1 Department of Obstetrics and Gynecology and 2 Institute of Pathology, Assaf Harofe Medical Center, affiliated to the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
3 To whom correspondence should be addressed at: Department of Obstetrics and Gynecology, Assaf Harofe Medical Center, Zerifin, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel. e-mail: intposgr{at}post.tau.ac.il
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Abstract |
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Key words: caseseries/methotrexate/pregnancy in scar/transvaginal sonography
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Introduction |
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The true incidence of pregnancy in scar has not been determined because so few cases have been reported in the literature: there are only 18 published cases in the English medical literature between 1978 and 2001 (Fylstra, 2002). Between 2002 and mid-2003, however, 25 additional cases were reported (Fylstra et al., 2002
; Ghezzi et al., 2002
; Haimov-Kochman et al., 2002
; Lam and Lo, 2002
; Hartung and Meckies, 2003
; Jurkovic et al., 2003
; Salomon et al., 2003
), 18 of which took place in a single centre (Jurkovic et al., 2003
). This may reflect both the increasing number of Caesarean sections being performed and the more widespread use of the transvaginal scan that allows earlier detection of such pregnancies (Jurkovic et al., 2003
). Notwithstanding this recent trend, current knowledge continues to be based mainly upon individual case reports.
We present our medical centres experience of eight ectopic pregnancies implanted in Caesarean scars.
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Materials and methods |
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All those women had delivered by a Caesarean section for which the most frequent indication (5/8, 63%) was breech presentation. Previous >2 Caesarean sections were reported in 4/8 (50%) of the women. Two patients had associated complications, i.e. placenta previa (case 3) and cervical pregnancy (case 4). All eight parturient women fulfilled the criteria for sonographic diagnosis of pregnancy in scar: (i) an empty uterus; (ii) an empty cervical canal; (iii) on a sagittal view of the uterus a discontinuity in the anterior uterine wall when running through the amniotic sac is demonstrated (Vial et al., 2000); (iv) the gestational sac is located in the anterior part of the isthmic portion of the uterus with a diminished myometrial layer between the bladder and the sac (Figure 1) (Godin et al., 1997
; Seow et al., 2001
; Fylstra, 2002
). In addition, prominent peritrophoblastic flow has been demonstrated on Doppler flow sonography (Seow et al., 2001
), which was also found in our cases 27.
-hCG levels were determined using Micro particle Enzyme Immunoassay (MEIA) (Abbot AXSYMR system; Abbot laboratories, USA). Pre-treatment maternal serum levels are presented in Table I.
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Results |
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Discussion |
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In case 1 during first trimester of gestation after the diagnosis was made we decided to manage this pregnancy expectantly. This policy was adopted following discussion with the couple and reaching a mutual decision to avoid any intervention at that stage. It was judged that the sac, located in the isthmic region, would later coalesce with the uterine cavity and continue as a normal pregnancy. Later on, the sac still remained outside the uterine cavity, but because of the increased risk of hysterectomy associated with termination at that stage, the expected management did not change (Herman et al., 1995). We agree with Jurkovic et al. (2003
) that in view of the lack of significant data, each woman should be given all the available information and the opportunity to decide on the management of her pregnancy. Nevertheless, based on our experience reported herein, we believe that the prognosis for an uneventful term pregnancy is still very poor and therefore our current policy is to recommend termination of such a pregnancy once the correct diagnosis is made.
We decided not to perform magnetic resonance imaging, and we agree that sonography combined with Doppler flow imaging is a very reliable tool for detecting these cases (Nawroth et al., 2001; Jurkovic et al., 2003
). We now prefer to combine transvaginal scanning for obtaining fine details of the gestation and its relation to the scar with a meticulous abdominal scan with full bladder (Ravhon et al., 1997
). The latter provides a panoramic view of the uterus and an accurate measurement of the distance between the gestational sac and the bladder. The importance of correct diagnosis is emphasized also in case 8, which originally was managed as an intrauterine non-viable pregnancy leading to massive bleeding and laparotomy.
Although no treatment policy should be based on anecdotal reports because of the infrequent occurrence of uterine scar gestation, much is to be learned from each report (Haimov-Kochman et al., 2002; Jurkovic et al., 2003
).
Two principal management options may be considered, i.e. the medical or the surgical. The medical treatment mainly consists of MTX, administered either systemically (Ravhon et al., 1997; Shufaro and Nadjari, 2001
; Lam and Lo, 2002
), locally (Lai et al., 1995
; Jurkovic et al., 2003
) or combined (Nawroth et al., 2001
). Theoretically, the combined approach might expose the patient to higher MTX dose and side-effects may result. However, this was not currently found. This is because such a pregnancy is surrounded by fibrous scar rather than by a normally vascularized myometrium. Therefore, systemic absorption of local MTX is minute. This also may potentially limit the systemic absorption of the drug and delay complete resorption of the pregnancy (Ravhon et al., 1997
). Therefore, concomitant fine needle aspiration of the remaining fluid in the sac may be required (Ravhon et al., 1997
). Others have combined potassium chloride (KCl) injections directly into the fetal thorax, with MTX being injected into the sac and the surrounding myometrium (Godin et al., 1997
). Nevertheless, on rare occasions, rupture of the scar and heavy bleeding may occur following medical treatment (Lai et al., 1995
; Jurkovic et al., 2003
). This may occur even 15 days following MTX treatment (Lai et al., 1995
). Therefore, the medical approach may be combined with bilateral uterine artery embolization, thus minimizing such complications (Ghezzi et al., 2002
).
A number of reports support the surgical alternative, even in the presence of a non-bleeding patient (Rampen, 1997; Vial et al., 2000
; Seow et al., 2001
; Fylstra, 2002
; Fylstra et al., 2002
). This includes elective laparotomy and excision of the gestational mass. These authors believe that even if recurrence is unlikely, the resection of the old scar with a new uterine closure can reduce the risk of recurrence. In addition, if no complication occurs, the follow-up period seems to be shorter compared with the medical treatment options.
A minimally invasive approach that has recently been described is endoscopic surgery (Lee et al., 1999). This includes hysteroscopy for visualizing the uterine cavity combined with incision and aspiration of the ectopic mass by operative laparoscopy. Currently, no modality appears to be entirely reliable and none can guarantee uterine integrity (Lee et al., 1999
; Jurkovic et al., 2003
).
It is recognized that a Caesarean section presents one of the risk factors for ectopic pregnancies and placental pathologies (i.e. placenta praevia, placental abruption and placenta percreta) in the subsequent pregnancies (Hemminki and Merilainen, 1996). This was also the case in two of our eight patients. A similar association has also been described in other case reports (Haimov-Kochman et al., 2002
; Salomon et al., 2003
). Placenta accreta is a catastrophic complication of pregnancy in which trophoblastic tissues invade the myometrial layer and implant on a Caesarean scar (Chazotte and Cohen, 1990
). A Caesarean scar pregnancy is, however, considered to be even more aggressive than placenta previa or accreta because of its invasion of the myometrium in the first trimester (Seow et al., 2001
).
The high rate of Caesarean section because of breech presentation and the subsequent occurrence of pregnancy in the resultant scar is an intriguing association. Since their concomitant appearance was also described in another four reported cases (Neiger et al., 1998; Vial et al., 2000
; Ghezzi et al., 2002
; Hartung and Meckies, 2003
), this association might not be coincidental. Many of these operations are currently elective procedures performed in a non-developed lower uterine segment, so that the healing processes following the operations might facilitate implantation of the blastocyst within the scar. Jurkovic et al. (2003
) have found that 72% of their patients underwent multiple (
2) Caesarean sections; and we found this rate in 50% of our patients. This seems to be another risk factor for in-scar implantation of the subsequent pregnancy because of increased scar surface area (Jurkovic et al., 2003
). In addition, the increasing number of Caesarean sections currently performed, together with the changing of the surgical technique, might also have same impact. In the past, the uterus was closed using a double layer of multiple sutures inverting the first layer with the second row. However, a single non-inverting running suture technique is currently more frequently used. Larger series would be needed to further elucidate these issues.
Nowadays, with the advent of transvaginal sonography and with the use of saline infusion, post-Caesarean section uterine wall integrity can be detected even in the non-pregnant state (Monteagudo et al., 2001; Armstrong et al., 2003
; Jurkovic et al., 2003
). Caesarean section scar defect, defined by the presence of fluid within the incision site (Armstrong et al., 2003
), or any filling defect (niche), defined as a triangular anechoic structure at the presumed site of the scar (Monteagudo et al., 2001
), might alert for uterine scar complication in the subsequent pregnancy (Armstrong et al., 2003
; Jurkovic et al., 2003
). This might also be important for women at risk for pregnancy in scar, such those with a history of either ectopic pregnancies, placental pathologies, multiple Caesarean sections (Jurkovic et al., 2003
) or breech delivery by a Caesarean section. In addition, this will alert the sonographer to look for scars in the pregnant uterus and to verify the integrity of the uterine wall, especially in the presence of an anterior gestational sac closely localized to the Caesarean section scar.
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Acknowledgement |
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References |
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Submitted on April 7, 2003; resubmitted on July 25, 2003; accepted on October 6, 2003.