O2-6.1 A second chance? Probability of a live birth following initial pregnancy loss: survival analysis of Scottish national data

Objective To ascertain the chance of a second pregnancy resulting in live birth following pregnancy loss. Methods Scottish data on all women whose first pregnancy occurred between 1981 and 2000 were linked to records of a subsequent pregnancy. The exposed cohorts comprised women with a first ectopic pregnancy, miscarriage, stillbirth or termination. The unexposed cohort comprised women who had an initial live birth. Kaplan–Meier curves of time to second pregnancy outcome and live birth from the date of first pregnancy were constructed. Cox's proportional hazards models were used to calculate the HR with 95% CI of any second pregnancy and live birth. The reference category was women whose first pregnancy ended in a live birth. Results There were 667 144 women with an initial live birth, 39 530 with a miscarriage, 2969 with an ectopic first pregnancy, 3094 with a stillbirth and 78 493 with termination of their first pregnancy. After adjusting for maternal age at first delivery, socioeconomic status and year of first pregnancy event, the HR (95% CI) of any second pregnancy was 1.35 (1.28 to 1.42), 2.24 (2.21 to 2.27), 2.44 (2.35 to 2.54), 0.66 (0.65 to 0.67) following ectopic, miscarriage, stillbirth and termination respectively. The adjusted hazards of a live birth following ectopic, miscarriage, stillbirth and termination were 0.71 (0.64 to 0.79); 0.92 (0.90 to 0.95), 1.17 (1.06 to 1.29), 0.62 (0.60 to 0.63) respectively. Conclusion Compared to an initial live birth, pregnancy loss increased the chance of another pregnancy (except in case of termination) but decreased the chance of a live birth (except stillbirth), emphasising the role of voluntary contraception in fertility patterns.