Efficacy and safety of high-intensity focused ultrasound combined with suction curettage for the treatment of caesarean scar pregnancy: a systematic review and single-arm meta-analysis

Abstract

Purpose

Caesarean scar pregnancy (CSP) presents a significant clinical challenge owing to the associated risks of uterine scar rupture, severe haemorrhage and adverse maternal outcomes. This study aimed to assess the safety and efficacy of combining high-intensity focused ultrasound (HIFU) with suction curettage for treating CSP.

Methods

We conducted a comprehensive search in four databases, namely PubMed, Web of Science, Embase and Cochrane Library, to identify published studies evaluating the use of HIFU combined with suction curettage to treat CSP. Intraoperative blood loss, treatment success rate, and reproductive results were the primary outcomes assessed.

Results

A total of 18 studies involving 1251 patients with CSP, all of whom received preoperative HIFU therapy were included. The average hospital stay was 6.22 days, the intraoperative blood loss was 26.29 ml and the incidence of adverse events was 15.60%, including abdominal or lower limb pain, fever, vaginal bleeding, haematuria and vomiting. Furthermore, post-treatment follow-up showed that serum β-human chorionic gonadotropin levels were rapidly normalized (average of 25.48 days) and menstruation returned (average of 33.03 days). The treatment had a remarkable success rate of 97.60% and a subsequent pregnancy rate of 68.70%.

Conclusion

While the combination of HIFU and suction-curettage may induce common adverse effects such as lower abdominal or limb pain, these reactions typically do not necessitate therapeutic intervention. Additionally, the size of the gestational sac is a determinant of the procedure’s success. In conclusion, HIFU combined with suction curettage demonstrates promising clinical efficacy, safety and favourable reproductive outcomes in managing CSP.

Keywords:

• Caesarean scar pregnancy
• high-intensity focused ultrasound
• suction curettage
• clinical efficacy
• safety
• favourable reproductive outcomes

Introduction

Caesarean scar pregnancy (CSP) is an ectopic pregnancy in which the gestational sac gets implanted on the scar from a previous caesarean section [1,2]. With the increasing rate of caesarean section deliveries, the incidence of CSP has also increased [3,4]. CSP poses various life-threatening complications, such as uterine scar rupture, severe haemorrhage and adverse maternal outcomes. Thus, clinicians recommend the termination of pregnancy when a definitive diagnosis is made [4,5]. Currently, standardized treatment protocols for CSP are lacking, which presents a considerable challenge to clinicians [6,7].

During the surgical intervention, patient safety, haemorrhage control, lesion clearance, pregnancy termination and preservation of fertility are prioritized [8–10]. Suction curettage is a cost-effective, simple and efficacious approach to treat CSP, with little impact on fertility in patients with CSP who are hemodynamically stable [11]. However, single uterine curettage may have the risk of complications such as massive bleeding, uterine perforation and incomplete uterine clearance [2,12].

Studies have reported that pretreatment of patients with procedures such as uterine artery embolization (UAE) or high-intensity focused ultrasound (HIFU) before suction curettage can alleviate intraoperative bleeding and adverse reactions [8], shorten the hospital stay and enhance surgical success rates as well as subsequent pregnancy rates [13–15]. Although UAE pretreatment followed by suction curettage has been widely applied in clinical practice to treat CSP, it may impede the blood supply not only to the cervical pregnancy sac but also to the entire uterus, fallopian tubes, and ovaries. Therefore, the UAE may lead to severe complications and adverse reactions, including infection, fever, abdominal pain, infertility and ovarian dysfunction [16,17]. HIFU is a non-invasive, focal thermal ablation technique that precisely focuses ultrasound waves from outside the body onto targeted lesions within the body, thereby inducing coagulative necrosis [18]. HIFU effectively complements conventional surgical interventions. The process exhibits advantages in reducing blood loss and adverse events, as well as in increasing treatment success rates and subsequent pregnancy rates, which makes it a promising intervention [19]. Nonetheless, few studies have reported on HIFU combined with suction curettage for the treatment of CSP, and to date, there is no comprehensive review of the efficacy and safety of HIFU combined with suction curettage in treating CSP [19–22]. Hence, the existing evidence for HIFU combined with suction curettage should be comprehensively assessed. Therefore, this study aimed to perform a comprehensive analysis of the available literature to evaluate the clinical efficacy, safety and reproductive outcomes of HIFU combined with suction curettage for treating CSP.

Materials and methods

Literature search strategy and study selection

Before commencing this study, the protocol was registered on PROSPERO (CRD42023445428). As of July 2023, four databases, namely, PubMed, Web of Science, Embase and Cochrane Library, were comprehensively searched to retrieve literature pertaining to clinical research on the use of HIFU in conjunction with suction curettage for treating CSP. In accordance with the principles of PICOS, a set of keywords were constructed using a combination of controlled vocabulary and free-text terms. The search was restricted to publications in the English language. The search terms included ‘(caesarean scar pregnancy) OR (caesarean*) OR (CSP),’ ‘(high-intensity focused ultrasound ablation) OR (HIFU) OR (focused ultrasound) OR (MRgFUS)”’ and ‘(vacuum curettage) OR (suction curettage) OR (uterine aspirator)’.

This research adhered to the PRISMA-P (Cochrane Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols) guideline [23]. Titles, abstracts, and full texts of the literature were reviewed according to the following inclusion and exclusion criteria: Inclusion criteria: (1) Original clinical studies, including observational and experimental research designs; (2) Studies designed as either controlled trials or single-arm studies; (3) Studies involving patients receiving HIFU combined with suction curettage for treating CSP; (4) Studies reporting at least one outcome measure of interest; (5) Data for patients receiving HIFU intervention presented separately from data for those receiving other interventions; and (6) Studies published in peer-reviewed journals. Exclusion criteria: (1) Duplicate studies add those that lack data for analysis; (2) Conference reports, editorials, reviews, case reports, or conference abstracts; and (3) Non-English studies. Additionally, the references of the included studies were searched to prevent potential omissions.

Data extraction and quality assessment

One reviewer (YJ) performed data extraction and quality assessment for all selected studies, and two reviewers (YL and SZQ) verified the accuracy of the extracted data and conducted quality assessment. The following data were extracted: (1) Study characteristics, such as the first author’s name, year of publication and sample size; (2) Demographic and baseline characteristics, such as patient age, gestational age, the largest diameter of the sac, the interval between caesarean sections and the number of caesarean deliveries; (3) Perioperative factors: intraoperative blood loss, length of hospital stay and adverse events (including abdominal or lower limb pain, fever, vaginal bleeding, haematuria and vomiting); (4) Postoperative follow-up: time to normalization of serum β-human chorionic gonadotropin (β-HCG) levels and time to normal menstruation; and (5) Success rate of HIFU treatment and outcomes of subsequent pregnancies.

The Newcastle–Ottawa Scale (NOS) (https://www.ohri.ca//programs/clinical_epidemiology/oxford.asp) was used to determine the quality of the included controlled studies. Studies with NOS scores >5 are considered to be of high quality. Additionally, a customized questionnaire was employed to assess the quality of the included single-arm studies. As existing evidence for HIFU combined with suction curettage to treat CSP was comprehensively assessed in this study, publication bias was not tested.

Statistical analysis

The I² statistic was used to evaluate heterogeneity among the studies. I² values <25% indicated low heterogeneity, >25% and <50%moderate heterogeneity, >50% substantial heterogeneity, and >75% high heterogeneity. When I² was ≥ 50%, a random-effects model was employed, and when it was < 50%, a fixed-effects model was used. Summary data were presented as effect sizes and their corresponding 95% confidence intervals (CIs). P < 0.05 was set as the threshold for significance, and all analyses were performed using the Stata (Version 15.1 SE USA) software.

Results

Literature search

In this analysis, four databases were searched and 432 studies were identified. After duplicate screening, 135 studies were excluded. Subsequently, another 273 studies were excluded based on title/abstract review. Of the remaining 24 studies, 3 were excluded owing to inadequate sample size, and three more as they did not include the outcome measures of interest. Ultimately, 18 studies were included in this meta-analysis[9,14,15,20,21,24–36]. Detailed information about the selection process is provided in Figure 1.

Figure 1. Flow chart of reports recruitment with inclusion and exclusion criteria.

Research characteristics and quality assessment

Of the included studies (Table 1), seven were single-arm studies that investigated the use of HIFU in combination with suction curettage to treat CSP and 11 were controlled studies. These studies were published between 2014 and 2023, and analysed 1251 patients with CSP (sample size: 9-256).

Table 1. Characteristics of studies included in this meta-analysis.

Study	Grouping situation	No. Of patients	Age (mean ± SD, years)	Gestational age (days)	Largest diameter of the sac(mm)	No. of pregnancies after treatment	CS interval (mean ± SD, years)	No. of cesarean deliveries	Quality indicators	Type of uterine suction curettage
Fang 2020 [24]	NA	27	30.55 ± 4.01	51.08 ± 13.47	24.35 ± 10.22	NA	58.92 ± 30.96	1.37 ± 0.63	7	Simple uterine suction curettage
Hong 2017 [25]	NA	85	32.87 ± 4.64	50.58 ± 9.02	39.18 ± 21.61	NA	54.92 ± 35.73	NA	8	Hysteroscopy combined with uterine suction curettage
Huang 2014[26]	NA	10	28.70 ± 15.50	NA	NA	1	0.50–1.42	NA	5	Hysteroscopy combined with uterine suction curettage
Huo 2020 [27]	NA	46	30.61 ± 2.54	NA	NA	NA	4.67 ± 1.38	3.70 ± 0.50	NA	Simple uterine suction curettage
Liu 2020 [28]	NA	103	32.40 ± 4.65	47.67 ± 6.79	24.35 ± 10.22	NA	NA	1.50 ± 0.30	8	Hysteroscopy combined with uterine suction curettage
Liu 2022 [9]	Type I CSP	101	31.56 ± 4.05	55.75 ± 6.13	35.17 ± 7.05	NA	NA	NA	NA	Ultrasound-guided uterine suction curettage
Liu 2022 [9]	Type II CSP	52	33.61 ± 4.46	57.85 ± 5.19	36.12 ± 8.60	NA	NA	NA	NA	Ultrasound-guided uterine suction curettage
Mu 2022 [29]	NA	41	33.60 ± 7.80	50.31 ± 8.27	3.49 ± 0.94	NA	38.00(21.00, 84.00)	1.60 ± 0.70	NA	Ultrasound-guided uterine suction curettage
Peng 2022 [30]	Type I CSP	43	35.60 ± 3.80	46.00 (42.00, 55.00)	19.00(12.00, 23.20)	NA	60.00(36.00, 84.00)	2.00 ± 0.60	NA	Ultrasound-guided uterine suction curettage
Peng 2022 [30]	Type II CSP	89	34.00 ± 4.00	46.00 (43.00, 53.00)	20.30 (17.00, 27.00)	NA	60.00 (35.00, 84.00)	1.24 ± 0.40	NA	Ultrasound-guided uterine suction curettage
Peng 2022 [30]	Type III CSP	21	35.00 ± 4.10	51.00 (48.00, 56.00)	26.70 (20.50, 31.20)	18	84.00 (30.00, 114.00)	1.00 ± 0.70	NA	Ultrasound-guided uterine suction curettage
Wang 2022 [31]	NA	100	32.53 ± 4.88	48.31 ± 7.10	26.00 ± 9.91	78	NA	1.00(1.00–3.00)	8	Ultrasound-guided uterine suction curettage
Wang 2023[15]	NA	154	31.39 ± 5.02	48.00(42.00–55.00)	27.23 ± 11.10	NA	4.00(2.00–6.00)	NA	8	Ultrasound-guided uterine suction curettage
Xiao 2014 [14]	NA	16	30.70 ± 3.40	48.30 ± 8.70	24.80 ± 5.90	NA	40.90 ± 39.10	1.10 ± 0.30	NA	Simple uterine suction curettage
Xiao 2016 [32]	NA	31	30.84 ± 4.05	52.03 ± 8.18	25.03 ± 8.75	NA	4.34 ± 3.19	1.29 ± 0.59	9	Ultrasound-guided uterine suction curettage
Yin 2022 [21]	‘C-shape’ sonication	44	31.50 (30.25, 35.00)	31.50 (30.25, 35.00)	26.86 ± 10.13	NA	5.50 (3.33,8.75)	1.10 ± 0.30	7	Ultrasound-guided uterine suction curettage
Yin 2022 [21]	‘I-shape’ sonication	47	33.00 (30.00, 37.00)	33.00 (30.00, 37.00)	23.57 ± 10.03	8	5.00 (4.00,9.00)	1.00 ± 0.30	NA	Ultrasound-guided uterine suction curettage
Yuan 2021 [33]	NA	52	31.33 ± 4.74	48.67 ± 6.87	33.04 ± 1.45	NA	NA	1.80 ± 0.40	NA	Ultrasound-guided uterine suction curettage
Zhang 2019 [20]	NA	28	31.18 ± 4.88	44.00 (41.00, 48.00)	28.69 ± 9.51	12	4.79 ± 3.93	NA	NA	Ultrasound-guided uterine suction curettage
Zhang 2021 [34]	NA	9	NA	NA	NA	NA	NA	NA	5	Simple uterine suction curettage
Zhu 2015 [35]	NA	53	31.80 ± 4.80	47.70 ± 5.00	37.00 (13.00–60.00)	NA	48.00 (4.00–218.00)	1.40 ± 0.50	9	Hysteroscopy combined with uterine suction curettage
Zhu 2016 [36]	NA	76	32.50 ± 5.00	55.20 ± 16.20	33.10 ± 15.70	NA	60.00 ± 59.00	1.30 ± 0.50	7	Hysteroscopy combined with uterine suction curettage

Abbreviations: SD, standard deviation; CS, caesarean delivery; CSP, caesarean scar pregnancy.

According to the NOS assessment, all controlled studies that were included scored ≥5, with a median score of 8. Two studies achieved a score of 9, and four studies received a score of 8. Further details are listed in Table 1, and questionnaire-based quality assessments for single-arm studies are presented in Table 2.

Table 2. Quality assessment of case series.

Description	Selection	Ascertainment		Causality				Reporting
	1. Does the patient(s) represent(s) the whole experience of the investigator (centre) or is the selection method unclear to the extent that other patients with similar presentation may not have been reported?	2. Was the exposure adequately ascertained?	3. Was the outcome adequately ascertained?	4. Were other alternative causes that may explain the observation ruled out?	5. Was there a challenge/ rechallenge phenomenon?	6. Was there a dose– response effect?	7. Was follow-up long enough for outcomes to occur?	8. Is the case(s) described with sufficient details to allow other investigators to replicate the research or to a llow practitioners make inferences related to their own practice?
Huo 2020	U	Y	Y	Y	Y	N	Y	Y
Liu 2022	U	Y	Y	Y	Y	N	Y	Y
Mu 2022	U	Y	Y	Y	Y	N	Y	Y
Peng 2022	U	Y	Y	Y	Y	N	Y	Y
Xiao 2014	U	Y	Y	Y	Y	N	Y	Y
Yuan 2021	U	Y	Y	Y	Y	N	Y	Y
Zhang 2019	U	Y	Y	Y	Y	N	Y	Y

Notes: Y: yes; U: unclear; N: no.

Results of meta-analysis

Perioperative period

Single-arm meta-analysis revealed that the average hospital stay was 6.22 days (95% CI: 4.80–7.65; I² = 99.30%) for patients with CSP treated using the combination of HIFU and suction curettage (Figure 2(A)). The average intraoperative blood loss was 26.29 ml (95% CI: 20.38–32.20; I² = 98.20%) (Figure 2(B)), and the incidence of adverse events was 15.60% (95% CI: 1.16%–20.10%; I² = 50.04%) (Figure 2(C)) (p < 0.05). According to the Society of Interventional Radiology (SIR) classification of adverse reactions (graded as A, B, C, D, E, F), no adverse events of grade D or higher were reported in the literature (Supplementary Table 1).

Figure 2. Forest plots showing the perioperative factors of patients with CSP treated with HIFU combined with suction curettage. (A) length of hospital stay; (B) intraoperative blood loss; (C) rates of adverse events. Abbreviations: CSP: caesarean scar pregnancy; HIFU: high-intensity focused ultrasound.

Postoperative follow-up

The average time for normalization of serum β-HCG following the combined treatment of HIFU and suction curettage for CSP was 25.48 days (95% CI: 21.26–29.69; I² = 99.50%) (Figure 3(A)). The average time for menstrual recovery was 33.03 days (95% CI: 24.86–41.21; I² = 99.80%) (Figure 3(B)) (p < 0.05).

Figure 3. Forest plots showing the postoperative follow-up of patients with CSP treated with HIFU combined with suction curettage. (A) time to normalization of serum β-human chorionic gonadotropin levels; (B) time to normal menstrual recovery. Abbreviations: CSP: caesarean scar pregnancy; HIFU: high-intensity focused ultrasound.

Treatment success rate and subsequent pregnancy outcomes

The treatment success rate was 97.60% (95% CI: 94.60%–99.60%; I² = 75.64%) for patients with CSP treated using HIFU combined with suction curettage (Figure 4(A)). Moreover, the rate of subsequent pregnancies was 68.70% (95% CI: 52.50%–83.00%; I² = 61.42%) (Figure 4(B)).

Figure 4. (A) Forest plots showing the success rate of patients with CSP treated with HIFU combined with suction curettage. (B) Forest plots showing the subsequent pregnancy outcomes of patients with CSP treated with HIFU combined with suction curettage. Abbreviations: CSP: caesarean scar pregnancy; HIFU: high-intensity focused ultrasound.

Grouped analysis

Grouped analysis was conducted based on three different types of uterine suction curettage following HIFU treatment, which included hysteroscopy combined with uterine suction curettage, ultrasound-guided uterine suction curettage, and simple uterine suction curettage. The findings signified that the hospitalization duration for hysteroscopy combined with uterine suction curettage was 7.75 days (95% CI: 7.56–7.95; I² = 0) and that for ultrasound-guided uterine suction curettage was 5.59 days (95% CI: 3.99–7.2; I² = 99.1%) (Figure 5(A)). The menstrual recovery time for hysteroscopy combined with uterine suction curettage was 34.25 days (95% CI: 31.01–37.49; I² = 94.1%) and that for ultrasound-guided uterine suction curettage was 32.41 days (95% CI: 21.11–43.7; I² = 99.9%) (Figure 5(B)). The average time for serum β-HCG normalization was 30.12 days for hysteroscopy combined with uterine suction curettage (95% CI: 25.51–34.73; I² = 95%), 25.94 days for ultrasound-guided uterine suction curettage (95% CI: 21.66–30.21; I² = 99.4%), and 4.94 days for simple uterine suction curettage (95% CI: 3.80–6.08) (Figure 5(C)).

Figure 5. (A) Forest plot showing the average hospital stay of patients with CSP treated with HIFU combined with different types of suction curettage. (B) Forest plot showing the average time for menstrual recovery of patients with CSP treated with HIFU combined with different types of suction curettage. (C) Forest plot showing the average time for serum β-HCG normalization of patients with CSP treated with HIFU combined with different types of suction curettage. Abbreviations: CSP, caesarean scar pregnancy; HIFU: high-intensity focused ultrasound; HCG: human chorionic gonadotropin.

Heterogeneity assessment

Of the seven outcome measures analysed in this study, three indicators showed moderate to substantial heterogeneity. However, high heterogeneity was observed in hospital stay (I² = 99.30%), blood loss (I² = 98.20%), time for serum β-HCG normalization (I² = 99.50%), and time for menstrual recovery (I² = 99.80%).

Discussion

CSP is clinically challenging owing to the associated risks of uterine scar rupture, severe haemorrhage, and adverse maternal outcomes[7]. Currently, definitive treatment guidelines are not available in clinical practice. This study comprehensively analysed the clinical efficacy, safety and subsequent pregnancy outcomes of using HIFU in conjunction with suction curettage to treat CSP. Via a rigorous selection process involving searches across multiple databases, 18 studies encompassing both controlled and single-arm studies were ultimately included in the analysis. The findings suggested that the success rate of CSP treated using the combination of HIFU and uterine curettage was 97.60%, the subsequent pregnancy rate was 68.70%, and the incidence of adverse events was 15.60%. Furthermore, major complications were not observed. Collectively, these findings imply that HIFU combined with uterine curettage is a safe and effective alternative for treating CSP.

This single-arm meta-analysis indicated that the treatment protocol demonstrated favourable safety profiles during the perioperative period. The average length of hospital stay was 6.22 days, the average intraoperative blood loss was merely 26.29 ml, and the adverse event occurrence rate was 15.60%, including abdominal or lower limb pain, fever, vaginal bleeding, haematuria and vomiting. These outcomes may be attributed to the non-invasive nature of the HIFU technology, which enables precise targeting of pathological sites without the need for surgical incisions. Thus, patient trauma is minimized, and bleeding risks are reduced. Following HIFU treatment, the microvascular system within the pregnancy tissue is disrupted, which impacts the blood supply and transforms the gestational sac into a thick-walled cystic mass devoid of a yolk sac or embryo [14]. Studies [37,38] have reported that HIFU can damage small vessels with diameters of <2 mm surrounding the scar of the gestational sac. Hence, the risk of haemorrhage is alleviated, and intraoperative blood loss during subsequent curettage procedures is reduced. In addition, HIFU aids in loosening the adhesions between the gestational sac and the scarred uterine wall, which facilitates suction curettage. When compared with the control group without any pretreatment before the curettage, the HIFU pretreatment group exhibited lower intraoperative blood loss. Moreover, severe adverse reactions did not occur in either group. Common mild adverse reactions in the HIFU pretreatment group, such as abdominal pain and leg pain, were alleviated within a day [28]. In comparison with the UAE pretreatment group, the HIFU pretreatment group demonstrated lower pain scores and fewer adverse reactions. Nonetheless, statistically significant differences were not observed between the two groups in terms of intraoperative blood loss or length of hospital stay [36]. Studies have shown that the size of the gestational sac and the thickness of the scarred anterior uterine wall are independent risk factors for intraoperative bleeding in patients with CSP [10,39]. HIFU pretreatment has been documented to exhibit better efficacy for exogenous CSP with a gestational age of <9 weeks [29]. However, there was a high degree of heterogeneity in the length of hospital stay (I² = 99.30%) and blood loss (I² = 98.20%). These differences could be ascribed to variations in sample sizes, patient characteristics, measurement methods for intraoperative blood loss, study designs and other factors in the studies. This issue warrants further investigation.

In terms of postoperative follow-up, the average time for serum β-HCG normalization following HIFU combined with suction curettage treatment for CSP was 25.48 days. The recovery of serum β-HCG levels after treatment was swift, which may be attributed to the non-invasive focal thermal ablation effect of HIFU. Different measures taken after undergoing HIFU treatment can have varying impacts on the therapeutic outcome. For instance, employing different ultrasound strategies, such as reducing the distribution of ultrasound points, can lower the risk of adverse events [21]. Additionally, the clinical outcomes may differ when HIFU is combined with or without suction curettage in treating CSP, although the surgical outcomes are both deemed safe [26,32,35]. Following HIFU treatment, the blood supply to the gestational sac within the uterine cavity is inadequate, which indirectly causes a decrease in serum β-HCG levels. A study [14] has noted that after pretreatment with HIFU, there is no significant decline in serum β-HCG levels from the 1^st to 5^th day, and in fact, many patients experience an increase in β-HCG levels. This initial rise in β-HCG levels is not completely understood. HIFU possibly disrupts the nurse cells within the pregnancy tissue, which releases β-HCG into the bloodstream, causing the initial elevation [32]. Additionally, viable gestational tissue capable of secreting β-HCG may persist after HIFU treatment, and a significant decline in β-HCG levels can only be observed after the removal of the CSP mass [40]. Moreover, suboptimal postoperative decline in β-hCG may be attributed to a history of curettage, a strong desire to preserve fertility, and a relatively short duration of suction curettage [30]. They observed that the clinical classification of patients with CSP influences the rate of recovery of serum β-HCG levels. Patients with type II and type III CSP exhibited significantly lower recovery rates than those with type I CSP [30]. However, there was no significant difference in the recovery time of serum β-HCG levels between UAE and HIFU treatments [41]. It is important to note that differences in treatment timing and measurement methods may exist across different studies, which can potentially affect the comparability of results. The average time for menstrual recovery after the combined treatment of HIFU and suction curettage for CSP was 33.03 days. Similar to the normalization of serum β-HCG levels, the recovery of menstruation post-treatment was relatively rapid. When compared with UAE, HIFU treatment resulted in faster menstrual recovery [41]. Nonetheless, definitions and assessment methods of menstrual recovery may differ across different studies and careful standardization is needed in future research.

Our single-arm meta-analysis exhibited an impressive treatment success rate of 97.60% for CSP with HIFU combined using suction curettage. This high rate highlights the effectiveness of this therapeutic approach in addressing CSP. Nevertheless, in terms of subsequent pregnancy outcomes, a pregnancy rate of 68.70% was observed following HIFU combined with suction curettage. Although statistical significance was not reached, it demonstrates the potential of this approach in preserving fertility [33]. The treatment with HIFU is noninvasive, preserving the structural integrity of the uterus and ovarian function. Patients can plan for pregnancy as early as three months after menstrual recovery. In the included studies, some follow-up patients who did not conceive after treatment cited reasons such as strict contraception due to no desire for fertility, unintentional ingestion of drugs affecting foetal development in early pregnancy, or familial factors [20]. Due to the limited sample size, larger studies are warranted in the future to focus on this outcome. According to a study [42] HIFU surpasses UAE in reducing the risk of CSP recurrence. Factors such as patient age, serumβ-HCG levels, and menstrual recovery status influence subsequent pregnancy outcomes. Early diagnosis and treatment of CSP can mitigate the risk of infertility and CSP recurrence. The longer the amenorrhea period, the longer the surgical duration, and the greater the extent of curettage, the more significant is the damage to the endometrium; hence, CSP is prone to recurrence [42]. Therefore, clinicians and patients should remain highly vigilant to identify asymptomatic CSP and its recurrence.

Previous meta-analyses [19,43,44] have compared HIFU with suction curettage and UAE with suction curettage for treating CSP. The findings indicated that the curative effects of both treatments are comparable, but HIFU was associated with lower costs and fewer complications. Additionally, HIFU is a better choice for patients with CSP with a high gestational age, large gestational sac diameter, and high serum β-HCG level. However, no studies have so far specifically examined the clinical efficacy and safety of HIFU combined with suction curettage for treating CSP. Our study comprehensively included original studies evaluating HIFU combined with suction curettage in the treatment of CSP, both controlled studies and single-arm studies. In addition, our outcome indicators covered the perioperative period, postoperative follow-up, and reproductive outcomes and evaluated the efficacy and safety of the treatment in a detailed manner.

This study has the following limitations: (1) Presence of heterogeneity: In the meta-analysis, certain indicators displayed noticeable heterogeneity, which affected the interpretation and generalizability of the results. This heterogeneity might have stemmed from disparities in patient selection, clinical experience of the operators, and HIFU treatment parameters (such as average ablation time, average power and duration, type of HIFU equipment, and anesthesia method) across different studies. (2) All studies were from China, which inevitably led to bias in the results. (3) Sample size: Despite the inclusion of multiple studies in this research, some had relatively small sample sizes, which potentially affected the stability and reliability of the results. In addition, owing to the limited data of the included studies, group statistical analysis for more indicators could not be performed. (4) Study design: This study primarily encompassed nonrandomized controlled trials and single-arm studies, which lacked higher-level evidence support, thereby possibly influencing the reliability of the results.

Conclusion

While the combination of HIFU and suction-curettage may induce common adverse effects such as lower abdominal or limb pain, these reactions typically do not necessitate therapeutic intervention. Additionally, the size of the gestational sac is a determinant of the procedure’s success. In conclusion, HIFU combined with suction curettage demonstrates promising clinical efficacy, safety, and favourable reproductive outcomes in managing CSP. This technique is expected to become a safe and effective alternative for handling CSP.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data used to support the findings of this study are available from the corresponding author upon request.