Staying pregnant to full term, or 39-40 weeks, is one of the best ways to give babies the time they need to grow. Preterm birth—or delivery before 37 weeks of pregnancy—can prevent growth and development from happening inside a baby's body during the final weeks of pregnancy.1,2
Read on to learn about preterm birth, risk factors for preterm birth, and the important growth and development that occurs inside the womb.
Read on to learn about preterm birth, risk factors for preterm birth, and the important growth and development that occurs inside the womb.
In The News
- 2020 Premature Birth Report Cards March of Dimes
- Association Between Moderate and Late Preterm Birth and Neurodevelopment and Social-Emotional Development at Age 2 Years JAMA Pediatrics
- Births: Final Data for 2016 National Center for Health Statistics
What is Preterm Birth?
Preterm birth is the delivery of a baby less than 37 weeks of pregnancy.2 The last weeks of pregnancy are critical to a baby's growth and development. Click below to understand the definitions week by week.Click labels below to learn definitions.
Preterm birth is more common than you may think. In the United States, approximately 400,000 babies are born too early—or preterm—each year.6 More than 70% of all preterm births in the United States are late preterm births, a time in which important developments are still happening.7
Approximately 1 in 10 babies in the United States is born premature6
Babies Continue Important Development,
Even in those Final Weeks of Pregnancy
Explore inside the womb through this interactive 360° video, and discover the growth you can’t see and what a baby has to gain by reaching full term.
Important developments occur during the last weeks of pregnancy. Babies need every week inside the womb, as the brain, lungs, and liver are among the last organs to develop. Regardless of birth weight, babies born early are also more likely to be re-hospitalized.8 That's why getting to full term is important.
Around week 35, the brain is only 2/3 the size of a full term baby's.8
Hearing is not fully developed until full term.9
A baby's liver is not mature enough to prevent jaundice until full term.8,10
A baby may not have enough body fat to keep temperature steady until week 37.8,10
Breathing, sucking and swallowing reflexes are not ready until 34 weeks or later. A preterm birth may cause feeding and nutrition problems.8,10
Lungs continue to develop until the end of pregnancy, and babies may have trouble breathing if born early.8
Compared to term infants, late preterm infants were:8
Risk Factors
It's important to know and understand the risk factors for preterm birth. Preterm birth is often unexpected. Some women may have an early delivery due to a medical situation, and sometimes one may have a greater chance of preterm birth due to known risk factors.1,2
Leading Risk Factors
- Prior preterm birth (unexpectedly delivered a baby before 37 weeks in the past)
- Pregnant with twins, triplets, or other multiples
- Problems with uterus or cervix
- African-American heritage
Other Risk Factors
- High blood pressure, stress, diabetes, or being overweight or underweight
- Smoking, drinking alcohol, or using drugs
- Short time between pregnancies
- Certain infections during pregnancy
Are You At Risk?
If you think you may be at risk for preterm birth, seek early prenatal care. Bring the risk factors checklist to your healthcare provider and talk with him or her about ways you can reduce your risk, including possible treatment options.
Signs & Symptoms of
Preterm Labor
Pregnant women should be familiar with the signs of preterm labor.12 If any signs or symptoms of preterm labor occur before a baby's due date, contact a healthcare provider as soon as possible.
Contractions, or tightening of the belly muscles, every ten minutes or less
Belly cramps with or without diarrhea
Low, dull backache
Cramps resembling menstrual cramps
Feeling of pressure in the pelvic area
A change in vaginal discharge
A Message from Moms to Moms
Hear how other moms learned about their preterm risk through these stories and video.
Learn More About Preterm Birth: Free Educational Resources
If you’re a healthcare provider, patient advocacy organization, insurance company, or someone interested in sharing educational materials, you can order free The Growth You Can’t See materials to help bring the importance of the last six weeks to life. Materials for order include a postcard to share with your patients to go inside the womb for a virtual reality experience, as well as an educational brochure and poster. You can also download a free digital toolkit of all the materials offered in the resource center below. Some materials are available in multiple languages.
Preterm Birth Resource Center
In the Womb: An Interactive 360º Video Experience
Explore the important development milestones during the last weeks of pregnancy with this interactive video.
In the Womb: Video Postcard
This postcard provides helpful information on how to view the interactive video, In The Womb: From Head to Toe.
Are You At Risk For Preterm Birth? Checklist
Bring this checklist with you to your next doctor appointment to learn if you may be at risk for preterm birth.
Development Milestones Poster
View important development milestones that occur during the last few weeks of pregnancy. It is also available in Spanish.
Preterm Birth 101 Video
Featuring Dr. Judette Louis, a Maternal-Fetal Medicine specialist, this video helps you learn about whether you may be at risk of delivering preterm. At the time of video filming, Dr. Louis was a consultant of AMAG Pharmaceuticals, Inc.
Health & Family Segment
Hear from a Maternal-Fetal Medicine specialist on preterm birth and its risk factors, and from a mom of two premature babies who also shares her experiences. At the time of video filming, Dr. Biggio was a consultant of AMAG Pharmaceuticals, Inc.
40 Weeks Webisode Video
Hear a mom discuss her pregnancy story and share her experience of how she learned she was at risk for delivering preterm. The video was sponsored by AMAG Pharmaceuticals, Inc. as part of their sponsorship of 40 Weeks.