Understanding the Range of Premature Birth
Lindsay Knake
| 3 min read
About one in 10 babies are born prematurely in the United States.
A preterm baby is born at 37 weeks or earlier, while atypical pregnancy is 40 weeks. Being born early can mean serious health risks for infants, particularly in their brain and lungs. The range of premature birth spans several weeks, and premature babies will require more care.
Let’s look at the range of premature birth and what it means for infants and their caregivers.
The range of premature birth
There are four categories of premature births, according to the Mayo Clinic:
Late preterm, born between 34 weeks and 36 weeks, 6 days. Most premature births are at this stage.
- For girls, average weight and length at 35 weeks are: 5 lbs., 4.7 oz. and 17.7 in.
- For boys, average weight and length at 35 weeks are: 5 lbs., 8 oz. and 18.1 in.
Moderately preterm, born between 32 and 34 weeks.
- For girls, average weight and length at 32 weeks are: 3 lbs., 12 oz. and 16.5 in.
- For boys, average weight and length at 32 weeks are: 3 lbs., 15.5 oz. and 16.5 in.
Very preterm, born between 28 and 32 weeks.
- For girls, average weight and length at 28 weeks are: 2 lbs., 3.3 oz. and 14.1 in.
- For boys, average weight and length at 28 weeks are: 2 lbs., 6.8 oz. and 14.4 in.
Extremely preterm, born before 28 weeks.
- For girls, average weight and length at 24 weeks are: 1 lb., 5.2 oz. and 12.6 in.
- For boys, average weight and length at 24 weeks are: 1 lb., 6.9 oz. and 12.2 in.
The risk for health problems and complications increases the earlier a baby is born, especially before 32 weeks of gestation, according to the U.S. Centers for Disease Control and Prevention (CDC). Premature infants may need to spend weeks or even months in a neonatal intensive care unit (NICU).
Organs such as the lungs and liver are still developing late into pregnancy. Anemia, underdeveloped lungs, jaundice and sepsis are common health problems for preemies, according to the Cleveland Clinic. Being born early also increases the risk of developmental delays and disabilities such as cerebral palsy.
Common symptoms of premature birth include:
- Low birth weight
- Trouble breathing
- Difficulty feeding
- Low body temperature right after birth
- Fine hair covering the baby’s body
Risk factors for premature births
There are many risk factors for premature births, according to the CDC. Some risk factors are preventable or manageable, while others are not. Preterm births can also happen without cause.
Common risk factors include:
- Teenagers who are pregnant
- Women age 35 or older
- Carrying two or more babies
- Black women
- Native Hawaiian and Pacific Islander women
- American Indian or Alaska Native women
- Women with lower incomes
- A prior preterm birth
- Preeclampsia
- High blood pressure during pregnancy
- Tobacco or drug use during pregnancy
There is no one way to prevent premature births, but there are steps you can take to reduce the risk. If you are pregnant and have any of these risk factors, start prenatal care as soon as you know you are pregnant. Attend all of your prenatal appointments and talk to your primary care physician or obstetrician about any health conditions you have. During pregnancy, eat a healthy diet.
Image: Getty Images
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