Epidemiology of the early amnion rupture spectrum of defects
A. Garza, J. F. Cordero and J. Mulinare
Division of Birth Defects and Developmental Disabilities, Centers for Disease Control, Atlanta.
We used data from the population-based Metropolitan Atlanta Congenital
Defects Program to study the epidemiology of the early amnion rupture
spectrum of defects. For the period 1968 through 1982, we identified 45
patients among 388,325 live births, for a birth prevalence rate of 1.16 per
10,000. The prevalence for male infants was 0.91 and for female infants,
1.44. The defects occurred 1.76 times more often in blacks than in whites
(95% confidence interval 0.98, 3.13). Infants of young, black multigravidas
(less than 20 years, more than one pregnancy) showed the highest rate
(6.2), and infants of older, black multigravidas showed the lowest rate
(0.5) (rate ratio = 12.4, 95% confidence interval 4.2, 36.4). These
findings suggest that young, black multigravidas are at much higher risk
than are older, black multigravidas of having infants with this spectrum of
defects. Ascertainment (diagnostic) differences between hospitals probably
account for some of the racial discrepancy in birth prevalence, but they do
not explain the maternal age effects in black multigravidas. Because the
higher rates for blacks probably reflect more accurate diagnoses, the
findings also suggest that a closer estimate of the true birth prevalence
may be about 3 per 10,000 live births.
