A premature birth means that your baby hasn't had the usual amount of time to develop in the womb before needing to adapt to life outside the womb.
The signs that a baby's gestation has been cut short include:
- Small size, with a disproportionately large head
- Sharper looking, less rounded features than a full-term baby's features, due to a lack of fat stores
- Fine hair (lanugo) covering much of the body
- Low body temperature, especially immediately after birth in the delivery room, due to a lack of stored body fat
- Labored breathing or respiratory distress
- Lack of reflexes for sucking and swallowing, leading to feeding difficulties
The following tables show the median birth weight, length and head circumference of premature babies at different gestational ages for each sex.
|Weight, length and head circumference by gestational age for boys
||7 lbs., 15 oz.
|20 in. (51 cm)
||13.8 in. (35 cm)
||5 lbs., 8 oz.
|18.1 in. (46 cm)
||12.6 in. (32 cm)
||3 lbs., 15.5 oz.
|16.5 in. (42 cm)
||11.6 in. (29.5 cm)
||2 lbs., 6.8 oz.
|14.4 in. (36.5 cm)
||10.2 in. (26 cm)
||1 lb., 6.9 oz.
|12.2 in. (31 cm)
||8.7 in. (22 cm)
|Weight, length and head circumference by gestational age for girls
||7 lbs., 7.9 oz.
|20 in. (51 cm)
||13.8 in. (35 cm)
||5 lbs., 4.7 oz.
|17.7 in. (45 cm)
||12.4 in. (31.5 cm)
||3 lbs., 12 oz.
|16.5 in. (42 cm)
||11.4 in. (29 cm)
||2 lbs., 3.3 oz.
|14.1 in. (36 cm)
||9.8 in. (25 cm)
||1 lb., 5.2 oz.
|12.6 in. (32 cm)
||8.3 in. (21 cm)
Premature babies can quickly develop serious complications, such as infection in the bloodstream (sepsis) and respiratory distress syndrome.
When to see a doctor
You'll be seeing members of the neonatal intensive care unit (NICU) often. Doctors often visit NICUs at a similar time each day. But, don't hesitate to ask questions even when there's not a regularly scheduled meeting, especially if your baby seems listless, has poor color, or refuses the bottle or breast after trouble-free feedings.
Nov. 27, 2014
- Cunningham FG, et al. Williams Obstetrics. 24th ed. New York, N.Y.: The McGraw-Hill Companies; 2013. http://www.accessmedicine.com/resourceTOC.aspx?resourceID=46. Accessed Oct. 3, 2014.
- Creasy RK, et al., eds. Creasy and Resnik's Maternal-Fetal Medicine: Principles and Practice. 7th ed. Philadelphia, Pa.; Saunders Elsevier: 2014. http://www.clinicalkey.com. Accessed Sept. 30, 2014.
- Cook WJ, et al. Mayo Clinic Guide to Your Baby's First Year. Intercourse, Penn.: Good Books; 2012:503.
- Kliegman RM, et al. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, Pa.: Saunders Elsevier; 2011. http://www.clinicalkey.com. Accessed Oct. 13, 2014.
- Hay WW, et al. Current Diagnosis & Treatment: Pediatrics. 21st ed. New York, N.Y.: The McGraw-Hill Companies; 2012. http://accessmedicine.mhmedical.com/book.aspx?bookid=497. Accessed Oct. 17, 2014.
- Fenton TR, et al. A systematic review and meta-analysis to revise the Fenton growth chart for preterm infants. BMC Pediatrics. 2013;13:59.
- Norwitz ER. Prevention of spontaneous preterm birth. http://www.uptodate.com/home. Accessed Sept. 30, 2014.
- Robinson JN, et al. Risk factors for preterm labor and delivery. http://www.uptodate.com/home. Accessed Sept. 30, 2014.
- Mandy GT. Short-term complications of the premature infant. http://www.uptodate.com/home. Accessed Oct. 18, 2014.
- Cerebral palsy. March of Dimes. http://www.marchofdimes.org/baby/cerebral-palsy.aspx. Accessed Oct. 18, 2014
- Stewart J. Care of the neonatal intensive care unit graduate. http://www.uptodate.com/home. Accessed Oct. 18, 2014.
- Common NICU tests. March of Dimes. http://www.marchofdimes.org/baby/common-nicu-tests.aspx. Accessed Oct. 18, 2014.
- Mandy GT. Long-term complications of the premature infant. http://www.uptodate.com/home. Accessed Oct. 18, 2014.
- Harris MN, et al. ADHD and learning disabilities in former late preterm infants: A population-based birth cohort. Pediatrics. 2013;132:e630.
- Pertussis: Summary of vaccine recommendations. Centers for Disease Control and Prevention. http://www.cdc.gov/vaccines/vpd-vac/pertussis/recs-summary.htm. Accessed Oct. 18, 2014.
- Grieger JA, et al. Preconception dietary patterns in human pregnancies are associated with preterm delivery. Journal of Nutrition. 2014;144:1075.
- Hypertension in pregnancy. Washington, D.C.: American College of Obstetricians and Gynecologists. http://www.acog.org. Accessed Oct. 10, 2014.
- Hofmeyr GJ, et al. Calcium supplementation during pregnancy for preventing hypertensive disorders and related problems (Review). Cochrane Database of Systematic Reviews. http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD001059.pub4/abstract. Accessed Oct. 10, 2014.
- Stampalija AZ, et al. Cervical stitch (cerclage) for preventing preterm birth in singleton pregnancy (Review). Cochrane Database of Systematic Reviews. http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD008991.pub2/abstract. Accessed Oct. 10, 2014.
- Goya M, et al. Cervical pessary in pregnant women with a short cervix (PECEP): An open-label randomised controlled trial. The Lancet. 2012;379:1800.
- Abdel-Aleem H, el al. Cervical pessary for preventing preterm birth (Review) Cochrane Database of Systematic Reviews. http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD007873.pub3/abstract. Accessed Oct. 10, 2014.
- Ferguson KK, at al. Environmental phthalate exposure and preterm birth. JAMA Pediatrics. http://archpedi.jamanetwork.com/article.aspx?articleid=1769137. Accessed Oct. 10, 2014.
- Harms RW (expert opinion). Mayo Clinic, Rochester, Minn. Oct. 23, 2014.
You Are ... The Campaign for Mayo Clinic
Mayo Clinic is a not-for-profit organization. Make a difference today.