A population-based incidence of gastroschisis using the unique characteristics of a geographically isolated state with a single tertiary obstetric and pediatric hospital has been developed via retrospective data review. Sixty-four cases of gastroschisis were identified during the period 1980 to 1993. With 332,530 deliveries in the 14-year review period, the population incidence of gastroschisis is 1.80 per 10,000 births (95% CI 1.40-2.32). There has been a rise in incidence from 0.48 per 10,000 births in 1980 to 3.16 per 10,000 births in 1993 (NS). This alteration in incidence is an age-group specific event. The age group 15-19 years, which accounts for a consistent 6.5% of total deliveries, has 10 times the incidence of the age range 25-29 years. A sharp rise in the occurrence of gastroschisis in women 15-19 years was observed, with the incidence increasing from 4.0 to 26.5 per 10,000 births over the period of review. Increased use of prenatal ultrasound has made antenatal diagnosis usual and consequent referral to the tertiary referral hospital for delivery. There was a 46% incidence of smoking, and 19% of women admitted to recreational drug use. A strong association with preterm delivery and low birthweight was present with a 50% incidence of low birthweight, eight times the state incidence (OR 14.82, 95% CI 8.97-24.51). The rate of preterm birth was 46.1% vs. 6.6% in the general obstetric population (OR 12.11, 95% CI 6.45-22.73). There was a high incidence of perceived fetal distress, reflected in an increased rate of emergency cesarean section (23% vs. 8%, OR 4.31, 95% CI 1.91-9.74). The early neonatal outcome was satisfactory with three neonatal deaths and an overall perinatal survival rate of 85%. The increase in incidence of gastroschisis in this population-based study reveals a strong association with young maternal age. Investigation into possible etiologic factors to explain this observation is required.