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Loop Electrosurgical Excision Procedure and the Risk for Preterm Delivery

Heinonen, Annu MD; Gissler, Mika DSc, MPolSc; Riska, Annika MD, PhD; Paavonen, Jorma MD, PhD; Tapper, Anna-Maija MD, PhD; Jakobsson, Maija MD, PhD

doi: 10.1097/AOG.0b013e31828caa31
Original Research

OBJECTIVE: To estimate whether the severity of cervical intraepithelial neoplasia (CIN) and the loop electrosurgical excision procedure (LEEP) increase the risk for preterm delivery, and to evaluate the role of repeat LEEP and time interval since LEEP.

METHODS: This was a retrospective register-based study from Finland from 1997 to 2009. We linked Hospital Discharge Register and Finnish Medical Birth Register data. Case group women consisted of 20,011 women who underwent LEEP during the study period and their subsequent singleton deliveries in 1998–2009. Control population included women from the Medical Birth Register with no LEEP (n=430,975). The main outcome measure was preterm delivery before 37 weeks of gestation.

RESULTS: The risk for preterm delivery increased after LEEP. Women with previous LEEP had 547 (7.2%) preterm deliveries, whereas the control population had 30,151 (4.6%) preterm deliveries (odds ratio [OR] 1.61, confidence interval [CI] 1.47–1.75, number needed to harm 38.5). The overall preterm delivery rate in the study period was 4.6% for singleton deliveries. Repeat LEEP was associated with an almost threefold risk for preterm delivery (OR 2.80, CI 2.28–3.44). The severity of CIN did not increase the risk for preterm delivery. However, with LEEP for carcinoma in situ or microinvasive cancer, the risk for preterm delivery was higher (OR 2.55, CI 1.68–3.87). The increased risk also was associated with non-CIN lesions (OR 2.04, CI 1.46–2.87). Similarly, the risk was increased after diagnostic LEEP (OR 1.39, 95% CI 1.16–1.67). Time interval since LEEP was not associated with preterm delivery. Adjusting for maternal age, parity, socioeconomic or marital status, urbanism, and previous preterm deliveries did not change the results.

CONCLUSION: The risk for preterm delivery was increased after LEEP regardless of the histopathologic diagnosis. The risk was highest after repeat LEEP, which should be avoided, especially among women of reproductive age.


The risk for preterm delivery is increased after loop electrosurgical excision procedure regardless of histopathology, and the risk was highest after repeat loop electrosurgical excision procedure.

Department of Obstetrics and Gynecology, Helsinki University Central Hospital, and the National Institute of Health and Welfare, Helsinki, Finland; and the Nordic School of Public Health, Gothenburg, Sweden.

Corresponding author: Annu Heinonen, MD, Women's Hospital, Helsinki University Hospital Haartmaninkatu 2, PL 140, 00029 HUS Finland; e-mail:

Supported by grants from the Research Foundation of the University of Helsinki, Helsinki, Finland.

Financial Disclosure The authors did not report any potential conflicts of interest.

Presented in abstract form at the EUROGIN Conference, May 8–11, 2011, Lisbon, Portugal, and as a poster at the 28th International Papillomavirus Conference, November 30–December 6, 2012San Juan, Puerto Rico,.

© 2013 by The American College of Obstetricians and Gynecologists. Published by Wolters Kluwer Health, Inc. All rights reserved.