Dataset Information

Risk of preterm delivery with increasing depth of excision for cervical intraepithelial neoplasia in England: nested case-control study.

ABSTRACT:

Objective

To determine the association between depth of excision of cervical intraepithelial neoplasia and risk of preterm birth.

Design

Case-control study nested in record linkage cohort study.

Setting

12 hospitals in England.

Participants

From a cohort of 11 471 women with at least one histological sample taken at colposcopy and a live singleton birth (before or after colposcopy), 1313 women with a preterm birth (20-36 weeks) were identified and frequency matched on maternal age at delivery, parity, and study site to 1313 women with term births (38-42 weeks).

Main outcome measures

Risk of preterm birth and very/extreme preterm birth by depth of excisional treatment of the cervical transformation zone.

Results

After exclusions, 768 preterm births (cases) and 830 term births after colposcopy remained. The risk of preterm birth was no greater in women with a previous small (<10 mm) excision (absolute risk 7.5%, 95% confidence interval 6.0% to 8.9%) than in women with a diagnostic punch biopsy (7.2%, 5.9% to 8.5%). Women with a medium (10-14 mm) (absolute risk 9.6%; relative risk 1.28, 0.98 to 1.68), large (15-19 mm) (15.3%; 2.04, 1.41 to 2.96), or very large (≥ 20 mm) excision (18.0%; 2.40, 1.53 to 3.75) had a higher risk of preterm delivery than those with small excision. The same pattern was seen in 161 women with very/extremely preterm births (20-31 weeks) and with increasing volume excised. Most births were conceived more than three years after colposcopy, and the risk of preterm delivery did not seem to depend on time from excision to conception.

Conclusions

The risk of preterm birth is at most minimally affected by a small excision. Larger excisions, particularly over 15 mm or 2.66 cm(3), are associated with a doubling of the risk of both preterm and very preterm births. The risk does not decrease with increasing time from excision to conception. Efforts should be made to excise the entire lesion while preserving as much healthy cervical tissue as possible. Close obstetric monitoring is warranted for women who have large excisions of the cervical transformation zone.

SUBMITTER: Castanon A

PROVIDER: S-EPMC4220819 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:ObjectiveTo explore the association between preterm delivery and treatment at colposcopy.DesignRetrospective-prospective cohort study using record linkage.Setting12 National Health Service hospitals in England.ParticipantsWomen who had a cervical histology sample taken between 1987 and 2009. These women were linked by hospital episode statistics to hospital obstetric records between 1998 and 2009 for the whole of England to identify singleton live births between 20-43 gestational weeks before or after cervical histology.Main outcome measuresProportion of preterm births (<37 weeks); the relative risk for the strength of association between preterm births and treatment for cervical intraepithelial neoplasia.Results18,441 singleton births occurred: 4176 before histology and 14,265 after histology. Of the singleton births after histology, 9.0% (n=1284) were preterm compared with 6.7% of all births in England over the same period (excess risk 2.3 per 100 births, 95% confidence interval 1.8% to 2.8%). Among first births after histology, the adjusted relative risk associated with previous treatment was 1.19 (95% confidence interval 1.01 to 1.41); among first births before histology the relative risk associated with subsequent treatment was 1.47 (1.05 to 2.05). Combining these, the relative risk associated with treatment adjusted for timing relative to histology was 0.91 (0.66 to 1.26) corresponding to an absolute difference of -0.25 (-2.61 to 2.11) per 100 singleton births. Among 372 women who gave birth both before and after treatment, there were 30 preterm births after treatment and 32 before treatment (relative risk 0.94, 0.62 to 1.43).ConclusionThe risk of preterm delivery in women treated by colposcopy in England was substantially less than that in many other studies, predominantly from Nordic countries. The increased risk may be a consequence of confounding and not caused by treatment. Although this study is reassuring for large loop excision of the transformation zone overall, it is possible that deep conisation or repeated treatment leads to an increased risk of preterm delivery.

Project description:BackgroundAs LEEP (loop electrosurgical excision procedure) is being increasingly used for the diagnosis and treatment of uterine cervical intraepithelial neoplasia, surgical smoke during LEEP has become an inevitable health issue. Therefore, in this study, exposure to the chemical substances in surgical smoke produced during LEEP was assessed.MethodsSmoke samples from patients with high-grade cervical intraepithelial neoplasia undergoing LEEP were collected by smoke-absorbing devices situated 1 m away from the operating table and near the nose of the operator during LEEP. Each plume sample was collected after 5 patients underwent LEEP, requiring 5 min for smoke collection for each patient. The chemicals of exposure to surgical smoke were assessed, and the hazard classes of these chemical components were evaluated by the International Agency for Research on Cancer.ResultsQualitative analysis of the smoke produced during LEEP revealed a variety of potentially toxic chemicals under standard detection, such as benzene, toluene, xylene, ethylbenzene, styrene, butyl acetate, acrylonitrile, 1,2-dichloroethane, phenol, chlorine, cyanide, hydrogen cyanide and carbon monoxide. Additionally, the average concentration of carbon dioxide was 0.098 ± 0.015% during surgery and was higher than that before surgery (0.072 ± 0.007%, P < 0.001), and the concentration of formaldehyde was significantly higher during surgery (0.023 ± 0.009 mg/m3, P < 0.05) than before surgery (0.012 ± 0.001 mg/m3, P < 0.05).ConclusionsMost of the detected chemical concentrations in smoke generated during LEEP were below the exposure limits when local exhaust ventilation procedures were efficiently used. However, the concentrations of carbon dioxide and formaldehyde found in smoke were significantly higher after surgery. Wearing a high-filtration mask and using evacuation devices routinely and consistently when performing LEEP are recommended to protect perioperative personnel.