OBJECTIVE: To assess pregnancy outcomes in women with threatened miscarriage in the first trimester.
METHODS: This was a retrospective cohort study based on data extracted from the Aberdeen Maternity and Neonatal Databank. Cases included all primigravid women with first-trimester vaginal bleeding who delivered after 24 weeks of gestation between 1976 and 2004. The control group comprised all other women who had first pregnancies during the same period. Data were analyzed by univariate and multivariate statistical methods.
RESULTS: Compared with the control group (n = 31,633), women with threatened miscarriage (n = 7,627) were more likely to have antepartum hemorrhage of unknown origin (odds ratio [OR] 1.83, 95% confidence interval [CI] 1.73–2.01). Elective cesarean (OR 1.30, 95% CI 1.14–1.48) and manual removal of placenta (OR 1.40, 95% CI 1.21–1.62) were performed more frequently in these women, who also had a higher risk of preterm delivery (OR 1.56, 95% CI 1.43–1.71) and malpresentation (OR 1.26, 95% CI 1.13–1.40). Threatened miscarriage in the first trimester is required in 112, 112, 17, 85, 32 patients, respectively, for each additional case of manual removal of placenta, elective cesarean, antepartum hemorrhage of unknown origin, malpresentation, and preterm delivery.
CONCLUSION: Pregnancies complicated by threatened miscarriage are at a slightly higher risk of obstetric complications and interventions.
LEVEL OF EVIDENCE: II-2
Threatened miscarriage is associated with a slight increase in obstetric complications.
From the 1Department of Obstetrics and Gynaecology, Aberdeen Maternity Hospital; 2Dugald Baird Centre for Research on Women’s Health, Aberdeen Maternity Hospital; 3Ultrasound Department, Aberdeen Maternity Hospital; and 4Department of Obstetrics and Gynaecology, University of Aberdeen, Aberdeen, United Kingdom.
The authors thank Dr. Doris Campbell and Ms. Linda Murdoch for facilitating the extraction of data from the Aberdeen Maternity and Neonatal Databank.
Corresponding author: Dr. Ajith Wijesiriwardana, Consultant Obstetrician and Gynaecologist, Hon. Senior Clinical Lecturer, Department of Obstetrics & Gynaecology, Cumberland Infirmary, Carlisle, Cumbria, CA2 7HY United Kingdom; e-mail: firstname.lastname@example.org.