What is the impact of preconception abdominal cerclage on fertility: evidence from a randomized controlled trial.
BACKGROUND
There is documented concern that cerclage may cause cervical stenosis or changes to the cervical mucus, which may reduce fertility. The aim of this study is to determine whether placement of a preconception abdominal cerclage affects fertility.


METHODS
This was a planned subgroup analysis of a randomized controlled trial comparing abdominal cerclage, high vaginal cerclage or low vaginal cerclage. Women with a history of previous second-trimester miscarriage or preterm birth despite having a low vaginal cerclage, presenting to specialist preterm birth services in the UK, were eligible for inclusion. Only women randomized before conception were included in this analysis. Women randomized to abdominal cerclage had the surgery performed before conception (abdominal group). Women randomized to high or low transvaginal cerclage received it in the subsequent pregnancy (control group).


RESULTS
Abdominal cerclage was performed in 19 women and transvaginal cerclage in 48 women. Overall, there was no statistically significant difference between time to conception between the two groups (hazard ratio 1.34; 95% confidence interval 0.72-2.50, p = 0.35). Rates of conception at 6, 12, and 18 months were similar - 37% in abdominal group vs. 35% in control group at 6 months (relative risk 1.04; 95% confidence interval 0.52-2.10; p = 0.91); 58% in abdominal group vs. 42% in control group at 12 months (relative risk 1.39; 95% confidence interval 0.84-2.31, p = 0.21); 74% in abdominal group vs. 56% in control group at 18 months (relative risk 1.31; 95% confidence interval 0.91-1.89; p = 0.15).


CONCLUSIONS
This subgroup analysis of randomized data indicates that abdominal cerclage does not affect fertility rates.
Division of Women's Health, Women's Health Academic Centre, and Maternal and Fetal Research Unit, King's College London, Division of Reproduction and Endocrinology, St Thomas' Hospital, London, UK.
Nicola J
http://orcid.org/0000-0001-5216-8268
NJ
Vousden
Division of Women's Health, Women's Health Academic Centre, and Maternal and Fetal Research Unit, King's College London, Division of Reproduction and Endocrinology, St Thomas' Hospital, London, UK.
Jenny
J
Carter
Division of Women's Health, Women's Health Academic Centre, and Maternal and Fetal Research Unit, King's College London, Division of Reproduction and Endocrinology, St Thomas' Hospital, London, UK.
Paul T
PT
Seed
Division of Women's Health, Women's Health Academic Centre, and Maternal and Fetal Research Unit, King's College London, Division of Reproduction and Endocrinology, St Thomas' Hospital, London, UK.
Andrew H
AH
Shennan
D000328:Adult; D023802:Cerclage, Cervical; D005260:Female; D005298:Fertility; D006801:Humans; D007752:Obstetric Labor, Premature / Q000517:prevention & control*; D016742:Preconception Care; D011247:Pregnancy; D011256:Pregnancy Outcome; D016896:Treatment Outcome
Abdominal cerclage; cervical cerclage; fertility; randomized controlled trial