Using cycling as transportation and related adverse events during pregnancy: An anonymous questionnaire survey in urban Japan.

Many pregnant women worldwide use bicycles as a mode of transportation. However, there is limited evidence regarding attitudes toward and the safety of cycling as a mode of transportation during pregnancy. This study aimed to clarify the prevalence of cycling as a mode of transportation before and during pregnancy and the adverse events associated with cycling during pregnancy. An anonymous questionnaire survey was conducted among pregnant women who owned a bicycle, were at 37 weeks of gestation, and agreed to participate in the study at 14 institutions managing deliveries in Japan in 2024. Participants were provided with request forms containing a QR code linking to an anonymous questionnaire on Google Forms™. Among 1,130 women, the proportion who cycled for transportation decreased significantly from 80.8% before pregnancy to 51.2% during pregnancy (P < 0.001). One-third (34.2%) of women who cycled during pregnancy continued cycling until 37 weeks of gestation. The incidences of threatened abortion and preterm labor were similar regardless of cycling status during pregnancy. Of the 579 women who cycled during pregnancy, 21 (3.6%) fell off a bicycle, of whom 15 were injured. Eight women (1.4%) were involved in a bicycle accident during pregnancy, of whom four were injured. These adverse events occurred irrespective of gestational age. Logistic regression analysis showed that women who cycled ≥5 days per week during pregnancy had a significantly higher risk of falling off a bicycle (odds ratio, 3.17). Pregnancy was associated with a significant decrease in cycling as a mode of transportation; however, cycling-related adverse events during pregnancy were uncommon. Women who cycle ≥5 days per week during pregnancy should exercise particular caution to avoid falls. Safe cycling practices and helmet use should be more widely promoted during pregnancy.