A cluster study of gastroschisis: single center experience.

Background and methods: A cluster of 10 neonates admitted with a diagnosis of gastroschisis at birth to the Neonatal Intensive Care Unit (NICU) at the University of Kentucky Medical Center in the year 1996, prompted us to perform a retrospective analysis to determine environmental or genetic causes.

Results: A total of 36 neonates with gastroschisis were admitted during the period 1/1992 to 12/1996, and the maternal and patient demographics were evaluated by chart review. The mean maternal age was 21.5 years (14-35 years) of which 42% were teenagers, 66% were primiparous, 42% were smokers, 6% had a history of illicit drug use, and 72% had a history of taking prenatal vitamins. Mean birth weight was 2438g (990-3700g) with 54% being preterm with a mean gestational age of 36 wks (29-40 wks). Family history was negative and chromosomes were normal in patients in whom a karyotype was performed (25%). There was no recurring environmental or drug exposure in the study group. The mothers were from 24 different counties of Kentucky. The 36 cases were not uniformly distributed over the five-year period (chi square statistic = 46.8, degrees of freedom = 4, p < 0.0001). However, there was no evidence that the cases clustered in any 1 year (p = 0.99 for Ederer-Myers-Mantel test).

Conclusions: This is one of the few cluster studies of babies born with gastroschisis. Many of the mothers were teenagers, primiparous, and had an increased frequency of smoking. There was no evidence of temporal or spatial clustering in the gastroschisis cases. We conclude that the cluster of gastroschisis cases in our study occurred as a matter of chance.