LEEP Linked to High Miscarriage Rate Within First Year

Yael Waknine

November 13, 2013

Women who get pregnant within 12 months of loop electrosurgical excision procedures (LEEP) are at almost 6-fold increased risk for miscarriage compared with those who wait, according to a study published online November 6 in Obstetrics & Gynecology.

To assess the potential effect of LEEP on subsequent pregnancy, Shayna N. Conner, MD, a resident physician at Washington University in St. Louis, Missouri and colleagues performed a secondary analysis of medical and telephone interview data from a 10-year, multicenter, retrospective cohort study originally conducted from 1996 to 2006.

The 596 participants had a median interval from LEEP to pregnancy of 30.8 months (interquartile range [IQR], 18.4 - 50.7 months); 56 women (9.4%) had a LEEP lag of less than 12 months, and 540 (90.6%) had a lag of 1 year or longer. The overall rates of spontaneous abortion, preterm birth at less than 34 weeks, and preterm birth at less than 37 weeks were 6%, 8.7%, and 18.1%, respectively. Most miscarriages (30/35) occurred before 12 weeks' gestation.

The researchers found that a LEEP–pregnancy lag of less than 12 months was linked to a spontaneous abortion rate of 17.9% compared with 4.6% for intervals of 1 year or more (adjusted odds ratio [OR], 5.6; 95% confidence interval [CI], 2.5 - 12.7), with the risk being highest within the first 6 months (OR, 16.8; 95% CI, 3.5 - 81.6).

More specifically, spontaneous abortion before 20 and before 12 weeks' gestation were linked to a significantly shorter median LEEP lag (20.3 months [IQR, 11.2 - 40.9 months] and 17.9 months [IQR, 8.9 - 40.9 months; P < .01]) compared with no spontaneous abortion (31.2 months; IQR, 18.7 - 51.2 months; P = .01). No significant difference was observed for the 5 miscarriages occurring between 12 and 19 weeks' gestation (P = .85).

Interestingly, the authors found no relationship between shortened LEEP lag and an increased risk for preterm birth either before 37 (26.2% vs 19.1%; adjusted OR, 1.5; 95% CI, 0.7 - 3.1) or 34 (16.2% vs 9.7%; adjusted OR, 1.8; 95% CI, 0.7 - 4.5) weeks' gestation, after accounting for age, body mass index, prior miscarriage/preterm birth, race (preterm birth only), and smoking.

Prior studies have yielded mixed results with respect to the relationship between LEEP lag and pregnancy complications such as preterm birth, but none have examined the potential link with miscarriage, the authors point out.

"Removing a portion of the cervix theoretically leaves future pregnancies at higher risk for complications related to cervical integrity. In addition, given that healing and remodeling from a LEEP occurs over time, it is biologically plausible that the time interval from LEEP to pregnancy is an important factor in determining risk for complications," the authors note.

Limitations of the study include its retrospective design, a low incidence of spontaneous abortion in the study population, and the potential for recall bias in telephone interviews.

"[O]ur negative findings with respect to preterm births as well as spontaneous abortions at 12–19 weeks of gestation may be secondary to inadequate power," the authors conclude. They note larger studies are needed to confirm their findings and evaluate trends in different populations.

The study was supported by a grant from the National Institutes of Health. Dr. Conner has reported receiving grants from the Eunice Kennedy Shriver National Institute of Child Health and the Washington University Institute of Clinical and Translational Sciences. The other authors have disclosed no relevant financial relationships.

Obstet Gynecol. 2013;122:1154-1159. Abstract


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