In the past 2 decades there has been a dramatic rise in the number of multiple gestations born in the United States. The National Center for Health Statistics reported more than 132,000 multiple births for 2002.1 Although twins represent the largest percentage of these births, triplets and higher-order multiple gestations account for nearly 6%. Multiple gestations have significantly higher maternal, obstetric, and neonatal morbidity and mortality rates.2–9 One such potential morbidity is peripartum hysterectomy.
Peripartum hysterectomy is defined as a hysterectomy performed at the time of delivery or in the immediate postpartum period. Contemporary data suggest that the vast majority of peripartum hysterectomies occur emergently in the setting of invasive placentation or uterine atony.10–17 In addition, cesarean delivery is often cited as a primary risk factor.10,12–14,16–19 Because multiple gestations, especially higher-order multiple gestations, are at risk for uterine atony due to overdistension and cesarean delivery due to fetal malpresentation, it would seem reasonable to conclude that multiple gestations are at greater risk for peripartum hysterectomy. Despite this assumption, there is minimal literature support. Recently, a retrospective cohort study by Walker et al9 discussed an increased rate of multiple adverse maternal outcomes, including peripartum hysterectomy, in multifetal pregnancies. A comprehensive English-based MEDLINE search from 1966 to December 31, 2004, using the key phrases of “multiple gestation” and “peripartum hysterectomy” failed to find any additional studies describing an increased occurrence of peripartum hysterectomy among multiple gestations. The current study was designed to estimate whether multiple gestations are truly at greater risk for peripartum hysterectomy.
The current study is an historical cohort design comparing the occurrence of peripartum hysterectomy between singleton and multiple gestations at Banner Good Samaritan Regional Medical Center, Phoenix, Arizona, from January 1, 1996, to December 31, 2001. Peripartum hysterectomy was defined as hysterectomy performed within 24 hours of delivery. The institutional review board provided approval for this retrospective study.
All available charts were identified electronically by International Classification of Diseases, 9th Revision codes that corresponded to delivery and hysterectomy within the same hospitalization. The identified charts were assessed by a single reviewer (J.E.O.) to confirm that hysterectomy was performed within 24 hours of delivery. Demographic data of maternal age, parity, prior cesarean delivery, placental location, labor induction, and obstetric complications (preterm labor requiring tocolysis, preterm premature rupture of membranes, preeclampsia) were obtained. In addition, the timing of delivery, urgency of hysterectomy (elective or emergent), primary indication for hysterectomy, total fetal weight, mean estimated blood loss, and mean number of packed red blood cell transfusions were recorded. The database encompassed hysterectomies performed by multiple practitioners. No information regarding the number of interventions (medical or surgical) used before hysterectomy were recorded, and no formal institutional policy existed before the performance of the hysterectomies.
The data were entered into a computerized database and analyzed by Kruskall-Wallis tests for continuous variables, Fisher exact tests for categorical variables, and odds ratios for comparisons between singleton and multiple gestations.
During the study years, 42,595 singleton, 1,131 twin, 164 triplet, 35 quadruplet, and 2 quintuplet pregnancies were delivered. Of these deliveries, 100 peripartum hysterectomies occurred. Eighty-eight hysterectomies were performed in singletons, 5 in twins, 6 in triplets, and 1 in quadruplets. The overall occurrence of peripartum hysterectomy was 2.28 per 1,000. Table 1 stratifies the percentage of pregnancies requiring peripartum hysterectomy by gestation type. Among the singleton hysterectomies, 24 (27%) were performed electively, and 64 (73%) were performed emergently. Of the 24 elective singleton hysterectomies, 12 were performed primarily for preexisting gynecologic complaints, 6 for sterilization, 2 for cervical carcinoma, and 4 for undocumented reasons. All of the multiple gestation hysterectomies were performed emergently. The occurrence of emergent peripartum hysterectomy was 1.73 per 1,000.
Table 2 lists the maternal demographic and obstetric comparisons among the singletons, twins, and higher-order multiple gestations that required peripartum hysterectomy. Singletons had greater maternal parity, more prior cesarean deliveries, and more placenta previas, whereas multiple gestations had more antepartum complications of preterm labor, preterm premature rupture of membranes, and preeclampsia. Table 3 compares the delivery and hysterectomy characteristics among the groups. When compared with singletons, multiple gestations had significantly greater total fetal weights and peripartum hysterectomies due to atony.
Multiple gestations had a significantly higher risk of emergent peripartum hysterectomy than singletons (odds ratio [OR] 6.04, 95% confidence interval [CI] 3.28–11.11; P < .001). Upon stratification, this difference was more pronounced among higher-order multiple gestations: twins (OR 2.95, 95% CI 1.22–7.13, P = .03), triplets (OR 25.22, 95% CI 11.02–57.77, P < .001), and quadruplets (OR 19.53, 95% CI 3.34–114.69, P = .04). When compared with singletons, higher-order multiple gestations had nearly a 24-fold increased risk of emergent peripartum hysterectomy (OR 23.97, 95% CI 11.05–51.99, P < .001).
Since 1980, the rate of multiple births in the United States has risen dramatically.1 This rise has been attributed to delayed child bearing and advances in reproductive technology. Although numerous studies have focused on the antepartum and neonatal morbidities that can accompany multiple gestations,2–9 few thus far have evaluated the intrapartum risk of peripartum hysterectomy.
Contemporary data suggest that the vast majority of peripartum hysterectomies occur emergently in the setting of invasive placentation or uterine atony.10–17 The current study corroborates this literature. The overall occurrence of emergent peripartum hysterectomy in this study was 1.73 per 1,000. This rate is slightly higher than previous reports and may be reflective of the different practitioner styles and thresholds for hysterectomy at our institution as well as the inclusion of multiple gestations within our study.
Placental invasion was the primary indication for peripartum hysterectomy among singletons, whereas uterine atony emerged as the cause for hysterectomy in all but 1 of the multiple gestations. A variety of demographic and obstetric factors may explain these findings. The singleton cohort had a significantly greater percentage of prior cesarean deliveries and placenta previas than the multiple gestations. Both of these variables are known risk factors for invasive placentation.10 The multiple gestations, on the other hand, had higher rates of preterm labor requiring tocolysis and uterine distension with greater total fetal weight at delivery. These variables represent significant contributors to uterine atony. Of interest, the estimated blood loss and total number of transfusions between the singletons and multiple gestations was similar, suggesting that the primary indication for hysterectomy did not significantly affect these variables.
This study also demonstrated a strong association between multiple gestations and need for peripartum hysterectomy. The percentage of singletons requiring emergent peripartum hysterectomy was 0.15%, whereas the percentages of twins and higher-order multiple gestations were 0.44% and 3.48%, respectively. This significantly increased risk for peripartum hysterectomy among multiple gestations confirms the findings of Walker et al.9
Two significant limitations of this study are its retrospective design and its inability to adjust for potential covariates, such as mode of delivery and gestational age at delivery. The cases within this study were pulled from International Classification of Diseases, 9th Revision codes, and the corresponding charts were subsequently evaluated. We did not have access to similar information from all of the nonhysterectomy deliveries that occurred during the study period to compare whether these variables affected the occurrence of peripartum hysterectomy. Another limitation is that we were unable to control for the number of intervention modalities that were used before the performance of the hysterectomy. Some physicians at our institution may have lower thresholds for surgical intervention in the face of postpartum hemorrhage than others. This lack of control may have biased our results.
Despite these limitations, the large sample size and inclusion of multiple gestations within this study mitigate its weaknesses. The only review in the literature with more cases of peripartum hysterectomy at a single institution is that of Castaneda et al.12 This review covered a 28-year period, whereas our study encompassed only 5 years. In addition, our study is one of the few investigations in the literature to compare the occurrence of peripartum hysterectomy among singletons and multiple gestations, and its results suggest a substantially increased risk for peripartum hysterectomy among multiple gestations. Two prior studies17,20 each included 1 twin gestation within their analyses; however, no comparisons against singletons could be made from these selected cases. Recently, Walker et al9 noted an increased risk of peripartum hysterectomy among multifetal pregnancies in their large retrospective cohort over a 16-year period.
The information gained from this study is helpful to clinicians for several reasons. First of all, it allows for more thorough reproductive counseling, especially in patients with higher-order multiple gestations. Next, although the clinician's decision to proceed with hysterectomy could not be controlled within this study, the results suggest that a woman's risk for peripartum hysterectomy is increased simply by the virtue of delivering a multiple gestation. This fact should encourage physicians to plan for intrapartum support services and delivery at a facility equipped to handle peripartum hysterectomies. Lastly, our results may stimulate the institutional development of standardized protocols for the delivery of multiple gestations. These protocols should address the need for multiple uterotonic agents, blood product availability, and additional personnel and instrumentation for operative assistance.
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© 2005 The American College of Obstetricians and Gynecologists
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