Adverse outcome of pregnancy following air travel: a myth or a concern?

To assess whether air travel elevates the risk of adverse pregnancy outcomes in essentially healthy women with single non-anomalous fetuses at a gestational age greater than 20 weeks.

A retrospective analysis of air travel during the current pregnancy and pregnancy outcome was undertaken in 992 women admitted for delivery over a 12-month period. The study group of 546 (55%) women, of whom 57% were primigravidae, travelled at least once during pregnancy, and were compared with a control group of 447 women (45%), of whom 54% were primigravidae, who did not travel by air.

The primigravidae in the study group showed an increased risk of preterm birth, and this risk was statistically significant between the gestations of 34 and 37 weeks (adjusted odds ratio 1.5, 95% confidence intervals 1.2, 1.8); this risk remained elevated after adjustment for covariates. These women's pregnancies were appreciably shorter than those of primigravidae who did not fly (36.1 +/- 0.8 vs. 39.2 +/- 2.1 weeks) and their babies had lower birthweights (2684 +/- 481 vs. 3481 +/- 703 g). and were more likely to be admitted to the neonatal intensive care unit. This group of air travellers is unusual for the uncommonly long and frequent duration of air travel, which is not routinely undertaken in most parts of the world. There were no thromboembolic events complicating any pregnancies.

Primigravid women who travel by air appear to be at higher risk for preterm birth. Multicentre large studies are required to confirm or repute these findings.