Contraception in use by respondents; different (overlapping) subgroups.

If several methods were used (e.g., condoms plus fertility awareness), the most reliable method was recorded in this table. LNG IUD = Levonorgestrel-releasing intra-uterine device; OC = Oral contraception; TO = Tubal occlusion; CS = Caesarean section; VBAC = Vaginal birth after CS; HYS = post hysterectomy. Remainder: unknown, not at risk, abstinence, lactation amenorrhoea, depot medroxyprogesterone acetate injection, fertility awareness and coitus interruptus.