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When a baby is born before 37 weeks of pregnancy, he or she is said to be preterm. Preterm births affect approximately 10% of pregnancies, according to the Centers for Disease Control (CDC). While all preterm babies are at risk, the biggest risk is for those born prior to 32 weeks. When can a baby survive outside the womb? This article will answer the questions that you have about premature birth.
What does fetal viability mean?

Fetal viability is the ability of a fetus to survive outside the womb when born. We look at fetal viability in terms of the age of the fetus, measured in the number of weeks that you are pregnant, known as gestational age. Gestational age is a good indication as it usually helps account for other measurements that affect fetal viability.
Other measurements include:
- Fetal weight: Babies that are at least 600 grams are more likely to survive than lighter babies.
- Sex: Girls are said to have a better chance of survival than premature boys.
- Plurality: Singletons have a better chance of survival than multiples.
- Prenatal care: If a woman receives corticosteroids, antibiotics, or magnesium prior to delivery, the baby has a higher chance of survival.
- Baby’s care immediately after birth: Babies born in hospitals with a neonatal intensive care unit (NICU) have a better chance of survival because they receive lifesaving care immediately.
What is the earliest a baby can be born: Age of viability

Babies born prior to 37 weeks are considered premature. However, there is still a high viability rate for these babies. It is when babies are less than 27 weeks of gestational age that the concern grows. Babies that reach the third trimester have the best chances of survival. Fortunately, birth prior to 27 weeks is rare, only happening 0.5% of the time according to a study conducted by the American College of Obstetricians and Gynecologists.
The rate of survival for babies born prior to 27 weeks is:
- 26 weeks: 86-89% survival
- 25 weeks: 67-76% survival
- 24 weeks: 42-59% survival
- 23 weeks: 23-27% survival
- 22 weeks or earlier: 5-6% survival
You can see that the survival rate significantly drops before 24 weeks. This is considered the potential point of viability among most doctors. “A baby is considered viable at around 24 weeks of gestation. However, survival rates depend on various factors, including the need for specialized medical care,” midwife Daniela Meier told Mom.com.
More from Mom.com: 15 Celebrity Parents Who’ve Opened Up About Their NICU Experiences
The problems with premature birth

The gestational period is there to give fetuses the time to grow and develop. When they are born early, they haven’t developed certain abilities. When a baby is born preterm, they may survive but have certain issues that include:
- Breathing problems as their lungs have not developed fully
- Feeding difficulties
- Cerebral palsy
- Developmental delay
- Vision problems
- Hearing problems
Amanda Hoffman is a mother whose son was born at 26 weeks. “Our biggest fear giving birth that early was whether or not he would live,” she told Mom.com. “Our secondary concerns were whether or not he would have cognitive and motor delays, in addition to issues with his lungs, brain, eyes, and heart.” Amanda’s concerns are common among moms giving birth preterm.
What are the warning signs of preterm labor?
If you feel you may be having preterm labor, it is important to get to the hospital as soon as possible so that your baby can receive the lifesaving care needed for preterm births. This means that you should be aware of the warning signs of preterm labor.
The warning signs of preterm labor include:
- Contractions that happen at least every 10 minutes (a contraction is where the abdomen tightens like a fist)
- An increase in vaginal discharge where you are leaking fluid or bleeding from the vagina
- Pelvic pressure where it feels like the baby is pushing down in the womb
- A backache that is located in the lower back
- Cramping that is reminiscent of your menstrual periods
- Abdominal cramping
Note: If you are experiencing preterm labor, it is important to see your doctor as soon as possible. They may be able to administer tocolytic medication. What this does is suppress labor to give your baby more time to develop, increasing his or her chances of survival. Tocolytics are known to reduce contractions and delay labor for days.
*Disclaimer: The advice on Mom.com is not a substitute for consultation with a medical professional or treatment for a specific condition. You should not use this information to diagnose or treat a health problem without consulting a qualified professional. Please contact your health-care provider with questions and concerns.