Are you a candidate for cerclage?

It is always difficult to tell after the fact, whether the cervix is incompetent or if the loss was preterm labor. The distinction is crucial, as the treatments are different with each. With the description provided, I would lean in the direction of an incompetent cervix. The signs of that are the gestational age, which goes more with incompetent cervix than preterm labor -- incompetent cervix is usually from 18 to 22 weeks while preterm labor can be that early, but is usually later, in the 26 to 30 week range. The lack of contractions is another key, though preterm labor may not be felt by the patient. Many patients with incompetent cervix will have contractions toward the last part of cervical dilation, but if there is cervical dilation before labor begins (usually substantial dilation, like more than four to five centimeters). When the cervix is more dilated than normal, there is an increased risk of the bag of water breaking, too.

What is confusing is the D&C. That may be necessary after a miscarriage, but frequently at 20 weeks, the fetus and placenta pass and do not require a D&C. Was your cervix dilated at the time you were seen? Or did your bag of water just break, but your cervix wasn't dilated and had to be opened to get the baby out? At 20 weeks, that is a substantial undertaking, one we usually bypass in favor of putting you into labor with medications, rather than doing a D&C, as, if the fetus has not passed, the amount of dilation needed to get the baby out is large.

While more information might help make the decision, with what we have, I would lean toward a cerclage. If you have an incompetent cervix, it will give you about a 95 percent chance of carrying the baby to term. If you don't have an incompetent cervix, it does give you a slightly higher risk of infection or bleeding, which might lead to an increased risk of preterm labor and early delivery. The chances of an infection happening are fairly low, though.

So I would have an ultrasound at 12 weeks to make sure everything is fine, as far as we can tell. Then I would suggest a cerclage between 13 and 16 weeks. We know that is the best time to put in a cerclage -- before the cervix has started to dilate. Then sit back, take it easy and wait. You may want to get a sit-down job and avoid exercise (and possibly sex), but the likelihood of needing to do any of that with a cerclage in place is small.

Another possibility for you would be to follow your cervical length with ultrasound. If the cervix starts to shorten to less than 2 to 2.5 cm, then a cerclage could be considered. The risks of this are missing the cervical change. An incompetent cervix can change from appearing normal to being fairly dilated in literally a matter of a few minutes. Whether that is common is unclear, but it can happen, so there is the possibility that the cervix could be too dilated to have a successful cerclage placed once it starts to dilate. That would worry most women enough to cause them to lean toward just getting the cerclage, recalling that there are some risks to that too, including causing preterm labor and infection. There is no approach to your dilemma that is worry-free.

Once you have lost a baby, you usually don't want to take any extra risk with the pregnancy, so avoiding anything that might stimulate uterine activity would make you feel safer. Of course, your doctor can go over his/her feelings about the advisability of cerclage placement in your situation, hopefully with access to your records at the time of the previous loss. That would give them a better idea if you need the cerclage. Meanwhile, good luck on getting pregnant, and on maintaining your pregnancy until term.

Editor's Note: A study in the September 2003 issue of Obstetrics & Gynecology finds that the use of cervical cerclage (a stitch in the opening of the cervix to keep it closed) is not effective in preventing preterm birth or miscarriage in women at moderate risk of preterm birth or second-trimester pregnancy loss.