High-grade cervical abnormalities are common in young women who could become pregnant. Studies linking laser conization or loop electrosurgical excision procedure (LEEP) to an increased risk for preterm delivery have been inconclusive. Sadler and colleagues investigated the risk of preterm delivery subsequent to treatment of cervical neoplasia.

The retrospective cohort study included female patients of a large New Zealand hospital that offered centralized colposcopy and obstetric services. The authors assessed patients who, according to the hospital database, gave birth after at least 20 weeks’ gestation and had LEEP or laser procedures for cervical intraepithelial neoplasia (CIN) before becoming pregnant. The study also included a control group of women who visited the colposcopy clinic but did not receive treatment. The authors collected data on demographics, medical history, cervical cytology and histology, colposcopic findings, and obstetric history and complications. Assessment also included vertical height of excised tissue, treatment mode, and number of treatments. The data were adjusted to include risk factors for preterm delivery or premature rupture of membranes not related to CIN treatment.

The final analysis included 1,020 of the 9,226 women in the database. About 14 percent (n = 149) had preterm deliveries. Forty-one were caused by iatrogenic reasons, including induction; 41 occurred spontaneously; and 67 were caused by premature rupture of membranes (PROM) before 37 weeks’ gestation. Total preterm delivery rates for treated patients were 14.9 percent compared with 12.2 percent for untreated patients. PROM occurred in 8 percent of treated patients and in 3.5 percent of untreated patients. Spontaneous preterm labor occurred in 4 percent of treated patients and 3.5 percent of untreated patients. CIN treatment did not appear to increase risk for total preterm delivery or spontaneous preterm delivery after data were adjusted for outside risk factors. The adjusted relative risk increased for PROM following laser conization and LEEP treatments (2.7 and 1.9 percent, respectively), but not following laser ablation. The risk of PROM and preterm delivery increased as the height of tissue removed increased.

The authors conclude that there is an increased risk of PROM and preterm delivery, but not overall preterm deliveries following laser conization or LEEP. Although PROM leads to preterm deliveries, these were higher in the untreated group after adjustments compared with the treated group. The authors attribute this incongruity to the higher rate of iatrogenic preterm deliveries in the untreated group. The authors suggest careful adherence to CIN management guidelines, avoidance of unnecessary excisions, and appropriate counseling of previously treated women when they become pregnant.