Fertility and Reproductive Outcomes Following Recurrent Miscarriage : A Retrospective Cohort Study

We undertook a retrospective cohort study to identify subsequent reproductive outcomes in women with recurrent miscarriage (RM), defined as three consecutive first-trimester miscarriages, to examine if maternal characteristics were linked to subsequent fertility or pregnancy outcomes. Women attending a consultant-led RM clinic at a tertiary university hospital in the Republic of Ireland over a 12-year period (2008 - 2020) with a confirmed diagnosis of first-trimester RM were eligible for inclusion. Women with non-consecutive miscarriages or ectopic pregnancy were excluded. Maternal characteristics were gathered from paper and electronic medical records. Data were analysed using SPSS (V27). Associations between maternal characteristics and outcomes were explored using χ2 test, (significance; p< 0.05). Multinomial regression analysis was performed using a stepwise approach. 748 women were included; 573 women had a subsequent pregnancy (77%); 359 (63%) had a live birth and 208 (36%) had a further pregnancy loss. Women aged 35-39 were more likely to to have a livebirth than no pregnancy (RR 2.3(95% CI [1.51,5.30])). Women aged 30-34 were more likely to have a livebirth (RR 3.74 (95% CI [1.80,7.79])) or a miscarriage (RR 2.3 (95% CI [1.07,4.96])) than no pregnancy. Smokers were less likely to have a livebirth (RR 0.37 (95% CI [0.20, 0.69])) or a miscarriage (RR 0.45 (95% CI [ 0.22, 0.90])) than no further pregnancy. Women with an abnormal parental karyotype were less likely to have a miscarriage than no further pregnancy (RR 0.09 (95% CI [0.01,0.79])). Including successive pregnancies conceived over the study period, the overall live birth rate was 81% (n= 466), falling to 44% in women aged >40 and 54% in women with infertility. Age, smoking and balanced translocations were associated with subsequent reproductive outcomes. Tailored counselling regarding individual risk factors for women with RM is imperative.