Preterm Labor or Cervical Incompetence?: Unclear Diagnoses Complicate Choices for Therapy

Below are three comments from readers that appeared under my recent post on the safety of 17-hydroxyprogesterone caproate (17P) in the treatment of premature labor. They give us pause to reflect on the fact that the distinction between preterm labor and preterm labor and delvery secondary to cervical incompetence is often blurred, a fact that means selection of a therapeutic regimen is often not straightforward, sometimes delayed, and sometimes too late to improve the outcome in another pregnancy...

Thu Feb 07, 02:36:00 PM 2008 Anonymous said...

I have previously been pregnant 3 times and have delivered prematurely with all of them, 17 wks, 22 1/2 wks, and 7 1/2 wks. I am currently pregnant for the fourth time, and will be 16 wks this saturday. My doctors suggest that I have weekly injections of 17-hydroxyprogesterone to prevent preterm labor of this pregnancy, however, they are uncertain as to whether the cause is preterm labor or incompetent cervix. I am very skeptical when it comes to relying on drugs of any sort, and am not sure as to whether I should go through with this treatment or not, only to regret it later I have researched this and have not found enough inormation assuring its safety. I am currently on bed rest. Can strict bed rest keep me from delivering prematurely again, or will I need to have the injections administered? Are there any alternatives to this?

Thu Feb 14, 07:24:00 PM 2008 Kenneth F. Trofatter, Jr., MD, PhD said...

To Anonymous Feb 7: Personally, with your history, I would have placed the cerclage at 13-14 weeks, still followed your cervix with serial ultrasound examinations, starting at about 16 weeks, and considered the 17P if you had any evidence of uterine activity or cervical shortening. I think you would "regret" delivering early again much more than you will ever have cause for regretting the use of 17P. As an alternative, however, we have done a study with a vaginal progesterone compound (Prochieve) that seemed to be most effective in preventing early delivery in women with a short cervix (De Franco, et al., Ultrasound Obstet Gynecol 2007;30:697-705). Since this is a compound with the same 'natural' progesterone that your body and the placenta make, it should be completely safe for the baby. I do NOT trust bedrest alone under these circumstances for various reasons, especially if you have an incompetent cervix (and there are risks such as deep venous thrombosis and pulmonary emboli from prolonged bedrest). And I certainly do not trust progesterone alone in any form for a true incompetent cervix! Good luck and let us know how things turn out. Dr T

Thu Feb 07, 02:51:00 PM 2008 Anonymous said...

Dear Dr. T:

In your opinion, which is more beneficial, a cerclage or 17-hydroxyprogesterone injections? I was recently told What factors make me a candidate for either of these and determine their effectiveness? What are the risks and side-effects, long-term and short-term?

Thu Feb 14, 06:58:00 PM 2008 Kenneth F. Trofatter, Jr., MD, PhD said...

To Anonymous Feb 7: Your questions are straightforward and excellent and the answer is not so simple. At some point I will have to devote another whole post to cerclage. The answer depends on what your doctors think they might be treating and quite frankly, that depends, somehwat, on a detailed review of the previous pregnancy complications that have led you to this point. If you truly have an 'incompetent cervix', personally, I am a cerclage person. Placed early in pregnancy (13-14 weeks), a cerclage carries very low risks and is highly effective if the person who has placed it really does it right. Unfortunately, many cerclages are NOT well-placed and their efficacy has come into question more for this reason than anything else.

Your doctors probably have not been able to determine (based presumably on your past OB history) whether you had problems related to premature labor or whether you have an incompetent cervix. (It can be extremely difficult once the cervix has begun to change to decide which came first, the cervical change or the contractions). Under those circumstances, we will often follow you with cervical ultrasounds, consider using 17P if the history is strong enough, and then place a 'rescue cerclage' if and when the cervix starts to shorten (particularly if there is "funneling" of the membranes into the cervical canal), although this might not happen until 18-22 weeks (and sometimes even later). Of course, placing a cerclage at this point always carries more risk (primarily related to infection) than if placed earlier in the pregnancy, but again, in experienced hands, it is often successful in prolonging pregnancy, especially if very early preterm birth appears imminent if something isn't done (and there is no evidence of intrauterine infection already). The 17P appears to be relatively safe from midtrimester on, but I would suggest you read the blogs I have already posted on this subject. I wish you luck! Please let us know how things turn out.
Dr T

Fri Feb 08, 05:46:00 PM 2008 Anonymous said...

Dear Dr. Trofatter:

If I take 17P for one pregnancy, would I be required to take it for all future pregnancies, or will I be given the option?

Thu Feb 14, 07:29:00 PM 2008 Kenneth F. Trofatter, Jr., MD, PhD said...

To Anonymous Feb 8: If the 17P has a beneficial effect in your case, that will not carry over to another pregnancy. It has no long-term benefits. If you take it for one pregnancy, didn't really need it, and did well, you'll probably do well the next time whether or not you take it! The question is, do you want to take the chance of not taking it if you really do benefit it! Wish the answers were simple, but they are not! Thanks for reading!
Dr T

Labels: 17-hydroxyprogesterone caproate, 17P, cervical incompetence, preterm labor

Permalink | Email Post