Understanding the Incompetent Cervix
Causes and treatments for a common factor of premature delivery
Treating an Incompetent Cervix
The surgery is actually a simple matter of inserting a noose-like tape around the perimeter of the cervix to keep it closed until it can be snipped to allow delivery. Called a cerclage, it usually works well, but sometimes the compromise to the cervix is so profound that there’s nothing left into which to sink the cerclage, thereby eliminating the benefit of this surgery. When this happens, prolonged bed rest, even in a hospital, may be necessary.
The usual cerclage placement is from a vaginal approach, but when there’s nothing left of the cervix to work with, an abdominal approach is necessary to purse-string the portion of the cervix that extends internally past the wall that is the back of the vagina. Called an internal or transabdominal cerclage, it involves an abdominal incision and is best done before conception rather than after, because any surgery done during pregnancy, especially abdominal, is fraught with problem bleeding due to the extra blood vessel development that accompanies pregnancy.
That’s the trick: to predict which patients won’t do well with a second-trimester vaginal cerclage before they even become pregnant, so that the internal one can be done before the pregnancy.
Internal cerclage has other problems. Because it’s placed via an abdominal operation, this mandates a C-section, because the vaginal birth route is closed off from within the abdomen. And although the cerclage can be left in for subsequent pregnancies, we’re also talking about subsequent C-sections. Also, few OB-GYNs have actually done them at all and are therefore uncomfortable with learning to do it on one of their patients. Even in our practice, where we offer internal cerclage when clearly indicated, we’ve done less than ten in 15 years. It’s a simple operation, actually, but it is nevertheless … an operation.
Unlike the permanence of the internal cerclage, the vaginal cerclage is designed to be removed near the end of each pregnancy—a mere office procedure—allowing a vaginal delivery soon thereafter in the hospital.
So it’s easy to see the pros and cons for each of these approaches. A vaginal approach is simpler and safer and can be removed to allow for a natural delivery later, but it is structurally more risky as success rates go. The internal cerclage is a better cerclage, but you’re talking a surgery to put it in and a C-section for each baby thereafter. The perfect choice between the two does not exist—it’s got to be a decision individualized for the patient.
Although it’s somewhat barbaric to think of preventing premature delivery by “tying the sack” closed, still a cerclage is a lifesaver and an intuitively obvious solution to the problem of incompetent cervix.
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