Premature Birth Raises Future Stillbirth Risk
Previous Preterm Delivery or Low Birth Weight Infant Signals Risk for Future Stillbirth
Feb. 18, 2004 -- Women who gave birth to a premature or a low-birth-weight infant in the past may face a much higher risk of stillbirth in future pregnancies than others, a new study shows.
Researchers say stillbirth accounts for more than half of infant deaths in developed countries. Although many of the causes of stillbirth are not understood, researchers say fetal growth restriction may be a major factor.
Problem Pregnancy Raises Stillbirth Risks
In this study, researchers looked at whether the birth of a previous premature infant or an infant of low birth weight increased the risk of stillbirth in future pregnancies among 410,021 women in Sweden who gave birth to their first and second children between 1983 and 1997.
Among these women, there were 1,842 stillbirths during the first pregnancy and 1,062 during the second.
Compared with women whose first infant was born at full term (37 weeks gestation or longer) and was of normal weight, women whose first infant was of low birth weight and delivered either at term or prematurely were more than twice as likely to suffer a stillbirth during their second pregnancy.
But the risk of stillbirth during the second pregnancy was greatest among women who gave birth prematurely during their first pregnancy. For example:
- Women whose first child was both a low-birth-weight infant and was born moderately preterm (32 to 36 weeks gestation) were 3.4 times more likely to suffer stillbirth.
- Women whose first child was both a low birth-weight-infant and was born very preterm (before 32 weeks gestation) were five times more likely to suffer stillbirth.
The study showed the risk of stillbirth for women whose first infant was stillborn was 2.5 greater compared with women whose first infant was not stillborn.
The overall rate of stillbirths ranged from 2.4 per 1,000 births among women whose first infant was born at term and was normal weight to 19 per 1,000 births among those whose first child was very premature and small for gestational age.
Researchers say recognizing the early signs of growth problems in the fetus may one day help prevent future stillbirths. But effective interventions must first be developed to treat these problems.