Factors included in the bivariate and logistic regression modelling
| Category | Factors |
|---|---|
| Demographic/background | Age (continuous, grouped), region, ethnicity, religion, social deprivation, social class, tenure, marital status, family formation, educational achievement, schooling, parental openness |
| Lifestyle | Alcohol consumption, smoking behaviour, body mass index, drug usage |
| Sexual initiation | Age at first sexual experience (continuous, grouped), age at first intercourse (continuous, grouped), sexual competency |
| Sexual history | Number of partnerships (ever, last year, last 5 years), concurrent partnerships, sexually transmitted infection history |
| Contraceptive use | Contraceptive use at first intercourse (ever, most recent partner), typical use, occasions of unprotected intercourse, use of condoms |
| Pregnancy history | Parity, number of children, fatherhood, births prior to first abortion, age at last abortion/first abortion (continuous, grouped), experience of spontaneous abortion and stillbirth |