Cervical Incompetence and Cerclage - 11 - Rescue Cerclage (2)

A 17 year old primigravida was sent on referral when she was found to have significant “ballooning” of the membranes into the cervical canal at 20 2/7 weeks gestation. She was obese and a smoker but otherwise had an unremarkable medical and pregnancy history to that point. She reported some spotting after intercourse 2 days earlier and cramping lower abdominal pain and “pressure” during her transfer to our hospital, but denied fever, chills, constant pain, frank bleeding, leakage of fluid, or symptoms of urinary tract infection. On admission, the patient was found to be having irregular uterine contractions, the uterus was nontender, and the membranes were intact. She did not have a fever. Her cervix was 4-5 cm dilated, “completely” effaced, and membranes were bulging at the external cervical os.

She was begun on IV antibiotics (the same “cocktail” mentioned in my last post) and also started on magnesium sulfate. A Foley catheter was placed in her bladder. Her white blood count was noted to be mildly elevated at 14,300 but the differential was normal. Her urine analysis and, subsequently, a culture were negative as were cervical cultures for gonorrhea and Chlamydia. She remained stable overnight on the magnesium sulfate and antibiotics with no further change in her cervix. At that point we had a frank discussion regarding the potential risks and benefits of attempting to place a cerclage with which she elected to proceed with the comment “what have I got to lose by trying at this point anyway.” Points of the counseling did include that the procedure would be risky and that the chances for success were low and that it could precipitate delivery, but that delivery seemed imminent regardless and the baby was remote from good viability…

1) The patient was given an oral dose of indomethacin 100 mg and taken to the operating room

2) As she was receiving her fluid bolus for the spinal anesthetic, the Foley catheter was clamped off

3) She was prepped (but not deeply in the vagina) and draped

4) A weighted speculum was placed in the vagina and the cervix visualized with retractors

5) The cervix was noted to be at least 4-5 cm dilated and 100% effaced with membranes bulging at the external cervical os – indeed, with each breath she took, the membranes appeared to be ready to completely prolapse into the vagina – and the fetal head was visible above the membranes

6) The rest of the vagina was then gently prepped with betadine solution, avoiding direct contact with the membranes

7) The cervix was grasped on its anterior lip with a sponge stick and drawn slightly downward

8) A suture of #1 chromic was then placed very superficially around the cervix, starting and ending at the 12:00 o’clock position 1 to 1.5 cm up the cervix

9) This was gently cinched up (without pushing directly on the membranes, and when the knot was being tied, just before the cervix was closed, a Foley catheter was placed into the cervical canal - the knot was then tied securely and the Foley bulb inflated

10) The cervix was then grasped on its anterior lip again and a cerclage was placed using a double-strand #5 Ethibond beginning at the 12 o'clock position approximately 1 to 1.5 cm above the initial stitch

11) When the 12 o'clock position was reached, this was cinched up and then tied as described in our previous posts, deflating and removing the Foley catheter, just as the knot was being tightened

12) The chromic suture placed initially was then cut out of the cervix

13) The vagina was irrigated with warm saline and then dried

14) The Foley catheter draining the bladder was then released, allowing the bladder to drain freely

15) There was no evidence of ruptured membranes at the conclusion of the procedure and the final cerclage was approximately 2.5 cm up the cervix

16) The external cervical os was still patulous but membranes were restored to above the level of the cerclage and less than 0.5 cm diameter of cervical canal was left

17) Following the procedure, the patient was continued on magnesium sulfate for 24 hours, placed on indomethacin 50 mg q6h for 72 hours, cefazolin 2.0 g q6h pending results of the urine culture obtained at admission, azithromycin 500 mg per day for 5 days, and metronidazole 500 mg tid intravenously until discharge

18) She was discharged 4-5 days postoperatively to modified bedrest at home on metronidazole 500 mg bid and is still pregnant a month following her cerclage

One of the points I did not mention earlier is that during our preoperative discussion, the patient was told if the membranes completely prolapsed into the vagina before or after starting the procedure, I probably would not continue with the operation. Although techniques, such as pushing on the membranes with a moistened sponge and performing an amniocentesis to decompress the uterus, have been used successfully under these circumstances (and I have done so on occasions in the past when patients asked that “everything possible be done”), the risk for rupturing membranes and infection are so high during and after the procedure, I have leaned toward using this a ‘deal breaker’ when the pregnancy is so remote from a reasonable outcome for the baby. And, it should also be mentioned, that one condition always discussed with the patient, and must be agreed to before I attempt to place a rescue cerclage, is that anytime following the procedure they develop clear evidence of intrauterine infection, they must allow me to remove the cerclage and proceed with delivery.

Using the management protocols, surgical techniques, and criteria we have outlined in the last two posts, we have actually achieved ‘success’ rates (in terms of pregnancy prolongation to ‘good viability’, generally in excess of 28 weeks and minimal, if any, maternal or fetal morbidity) in more than 95% of our cases of rescue cerclage.

Labels: cerclage, cervical incompetence, cervical insufficiency; premature labor

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Cervical Incompetence and Cerclage - 10 - Rescue Cerclage

In my last post, I detailed my approach to placement of a prophylactic cerclage. Now let’s make things a little more challenging and discuss ‘rescue’ or ‘emergency’ cerclage. Actually, these usually fall into two broad categories, challenging and heroic! The challenging ones have funneling of the membranes to just inside or even just at the external cervical os and may be accompanied by dilation of the cervix as much as 2-3 cm; the heroic ones have more advanced dilation and effacement of the cervix with membranes bulging at, and slightly through, or completely prolapsed through the external cervical os. Let me give you a couple of case examples to help illustrate my differences in management under these two situations.

The first patient is a 35 year old woman who had primary infertility problems related to polycystic ovary syndrome. She is oligoovulatory, overweight, mildly hypertensive, somewhat androgenized, has insulin resistance (but not overt pregestational diabetes), and finally conceived after 3 months of metformin therapy followed by ovulation induction and intrauterine insemination. She had first trimester screening for aneuploidy done at 12 weeks because of her age (which she passed with flying colors) and returned at 20 weeks for a genetic sonogram. The baby looked wonderful, but during the course of the abdominal examination, the sonographer thought she saw ballooning of the membranes into the cervix. We performed a transvaginal ultrasound and the membranes were found to be ballooning to within 3-4 mm of the external os without any fundal compression. In discussion with the patient, she reported some pelvic “pressure” and had noted an increase in clear, mucous discharge, but reported no bleeding, cramping pain, or gross rupture of membranes. She had no fever or uterine tenderness. She was admitted that day for cerclage placement. I intentionally did NOT perform a bimanual pelvic examination on her in the office. So, how was her case handled…

1) She was admitted to our surgical unit on L&D

2) Urine analysis and culture and CBC with differential were sent

3) An IV was placed and the patient was given an antibiotic cocktail (after obtaining the urine culture) of cefazolin 2.0 g q6h, azithromycin 500 mg, and metronidazole 500 mg q6h

4) She was also given indomethacin 100 mg by mouth

5) She was taken to the operating room and given a spinal anesthetic

6) The patient was placed in the dorsal lithotomy position and the perineum and vagina (very gently) prepped with a betadine solution

7) After the patient was prepped and draped, a foley catheter was placed, the foley was clamped so that urine would not drain from the bladder, and the bag draped over her leg so as to be out of the operative field

8) A weighted speculum was placed in the vagina and the cervix was visualized with retractors

9) She was noted to be visibly dilated 1-2 cm and membranes could be seen approximately 4-5 mm inside the external cervical os, correlating well with the ultrasound findings

10) A cerclage was then placed approximately 2.5-3 cm above the external os following the exact procedure I reported in Steps 11 to 20 in our last post

11) The foley catheter was then unclamped and allowed to drain

12) As is so often the case in these circumstances, as the bladder filled, and as the cerclage was placed around the cervix, the membranes retracted higher into the cervical canal without having to be displaced by any instrumentation or insertion of a finger into the cervical canal (Personally, I think avoiding manipulation of the membranes may be very important to the success of rescue cerclages)

13) The patient was taken from the operating room and admitted overnight

14) The foley catheter was left in place

15) The cefazolin 2 g q6h, metronidazole 500 mg q6h, and indomethacin 50 mg q6h were continued overnight

16) The foley was removed the next morning and the patient was asked to void on her own before discharge

17) She was given a prescription for indomethacin 50 mg q 6 hour to complete a 72 hour course, azithromycin 250 mg daily for 4 days, and metronidazole 500 mg twice daily (to be continued until at least 30 weeks); she was placed on a stool softener and discharged to home with instructions for modified bedrest for 72 hours and then no intercourse or heavy exertional activity

18) She was scheduled for a transvaginal ultrasound 2 weeks following the procedure to assess cervical length and the level of the cerclage placement and told to return sooner with pain, cramping bleeding, rupture of membranes, or fever

19) When she returned, the transvaginal ultrasound showed the cerclage to be placed more than halfway up her cervix with another 1.5 cm of cervical canal free of membranes above the level of the cerclage. She still had V-shaped funneling at the level of the internal cervical os. Cervical evaluation was performed every other week until 28 weeks.

20) The metronidazole was discontinued at 30 weeks, but she subsequently developed a bacterial vaginosis-like discharge (commonly seen with cerclages) and she resumed the metronidazole until delivery.

21) During the course of her pregnancy, she developed insulin-dependent gestational diabetes and was eventually delivered after removal of the cerclage at 37 weeks when she underwent induction of labor for preeclampsia.

In our next post, we will discuss the approach to cerclage placement in a slightly more challenging case….

Labels: cerclage, cervical incompetence, cervical insufficiency; premature labor

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Cervical Incompetence and Cerclage - 9 - My Approach to Prophylactic Cerclage

At the end of my last post, I mentioned that the McDonald cerclage procedure is the type I have preferred for many years for most routine and ‘rescue cerclages’, but I also mentioned that if the suture is not placed highly enough, deeply enough, or tied tightly enough, it is at risk for failure. The first caveat, “highly enough,” is readily apparent but still often not done adequately. When I explain this to patients, I ask them to approximate the tips of their thumb and index fingers on one hand and imagine this to be the cervix with the surface of contact being the cervical canal. Then take the other thumb and index finger and squeeze the first two together. By compression even 2 cm up our surrogate cervix, and squeezing snugly, we can restore 3 to 4 cm of ‘cervical length.’

“Deeply enough” and “tightly enough” were technical components of good cerclage placement that I learned on my own early in my career and were actually contrary, especially the latter, to the classical approach to cerclage placement that I had been taught. I found that by placing the cerclage deeply into the cervical stroma, it is much more secure, less likely to dislodge, and goes beneath the major blood supply to the cervix so that when you tie the knot “tightly enough”, you do not run the risk of strangulating the cervix. Indeed, when I was originally taught to perform a cerclage I was specifically instructed never to tie the knot too tightly and to place either a finger or a small diameter dilator into the cervical canal and to tie the knot down against that. “Don’t close up an abscess” was the mantra that was drilled into my head. But, as I soon learned, patients with true cervical insufficiency would use the opportunity of the slight opening this left in the cervical canal to eventually ‘balloon’ their membranes past the point of the cerclage.

With these points in mind, my step-by-step approach to cerclage placement in the patient who is having this done prophylactically at 13-14 weeks is the following:

1) Perform an ultrasound and offer combined first trimester screening for aneuploidy at 11-12 weeks

2) Evaluate the cervix by speculum examination to determine the amount of cervix present in the vagina (portio vaginalis)

3) During the latter, send diagnostic studies for Chlamydia and gonorrhea if appropriate and evaluate the vaginal fluid for evidence of bacterial vaginosis

4) Evaluate the urine for evidence of a urinary tract infection

5) Treat any cervical, vaginal, or urinary tract infections before cerclage placement

6) Prophylactic antibiotics and tocolytic agents are usually not used for prophylactic early cerclages

7) The procedure itself is usually performed under regional (epidural or spinal) anesthesia

8) The patient is placed in the dorsal lithotomy position and the perineum and vagina prepped with a betadine solution

9) The bladder is emptied or a foley catheter is placed after the patient is prepped

10) A weighted speculum is placed in the vagina and the cervix is visualized with retractors – good assistance and visualization is very important to adequate cerclage placement

11) The cervix is grasped at the 12:00 o’clock position with a sponge stick and downward traction applied to ascertain the junction between the vaginal mucosa and the cervix – in and out movement of the sponge stick while holding the cervix can help to readily identify this anatomical landmark

12) A double-strand of #5 Ethibond is loaded on a free CT-1 needle and the tails are together held with a hemostat

13) Using the edge of the needle to push up on the junction between the cervix and vaginal mucosa (this will often give an additional cm or more of cervical length) the cerclage is begun at the 12:00 o’clock position by deeply seating (about two-thirds of the depth of the cervical stroma) the suture, angling the needle somewhat cephalad with each ‘bite’ of the cervix, and exiting between 9:00 and 10:00 o’clock.

14) The sponge stick is then moved to 9:00 o’clock, the retractors are repositioned, the next ‘bite’ of the cervix is begun right where the needle last exited (being careful not to place the needle between the double-strand of suture), and then exited between 7:00 and 8:00 o’clock.

15) The next stitch is VERY important (and also very risky once there has been cervical change later in the pregnancy). The cervix is grasped at 6:00 o’clock and the cervix pulled upward, retractors repositioned, and the next bite is placed as high as possible posteriorally on the cervix exiting between the 4:00 and 5:00 o’clock positions.

16) Movement of the sponge stick to 3:00 o’clock is done, the next stitch exited at 2:00 to 3:00 o’clock and then one more time brings the suture back to the 12:00 o’clock position (As you can see, I typically use a “five point” approach to cerclage placement with significant support brought to the posterior aspect of the cervix)

17) The next step is also VERY important. Before tying the knot, I cinch the suture material up snugly by grasping both ends of the suture and moving it through the tissue 3-4 times, seating the suture material even more deeply

18) I then tie the knot TIGHTLY with 6-7 knots – enough to cause slight cyanosis of the cervix before I leave the operating room

19) Irrigate the vagina with warm (not hot) saline (not squirting this into the cervical canal) and then DRY the vagina completely with sponges

20) The cervix should be slightly cyanotic at this point and ‘pouting’ at you; if the cerclage is well-placed, this pouting should be very symmetrical

21) The patient is not discharged until she can void on her own (and I will often leave the catheter in place until her full sensation to void has returned to avoid overdistention of the bladder and a call from the operating room nurse informing me that the patient has “ruptured membranes,” usually leaking urine from an overly full bladder)

22) The patient is given a prescription for ibuprofen 600 mg q 6 hour, instructed to use this for the expected cramping sensation she will experience, and told to call if she needs to use the medication for more than 72 hours.

23) She is scheduled for a tranvaginal ultrasound 2-3 weeks following the procedure to assess cervical length, integrity at the internal os, and the level of the cerclage placement

I fully realize that some components of my approach to cerclage placement may be controversial, but I can assure all of you who read this that this approach has worked well and has been accompanied by virtually no complications in the prophylactic cerclages I have performed for more than 20 years. In the next post, I will go through my approach to ‘rescue cerclage’ placement….

Labels: cerclage, cervical incompetence, cervical insufficiency; premature labor

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Cervical Incompetence and Cerclage - 8 - Shirodkar vs McDonald Cerclage

I just realized that since the outset of this series, we have talked about cervical cerclage but we have not explained what that is for the general reader. A cerclage is a ‘stitch’ placed around the cervix in a fashion that will, hopefully, prevent progressive cervical change and/or ballooning of the membranes through the cervical canal. There are various types of cerclages, but the three with which I have had the most experience can be found in our literature by the names Shirodkar cerclage, McDonald cerclage, and abdominal cerclage.

When I trained, we were almost exclusively taught to perform a Shirodkar cerclage (Antiseptic 1955;52:299). This procedure is done by dissecting the vaginal mucosa and bladder off the cervix anteriorally, and if necessary, opening the cul-de-sac (dissecting the vaginal mucosa off the cervix) posteriorally and then placing the suture as high as possible around the cervix tunneling through the cervical stroma. The cerclage is usually begun at the 12:00 o’clock position and then placed circumferentially with as few exit points as possible until the starting point is reached and the suture is tied. The vaginal mucosa is then reapproximated to cover the cerclage.

The procedure was first described by Shirodkar using absorbable catgut suture, but this was soon replaced with Mersilene tape – the ‘permanent’ material still most often used for this procedure today. The advantage of the Shirodkar cerclage is that one can place the suture almost as high (if not as high) as the internal cervical os. However, the disadvantages are that it is a more challenging procedure (especially with obese, primigravida patients or those with advanced cervical changes), often requiring more time in the operating room, with greater risk for hemorrhage, and perhaps infection, using a material that is sometimes more difficult to pass through the cervical tissue, and certainly more difficult to remove. Indeed, many patients with successful pregnancies and ‘good’ Shirodkars simply have a cesarean section performed for delivery and leave the original suture in place for a subsequent pregnancy. It is not a very practical procedure for ‘emergent’ or ‘rescue’ procedures when the membranes are deep in the cervical canal or ballooning past the external cervical os.

From my perspective, I mention the Shirodkar almost for historical purposes since most of the cerclages I have performed over the past 20-odd years have been McDonald cerclages. This procedure was described by McDonald (J Obstet Gynaecol Br Empire 1957;64:356) a few years after Shirodkar. It does not involve dissection of the vaginal mucosa off the cervix and is simply a ‘purse string’ suture placed around the cervix in 4 to 6 ‘bites’. Again, when I was first taught this procedure, I used Mersilene tape, but soon learned that the disadvantages, for the reasons noted above, made this suture material especially impractical when a ‘rescue’ procedure was necessary – something I was being called upon to perform more often in my consulting role in Maternal-Fetal Medicine. Indeed, despite taking great care, I remember iatrogenically rupturing membranes several times during ‘rescue’ procedures simply as the result of the difficulty of tightening the mersilene tape around the cervix after the cerclage had been placed. As the result of these experiences, I switched to #5 Ethibond and have used this successfully for more than 20 years as will be described in our next post.

The primary advantages of the McDonald procedure are that it can be performed quite rapidly, with minimal risk for blood loss or infection, and can be more easily removed to permit a vaginal delivery. The disadvantages are that it usually cannot be placed as high on the cervix as a Shirodkar, and many clinicians shy away from adequate placement for fear of damaging the bladder or rectum. Indeed, in my experience, the greatest reasons for failure of McDonald cerclages are threefold: they are not placed highly enough, deeply enough, or tied tightly enough to prevent cervical change and downward displacement of the membranes….

Labels: cerclage, cervical incompetence, cervical insufficiency; premature labor

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Cervical Incompetence and Cerclage - 7 - All Cerclages are Not Created Equally

In today’s post, I was originally going to discuss the surgical and medical approach I have used for many years in management of cervical incompetence, but I thought it would first be best to introduce why I think this will be a worthwhile endeavor…

In February of 2006, Dr. Zarko Alfirevic published an editorial entitled: "Cerclage: We All Know How to Do It but Can’t Agree When to Do It.” (Obstet Gynecol 2006;107:219-20). The editorial was written as a commentary to an article in the same issue by Daskalakis and colleagues (Obstet Gynecol 2006;107:221-26) in which the authors described their success with rescue cerclage placed in women between 18 and 26 weeks in whom significant cervical changes (dilation and bulging of membranes) were detected by transvaginal ultrasound screening. The study was not randomized, comprised a total of 46 women, and simply compared outcomes between the 29 who elected to proceed with cerclage and the 17 who chose simply to be treated with bedrest, tocolysis, and antibiotics (also prescribed to the ‘cerclage group’).

The results of the study were quite impressive. In the cerclage group, the mean prolongation of pregnancy was almost 9 weeks and the mean birth weight was 2101 g. These results contrasted dramatically with the ‘control’ group, mean prolongation of 3 weeks and birth weight of 739 g. Twenty-five of the cerclage pregnancies resulted in live births compared with 7 of 17 in the bedrest group. Other outcomes in cerclage vs controls included: neonatal survival 96% vs 57%; delivery at less than 32 weeks 31% vs 94%; and, adnissions to the neonatal intensive care unit 28% vs 86%. The reduction in overall perinatal mortality from the bedrest group of 76% to the cerclage group of 17% is certainly hard to ignore (and even harder to explain to a patient in the same situation in an objective manner). Furthermore, no significant surgical complications were noted in the group that received a cerclage.

Although the potential flaws of a nonrandomized study with a small cohort of women are correctly pointed out by Dr. Alfirevic in his editorial review, and his compliment regarding the success and low maternal morbidity as “testament to the surgical skills of the team” was warranted, I sense a degree of skepticism throughout his comments. And, while it is true that the published literature does not necessarily support the results, personally, I believe them because of the similar (if not even better) success rates we have experienced throughout the years. Indeed, I now fully believe that the premise of the editorial’s title regarding “Cerclage: We All Know How to Do It…” is what is fundamentally flawed and that is perhaps the major reason such disparate results regarding cerclage pervade the literature.

Although cervical cerclage often can be a relatively simple procedure, to say all cerclages are placed equally well is like saying all physicians have comparable skills because they all happened to finish residencies. The bottom line is it just ain’t so! Like any other surgical procedure, the results depend on the skills and experiences of the surgeon. So, with that as background, in our next post, I really will discuss the technique and rationale for the same we regularly use for cerclage…

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Cervical Incompetence and Cerclage - 6 - Evaluation and Decisions in Midtrimester

In the last post, we discussed the approach I have chosen to take regarding cervical incompetence and cerclage under fairly straightforward circumstances. Let’s up the ante in today’s post since I care for far more women under more urgent conditions than I do those with a prior history of cervical incompetence who qualify for an early cerclage prior to cervical changes. I would estimate that at least two-thirds of the 200-odd women in whom I have placed a cerclage in the last 6 years, had this performed between 18 and 26 weeks on an ‘emergent’ or ‘indicated’ basis as the result of significant cervical changes in midtrimester. And, I will say at the outset, management under these circumstances is considerably more controversial than that mentioned in our last post!

However, let me start again with a situation that I consider to be relatively ‘straightforward’ – the patient who presents at 18-22 weeks with little or no cervical length and membranes bulging near, at, or even through the external cervical os. This patient is going to usually deliver imminently and I have selected the range of gestational ages because the baby is previable at this point (although 22 weeks is getting very close to that as a possibility) and the importance of this will become more apparent in a moment.

One does not have a lot of time to make decisions under these circumstances, but the patient needs to be adequately evaluated before a recommendation for therapy can be suggested. The main focus of the evaluation is to try to establish whether or not overt intrauterine infection (chorioamnionitis) is driving the process – and that is sometimes not as easy as one might think – because if it clearly is, then the only therapeutic choice is delivery. When a patient in this situation hits the door, the first steps we take after obtaining vital signs (blood pressure, pulse, temperature) include: a complete blood count with differential; blood type and screen; a catheterized urine analysis and culture; cervical cultures for gonorrhea and Chlamydia (if these can be obtained safely – otherwise they may be deferred); a vaginal slide to look for evidence of bacterial vaginosis; and vaginal fluid to screen for ruptured membranes; an ultrasound to assess fetal size, evidence of anomalies, and Doppler flow studies if indicated; and, oftentimes blood chemistries to include electrolytes and liver function tests.

The patient is then connected to a uterine contraction monitor if that is possible, although one must realize that most patients will have contractions or some degree of uterine irritability once the cervix has gotten to this stage and I have found this to be only a relative contraindication to treatment. If cervical change has been documented by ultrasound, I usually do NOT perform a digital exam on the cervix – saving any further evaluation in that regard until the patient is in the operating room if it appears a cerclage will be attempted.

Although I do not routinely perform an amniocentesis on all patients in this situation, there are many providers who do and so do I in selected cases. When amniocentesis is done, the primary purpose, again, is to look for evidence of overt intrauterine infection (when this is not clearly apparent by physical examination or laboratory studies) as might be reflected by the presence of white blood cells, low amniotic fluid glucose levels, and positive amniotic fluid cultures. We do not routinely screen for inflammatory cytokines in the amniotic fluid at this time.

The next step is to put the pieces of the situation together, have a frank discussion with the patient and her family, and provide options for management. If the patient has a fever (not related to a urinary tract infection), and/or high white blood count and differential suggestive of acute infection, and/or a tender uterus with painful contractions and pain between contractions, and/or a purulent cervicovaginal discharge, the presumptive diagnosis is chorioamnionitis and the only safe option is to allow delivery – indeed, delivery is inevitable regardless of what we might do to intervene. The baby is previable and the mother’s life and future fertility may be at risk. I usually begin broad spectrum antibiotic coverage and, if necessary, recommend augmenting the labor process with oxytocin or misoprostol.

If overt infection is not clearly present, then the patient has basically two options – undergo ‘conservative management’ and wait to see what happens or undergo cerclage. I make several points during the counseling session: if delivery appears imminent and remote from fetal viability, she is told this bluntly (or if some cervical length remains and we honestly cannot predict when delivery might occur, she is also told this); if a cerclage is placed, it may precipitate delivery; if infection develops, regardless of the decision to perform cerclage or not, the "ballgame is over" and delivery will be necessary. While the patient is making her decision, I usually will begin indomethacin 50-100 mg initial dose followed by 25-50 mg every 6 hours and an antibiotic cocktail of a cephalosporin (or ‘penicillin’), azithromycin, and metronidazole administered intravenously. Most patients will opt for cerclage under these circumstances simply because they feel like “what have I got to lose” if the chances for the baby are otherwise hopeless.

The decisions are a little tougher when the baby is in the range of potential viability, especially from 23 weeks on. As in most neonatal intensive care units with high volume services, our neonatal survival rate between 23 and 24 weeks is in the range of 30-50% and it goes up dramatically from that point on, although at the earlier gestational ages, there is also a very high risk of long-term morbidity and mortality secondary to complications of prematurity. Patients at these gestational ages are evaluated and begun on the same treatment regimen I have detailed above with the addition of corticosteroids to accelerate fetal lung maturation. Usually we provide consultation with one of the neonataologists as well.

Under these circumstances, if the membranes are above or at the external cervical os, I still offer cerclage as an option – although the risks are clearly delineated that we could precipitate a delivery as a result of the procedure itself at a time in pregnancy when even days can have a significant impact on potential outcome for the baby. If the membranes have completely prolapsed into the vagina, the success of the procedure is so low with the risk of rupturing membranes during the procedure and the risk of subsequent infection following the procedure so high, that I will usually advise only conservative management with bedrest, antibiotics, corticosteroids, and tocolytic therapy in the hospital until delivery.

Although many years ago, before the dramatic advances in neonatal intensive care, I would perform cerclages if appropriate up to 30 weeks gestation, it is difficult to justify that now – indeed, I have to think long and hard before even offering it as a possibility once a pregnancy has reached 26 weeks. In our next post, I will detail the technique I have used for cerclage placement in these situations for the better part of 20 years…

Labels: cerclage, cervical incompetence, cervical insufficiency; premature labor

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Cervical Incompetence and Cerclage - 5 - Cervical Assessment

Once the suspected diagnosis of cervical incompetence has been established, a decision has to be made regarding what therapy is offered to the patient. I have found that the patient’s participation in that decision is often very important. When discussing options, one must consider the gestational age, the extent of the cervical changes, the risks and benefits of different interventions and noninterventions, indications and relative and absolute contraindications to various treatment options, and the patient’s own risk tolerance. When all is considered, the possible range of ‘therapeutic options’ may include anything from simply following cervical length, to no intervention, to induction/augmentation of labor, conservative ‘medical’ therapy, or cerclage.

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

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