Fig 1.
The flowchart of study sample selection from the National Health Insurance Research Database in Taiwan.
PID = Pelvic inflammatory disease: ICD-9-CM 614.9. Preterm labor: ICD-9-CM 644. Ectopic pregnancy: ICD-9-CM 633.
Fig 2.
Kaplan-Meier analysis for the cumulative risk of preterm labor/ectopic pregnancy among females aged 12–55 stratified by pelvic inflammatory disease (PID) with the log-rank test.
Left-button events: preterm labor. Right-button events: ectopic pregnancy.
Table 1.
Characteristics of the study endpoints.
Table 2.
Factors of preterm labor/ectopic pregnancy by using Cox regression.
Table 3.
Factors of preterm labor/ectopic pregnancy stratified by the variables listed in the table by using Cox regression.