Improved maternal outcome in placenta accreta spectrum disorders: a single-institute observational cohort study

Abstract

Background

To describe the evolution and outcomes of protocol-orientated multidisciplinary quality improvement for clinically confirmed placenta accreta spectrum (PAS) disorders mainly receiving uterine preservation.

Methods

This single-institute, retrospective cohort study compared clinical outcomes of patients within three periods of 2013–2016 (initial period), 2017–2019 (transition period), and 2020–2023 (current period) during January 1st, 2013, to December 31st ,2023. The quality improvement elements were introduced mainly in the transition period, including optimization of peripartum care, prenatal diagnosis, surgical plan and preparation of autologous blood products. The primary outcomes included early composite maternal morbidity and uterine preservation rate. Meanwhile, secondary outcomes were late composite maternal morbidity, estimated blood loss and allogenic blood transfusion.

Results

This study enrolled 474 consecutive patients, involving 153 patients in initial period, 202 patients in transition period and 119 patients in current period. There was a large proportion of patients (97.5%) receiving surgery for uterine preservation in current period than in initial period (81.0%) and transition period (93.6%) (P < 0.001). Early maternal morbidity gradually decreased from 23.5% in initial period to 17.8% and 11.8% in transition period and current period (P = 0.044). The major contributors included reduced transfusion of 4 or more red blood cells (22.9% vs. 16.3% vs. 10.9%; P = 0.032) and early reoperation (5.2% vs. 1.5% vs. 0.8%; P = 0.034). There was also increase of 400 ml in intraoperative blood loss and overall blood loss (P = 0.003 and P = 0.034, respectively), which might relate with less application of invasive hemostatic procedures, including preoperative balloon occlusion and intrauterine tamponade. However, no significant difference in allogenic blood transfusion was revealed due to raising in preoperative hemoglobin level (107 g/L vs. 110 g/L vs. 113 g/L; P = 0.001) and establishing various forms of autologous blood preparation.

Conclusion

The implementation of quality improvement elements may result in lower composite maternal morbidity with more uterine preservation, coupled with less application of MRI and invasive intraoperative hemostatic procedures. Our findings suggest that institutional quality improvement may reduce morbidity and improve uterine preservation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-025-08435-w.

Background

Placenta accreta spectrum (PAS) is a life-threatening obstetric complication characterized by abnormal implantation of the villi into/through the myometrium [1]. As a trigger of major obstetric hemorrhage, this condition is associated with severe maternal morbidity, such as multi-organ dysfunction, acute respiratory distress, disseminated intravascular coagulation and even death [2, 3].

PAS disorders exhibit steady rise in their incidence from 1/2510 in the 1980 s to 1/533 in 2000 s in the United States [4, 5]. In a large survey from 2015 to 2016 in China, the prevalence of PAS reached 2.20% due to a high cesarean section rate [6]. Indeed, prior cesarean delivery has been recognized as the strongest risk factor for PAS, presenting with an increase observed with the escalated numbers of prior cesareans [7, 8]. Meanwhile, the risk of PAS disorders in subsequent pregnancies may also be attributable to procedures which may disturb the integrity of the uterine lining, such as uterine curettage, hysteroscopic surgery and uterine artery embolization [9].

Critically, strategies in peripartum management have been outlined in guidelines on PAS published around 2018 [10–15]. However, it remains controversial with regard to the optimal management of this disorder [16]. According to existing evidence, patients receiving cesarean hysterectomy might experience improved maternal outcomes when undergoing systemic multidisciplinary management [17–19]. Meanwhile, scheduled delivery, rather than urgent delivery, can also reduce hemorrhagic complications [20, 21]. Currently, there has been a definition of the suggested criteria for “center of excellence” regarding multidisciplinary team, intensive care unit, blood services, antenatal diagnosis, patient referral and intraoperative management at laparotomy. Nevertheless, given limited resource settings, especially in low- and middle-income countries, there may still be variance among protocols in different institutes [16, 17, 22].

Our Research Center has set up a multidisciplinary team to handle patients with suspected PAS disorders, with a purpose to mitigate the impact of clinical and logistical dilemma. Preoperative and intraoperative care plans were primarily established around 2012. With reference to published literature and guidelines, we have held comprehensive self-audit including monthly multidisciplinary team meeting and implemented postoperative follow-up to discuss items for improvement suitable for clinical practice [23–30].

Accordingly, the present study was carried out to describe the preoperative and intraoperative improvements in women with clinically confirmed PAS disorders over a 11-year period, and to assess the effect on maternal outcomes from the aspects of composite maternal morbidity and uterine preservation rate.

Materials and methods

This retrospective cohort study was approved by the Ethic Review Committee of GL Hospital (Approval No.: 2023−239-01). The study was conducted following the rules of Revised Standards for Quality Improvement Reporting Excellence (SQUIRE 2.0, 2015) and the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guideline [31, 32].

Initially, this study included 498 patients between January 1 st, 2013 and December 31 st,2023, including 418 patients suspected prenatally and 80 patients with identified condition during cesarean delivery. Eventually, 474 pregnancies of clinically confirmed PAS disorders (Fig. 1) were incorporated for subsequent analyses. The excluded cases included 2 patients less than 26 weeks’ gestation, 5 patients for intrauterine fetal demise, 5 duplicated cases and 12 patients for non-invasion of placenta during surgery. During this study time, our analyses were conducted within three distinct period: an initial period (January 1 st, 2013 - December 31 st, 2016), a current period (January 1 st, 2020 - December 31 st, 2023), and a 3-year transition period (2017–2019), with staged introduction of various elements of improvement (Table 1).

Fig. 1.

Flow chart for the inclusion and exclusion of study population

Table 1.

Quality improvement elements for PAS disorders

Quality improvement elements		Periods	Description
Peripartum care	Multidisciplinary team	2012-Up to now	Formulation of principles for patients’ assessment, management and follow-up. Programmatic update of peripartum care plan, checklist, standardized surgical and anesthetic approach by regular team audit.
	Optimization of iron supplementation	2012–2016	Measurement of ferritin with hemoglobin level < 110 g/L, followed by oral and/or parenteral iron supplementation where indicated.
		2017-Up to now	Routine examination of hemoglobin and ferritin around 20 weeks of gestational age, followed by oral and/or parenteral iron supplementation where indicated.
Prenatal diagnosis	Ultrasound screening	2012–2016	Screening based on the sonographer’s experience, mainly by observation of loss of “clear zone”, myometrial thinning, placental bulge and bridging vessels. No application of uniform sonographic signs or format.
		2017-Up to now	In accordance with the proposal by the European Working Group on Abnormally Invasive Placenta, emphasis on focal exophytic mass and utero-vesical hypervascularity with sensitivity of 98% and specificity of 56% in predicting PAS > 3a base on a Chinese article published by our Center. Simultaneous application of placenta mapping, drawing boundary of placenta localization and area of different grades of invasion, to guide the incision of the uterus.
	Adjunctive MRI	2012–2017	Use of MRI as an adjunct to most of patients suspected of PAS disorders.
		2018-Up to now	Application of MRI in predicting placenta increta and percreta with sensitivity of 79.7% and specificity of 83.1%, respectively. No priority of MRI than ultrasound in diagnostic accuracy, with the use of MRI in the case of requirement for further examination of the depth of invasion in certain patients.
Surgical plan	Prophylactic ballon occlusion	2012–2017	Application of prophylactic balloon occlusion to most of patients suspected of placenta increta and percreta preoperatively.
		2018-Up to now	Gradual removal of the procedure from common practice due to the clash of schedule on hybrid operating room, alongside potential complications.
	Surgical practice	2012–2017	Infiltration of the balloon to achieve temporal pelvic devascularization if needed. Manual removal of placenta and compression suture of invasion area without dissecting vesicouterine peritoneum and putting down the bladder. No intentional preservation of the placenta in situ as a strategy of conservative management.
		2018–2020	Dissection of vesicouterine peritoneum to ligate newly formed vessels and put down bladder. Placement of a Satinsky clamp or tourniquet as low as possible at the lower segment of the uterus before manual removal of the placenta for uterus conservation. No excision of the area where placenta was deeply adherent.
		2021-Up to now	Excision of the anterior wall of the uterus where placenta was deeply adherent. Implementation of other procedures according to the practice between 2018 and 2020.
Autologous blood transfusion	Preoperative autologous blood donation	2012-Up to now	Implementation of preoperative autologous donation for high-risk patients (hemoglobin > 110 g/L), with the maximum collection of 300 ml per time, and the minimum interval of repeated collection set to 2 weeks to allow recovery from anemia. Planning of the surgery with 5 weeks from the first collection, but not within 1 week from last collection. Initiation of the collection schedule at 32 weeks of gestation for patients with PAS disorders generally.
	Acute normovolemic hemodilution	2012–2016	Implementation of acute normovolemic hemodilution to patients (hemoglobin > 110 g/L) and planning of the surgery within 1 week.
	Cell salvage	2019-Up to now	Implementation of cell salvage as a main source of autologous blood transfusion.

A multidisciplinary team was established in 2012 to provide routine consultation services involving Obstetrics, Imaging (Ultrasound and Radiology), Anesthesiology, Neonatology and Transfusion medicine. Services consulted on as needed were Gynecologic Oncolgy, Urology, Critical Care Medicine and Interventional Radiology. The multidisciplinary team was responsible for patient-specific peripartum care, prenatal diagnosis and surgical plan, as well as advancement of the quality improvement program. Mos of the quality elements were initiated round 2017, including iron supplementation optimization, institutional diagnostic protocol development, surgical plan refinement, and multiple autologous blood preparation protocol implementation (Fig. 2).

Fig. 2.

Time trend of blood loss and RBC transfusion during the study period. A Time trend of mean blood loss (ml) by year. B Time trend of Mean volume of RBC (red blood cell) (ml) administrated per patient. In China, one unit of red blood cell was collected from 200ml of whole blood. Therefore, allogenic units are converted to milliliters here using the Chinese average volume per unit (200 mL) in order to compare uniform standard measures between autologous and allogenic blood. Purple lines indicate the temporal trends calculated by cubic spline for non-linear fit

The primary outcomes were uterine preservation rate and early maternal morbidity, defined as ≥ 1 occurrence of the following: admission to intensive care unit, transfusion of ≥ 4 red blood cells, disseminated intravascular coagulation, ureteral injury, early reoperation or death. The secondary outcomes included estimated intraoperative blood loss, allogenic blood transfusion, and late composite morbidity (including infection, readmission within 6 weeks, or delayed reoperation). The grade of PAS was made based on the clinical criteria as detailed in the FIGO Clinical Classification system, which was introduced clinically in our Center since 2019. Diagnosis prior to 2019 were updated based on the description of operation records by two core obstetricians in the multidisciplinary team. The definitions of variables and outcomes were provided in Table S1 [33–36]. All cases were followed up at 42 days postpartum, with all the analyzed variables sourced from medical records.

Analysis was performed by R 4.3.3. Given their non-normally distributed characteristics, continuous variables were reported as median and range, and analyzed by Kruskal-Wallis H tests. Categorized variables expressed as frequencies (proportion) were compared by chi-square test or Fisher’ exact test. Statistical significance was defined as P < 0.05. Figures were graphed using mean values to interpret average blood loss and transfusion volumes. Moreover, trends of graphed lines were calculated by restricted cubic splines to accommodate a nonlinear relationship.

Results

Within the 11-year period, our study was performed based on the inclusion of 474 consecutive patients with clinically confirmed PAS disorders. Antenatal characteristics of the enrolled population from 2013 to 2023 were summarized in Table 2. There were significant differences in maternal age, parity and gravity through the study period. Previous cesarean delivery was the predominant high-risk factor, with significant increase from 82.4% in initial period to 97.5% in transition period and a slight decrease to 91.6% in current period (P < 0.001). The rate of previous surgical scar, other than those undergoing cesarean delivery, gradually increased from 3.9% in 2013–2017 to 11.8% in 2020–2023. Nearly all patients had placenta previa, with the rates of 99.3%, 99.5% and 97.5% in initial, transition, and current periods, respectively (P = 0.307). Furthermore, 24.4% of the enrolled patients received MRI in current period, compared with 74.5% and 50.0% in initial and transient periods, respectively (P < 0.001). However, the diagnostic accuracy fluctuated around 85%, which seemed not to be affected by reduction of MRI referral. Meanwhile, patients in transition and current periods, in relative to the initial period, demonstrated higher median preoperative hemoglobin level [110 g/L (range 74–143 g/L) and 113 g/L (range 89–133 g/)] vs. 107 g/L (range 80–140 g/L]; P = 0.001), along with decreased preoperative anemia rate (P = 0.015).

Table 2.

Antenatal characteristics of patients with PAS disorders

Patient characteristics	2013–2023 N = 474	2013–2016 N = 153	2017–2019 N = 202	2020–2023 N = 119	P value
Clinical characteristics
Maternal age (years)	33 (20–47)	32 (20–43)	32 (21–47)	33 (22–41)	0.005
Parity	4 (1–9)	4 (1–9)	3 (2–9)	4 (1–9)	0.080
Gravity	1 (0–4)	1 (0–3)	1 (0–3)	1 (0–4)	<0.001
Maternal weight (kg)	70 (46–105)	70 (46–98)	70 (55–105)	70 (46–94)	0.406
Maternal height (cm)	160 (148–180)	160 (148–174)	160 (150–180)	160 (150–175)	0.868
BMI (kg/m2)	27.2 (18.4–38.6)	27.3 (19.1–36.4)	27.3 (21.6–38.6)	37.0 (18.4–38.6)	0.535
High-risk factors
History of CS	432 (91.1)	126 (82.4)	197 (97.5)	109 (91.6)	<0.001
Other surgical scar	29 (6.1)	6 (3.9)	9 (4.5)	14 (11.8)	0.012
IVF procedure	24 (5.1)	6 (3.9)	8 (4.0)	10 (8.4)	0.158
Other non-surgical scar	7 (1.5)	0 (0.0)	1 (0.5)	6 (5.0)	0.001
Adenomyosis	10 (2.1)	4 (2.6)	3 (1.5)	3 (2.5)	0.716
Prenatal diagnosis
Diagnostic method					-
Ultrasound	474 (100.0)	153 (100.0)	202 (100.0)	119 (100.0)	-
MRI	244 (51.5)	114 (74.5)	101 (50.0)	29 (24.4)	<0.001
Type of placenta previa					0.307
Marginal	41 (8.6)	15 (9.8)	19 (9.4)	7 (5.9)
Partial	7 (1.5)	1 (0.7)	5 (2.5)	1 (0.8)
Complete	421 (88.8)	136 (88.9)	177 (87.6)	108 (90.8)
Suspected PAS	399 (84.2)	134 (87.6)	164 (81.2)	101 (84.9)	0.255
Preoperative Hb	110 (74–143)	107 (80–140)	110 (74–143)	113 (89–133)	0.001
preoperative anemia	227 (47.9)	86 (56.2)	95 (47.0)	46 (38.7)	0.015

Other surgical scar: myomectomy, surgical termination of cesarean scar pregnancy, transcervical resection of adhesions, incision of uterine septum and curettage

Other non-surgical scar: uterine artery embolism, intra-uterine device and previous accreta

Abbreviations: CS cesarean section, IVF In Vitro Fertilization, Hb hemoglobin

Table 3 presented the intraoperative characteristic of PAS disorders. At cohort level, the proportion of recommended-delivery(34–36 weeks) increased to 30.3%, and the proportion of late-delivery (≥ 36 weeks) decreased to 57.1% (P = 0.024), which was still the leading part. The composition of PAS disorders remained statistically stable during the study period, with a decline to 19.3% in PAS1 and an increase to 48.7% in PAS3 (P = 0.181). Meanwhile, there was no statistical difference in the rates of initiating emergent surgery (P = 0.055). Similar to the use trend in intrauterine tamponade and uterus artery embolism, the rate of prophylactic balloon occlusion application was significantly declined from 81.7% to 0.0%. As one important outcome, uterine preservation rate, one important outcome in our study, steadily went up to 97.5%, compared with 81% in initial period and 93.7% in transition period (P < 0.001). We also observed a slight increase of the median intraoperative blood loss from 800 ml in initial period to 1200 ml in current period (P = 0.003)(Fig. 2A). However, unlike the rise in blood loss, there was a small reduction in allogenic blood transfusion rate, revealing no statistical significance (33.3% vs. 29.7% vs. 27.7%; P = 0.586). This study continued to analyze the characteristics of blood consumption, as shown in Table S2 and Fig. 2B. Specifically, autologous transfusion rate fluctuated between 29.2% and 53.8%. With cell salvage implemented, the procedure became the main source of autologous blood donation (reaching 44.5%), while the rate of preoperative autologous blood donation decreased from 37.9% to 21.0% (P < 0.001 and P = 0.001, respectively). Similarly, in terms of the characteristics of overall intraoperative allogenic blood transfusion, there was a 3% reduction every period, yet without any obvious difference. In addition, no differences were observed in transfusion rates and volume of packed red blood cell, fresh frozen plasma, as well as platelet and cryoprecipitate among different periods.

Table 3.

Intraoperative characteristics of patients with PAS disorders

Patient characteristics	2013–2023 N = 474	2013–2016 N = 153	2017–2019 N = 202	2020–2023 N = 119	P value
Basic characteristics
Gestational age (weeks)	36 (27–40)	36 (28–40)	35 (27–39)	36 (28–38)	0.002
Late-delivery (≥ 36 weeks)	269 (56.8)	102 (66.7)	99 (49.0)	68 (57.1)	0.024
Recommended-delivery (34–36 weeks)	149 (31.4)	38 (24.8)	75 (37.1)	36 (30.3)
Early-delivery (<34 weeks)	56 (11.8)	13 (8.5)	28 (13.9)	15(12.6)
Emergent surgery	99 (20.9)	22 (14.4)	49 (24.3)	28 (23.5)	0.055
General anesthesia	163 (34.4)	57 (37.3)	64 (31.7)	42 (35.3)	0.534
Intraoperative hemostatic procedures
Prophylactic ballon occlusion	190 (40.1)	125 (81.7)	65 (32.2)	0 (0.0)	<0.001
Ligation of ascending branch of uterine artery	159 (33.5)	14 (9.2)	66 (32.7)	79 (66.4)	<0.001
Satinsky clamp	68 (14.3)	0 (0.0)	45 (22.3)	23 (19.3)	<0.001
Tourniquet	2 (0.4)	0 (0.0)	0 (0.0)	2 (1.7)	0.050
Intrauterine tamponade	228 (48.1)	108 (70.6)	105 (52.0)	15 (12.6)	<0.001
Ballon tamponade	131 (57.5)	45 (41.7)	72 (68.6)	14 (93.3)	<0.001
Gauze packing	97 (42.5)	63 (58.3)	33 (31.4)	1 (6.7)
Uterine artery embolism	7 (1.5)	7 (4.6)	0 (0.0)	0 (0.0)	<0.001
Maternal outcomes
Intraoperative blood loss (ml)	1000 (200–13600)	800 (200–6000)	1000 (200–13600)	1200 (300–6800)	0.003
Intraoperative blood loss ≥ 1000 ml	239 (50.4)	65 (42.5)	103 (51.0)	71 (59.7)	0.019
Intraoperative blood loss ≥ 2000 ml	87 (18.4)	23 (15.0)	34 (16.8)	30 (25.2)	0.075
Intraoperative blood loss ≥ 3000 ml	49 (10.3)	13 (8.5)	18 (8.9)	18 (15.1)	0.139
Uterus Preservation	429 (90.5)	124 (81.0)	189 (93.6)	116 (97.5)	<0.001
Intraoperative allogenic blood transfusion	144 (30.4)	51 (33.3)	60 (29.7)	33 (27.7)	0.586
Type of PAS					0.181
PAS1	106 (22.4)	42 (27.5)	41 (20.3)	23 (19.3)
PAS2	169 (35.7)	57 (37.3)	74 (36.6)	38 (31.9)
PAS3	199 (42.0)	54 (35.5)	87 (43.1)	58 (48.7)
3a	152 (76.4)	38 (70.4)	72 (82.8)	42 (72.4)	0.311
3b	46 (23.1)	16 (29.6)	14 (16.1)	15 (25.9)
3c	1 (0.5)	0 (0.0)	1 (1.1)	1 (1.7)

As for postoperative outcomes (Table 4), median overall blood loss increased from 970 ml in initial period to 1340 ml in current period (P = 0.034). Compared with initial and transition periods, patients in current period showed higher hemoglobin levels postoperatively than those preoperatively [−7 g/L (−67 to 22 g/L) vs. −3 g/L (−55 to 41 g/L) and − 2 g/L (−37 to 37 g/L); P = 0.017], along with similar trend in median length of postoperative hospital stay. Early composite morbidity, halved from 23.5% initially to 11.8% currently (P = 0.044), with similar trend noticed in massive blood transfusion (≥ 4 units of RBC) and adverse complications/events (P = 0.032 and 0.006, respectively). Besides, the incidence of early reoperation declined significantly from 5.2% to 0.8% (P = 0.034), but coupled with a steady late composite morbidity. There were less complications/events during the study period (12.4% vs. 4.5% vs. 4.2; P = 0.006).

Table 4.

Postoperative characteristics of patients with PAS disorders

Patient characteristics	2013–2023 N = 474	2013–2016 N = 153	2017–2019 N = 202	2020–2023 N = 119	P value
Overall blood loss (ml)	1117.5 (200–1360)	970 (200–6110)	1117.5 (250–13600)	1340 (368–7550)	0.034
Postoperative Hb (g/L)	107 (60–150)	107 (67–150)	107 (60–146)	106 (60–147)	0.715
Hb change (g/L)	−3 (−67 to 41)	−2 (−37 to 37)	−3 (−55 to 41)	−7 (−67 to 22)	0.017
Length of postoperative hospital stay (Days)	5 (2–31)	5 (2–31)	5 (3–20)	6 (3–18)	0.003
Postoperative allogenic blood transfusion	49 (10.3)	17 (11.1)	19 (9.4)	13 (10.9)	0.847
Early composite morbidity	86 (18.1)	36 (23.5)	36 (17.8)	14 (11.8)	0.044
Admission to intensive care unit	20 (4.2)	7 (4.6)	10 (5.0)	3 (2.5)	0.559
Transfusion of 4 units or more red blood cells	81 (17.1)	35 (22.9)	33 (16.3)	13 (10.9)	0.032
DIC	1 (0.2)	0 (0.0)	1 (0.5)	0 (0.0)	0.509
Ureteral injury	6 (1.3)	3 (2.0)	2 (1.0)	1 (0.8)	0.642
Early reoperation	12 (2.5)	8 (5.2)	3 (1.5)	1 (0.8)	0.034
Relaparotomy for hysterectomy	6 (1.3)	3 (2.0)	2 (1.0)	1 (0.8)	-
Relaparotomy for surgical hemostasis	1 (0.2)	0 (0.0)	1 (0.5)	0 (0.0)	-
Intrauterine tamponade	1 (0.2)	1 (0.7)	0 (0.0)	0 (0.0)	-
Uterine artery embolism	3 (0.6)	3 (2.0)	0 (0.0)	0 (0.0)	-
Dilation and curettage	1 (0.2)	1 (0.7)	0 (0.0)	0 (0.0)	-
Death	0 (0.0)	0 (0.0)	0(0.0)	0 (0.0)	-
Late composite morbidity	23 (4.9)	11 (7.2)	8 (4.0)	4 (3.4)	0.255
Infection	19 (4.0)	11 (7.2)	5 (2.5)	3 (2.5)	0.051
Readmission within 6 weeks	5 (1.1)	1 (0.7)	3 (1.5)	1 (0.8)	0.724
Delayed operation	1 (0.2)	1 (0.7)	0 (0.0)	0 (0.0)	0.350
Adverse complications/events	33 (7.0)	19 (12.4)	9 (4.5)	5 (4.2)	0.006
Bowel obstruction	8 (1.7)	7 (4.6)	1 (0.5)	0 (0.0)	0.003
Urinary retention	3 (0.6)	2 (1.3)	1 (0.5)	0 (0.0)	0.382
Hematoma of surgical site	1 (0.2)	0 (0.0)	1 (0.5)	0 (0.0)	-
Impaired wound healing	1 (0.2)	0 (0.0)	1 (0.5)	0 (0.0)	-
Interventional radiology complications	1 (0.2)	1 (0.7)	0 (0.0)	0 (0.0)	-
Pulmonary embolism	1 (0.2)	0 (0.0)	0 (0.0)	1 (0.8)	-

Early composite morbidity: admission to intensive care unit, transfusion of 4 units or more red blood cells, DIC, ureteral injury, early reoperation or death

Late composite morbidity: infection, hospital readmission within 6 weeks, or delayed reoperation

Early reoperation: relaparotomy for hysterectomy or hemostatic procedure, intrauterine tamponade, uterine artery embolism and dilation and curettage

Adverse complications/complications: bowel obstruction, urinary retention, hematoma of surgical site, impaired wound healing, interventional radiology complications and pulmonary embolism

Abbreviations: HB hemoglobin, DIC disseminated intravascular coagulation

Discussion

In our study, the implementation of various elements of quality improvement program could contribute to increased uterine preservation and reduced early composite morbidity. Moreover, there was steady rate of allogenic transfusion, despite an increase in intraoperative blood loss, possibly attributable to elevated preoperative hemoglobin level and subsequent autologous blood donation.

According to previous retrospective cohort studies, management by core teams within regional centers of excellence can yield better outcomes clinically [19, 33]. Through management within these dedicated multidisciplinary programs, patients with PAS disorders were less likely to receive massive blood transfusion, admit to intensive care unit, occur reoperation or adverse complications, outperforming the outcomes of standard obstetric care [19, 33, 37]. So far, there is still a lack of identification regarding the ideal structure of the multidisciplinary team and care plan, despite the proposal of criteria for center of excellence. Moreover, even with gradually accumulated experience on PAS management, quality improvements depend largely on reflective changes in care plan by regular team audit, especially for patients with increta and percreta after cesarean hysterectomy [37]. However, further assessment is necessitated to clarify how these elements of quality improvement affect the outcomes of patients mainly receiving uterine preservation.

Principally, patient blood management can be developed from the aspects of preoperative hemoglobin optimization and autologous blood preparation utilization, which may enable the minimization of potential complications related to allogenic transfusion [38, 39]. Nearly 38% of pregnancies were estimated to be complicated by iron deficiency and/or anemia, demonstrating increased risk of postpartum hemorrhage [40, 41], while it could be corrected through oral and parenteral iron supplementation [42]. Furthermore, anemia/iron deficiency was independent risk factor of blood transfusion in PAS patients [43, 44]. Nevertheless, the US Preventive Services Task Force reviewed and declared limited benefit of routine iron supplementation and no studies addressed screening for iron deficiency and iron deficiency anemia, which, however, could be improved by prenatal iron supplementation during pregnancy [45]. In the present study, a program of iron supplementation optimization was implemented by our multidisciplinary team, allowing earlier screening around 20 weeks of gestational age. Consequently, it was demonstrated with elevated preoperative hemoglobin levels and reduced anemia during pregnancy, facilitating subsequent autologous blood preparation.

In accordance with the guideline issued by British Committee for Standards of in Haematology, we formulated corresponding criteria on preoperative autologous blood donation [29]. Our previous data on high-risk patients has documented the feasibility and safety of preoperative autologous blood donation during delivery, with median blood loss of 677.5 ml (255–8400 ml) followed by 17.9% allogenic blood transfusion, similar to the rate of 16.7% in placenta previa [38, 46]. But as reported by Lili Steblovnik, only 13.6% of patients could benefit from preoperative blood donation [38]. As a result, there was a gradual reduction of preoperative blood donation from 37.9% in initial period to 21.0% in current period. Furthermore, in terms of intraoperative cell salvage, which has been recommended in different guidelines, prior observational study has unveiled its role on minimizing allogenic blood transfusion [39, 47, 48]. Currently, it serves as a predominant plan in autologous blood preparation. In our study, acute normovolemic hemodilution was primarily regarded as a supplementary protocol in autologous blood preparation, sharing similar role in previous case reports on Jehovah’s Witness [49, 50]. However, it was quickly abandoned given its risk of decreasing oxygen delivery to the fetus. Through flexible strategy on autologous blood preparation, our study reported an overall rate of autologous blood transfusion of reaching 53.8%. However, significant reduction of allogenic transfusion was not expected as previous studies, despite the observation of a decreasing trend and less massive blood transfusion [39, 51].

It is believed that preoperative balloon occlusion may contribute to mitigating intraoperative bleeding in cesarean hysterectomy [52–54]. But some studies failed to demonstrate any benefit and criticize their use [55, 56]. Simultaneously, given its potential complications, the application was gradually replaced by surgical improvements and other blood conservation techniques. The implementation of uterine incision without penetrating placenta combined with the dissection of vesicouterine peritoneum to put down bladder provided the surgical foundation for uterine preservation. The previous one has been applied as the first step in Triple-P procedure, as well as one-step conservative surgery for PAS disorders, facilitating the delivery of fetus without interrupting placenta [57, 58]. Moreover, the dissection of vesicouterine peritoneum to ligate newly formed vessels and putting down bladder could provide convenience for the explosion of lower segment of uterus [58]. The adoption of such technique could allow the utilization of eight-figure suture to reconstruct the lower segment of uterus, an area frequently implicated in abnormal placental implantation during transition period. In junction with ligation of the ascending branch of uterine artery, the application of preoperative balloon occlusion and uterine balloon tamponade were reduced from 81.7% to 71.6% in initial period to 32.2% and 52.0% in transition period, respectively. Further modification of this surgery was realized through the resection of myometrium where placenta was deeply attached and manual removal of the remaining placenta. On the basis of thorough hemostasis of the surgical field, it was observed with further reduction of preoperative balloon occlusion and uterine balloon tamponade utilization.

However, this study revealed an augmentation of 400 ml blood loss, which contradicted other research on quality improvements on PAS [37, 59]. It was speculated that the elevated blood loss may be explained by the severity of PAS and less invasive hemostatic procedures (e.g., preoperative balloon occlusion and intrauterine tamponade). Furthermore, one randomized controlled trial reported slightly greater blood loss in the conservative surgery group compared to the cesarean hysterectomy group, which may account for the shifting trend in blood loss observed during our study [60]. However, this phenomenon did not lead to additional consumption of allogenic blood products, but with decreased early composited morbidity and adverse complications/events.

Despite a relatively large sample size, this study still has several limitations, such as the retrospective design and the inability to quantify the effect of each quality improvement element. It should be acknowledged that the implementation of quality improvement element for PAS disorders is actually not instantaneous. It requires time for adaption, especially considering the learning curve of surgical skills. In response to this issue, our study established a transition period, including the introduction of most of quality improvement elements, which filled the gaps of different outcomes from initial to current period, compare with other two-phase studies [37, 59]. In addition, part of patients undergoing surgery finally in our Center were referred from other institutes at different gestational weeks, which might produce more significant impact on our prenatal care plan and findings than we can measure. These included iron supplementation, preoperative autologous blood preparation, as well as schedule of surgery, especially in patients with vaginal bleeding and threatened preterm labor. Besides, the implementation of these quality improvement elements was completed in a single high-volume tertiary center with multidisciplinary teams or resources. However, this advantage may compromise the applicability of these measures in resource-limited settings.

In the present study, our general method was to achieve uterine preservation, rather than cesarean hysterectomy or expectant management, exhibiting significant difference from other Centers. The rationale of our general attempt relied on a Canadian study, which proposed that due to sepsis, severe vaginal bleeding and coagulopathy, 40% of hysterectomy were implemented after expectant management [61]. Besides, cesarean hysterectomy might not be preferred given the risk of fertility loss and future mental health [62, 63]. Anyway, with respect to the above, there is a need for multi-center cohort study to further evaluate the impact of quality improvement on maternal outcomes receive uterine preservation.

Conclusion

To sum up, the application of multiple quality improvement elements is crucial for patients with PAS disorders receiving uterine preservation. The quality improvement program involves two key changes, namely, the removal of certain elements such as routine MRI and invasive hemostatic procedures; and the introduction of specific measures, including iron supplementation and various forms of autologous blood preparation.

Abbreviations

PAS

Placenta accreta spectrum

MRI

Magnetic resonance imaging

MDS

Multi-organ disfunction

ARDS

Acute respiratory distress

DIC

Disseminated intravascular coagulation

CS

Cesarean section

IVF

In Vitro Fertilization

Hb

Hemoglobin

RBC

Red blood cell

FFP

Fresh frozen plasma

Authors’ contributions

HZ, WW and YD designed the study. NG, QL, LQ, ZZ and ZW collected the data for analysis. HZ, WW, NG and YD analyzed and interpreted the data. HZ, WW and QL wrote the first draft of the article. All authors discussed the results and commented on the manuscript. All authors have read and approved the manuscript.

Funding

This study was endorsed by the National Key Research and Development Program of China (2021YFC2701601), and fundings for Clinical Trials from the Affiliated Drum Tower Hospital, Medical School of Nanjing University (2022-YXZX-FC-02 and 2024-LCYJ-DBZ-06).

Data availability

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

Declarations

Ethics approval and consent to participate

All methods of the study were carried out in accordance with Declaration of Helsinki and the protocol of the retrospective study was approved by the Ethic Review Committee of Nanjing Drum Tower Hospital (reference number 2023-239-01). Written informed consent was obtained from all women enrolled in the study.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.