General characteristics of study participants
Out of the 595396 women included, 101900 (17.1%) were in the exposed group and the other 493496 (82.9%) were in the unexposed group (Table 1). The exposed group had higher proportions of participants older than 30 years (52.8% vs 49.4%), with GDM (15.4% vs 12.3%), multiparity (21.8% vs 15.9%), and natural delivery (62.2% vs 60.3%), but a lower proportion of HDP (2.3% vs 2.7%) than the unexposed group.