Objective
The purpose of this study was to assess the incidence, case fatality rates, and risk factors of peripartum hysterectomy and arterial embolization for major obstetric hemorrhage.
Study Design
This was a 2-year prospective nationwide population-based cohort study. All pregnant women in the Netherlands during the same period acted as reference cohort (n = 371,021).
Results
We included 205 women; the overall incidence was 5.7 per 10,000 deliveries. Arterial embolization was performed in 114 women (incidence, 3.2 per 10,000; case fatality rate, 2.0%). Peripartum hysterectomy was performed in 108 women (incidence, 3.0 per 10,000; case fatality rate, 1.9%). Seventeen women underwent hysterectomy after failure of embolization. Cesarean delivery (relative risk, 6.6; 95% confidence interval, 5.0–8.7) and multiple pregnancy (relative risk, 6.6; 95% confidence interval, 4.2–10.4) were the most important risk factors in univariable analysis.
Conclusion
The rate of obstetric hemorrhage that necessitates hysterectomy or arterial embolization in the Netherlands is 5.7 per 10,000 deliveries; fertility is preserved in 46% of women by successful arterial embolization.
Major obstetric hemorrhage is the most frequent cause of severe acute maternal morbidity worldwide. Although maternal death because of hemorrhage is rare in Western countries, major obstetric hemorrhage can lead to severe long-term sequelae, and saving the mother’s life sometimes demands the maximum of available resources. In the Netherlands, major obstetric hemorrhage is responsible for 49% of obstetric intensive care unit admissions. Recent studies demonstrate an increase of severe maternal morbidity that is related to major obstetric hemorrhage in Western countries. Possible explanations include the increasing age of women at birth, the increasing multiple pregnancy rate as a consequence of artificial reproductive techniques, and the increasing cesarean delivery rate.
Because the maternal mortality ratio caused by major obstetric hemorrhage in Western countries is extremely low and it takes years to collect the numbers that are needed to be able to draw valid conclusions and learn lessons, severe maternal morbidity from obstetric hemorrhage has gained interest as a new quality indicator of obstetric care. An important indicator would be the number of peripartum hysterectomies or arterial embolizations for major obstetric hemorrhage. Recently, the United Kingdom Obstetric Surveillance System reported on the incidence of peripartum hysterectomy in the United Kingdom, which was 4.1 per 10,000 births.
When facing major obstetric hemorrhage that is intractable with conventional therapies, hysterectomy or embolization of the uterine and/or internal iliac arteries can be the last resort. Arterial embolization is increasingly the treatment of choice in these women to preserve fertility. A recent study concludes that fertility is not affected adversely by arterial embolization and that women can conceive, with normal pregnancy outcomes. However, arterial embolization is not always appropriate, successful, or available.
A nationwide cohort study of severe maternal morbidity, called LEMMoN (Nationwide Study into Ethnical Determinants of Maternal Morbidity in the Netherlands), was conducted in the Netherlands to assess incidence, case fatality rates, and risk factors for different types of morbidity, which included major obstetric hemorrhage. Major obstetric hemorrhage appeared to be the major cause of severe maternal morbidity in the Netherlands, involving 51.1% of all women included. This article describes the severest cases from this study: women with peripartum hysterectomy or embolization. The main objectives of this study were to describe the nationwide population-based incidence of arterial embolization and peripartum hysterectomy for obstetric hemorrhage and to compare risk factors and outcomes of arterial embolization and peripartum hysterectomy.
Materials and Methods
Women were included from August 1, 2004–August 1, 2006. All 98 hospitals (100%) with a maternity unit in the Netherlands participated. Detailed methods were described previously. In each hospital, a local coordinator reported all cases monthly using a standardized web-based form. The absence of cases in a particular month was also communicated to control for underreporting. Cases were identified in the respective hospitals by multiple strategies, which included maternity computer databases, labor ward diaries, staff reports, intensive care unit admission registers, blood transfusion registers, discharge data, and personal communication. All women with hysterectomy or arterial embolization because of obstetric hemorrhage during pregnancy, delivery, and puerperium (limited to 6 weeks after delivery) were included. Cases of first- or second-trimester instrumental abortion or termination of pregnancy up to 24 weeks of gestation were classified as early pregnancy . The cases of women who had hysterectomy after failed arterial embolization were analyzed in the hysterectomy group, because hysterectomy was the ultimate treatment that stopped the hemorrhage.
We recorded maternal characteristics (age, prepregnancy body mass index, ethnicity, single household, and smoking), obstetric history, all data on pregnancy and delivery, and specific data on major obstetric hemorrhage (amount of blood loss, causes, surgical interventions, intensive care unit admission, blood products and medication administered, hemoglobin levels, clotting parameters). Cases with a missing value for a specific parameter were excluded when the rate for that variable was calculated. We assessed the availability of arterial embolization in the Netherlands through a national survey.
Incidence was calculated with the total number of births in the Netherlands during the study period as the denominator. Denominator data for the number of deliveries in the Netherlands were obtained from Statistics Netherlands. The data were based on birth registries after correction for stillbirths of ≥24 weeks of gestation and multiple pregnancies. Relative risks (RRs) with 95% confidence interval (CI) and absolute risks were calculated if national reference data were available. National reference values for possible risk factors were obtained from Statistics Netherlands and the Netherlands Perinatal Registry. We compared women in the current study with the total group of women who had experienced major obstetric hemorrhage in the Netherlands, which was defined as need for transfusion of ≥4 units of red blood cells.
We calculated the case fatality rates by dividing the numbers of deaths after hysterectomy or arterial embolization by the number of cases of hysterectomy or arterial embolization. Cases in the arterial embolization and hysterectomy group were further analyzed by cause of hemorrhage. Although ≤3 causes could be reported, we classified women according to the most important cause of hemorrhage. Statistical analysis was performed with the use of the SPSS statistical package (version 14.0; SPSS, Inc, Chicago, IL). Approval of the institutional review board was not necessary, because all data were collected anonymously.
Results
During the study period, there were 371,021 deliveries in the Netherlands. All 98 hospitals with an obstetric ward in the Netherlands participated (100%). A maximum of 2352 (98 hospitals × 24 months) “hospital-months” could be reported. Mainly because of later enrolment of some hospitals into the study, a total of 2275 hospital-months were actually returned (97%). Regarding only those maternities that occurred during the months each hospital actively participated in the study, the study represented 358,874 deliveries.
Hysterectomy or arterial embolization for major obstetric hemorrhage was performed in 205 women (5.7 per 10,000 deliveries), which constituted 12.8% of all cases (205/1606) of major obstetric hemorrhage reported in the Netherlands. Arterial embolization was performed in 114 women (incidence 3.2 per 10,000 deliveries), in 17 of whom hysterectomy was necessary. Hysterectomy was performed in 108 women (incidence 3.0 per 10,000 deliveries). Four women died: 2 after embolization, 1 after hysterectomy, and 1 after both procedures. Overall case fatality rate was 2.0% (4/205 women). In 95 women (46% of all cases) fertility could be preserved by the availability of arterial embolization.
Possible risk factors for arterial embolization or hysterectomy with reference to national data are given in Table 1 , including absolute risks. When both therapies were compared, women who were >35 years old had a higher risk of hysterectomy than arterial embolization (RR, 1.4; 95% CI, 1.1–1.8), whereas nulliparous women had a lower risk (RR, 0.3; 95% CI, 0.2–0.5).
| Variable | Hysterectomy/arterial embolization, % | The Netherlands, a % | Relative risk (95% CI) | Absolute risk: overall 1/1751, n/N |
|---|---|---|---|---|
| Patient | ||||
| Age ≥35 y | 43.4 | 24.7 b | 2.3 (1.8–3.1) | 1/748 |
| Low income | 26.7 | N/A | ||
| Single household | 3.4 | N/A | ||
| Body mass index, kg/m 2 | ||||
| ≥25 (overweight) | 28.2 | 31.7 b | 0.9 (0.6–1.2) | 1/2060 |
| ≥30 (obese) | 10.9 | 9.8 b | 1.1 (0.6–1.9) | 1/1591 |
| ≥35 (morbidly obese) | 4.7 | N/A | ||
| Non-Western immigrant | 24.4 | 16.8 b | 1.6 (1.2–2.2) | 1/1094 |
| Pregnancy | ||||
| Initial care by obstetrician | 52.7 | 14.3 b | 6.7 (5.1–8.8) | 1/262 |
| Previous cesarean delivery | 26.8 | 10.1 | 3.3 (2.4–4.5) | 1/529 |
| Placenta previa | 10.7 | N/A | ||
| Nulliparity | 39.5 | 45.2 b | 0.8 (0.6–1.1) | 1/2216 |
| Parity ≥3 | 7.3 | 5.0 b | 1.5 (0.9–2.5) | 1/1167 |
| Multiple pregnancy | 10.2 | 1.7 b | 6.6 (4.2–10.4) | 1/265 |
| Artificial reproduction techniques: in vitro fertilization/intracytoplasmic sperm injection | 9.5 | 1.9 | 5.4 (3.2–9.0) | 1/324 |
| Delivery | ||||
| Induction of labor | 29.8 | 12.3 c | 3.1 (2.3–4.2) | 1/568 |
| Cesarean delivery | 49.8 | 13.0 b | 6.6 (5.0–8.7) | 1/264 |
| Prelabor cesarean delivery | 23.9 | 5.9 b | 5.0 (3.6–6.9) | 1/349 |
| Ventouse/forceps | 11.7 | 8.6 b | 1.4 (0.9–2.2) | 1/1242 |
| Home delivery | 3.4 | 31.6 c | 0.1 (0.04–0.2) | 1/218,826 |
| Breech delivery | 9.3 | 4.9 b | 2.1 (1.3–3.4) | 1/834 |
a N = 358,874; national reference values from;
b Statistics Netherlands (exact study period) and;
Diagnosis
An overview of the causes of major obstetric hemorrhage, in both the peripartum hysterectomy and the arterial embolization group, is given in Table 2 . In 50% of women, >1 diagnosis was reported; the most important combinations were uterine atony with disorders of placentation or placental remnants.
| Primary diagnosis | Hysterectomy, n (%) c | Arterial embolization, n (%) d |
|---|---|---|
| Disorders of placentation e | 37 (35) | 5 (5) |
| Uterine atony f | 29 (28) | 32 (33) |
| Uterine rupture | 11 (10) | 0 |
| Retained placenta or placental remnants f | 10 (10) | 30 (31) |
| Iatrogenic during surgery g | 8 (8) | 13 (14) |
| Genital tract laceration | 4 (4) | 11 (11) |
| Blood coagulation disorders | 1 (1) | 0 |
| Miscellaneous h | 4 (4) | 4 (4) |
| Placenta previa as single diagnosis | 1 (1) | 1 (1) |
| Total placenta previa | 15 (14) | 7 (7) |
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