When a baby is born before 37 weeks, she’s considered premature. Depending on when the baby is born, she may have a greater likelihood of surviving outside the womb. Typically, the earliest a premature baby can survive is 22 weeks. Factors such as fetal distress and medications given to the mother may affect survival rates.
Survival and Age
While the earliest that a baby can typically survive outside of the womb is 22 weeks, not every infant will make it at this age. In the study “Improving Survival of Extremely Preterm Infants Born Between 22 and 25 Weeks Gestation" by Kathy Kyser and colleagues published in the April 2012 journal Obstetrics and Gynecology, 33 percent of premature babies lived after being born at 22 weeks. Roughly 80 percent of babies born at 26 weeks and 90 percent of those born at 27 weeks survive, notes the website BabyCenter. However, roughly one-quarter of premature babies have lifelong disabilities.
The baby's lungs continue developing through the end of the third trimester. Giving corticosteroids to the mother who is in pre-term labor can help the baby’s lungs develop quickly so they can function outside of the womb. Doctors use this medication to help the baby’s lungs mature at a faster than normal rate before birth. Corticosteroids are most effective when used with babies at least 26 weeks gestational age, according to the World Health Organization.
Age and Issues
A late preterm baby is an infant born between 35 and 37 weeks. Babies born at this time typically have very few problems surviving outside of the womb. Even though they’re more at risk for complications than full-term babies, they seldom require a stay in neonatal intensive care, according to the University of Maryland Medical Center.
Premature babies who are born earlier than 35 weeks may have trouble breathing, digestive problems, anemia, jaundice, infections or bleeding in the brain. Babies that have one or more of these conditions may need to stay in the neonatal intensive care unit -- or NICU -- until the doctor feels they are ready to survive without medical assistance. While there, premature babies are placed in incubators to regulate body temperature.
NICU and Going Home
As the preterm baby develops and grows in the NICU, he is also getting ready to go home. While the incubator in the NICU provides a womb-like environment, the baby is steadily putting on weight. When the baby weighs four pounds or more, can breathe without help and is steadily gaining weight, he is ready to go home.
Along with an incubator, preterm infants may need other help to survive on the outside world. These may include a tube down the baby’s windpipe, tubes inside the nose or oxygen given by a ventilator to help with breathing.
Babies born prematurely may also need a feeding tube or intravenous fluids.