MIAMI BEACH — Individuals born preterm have diminished short- and long-term survival, as well as diminished reproductive capacity, and women born preterm are at increased risk of giving birth to their own offspring preterm, an analysis of data from a large birth registry suggests.
Data from about 610,000 men and 578,000 women entered into the Medical Birth Registry of Norway between 1967 and 1988 were analyzed and showed an overall rate of preterm birth of 5.7%, with 5.3% among females and 6.2% among males.
Those born preterm, compared with those born between 37 and 42 weeks' gestation, had “considerably higher” perinatal and infant mortality, and the increased mortality risk persisted through adolescence, Dr. Geeta K. Swamy reported at the annual meeting of the Society for Maternal-Fetal Medicine.
The odds ratios for early childhood death in those born extremely preterm (from 22 to 27 weeks' gestation) were 6.1 for males and 8.7 for females, and for those born very preterm (28–32 weeks' gestation), the odds ratios were 2.5 for males and 2.1 for females.
The odds ratio for late childhood death in those born extremely preterm was 6.3 for males (no females died in late childhood in this group), and for those born very preterm they were 1.9 for males, and 0.9 for females, said Dr. Swamy of Duke University, Durham, N.C.
Reproduction was significantly diminished in both men and women born extremely preterm who survived until at least age 18 years (odds ratio 0.48 for men and 0.52 for women) and in those born very preterm who survived to at least age 18 years (odds ratio 0.75 for men and 0.81 for women).
The risk for having offspring born preterm was increased only among women who were born preterm.
Approximately 17% of those born extremely preterm gave birth prematurely, compared with 7% of those born at term.
“The findings emphasize the increased need for health care and social services well beyond the neonatal and infant life periods,” Dr. Swamy said, adding that further study will analyze gender-specific causes of mortality to better determine how preterm birth affects long-term health.
A reevaluation to determine how continually improving survival rates among the extremely preterm affect overall reproduction is also warranted, Dr. Swamy concluded.