Cerclage is a well-known medical procedure which places stitches around the cervix. These stitches are intended to provide support to the cervix in the hopes of reducing preterm birth in women at risk for early labor. Premature labor occurs in about 12 percent of pregnancies and is caused by many factors including a shortened cervix, which can be determined by transvaginal ultrasound.
A new evidence review from The Cochrane Library finds that cerclage provides no clinically significant difference in the number of fetal deaths or newborn complications compared to women who dont receive the treatment.
Lead study author, Zarko Alfirevic, M.D., head of the department for womens and childrens health at the University of Liverpool explained, While cervical cerclage has been found to prevent recurrent preterm birth in a small number of patients, it is quite an invasive procedure which may increase the risk of caesarean section, so potentially safer alternatives should be considered in the first instance.
The researchers analyzed 12 randomized control trials involving 3,328 women with single (not twins or triplets) pregnancies to determine whether cervical cerclage helped decrease preterm births and improve the outcome for mother and baby. When analyzing data for the review, Alfirevic said it became apparent that cerclage can lead to a small increased risk for caesarean section. Although this finding is not necessarily the key factor in the decision whether to do cerclage, it should be part of the counseling, he said.
Katharina Stewart, M.D., associate professor of obstetrics and gynecology at the University of Wisconsin-Madison said that her practice places very few cerclages. While cerclages have been shown to be of benefit for a small subset of patients with advanced cervical shortening, as the Cochrane data supports, in most patients they do not impact the clinical outcome of the pregnancy. In other words, there is no benefit for a procedure that has risks.
She pointed out, In our practice, we have found cerclage to be effective for patients who have experienced painless cervical dilation in previous pregnancies that led to a preterm delivery. Under these circumstances, we would place a cerclage for a patient in their current pregnancy if their cervical length was less than 1.5 cm at 16 to 24 weeks of gestation.
She added that preterm delivery due to cervical insufficiency is a tough diagnosis emotionally and clinically, as it is made after the loss of a pregnancy.
As patients and physicians she said, We want to do something to prevent another loss. Cerclage is potentially the appropriate treatment for a select number of women, but the vast majority of patients are better served by close pregnancy surveillance. Just because we can do a procedure doesnt mean we should.
As physicians weigh risk versus benefit in determining whether to use cerclage, Alfirevic pointed out, We need more head-to-head studies that compare the use of progesterone, cerclage and cervical pessary (a small ring-shaped device inserted around the cervix). Only then will we be in a position to offer sound, evidence-based advice as to what is the best possible preventative strategy for women at risk of recurrent spontaneous preterm birth.
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Alfirevic Z, Stampalija T, Roberts D, Jorgensen AL. (2012). Cervical stitch (cerclage) for preventing preterm birth in singleton pregnancy (Review). The Cochrane Library, Issue 4.