What are the chances that my baby will survive?

Many factors determine an individual baby's chances of survival. The most important of these are:

  • The baby's gestational age (number of completed weeks of pregnancy) at the time of birth

  • The baby's weight

  • The presence or absence of breathing problems

  • The presence or absence of congenital abnormalities or malformations

  • The presence or absence of other severe diseases, especially infection

In the smallest infants, gestational age is usually most important because it determines if the infant's organs, particularly the lungs, have developed enough to allow the baby to live within the limits of our current technology. Your baby's doctor will be able to give you the best estimate of your infant's chances since he/she can take into consideration many of the above factors. But, no estimate is perfect. Some babies suddenly get sick and die unexpectedly; others defy all odds. General estimates of survival for live born infants who receive neonatal intensive care in the USA in the late1990's are:

COMPLETED WEEKS OF GESTATION AT BIRTH

(using last menstrual period)

CHANCE OF SURVIVAL

21 weeks and less

0%

22 weeks

0-10%*

23 weeks

10-35%

24 weeks

40-70%

25 weeks

50-80%

26 weeks

80-90%

27 weeks

>90%

30 weeks

>95%

34 weeks

>98%

* Most babies at 22 weeks are not resuscitated because survival without major disability is so rare.

A baby's chances for survival increases 3-4% per day between 23 and 24 weeks of gestation and about 2-3% per day between 24 and 26 weeks of gestation. After 26 weeks the rate of survival increases at a much slower rate because survival is high already.

What other factors influence survival?

Other factors may influence survival by altering the rate of organ maturation or by changing the supply of oxygen to the developing fetus.

  • Rupture of the fetal membranes before 24 weeks of gestation with loss of amniotic fluid markedly decreases the baby's chances of survival even if the baby is delivered much later.

  • Male infants are slightly less mature and have a slightly higher risk of dying than female infants.

  • For a given weight, African-American babies have a slightly better survival than Caucasian; most other races are intermediate between the two.

  • Diabetes in the mother, if not well controlled, slows organ maturation and these infants have a higher mortality.

  • Severe high blood pressure before the 8th month of pregnancy may cause changes in the placenta, decreasing the delivery of nutrients and/or oxygen to the developing fetus and leading to problems before and after delivery.