Background/purpose: The incidence of gastroschisis has increased over the past 3 decades in a number of countries. To elucidate the Japanese status of anterior abdominal wall defects, the Japanese Society of Pediatric Surgeons conducted a national survey in Japan.
Methods: Information was obtained by sending out a questionnaire to 192 University Hospitals, Children's hospitals, and general hospitals that each had more than 200 beds. The characteristics of the patients including the birth date, birth weight, gestations, rate of associated anomalies, rate of antenatal diagnosis and prognosis, maternal age, gravidity, history of smoking, and drug use were analyzed.
Results: The authors obtained answers from 149 institutions, including 1,785 cases of omphalocele and 970 cases of gastroschisis, which were treated between 1975 to 1997. There was a significant increase in the incidence of gastroschisis, from 0.131 in 1975 to 1980, 0.269 in 1981 to 1985, 0.337 in 1986 to 1990, 0.461 in 1991 to 1995 to 0.467 per 10,000 births in 1996 to 1997. The incidence of omphalocele was 0.322 in 1975 to 1980, 0.567 in 1981 to 1985, 0.657 in 1986 to 1990, 0.741 in 1991 to 1995 to 0.626 per 10,000 births in 1996 to 1997, respectively. In the omphalocele group, 43.1% of the mothers were between 25 to 29 years of age, whereas in the gastroschisis group 42.6% of the mothers were 20 to 24 years of age. In the gastroschisis group, the number of primipara mothers was larger than that of multipara mothers. In the omphalocele group, approximately 10% of the mothers smoked during each period, whereas in the gastroschisis group, the percentage of smoking mothers increased chronologically from 12.9% in 1981 to 1985, 18.7% in 1986 to 1990, 23.5% in 1991 to 1995 and 29.3% in 1996 to 1997. A history of drug use by the mother was approximately 10% for both the omphalocele and gastroschisis groups. In the omphalocele group, 55.9% had associated anomalies against 21.8% in the gastroschisis group. Approximately 10% in the omphalocele group and less than 3% in the gastroschisis group showed chromosomal abnormalities. From 1986, a significant number of cases detected antenatally has been observed.
Conclusions: There have been substantial changes in the incidence of anterior abdominal wall defects, particularly regarding gastroschisis in Japan. The reasons for such changes are most likely multifactorial, further epidemiological monitoring is thus called for.