Treatment for cervical changes risks preterm birth
MedWire News: Women who undergo excisional treatment for precancerous changes to the cervix have an increased risk for a subsequent preterm birth compared with their counterparts who have no previous diagnosis of precancerous changes, show the results of a meta-analysis.
The risk for preterm birth is also higher among women treated excisionally for precancerous cervical changes compared with those with untreated cervical changes; however, the risk is small, indicating possible shared risk factors for preterm birth, say the researchers.
"This analysis has clearly demonstrated that the type of comparison group used is an important consideration when comparing the outcomes of studies," report Fiona Bruinsma (La Trobe University, Melbourne, Victoria, Australia) and her co-author.
"Studies that use women who were assessed but not treated as their comparison group should be considered separately from those that use an external comparison group," they add in BJOG.
The pair undertook a meta-analysis of 30 cohort studies to investigate the impact of type of comparison group on any association between treatment for precancerous changes in the cervix and subsequent preterm birth, and whether risks vary by treatment type.
Excisional treatments included cold-knife conisation (CKC) and loop electrosurgical excision procedure (LEEP), and ablative treatments included cryotherapy, laser ablation, and cold coagulation.
The results confirmed previous studies that show excisional treatment carries a higher preterm birth risk (2.19-fold) compared with an external group of women in the general population (no precancerous diagnosis). The risk was greater after CKC compared with LEEP.
A smaller risk for preterm birth was seen for women who were assessed for precancerous changes but not treated, indicating that "the presence of a lesion (even without treatment) is associated with an increased risk" write Bruinsma and co-author.
"A strength of using women who were assessed but not treated as the comparison group is that many possible confounding factors (eg, smoking status, age, and first intercourse) may be similar across the two groups," they add.
The analysis also showed a significant association between ablative treatment and preterm birth, increasing the risk by 1.47 times compared with an external comparison group.
However, there was no significant association between ablative treatment and preterm birth when an internal comparison group (outcomes of births compared before and after treatment) was used.
"Ideally, a randomized trial examining fertility and pregnancy outcomes, as well as rates of recurrence, of excisional versus ablative treatment should be conducted," conclude the researchers.
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By Sarah Guy