Ryan Patrick, Jackson Robert and Charlie Craig. The girl is MacKenzie Margaret.

'We saw them all and it's quite an experience,' said Mr Jack Kiewra, the grandfather. 'I'm very pleased everything went well. We have six new healthy grandbabies and my daughter is fine.'

The Bylers said they had used fertility drugs after their daughter, Zoe, 4, asked for a sibling.

The family were showered last week with clothing, diapers, baby wipes and gift cards. They also received a year's supply of ready-made meals and baby formula, six months of in-home wellness care and a US$7,000 (S$10,700) generator for backup electric power in this hurricane-prone state.

ASSOCIATED PRESS