Chances for Survival

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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 carefrom birth in the USA in the late1990's are:

COMPLETED WEEKS OF GESTATION AT BIRTH using last menstrual period	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 recuscitated because survival without major disabilities is so rare. Many at 23 weeks are also not resuscitated because outcome is poor.

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.

Can my obstetrician do anything to improve my baby's chances of survival?

Yes, there are things s/he can try if there is enough time and if you are the appropriate candidate for therapy. Sometimes women are too near delivery for treatments to be effective. Other women have complications such as infection, fetal distress or bleeding which make a more rapid delivery the best option.

You may be placed on bedrest.
Your obstetrician may try to stop your labor using labor-inhibiting drugs.
Your obstetrician may give you a steroid medication such as Betamethasone or Dexamethasone to try to speed up the baby's lung development. This is most effective if it is given more than 24 hours before delivery.

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Last reviewed or modified 04/20/00.

Contact jebrazy@facstaff.wisc.edu for corrections or comments. We will not answer specific medical questions about your baby. These should be directed to the physician and nurses who are caring for your baby.

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