Cervical Incompetence and Cerclage - 5 - Cervical Assessment
Monday, September 01, 2008
Kenneth F. Trofatter, Jr., MD, PhD
In today’s post, let’s put the simplest case behind us first – the patient who appears to have cervical incompetence by past obstetrical history. In most instances, the most sensible option is to simply place a cerclage in early pregnancy usually around 13 weeks. This timing was originally recommended (prior to ultrasound) because most patients who were going to spontaneously miscarry a pregnancy will usually do so by the end of first trimester – including most babies with chromosomal abnormalities – fetal heart tones could be detected to confirm ‘viability’ and, it is exceedingly rare to have any significant cervical change prior to this time that would lead to miscarriage in and of itself.
In recent years, we have another reason that this is a good time to place a cerclage – the opportunity to perform combined first trimester screening for aneuploidy and to obtain a definitive diagnosis by chorionic villus sampling (CVS) if the screening result appears to place the patient ‘at risk’ for a chromosomally abnormal baby prior to placing a cerclage. The patient must be told that this screening test will not detect all chromosomally abnormal babies, and that babies can have other problems not detectable by ultrasound at this time, but it certainly offers significant reassurance.
If the past obstetrical history raises some doubt as to the diagnosis of cervical incompetence, or if the patient simply prefers, the alternative is to serially follow cervical length in the hope of detecting changes that would permit timely placement of a cerclage should the need arise. Under these circumstances, I usually begin cervical assessment by transvaginal ultrasound at about 16 weeks with the interval of testing determined by the findings at a given visit. Incidentally, even after a late first trimester cerclage has been placed, it has been my approach to serially follow these patients by transvaginal ultrasound through midtrimester. The advantage of having the cerclage in place is that it often provides a margin of safety that allows additional intervention to prevent extremely preterm delivery before advanced cervical changes prevent that opportunity.
With regard to the transvaginal ultrasound assessment of the cervix, one of the points I did not discuss in our last post was what constitutes “significant cervical change.” I do not think anyone would argue that membranes bulging at the level of the external cervical os or that a patient with ‘risk factors’ who starts with a 40mm cervix and presents two weeks later with an endocervical length of 10 mm with membranes ballooning to that point in the cervix constitute problems. Nor would anyone argue that the patient who has a very ‘suspicious history’ for cervical incompetence but maintains a cervical length of 40 mm without any loss of integrity at the internal os throughout midtrimester is not likely to be a problem. However, what about the ‘in between’ cases?
In the latter, there are lots of shades of gray and multiple scientific publications dating back 20 years or more to provide some guidance to suggest the diagnosis of cervical incompetence. Personally, I rely on three factors: change from baseline (33% or more decrease), overall length (usually < 26 mm and definitely < 16 mm), and distention of the endocervical canal by membranes (indicating loss of integrity at the internal cervical os). And, it is not at all unusual to have ‘abnormalities’ in all of these parameters in the woman with an incompetent cervix. Although it is controversial, I will frequently ‘challenge’ the integrity of the internal os by exerting slow, steady fundal pressure on the uterus while observing the cervix transvaginally by ultrasound in women in whom I am very suspicious of having cervical incompetence. If by doing so, the internal os opens and membranes then extend into the cervical canal, significantly shortening the cervix, I am much more likely to view this dynamic event as an abnormality consistent with cervical incompetence. On the other hand, if a patient has a cervical length of only 25 mm at 16 weeks, but retains integrity at the internal os and does not shorten with funneling when challenged, I am not at all adverse to simply following that patient over time…
Labels: aneuploidy screening in first trimester, cerclage, cervical incompetence, cervical insufficiency; premature labor, chorionic villus sampling
15 Comments:
At Tue Sep 02, 04:38:00 AM 2008,
Anonymous said…
Dear Dr. Trofatter
I am 35 years old and we just lost our baby at 22 weeks pregnancy. It was my first pregnancy and at 20 weeks I was diagnosed with a short cervix (1.8cm cervix and 1.8cm funneling). I am healthy and I had no risk factors (no DC, no infection etc.). After 3 days on bed rest PROM occured.
Next to the grief for our baby I am terrifide that this could happen again. What are my chances in a next pregnancy? What kind of examinations should be performed before the next pregnancy? Would prophylactic cerclage help? Whn can I get pregnant again?
Thank you so much for answering my questions in advance!
At Tue Sep 02, 04:43:00 PM 2008,
Kenneth F. Trofatter, Jr., MD, PhD said…
To anonymous Sept 2: I am so sorry for your loss. The history is certainly consistent with cervical incompetence and because it occurred so early in this first pregnancy, I would strongly suggest a cerclage at 13 weeks in your next pregnancy. In anticipation of that, I would also recommend combined first trimester screening for aneuploidy at 11-12 weeks. I doubt any testing between pregnancies would be helpful, unless you would like to have a sonohysterogram done to evaluate the uterine cavity. I would recommend waiting 4-6 months before conceiving again to give your body and your spirits a chance to recover from the pregnancy and the loss. Kind regards,
Dr T
At Wed Sep 03, 04:59:00 AM 2008,
Anonymous said…
Dear Dr. Trofatter
Thank you very much for your quick answer to my questions and your suggestions!
At Thu Sep 04, 06:05:00 AM 2008,
Anonymous said…
Hi Dr. T
I had a rescue cerclage placed at 20 weeks,and a 2nd one placed at 22 weeks. Then was on strict bedrest for the remainder on my pregnancy, but delivered healthy twins at 36 weeks. I know I would have a cerclage placed early with any subsequent pregnancy, but is it likely I would be on bedrest again?
At Fri Sep 05, 08:07:00 PM 2008,
Anonymous said…
I am 34 years old and just miscarried for the 2nd time at 16 weeks. I have had 2 successful pregnancies. First time I miscarried I had a large fibroid tumor. The Dr's said my fibroid did not contribute to the miscarriage. I had the fibroid removed (larger than 6cm)and then carried my 2nd pregnancy to full term. I got pregnant 17 months later where I miscarried at 15 1/2 weeks. My doctor did a follow-up exam 2 weeks after the miscarriage and found a fibroid tumor. He then sent me to a fertility specialist. He said I had classic incompetent cervix and that the fibroid once again had nothing to do with the miscarriage. I h ave had 2 complete D & C's after both miscarriages as well. He is confident that we can do a cerclage and I should be fine. Could the fibroids in anyway be related to my miscarriages or incompetent cervix? I would love to have some insight from you! Please help!
At Sat Sep 06, 06:22:00 AM 2008,
lynn said…
dear dr. trofatter,
i have a dear family member awaiting the birth of her baby boy via surrogate after many many years of infertility. gestation is 22 weeks now and about 6 days ago, the surrogate was hospitalized with slow amniotic leak. iv antibiotics, fluids, etc. and avi of 16. no distress with baby heartrate about 160ish and continued good activity. shortly after admission, light red bleeding started without pain or contractions. there is no cervical dilation, but evidence of effacement. first ultrasound showed a shortened cervix, but a subsequent ultrasound yesterday showed cervix may not be as short as initially thought. it is hard to trust the ultrasonographer as she stated that the surrogates bladder was distended in the first ultrasound, so how can you even compare ultrasounds? subsequent avis have been 9.8 and yesterday 6.8. they removed iv fluids 3 days ago. i am worried that iv fluids should not have been stopped. your thoughts? the surrogate has had 4 successful births w/o complications, although also had 2 early spontaneous miscarriages. 2 embryos were implanted successfully with early miscarriage of one twin. my question is could the likely chromosomal abnormality of miscarried twin affect the placenta/hormones of the healthy twin to cause a temporary adjustment of the placenta placement? it is apparently low lying and could not that account for the light bleeding? the surrogate is leaking more fluid during the night and i am also wondering if it is positional and should she experiment with different positions while lying in bed? they are in a tiny hospital with no nicu or perinatologist. theyre consulting with a pernatologist in the city 2 hrs away. he says he will not transport until surrogate is stable. what is stable? no bleeding? he says no corticosteroids before 24 weeks because the baby is not viable. well, this baby is so strong and i found the study on prochieve 8% that was so helpful. if they surrogate stops bleeding, that could be used, yes? is there anything to do while there is light bleeding?
thank you thank you,
lynn
At Thu Sep 18, 10:46:00 AM 2008,
Meenu Prajeesh said…
Dear Dr. Trofatter
When I was 27, I lost my first baby in 17 weeks and the reason for that was not clear...the baby was not alive and no fluid also found.. cervix dilated without any pain and placenta came out. I had to under go a D&C.
In the 2nd pregnancy (when I was 28), McD suture was given at 13th week. Inspite of that at 21 weeks, cervix dilated (10 mm) and I was admitted to Hospital. Even after 4 weeks of antibiotics, infection was not controlled. They removed suture the previous day and labor was induced the next morning out of high fever. I delivered a live baby and she was alive for another 2 hours...
Now I am 30. What should I do in the next pregnancy? Some doctors are advising just to be in the bed rest with Progesteron. Somebody suggest a Trans Abdominal Encerclage. Kindly suggest me the right thing to do in my next pregnancy.
Thanking u in extreme anticipation.
At Sun Sep 21, 06:50:00 PM 2008,
Kenneth F. Trofatter, Jr., MD, PhD said…
To anonymous Sept 5: I apologize for the delay in answering, but I JUST got your comment delivered to my mailbox today. Your history is a little atypical for cervical incompetence because of the baby you carried, but I would probably still offer you a cerclage at the end of first trimester. Fibroids in the lower uterus can distort the confirguration of the cervix at the internal os and lead to cervical insufficiency. Also, surgery for fibroids, or D&Cs can damage the internal cervical os as well. A cerclage does NOT guarantee that "everything will be fine," but it is safer to put it in earlier than later when significant cervical changes have already occurred. Best of luck. Dr T
At Mon Sep 22, 07:20:00 PM 2008,
Kenneth F. Trofatter, Jr., MD, PhD said…
To Lynn: Sorry for my delayed response but I did not receive this comment in my mailbox until this past weekend. If the surrogate has had some bleeding, she might have ruptured the membranes as the result of an ascending infcetion. Bleeding changes the pH of the vagina and allows the overgrowth of unfavorable bacteria. Other than bedrest, I would not recommend any positional changes to help her retain fluid. When the baby reaches 24 weeks, we usually accept a patient with ruptured membranes to our regional perinatal center with our NICU, administer corticosteroids to aid in fetal lung maturation, continue antibiotics, and monitor the baby for evidence of compromise. Most women will develop an ascending infection and begin to separate the placenta (placental abruption) before delivery of the baby and need to be delivered rapidly (or spontaneously deliver). If you live 2 hours from a tertiary care center, often transport cannot be arranged prior to the birth of the baby under these circumstances so it is better to be at the tertiary care center to have ready access to the NICU team. I wish your family the best of luck and please let us know how things turn out. Dr T
At Mon Sep 22, 07:25:00 PM 2008,
Kenneth F. Trofatter, Jr., MD, PhD said…
To Meenu: I hope you find a physician who specializes in cerclage placement to evaluate you during your next pregnancy. I cannot tell you at this point whether you would benefit from an abdominal cerclage or simply a well-placed McDonald or Shirodkar cerclage. In your case I would NOT recommend progesterone alone. After you had a cerclage placed, I would recommend that you do not have intercourse and I would place you on an antibiotic called metronidazole 1 to 3 times daily until you reached good fetal viability. This is my approach to women who have had the difficulties you have. Best wishes and thank you for writing. Dr T
At Tue Sep 23, 09:05:00 AM 2008,
Meenu Prajeesh said…
Hello Dr. Trofatter,
Thank you for the reply and it was the most useful one I have ever got so far. I need one more suggestion from you. We have decided to try our next pregnancy with cerclage. But couldn't make out a choice. Will a TAC help me or will just a Shirodkar do?
Thanks once again.
At Fri Oct 03, 07:06:00 PM 2008,
Kenneth F. Trofatter, Jr., MD, PhD said…
To anonymous Sept 4: Sorry for the delayed response. Healthline has been very inconsistent about sending me comments in any sensible order. However, a well-placed cerclage early in pregnancy may save you the ordeal of bedrest for much of the next pregnancy. Best wishes. Dr T
At Fri Oct 03, 07:09:00 PM 2008,
Kenneth F. Trofatter, Jr., MD, PhD said…
To Meenu: In all honesty, ANY well-placed cerclage might be all you need. Although an abdominal cerclage has the best opportunity to be placed at the level of the internal cervical os, either a Shirodkar or a McDonald cerclage may provide the same benefit and they are much less complicated procedures. Dr T
At Thu Oct 23, 08:07:00 AM 2008,
Ckinneer said…
Dear Dr. Trofatter,
I am currently 10 weeks pregnant and at 9 weeks found out that my cervix is at 2.7cm instead of 3cm (where I guess it should be). I've been told I have a shortened cervix?? I have one son who is four years old and I dialated early with him (32 weeks) and was put on complete bedrest. I never felt a contraction until I was 7.5 cm dialated with him. The only reason they found out I was dialated at 32 weeks (3cm) was because I felt a lot of pressure and felt like he was "coming out". My current dr has recommended that I visit a perinatologist. I go visit him on Monday...I've been trying to find information on the internet to help me understand my condition better and what I have to look forward to. Could you please help?
At Fri Oct 31, 05:23:00 PM 2008,
Kenneth F. Trofatter, Jr., MD, PhD said…
To ckinneer: Read my whole series on cervical incompetence because it sounds like that may well be your problem based on your past pregnancy history! That will tell you what it is all about and what you can expect! Best wishes and let us know how things turn out. Dr T
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