Study population
A flowchart of patient enrollment is shown in Fig. 1. Using the KNHI
claims database, we identified all women who gave birth from January
2007 to December 2015. Inclusion criteria were as follows: women who
gave birth between January 2006 and December 2016, and had undergone the
National Health Screening Program for Infant and Children (NHSP-IC)
visit to evaluate neonatal characteristics. Women with no or missing
NHSP-IC data were excluded from this study. This study was approved by
the Institutional Review Board of Korea University Medical Center
(2020GR0109).
We identified pregnant women who underwent non-obstetric surgery from
the database. Patients who underwent non-obstetric surgery at the time
of cesarean delivery were excluded. In this study, non-obstetric
surgeries (by laparoscopy or laparotomy) included the two most common
operative procedures for benign diseases: appendectomy and adnexal mass
resection. The operative procedures were identified by the presence of a
Korea Medical Insurance electronic data interchange (EDI) code
(Appendectomy: Q2861/Q2862/Q2863, Adnexal mass resection: R4430/R4421).
Laparoscopic surgery was identified by the associated Korea Medical
Insurance EDI code (N0031001).