Premature Birth

In 2021, 1 in 10 babies was born too early in the United States. Learn about the problem, risk factors, and what we can do to reduce premature birth.

About Premature Birth

A developing baby goes through important growth throughout pregnancy—including in the final months and weeks. Premature (also known as preterm) birth is when a baby is born too early, before 37 weeks of pregnancy have been completed. The earlier a baby is born, the higher the risk of death or serious disability. In 2020 [PDF – 176 KB], preterm birth and low birth weight accounted for about 16% of infant deaths. Babies who survive can have breathing issues, intestinal (digestive) problems, and bleeding in their brains. Long-term problems may include developmental delay (not meeting the developmental milestones for his or her age) and lower performance in school.

Preterm Birth in the United States

Reducing preterm birth is a national public health priority. The preterm birth rate rose 4% in in 2021, from 10.1% in 2020 to 10.5% in 2021. However, racial and ethnic differences in preterm birth rates remain. In 2021, the rate of preterm birth among non-Hispanic black women (14.8%) was about 50% higher than the rate of preterm birth among non-Hispanic white women (9.5%) or Hispanic women (10.2%).

Risk Factors

Experts don’t know all the reasons that some babies are born too early. Some things (called risk factors) can increase the chance that a woman will have a preterm birth. However, a woman can still have a premature birth even if she has no known risk factors. Some risk factors for preterm birth include delivering a premature baby in the past, being pregnant with multiples, tobacco use and substance abuse, and short time (less than 18 months) between pregnancies. Additionally, pregnancy complications can result in preterm birth because the baby has to be delivered early.

Signs and Symptoms of Preterm Labor

In most cases, preterm labor (labor that happens too soon, before 37 weeks of pregnancy) begins unexpectedly and the cause is unknown. Like regular labor, signs of early labor include—

• Contractions (the abdomen tightens like a fist) every 10 minutes or more often
• Change in vaginal discharge (a significant increase in the amount of discharge or leaking fluid or bleeding from the vagina)
• Pelvic pressure—the feeling that the baby is pushing down
• Low, dull backache
• Abdominal cramps with or without diarrhea

If you have any signs or symptoms of preterm labor, call your healthcare provider right away.

What Can We Do?

We can work to reduce preterm birth using the following strategies:

• Providing women access to health care before and between pregnancies;
• Identifying women at risk for preterm delivery and offering treatments that may reduce the risk of preterm birth;
• Preventing unintended pregnancies and waiting at least 18 months between pregnancies;
• Choosing single embryo transfer as appropriate when undergoing in vitro fertilization because being pregnant with multiples (twins, triplets, or more) has a higher risk of preterm birth.

CDC Activities

CDC’s Division of Reproductive Health is engaged in a variety of activities to reduce preterm delivery and complications. CDC recently expanded support to 27 perinatal quality collaboratives (PQCs), which are state or multi-state networks of teams of healthcare providers and public health professionals working to improve the quality of care for mothers and babies. Funding supports the capabilities of PQCs to improve the quality of perinatal care in their states, including efforts to reduce preterm birth and improve prematurity outcomes. CDC works with experts to develop tools PQCs can use to further their development, including a resource guide [PDF – 566 KB].

In 2022, CDC awarded the National Institute for Children’s Health Quality to serve as the coordinating center for the National Network of Perinatal Quality Collaboratives (NNPQC), which supports statewide PQCs in making measurable improvements in statewide health care and health outcomes for mothers and babies. Learn about other efforts to address prematurity at CDC Preterm Birth Activities.