Perinatal/Neonatal Case Presentation

Journal of Perinatology (2006) 26, 135–137. doi:10.1038/sj.jp.7211442

Premature rupture of membranes, placenta increta, and hysterectomy in a pregnancy following endometrial ablation

B D Hamar1, E F Wolff2, P H Kodaman3 and I Marcovici2,4

  1. 1Maternal-Fetal Medicine, Yale University School of Medicine, New Haven, CT, USA
  2. 2OB/GYN, Yale University School of Medicine, New Haven, CT, USA
  3. 3Reproductive Endocrinology and Infertility, Yale University School of Medicine, New Haven, CT, USA
  4. 4OB/GYN, Bristol Hospital, Bristol, CT, USA

Correspondence: Dr BD Hamar, Maternal-Fetal Medicine, Yale University School of Medicine, OB/GYN, MFM, 333 Cedar Street, PO Box 208063, New Haven, CT 06511, USA. E-mail: ben.hamar@yale.edu

Received 8 November 2005; Revised 17 November 2005; Accepted 21 November 2005.

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Abstract

Endometrial ablation has become a popular method of managing menorrhagia. Pregnancy after endometrial ablation has a high rate of complications. We present the case of a parous woman with a history of endometrial ablation with preterm premature rupture of membranes. Despite the absence of established sonographic markers for abnormal placentation, placenta accreta was noted at the time of cesarean delivery. In women with history of endometrial ablation, the endometrium is not normal and may allow for more aggressive placental invasion or adherence. Consequently, the sonographic indices described for evaluating placenta accreta may not be present. We believe that placentation in women with prior endometrial ablations should be considered extremely high risk for placenta accreta or increta and managed accordingly when preparing for delivery.

Keywords:

placenta increta, endometrial ablation, ultrasound, prenatal diagnosis

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Case report

A 29-year-old Gravida 4, Para 2-1-0-3 female at 33 weeks 2 days gestation with a history of an endometrial ablation presented with preterm premature rupture of membranes. The patient had been amenorrheic since her ablation so the estimated due date was calculated by a 12-week ultrasound. She had two prior vaginal deliveries without complications. In the third pregnancy, she underwent a primary cesarean delivery with Kerr uterine incision at 35 weeks gestation for non-reassuring fetal status. Due to dysmenorrhea, she had undergone saline balloon thermal ablation of her endometrial lining 2 years prior to the current pregnancy. Rupture of membranes was confirmed on speculum exam. She was given 48 h of tocolysis, betamethasone for fetal lung maturity, and begun on a 7-day course of ampicillin and erythromycin to prolong the latency period. She had several ultrasound evaluations during the pregnancy by the maternal–fetal medicine service using grayscale, color Doppler, and power Doppler imaging (both prior to and following rupture of membranes), which showed a normal anterior placenta. The lower edge of the placenta was superior to the bladder and presumably away from her prior hysterotomy incision. Representative images are shown in Figures 1 and 2.

Figure 1.
Figure 1 - Unfortunately we are unable to provide accessible alternative text for this. If you require assistance to access this image, please contact help@nature.com or the author

(a and b) Transverse images of the placenta showing a normal decidual/placental interface without any sonographic markers of placenta accreta. (b) Is below the plane shown in (a).

Full figure and legend (127K)

Figure 2.
Figure 2 - Unfortunately we are unable to provide accessible alternative text for this. If you require assistance to access this image, please contact help@nature.com or the author

Transverse image of the placenta with power Doppler imaging showing a normal vascular architecture and no evidence of abnormal invasion into the myometrium. Arcuate vessels are visualized laterally and placental and umbilical vessels are seen centrally.

Full figure and legend (60K)

At 3 days after her initial presentation, she developed fundal tenderness, and there was a clinical suspicion of chorioamnionitis. A repeat cesarean delivery was performed and she was delivered of a healthy 2050 g male infant with Apgars 8 and 9. Despite adequate time to allow placental separation and gentle external uterine massage, the placenta failed to separate. A clinical diagnosis of placenta accreta was made and the patient underwent a supracervical cesarean hysterectomy. Estimated blood loss was 1800 cm3. Postoperative course was complicated by hemodynamic instability and dilutional coagulopathy with resulting hemoperitoneum. She received blood products and underwent pelvic angiography and embolization of the uterine artery remnants. She had a postpartum superficial wound separation with drainage of old blood tracking from the peritoneal cavity. She became febrile to 1014 and required additional antibiotics for 5 days. Both mother and baby were discharged home on postoperative day 10.

Pathologic evaluation of the uterus and placenta showed a placenta entirely adherent to the uterus with trophoblastic invasion of the myometrium consistent with placenta increta (Figure 3).

Figure 3.
Figure 3 - Unfortunately we are unable to provide accessible alternative text for this. If you require assistance to access this image, please contact help@nature.com or the author

Gross sagittal section of the uterus and placenta. Note how deeply the placenta invades the myometrium. (Picture courtesy of Dr Ben McCalip, Yale University, Department of Pathology).

Full figure and legend (88K)

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Discussion

Up to one in five women of reproductive age suffer from menorrhagia, with increased utilization of healthcare resources.1 For over 20 years, endometrial ablation has been a treatment for menorrhagia as an alternative to hysterectomy and a number of techniques have subsequently been developed.2 Endometrial ablation has since become an increasingly popular, minimally invasive outpatient treatment for symptomatic menorrhagia. The procedure can be performed under direct visualization via operative hysteroscopy, or by using thermal, laser, cryotherapy, or microwave instruments to destroy the endometrial lining. Endometrial ablation is typically used in premenopausal women without future fertility plans. Although endometrial ablation has been described as a possible method of birth control, subsequent pregnancy is possible.3 Pregnancy after endometrial ablation represents a relatively new clinical entity, with little known about the pathophysiology, clinical course, associated risks, diagnostic challenges, or management consensus.

Although pregnancy is possible following endometrial ablation, the literature suggests that there are frequent complications in such pregnancies and a high potential exists for poor obstetric outcome. One case series examined the outcomes of 45 pregnancies following endometrial ablation.4 A total of 22 were terminated at maternal request. Of the 23 remaining: five were first trimester miscarriages, six delivered between 24 and 37 weeks, and nine were term deliveries. Of the 17 pregnancies that continued beyond 20 weeks, the following complication rates were described: 70% cesarean sections, 41% preterm deliveries, 18% premature preterm rupture of membranes, 12% intrauterine growth restriction, 12% perinatal mortality, 35% abnormal placental adherence, and 18% placenta accreta/increta. Four of the 45 pregnancies were treated with cesarean hysterectomy.

The process of implantation and placentation involves a complex interplay between fetal tissues and the maternal decidua. Destruction of this decidual layer with endometrial ablation leaves a structurally abnormal uterine lining which may predispose to abnormal placentation. It is well known that a scarred uterine lining (so-called Asherman's syndrome) and other intracavitary abnormalities due to scarring follows endometrial ablation. The uterine lining following an endometrial ablation is not normal and the process of implantation and placentation may be different from that in normal uteri. It is thought that the uterine scar is unable to participate in the normal placental–decidual interaction and leads to increased rates of abnormal placentation in low-lying placentas in women with prior uterine surgery. This is supported by the finding that the rate of placenta previa and accreta increases with increasing numbers of prior cesarean deliveries.5 With endometrial ablation the entire lining of the uterus is iatrogenically disrupted, possibly predisposing to abnormal placentation regardless of where placentation occurs. In the case of our patient, there was an anterior, globally adherent placenta distant from the prior uterine scar.

Screening for abnormal placentation in women at risk for placental abnormalities has been described in the literature. Women with altered endometrial lining (prior cesarean delivery) or abnormal placental location (placenta previa) are thought to be at highest risk for abnormal placentation. The ultrasonographic findings of placenta accreta include vascular lacunae noted at the placental–myometrial junction in a 'Swiss Cheese' pattern, bladder–uterine serosa interphase hypervascularity, prominent subplacental venous complexes, and the absence of an echolucent area between the placenta and myometrium.6, 7 When color Doppler is used, efficacy of ultrasound to diagnose placenta accreta has been reported with 82% sensitivity, 97% specificity, 87% positive predictive value, and 95% negative predictive value.8

As the placentation in classic placenta accreta may differ from the placentation in our case, the sonographic findings may be different from those described for placenta accreta. Images of the placenta in our case did not display any lacunar spaces, obliteration of the echolucent region behind the placenta, abnormal placental vasculature, interruption of the bladder wall–uterine interface, or other sonographic findings described in the literature.6 We hypothesize that this is because the placenta was globally adherent to an abnormal uterine lining. This may have limited focal placental invasion and similarly may have prevented the development of the classic ultrasound findings in placenta accreta.

Endometrial ablation has become an important and effective minimally invasive alternative to hysterectomy for a common clinical problem. Owing to the very real possibility of pregnancy following endometrial ablation, contraceptive counseling is of utmost importance. When pregnancy after endometrial ablation does occur, the literature suggests that there is a high rate of abnormal placentation and cesarean hysterectomy. Practitioners may want to limit the use of this treatment younger women or counsel their patients to pursue a long-term or permanent method of birth control if they are still in their reproductive years. Because of the uterine lining in the setting of placenta accreta following ablation is abnormal and the placentation is likely different from the classic cases of placenta accreta and increta, traditional ultrasonographic appearances may not be present and may limit our ability to make this diagnosis. Owing to the high the rate of abnormal placentation following endometrial ablation and since sonographic imaging is often not informative, it may be prudent to assume pregnancy after ablation is accreta/increta until proven otherwise, and prepare preoperatively for deliveries in this setting accordingly.

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Financial disclosures

None.

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References

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  4. Cook JR, Seman EI. Pregnancy following endometrial ablation: case history and literature review. Obstet Gynecol Surv 2003; 58: 551–556. | Article | PubMed | ISI |
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  7. Comstock CH, Love Jr JJ, Bronsteen RA, Lee W, Vettraino IM, Huang RR et al. Sonographic detection of placenta accreta in the second and third trimesters of pregnancy. Am J Obstet Gynecol 2004; 190: 1135–1140. | Article | PubMed | ISI |
  8. Chou MM, Ho ES, Lee YH. Prenatal diagnosis of placenta previa accreta by transabdominal color Doppler ultrasound. Ultrasound Obstet Gynecol 2000; 15: 28–35. | Article | PubMed | ISI | ChemPort |
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