Purpose: There have been conflicting reports on the incidence of gastroschisis and its seasonal variation. Studies have found an increased risk of gastroschisis in deliveries occurring in the winter months in the northern hemisphere. Other studies have not found a seasonal variation. To evaluate the existence of a seasonal variation in the incidence of gastroschisis in our patients, a retrospective database analysis was conducted.
Materials and methods: Second and third trimester pregnancy screening was performed on 8031 patients between October 2001 und September 2005. Patients were evaluated throughout the year separately for their expected date of delivery and date of conception during the summer months (April-September) and the winter months (October-March).
Results: We diagnosed 17 fetuses having gastroschisis with a mean gestational age at diagnosis of 24 weeks (range 11-33). The number of second and third trimester screening examinations and the number of patients with an expected date of delivery was not different during summer and winter months, 3980 vs. 4051. The expected date of birth (corrected for early ultrasound measurement) of fetuses with gastroschisis was more common during the winter months (n=11) than during summer months (n=6). However, this difference is not statistically significant (p=0.21) as was also the case for the date of conception.
Conclusion: There seems to be no seasonal variation in the frequency of gastroschisis depending on the estimated date of birth or date of conception.