Preterm birth

Preterm birth
SynonymsPremature birth, preemies, premmies
Premature infant with ventilator.jpg
Intubated preterm baby in an incubator
SpecialtyObstetrics, pediatrics
SymptomsBirth of a baby at fewer than 37 weeks gestational age[1]
ComplicationsCerebral palsy, delays in development, hearing problems, sight problems[1]
CausesOften unknown[2]
Risk factorsDiabetes, high blood pressure, being pregnant with more than one baby, obesity or underweight, a number of vaginal infections, celiac disease, tobacco smoking, psychological stress[2][3][4]
TreatmentCorticosteroids, keeping the baby warm through skin to skin contact, supporting breastfeeding, treating infections, supporting breathing[2][6]
Frequency~15 million a year (12% of deliveries)[2]

Preterm birth, also known as premature birth, is the birth of a baby at fewer than 37 weeks gestational age.[1] These babies are known as preemies or premies.[1] Symptoms of preterm labor include uterine contractions which occur more often than every ten minutes or the leaking of fluid from the vagina.[8] Premature infants are at greater risk for cerebral palsy, delays in development, hearing problems and sight problems.[1] These risks are greater the earlier a baby is born.[1]

The cause of preterm birth is often not known.[2] Risk factors include diabetes, high blood pressure, being pregnant with more than one baby, being either obese or underweight, a number of vaginal infections, tobacco smoking and psychological stress, among others.[2][3] It is recommended that labor not be medically induced before 39 weeks unless required for other medical reasons.[2] The same recommendation applies to cesarean section.[2] Medical reasons for early delivery include preeclampsia.[9]

In those at risk, the hormone progesterone, if taken during pregnancy, may prevent preterm birth.[5] Evidence does not support the usefulness of bed rest.[5][10] It is estimated that at least 75% of preterm infants would survive with appropriate treatment, and the survival rate is highest among the infants born the latest.[2] In women who might deliver between 24 and 37 weeks, corticosteroids improve outcomes.[6][11] A number of medications, including nifedipine, may delay delivery so that a mother can be moved to where more medical care is available and the corticosteroids have a greater chance to work.[12] Once the baby is born, care includes keeping the baby warm through skin to skin contact, supporting breastfeeding, treating infections and supporting breathing.[2]

Preterm birth is the most common cause of death among infants worldwide.[1] About 15 million babies are preterm each year (5% to 18% of all deliveries).[2] Approximately 0.5% of births are extremely early periviable births, and these account for most of the deaths.[13] In many countries, rates of premature births have increased between the 1990s and 2010s.[2] Complications from preterm births resulted in 0.81 million deaths in 2015 down from 1.57 million in 1990.[7][14] The chance of survival at 22 weeks is about 6%, while at 23 weeks it is 26%, 24 weeks 55% and 25 weeks about 72%.[15] The chances of survival without any long-term difficulties are lower.[16]


Stages in prenatal development, with weeks and months numbered from last menstruation.

In humans, the usual definition of preterm birth is birth before a gestational age of 37 complete weeks.[17] In the normal human fetus, several organ systems mature between 34 and 37 weeks, and the fetus reaches adequate maturity by the end of this period. One of the main organs greatly affected by premature birth is the lungs. The lungs are one of the last organs to mature in the womb; because of this, many premature babies spend the first days and weeks of their lives on ventilators. Therefore, a significant overlap exists between preterm birth and prematurity. Generally, preterm babies are premature and term babies are mature. Preterm babies born near 37 weeks often have no problems relating to prematurity if their lungs have developed adequate surfactant, which allows the lungs to remain expanded between breaths. Sequelae of prematurity can be reduced to a small extent by using drugs to accelerate maturation of the fetus, and to a greater extent by preventing preterm birth.

Other Languages
العربية: ولادة مبكرة
беларуская: Неданошанае дзіця
català: Part preterme
Deutsch: Frühgeburt
한국어: 조산
Հայերեն: Անհաս երեխա
עברית: פג
മലയാളം: അകാലജനനം
日本語: 早産
oʻzbekcha/ўзбекча: Chala tugʻilgan bola
português: Parto pré-termo
Simple English: Premature birth
suomi: Keskonen
svenska: Prematur
Türkçe: Erken doğum
українська: Недоношена дитина
Tiếng Việt: Sinh non
中文: 早產