A babies lungs are developed at 35 weeks enough to where they can usually breathe on their own once they are out of the womb.
However a babies lungs are not usually fully developed until the baby is around 36 to 37 weeks.
Some babies born before 37 weeks may need to be in NICU and have breathing help for a few weeks but some babies may be okay and be able to breathe on their own at 35 to 36 weeks.
Any baby that is born before 37 weeks is considered to be premature.
Although some babies that are born before 37 weeks and at 35 weeks may not be premature at all and they may be developed enough in the womb to be healthy.
However some babies that are born before 37 weeks or are born at 35 or even 36 weeks may need to be in the NICU and are premature.
Babies that are born before 37 weeks are at a higher risk of health issues than those babies that are born at 37 weeks.
Some babies can be born at 35 weeks and be healthy.
My brother was born at 35 weeks of the pregnancy and he was very healthy and needed no additional care in the hospital.
He turned out just fine and had not other health issues.
Some babies may not be healthy though when born at 35 weeks but 35 weeks into the pregnancy means the baby is nearly fully developed.
A 35 week old baby that is still in the mother's womb should weigh at least 5 lbs and be nearly full term or may be full term.
A baby is usually full term completely when the baby is 36 weeks old in the womb which is 9 months of pregnancy.
At 36 weeks the baby is around 5.78 lbs in weight and around 18.66 inches in length.
Some babies are born at 35 weeks and some of those babies do just fine and are healthy babies.
However some babies born at 35 weeks may need to be in the NICU for awhile to make sure they are gonna be healthy and breathe properly.
If possible it's best to have the baby at 36 to 37 weeks and not at 35 weeks.
But that is usually out of the mother's or doctors control.