Comparison of clinical characteristics and perinatal outcomes between twin and singleton pregnancies with placenta accreta spectrum: a retrospective cohort study from a tertiary hospital in Eastern China.

No significant differences were observed in age, marital status, or occupation between the two groups. However, educational level differed significantly, with a higher proportion of women having a bachelor’s degree or higher in the twin PAS group (64.46% vs. 46.74%, Table  1 ). Table 1 Comparison of demographic characteristics Characteristic Singleton ( n  = 783) Twin ( n  = 101) Statistic P P -adj Maternal age (years) 32.82 ± 4.67 32.38 ± 3.87 t  = 1.06 0.290 0.308  ≤ 19 1 (0.13) 0 (0.00) 0.181 Δ  20–34 499 (63.73) 74 (73.27)  ≥ 35 283 (36.14) 27 (26.73) Marital Status χ2  = 0.16 0.691 0.605  Married 745 (95.15) 97 (96.04)  Unmarried 38 (4.85) 4 (3.96) Education Level χ2  = 14.00 0.001 0.002  Junior high school or less 298 (38.06) 20 (19.80)  High school or vocational 119 (15.20) 16 (15.84)  a bachelor’s degree or higher 366 (46.74) 65 (64.46) Employment Status χ2  = 2.11 0.146 0.176  Employed 351 (44.83) 53 (52.48)  Unemployed 432 (55.17) 48 (47.52) Δ: Fisher’s exact test was used for this comparison. Bold font signified statistically significant P values Comparison of demographic characteristics Δ: Fisher’s exact test was used for this comparison. Bold font signified statistically significant P values The twin group had fewer gravidities, parities, uterine surgeries and intrauterine procedures, higher rates of assisted reproductive technology (ART), greater gestational weight gain, lower body mass index (BMI) and preoperative PAS diagnosis rates ( P   1) was 8.05% (63/783) in singletons compared to 0.99% (1/101) in twins. Similarly, a history of multiple intrauterine procedures (> 2) was 26.69% (209/783) in singletons versus 15.84% (16/101) in twins. Notably, 2.04% (16/783) of singletons had a combined history of both multiple uterine surgeries and intrauterine procedures, a finding not observed in any twin pregnancy. The twin group demonstrated a lower prevalence of both multiple prior uterine surgeries and intrauterine procedures. Table 2 Comparison of obstetric clinical characteristics Characteristic Singleton ( n  = 783) Twin ( n  = 101) Statistic P P -adj Gravidity (times) 3(2,5) 2(1,3) Z = -6.21 < 0.001 < 0.001  1–2 246(32.96) 60(59.41) χ2  = 28.83 < 0.001  3–5 432(53.93) 37(36.63)  ≥ 6 105(13.11) 4(3.96) Parity (times) 1(0,1) 0(0,0) Z = -7.26 < 0.001 < 0.001  0 308(39.34) 81(80.20) χ2  = 60.83 < 0.001  1 378(48.28) 15(14.85)  2 85(10.86) 4(3.96)  ≥ 3 12(1.53) 1(0.99) History of uterine surgery 0.00(0.00,1.00) 0.00(0.00,0.00) Z = -5.23 < 0.001 < 0.001  0 425(54.28) 82(81.19) < 0.001 Δ  1 295(37.68) 18(17.82)  2 58(7.41) 1(0.99)  ≥ 3 5(0.64) 0(0.00) History of intrauterine procedure 1.00(1.00,3.00) 1.00(0.00,2.00) Z = -3.12 0.002 0.003  0 183(23.37) 35(34.66) χ2  = 10.21 0.037  1 224(28.61) 33(32.67)  2 167(21.33) 17(16.83)  3 101(12.90) 7(6.93)  ≥ 4 108(13.79) 9(8.91) BMI (kg/m 2 ) 22.05 ± 3.27 21.21 ± 2.60 t  = 2.98 0.003 0.004 Mode of conception χ2  = 204.69 < 0.001 < 0.001  Natural conception 653(83.40) 19(18.81)  Assisted reproduction 130(16.60) 82(81.19) Gestational weight gain (kg) 12.80 ± 4.80 14.66 ± 5.44 Z = -3.60 < 0.001 < 0.001 Preoperative diagnosis of PAS 183(23.37) 3(2.97) χ2  = 22.41 < 0.001 < 0.001 Δ: Fisher’s exact test was used for this comparison. Bold font signified statistically significant P values Comparison of obstetric clinical characteristics Δ: Fisher’s exact test was used for this comparison. Bold font signified statistically significant P values Twin pregnancies had a significantly higher prevalence of PAS ( χ² =21.70, P  < 0.001, P-adj  < 0.001). Twin gestation was associated with a 1.62-fold increase in the risk of placenta accreta spectrum compared to singleton gestation in the unadjusted regression analysis (OR 1.62, 95% CI 1.14–2.57). After adjusting the regression model for maternal age, education level, gravidity, parity, BMI and gestational weight gain, a significant association was found between twin gestation and PAS (aOR 1.43, 95% CI 1.08–2.26). When adjusting the regression model for maternal age, education level, gravidity, parity, BMI, gestational weight gain, the history of uterine surgery, intrauterine procedure, placenta previa and ART, the fully adjusted OR for placenta accreta spectrum was 1.53 (95% CI 1.21–2.14) (Table  3 ). Table 3 Association between twin pregnancy and PAS Unadjusted Odds Ratio (95% CI) 1 Adjusted Odds Ratio (95% CI) 2 Adjusted Odds Ratio (95% CI) Twin vs. singleton pregnancy 1.62 (1.14–2.57) 1.43 (1.08–2.26) 1.53 (1.21–2.14) 1 Adjusted for maternal age, education level, gravidity, parity, BMI, gestational weight gain 2 Adjusted for all variables in model 1 plus the history of uterine surgery, intrauterine procedure, placenta previa, ART Association between twin pregnancy and PAS 1 Adjusted for maternal age, education level, gravidity, parity, BMI, gestational weight gain 2 Adjusted for all variables in model 1 plus the history of uterine surgery, intrauterine procedure, placenta previa, ART The twin group had higher rates of preterm delivery, invasive PAS, postpartum hemorrhage, intrauterine tamponage, blood transfusion, concordance rate in pathological diagnosis, longer postoperative antibiotic use and hospital stays, and lower rate of placenta previa ( P  < 0.05). No significant differences were found between the groups in the type of cesarean section, incidence of uterine artery ligation, hysterectomy, surgeon seniority, operative time, or chorioamnionitis. (Table  4 ). For the indications for preterm delivery in the singleton PAS group, the top three causes of preterm birth were PAS (45.8%), spontaneous preterm labor (11.9%), and premature rupture of membranes (10.5%), while in the twin group, the leading causes were spontaneous preterm labor (34.1%), preeclampsia (15.9%), and premature rupture of membranes (9.8%). with delivery directly for PAS accounting for only 6.1% of cases (Table  5 ). Treatment strategies differed significantly across PAS grades( P  < 0.001). Manual placental removal was the predominant approach for placenta PA. As severity increased to PI, the use of localized lesion resection rose substantially. Hysterectomy was primarily reserved for the PP, with a rate of 40.0% in singletons. Overall, more radical interventions were employed with increasing PAS severity (Table  6 ). In aspect of concordance rate in pathological diagnosis for singletons, the Cochran-Armitage trend test demonstrated a significant increase in the clinical-pathological diagnostic concordance rate with increasing PAS severity ( Z  = 7.63, P  < 0.001, P-adj  < 0.002). Due to the limited number of PP cases in twin pregnancies ( n  = 1), valid trend analysis was not feasible. A descriptive presentation is provided, with concordance rates of 7.1% for accreta, 21.1% for increta, and 100.0% for the single percreta case (Table  7 ). Table 4 Comparison of maternal perioperative characteristics Variable Singleton ( n  = 783) Twin ( n  = 101) Statistic P P -adj Gestational age at delivery(weeks) 37.00(35.29, 38.57) 35.43(34.00, 36.64) Z = -6.71 < 0.001 < 0.001  < 34 89 (11.37) 21 (20.79) χ2  = 46.34 < 0.001 < 0.001  34–37 265 (33.84) 61 (60.40)  ≥ 37 429 (54.79) 19 (18.81) Type of cesarean section χ2  = 1.14 0.286 0.308  Scheduled cesarean delivery 515 (65.77) 61 (60.40)  Unscheduled cesarean delivery 268 (34.23) 40 (39.60) Placenta previa 349 (44.57) 18 (17.82) χ2  = 26.37 < 0.001 < 0.001 Type of PAS χ2  = 7.39 0.025 0.034  Placenta accreta 542 (69.22) 61 (60.40)  Placenta increta 211 (26.95) 39 (38.61)  Placenta percreta 30 (3.83) 1 (0.99) Surgeon seniority χ2  = 3.00 0.223 0.252  Consultant 386 (49.30) 54 (53.47)  Senior 222 (28.35) 32 (31.68)  Junior 175 (22.35) 15 (14.85) Postpartum hemorrhage (ml) 700.00 (500.00, 1000.00) 1000.00 (600.00, 1982.50) Z = -5.37 < 0.001 < 0.001  ≤ 1000 594 (75.86) 59 (58.42) χ2  = 16.25 < 0.001 < 0.001  1000–2500 139 (17.75) 27 (26.73)  ≥ 2500 50 (6.39) 15 (14.85) Intrauterine tamponage 381 (48.66) 69 (68.32) χ2  = 13.83 < 0.001 < 0.001 Uterine artery ligation 107 21 χ2  = 13.83 0.055 0.069 Hysterectomy 18 (2.30) 2 (1.98) χ2  = 0.04 0.839 0.710 Blood transfusion 215 (27.46) 42 (41.58) χ2  = 8.66 0.003 0.004 Operation time (minutes) 70.00 (60.00, 88.00) 69.00 (57.50, 83.00) Z = -0.83 0.405 0.405 Postoperative antibiotic therapy (days) 3.00 (2.00, 4.00) 4.00 (3.00, 5.00) Z = -2.08 0.037 0.048 Total length of stay (days) 8.00 (6.00, 11.00) 10.00 (8.00, 18.50) Z = -5.02 < 0.001 < 0.001 Pathological diagnosis of PAS 40 (5.60) a 13 (13.68) b χ2  = 8.95 0.003 0.004 Bold font signified statistically significant P values a Calculated in the Singleton PAS group with pathological examination ( n  = 714, because the other 69 cases refused placental pathological examination.) b Calculated in the twin PAS group with pathological examination ( n  = 95, because the other 6 cases refused placental pathological examination.) Comparison of maternal perioperative characteristics Bold font signified statistically significant P values a Calculated in the Singleton PAS group with pathological examination ( n  = 714, because the other 69 cases refused placental pathological examination.) b Calculated in the twin PAS group with pathological examination ( n  = 95, because the other 6 cases refused placental pathological examination.) Table 5 Comparison of preterm birth causes Causes of preterm birth Singleton ( n  = 354) Twin ( n  = 82) χ2 P P -adj PAS 162 (45.8%) 5 (6.1%) 44.02 < 0.001 < 0.001 Spontaneous preterm labor 42 (11.9%) 28 (34.1%) 24.53 < 0.001 < 0.001 Premature rupture of membrane 37 (10.5%) 8 (9.8%) 0.03 0.852 0.710 Placenta previa 28 (7.9%) 5 (6.1%) 0.31 0.576 0.531 Antepartum hemorrhage 20 (5.6%) 6 (7.3%) 0.566 Δ 0.531 Fetal distress 20 (5.6%) 7 (8.5%) 0.96 0.328 0.338 Preeclampsia 12 (3.4%) 13 (15.9%) < 0.001 Δ < 0.001 Other causes 33 (9.3%) 10 (12.2%) 0.62 0.432 0.420 Other causes include placental abruption, oligohydramnios, intraamniotic infection, vasa previa, cord presentation, early-stage heart failure, threatened uterine rupture, and severe intrahepatic cholestasis of pregnancy (ICP) Δ: Fisher’s exact test was used for this comparison. Bold font signified statistically significant P values Comparison of preterm birth causes Other causes include placental abruption, oligohydramnios, intraamniotic infection, vasa previa, cord presentation, early-stage heart failure, threatened uterine rupture, and severe intrahepatic cholestasis of pregnancy (ICP) Δ: Fisher’s exact test was used for this comparison. Bold font signified statistically significant P values Table 6 Management strategies for different PAS subtypes Group PAS Subtypes Management Strategies P P -adj Manual Removal Focal excision Hysterectomy Singleton ( n  = 783) Placenta Accreta ( n  = 542) 521(96.1) 21 (3.9) 0 (0) < 0.001 Δ < 0.001 Placenta Increta ( n  = 211) 143(67.8) 62 (29.4) 6 (2.8) Placenta Percreta ( n  = 30) 14 (46.7) 4 (13.3) 12 (40.0) Twin ( n  = 101) Placenta Accreta ( n  = 61) 53 (86.9) 7 (11.5) 1 (1.6) < 0.001 Δ < 0.001 Placenta Increta ( n  = 39) 20 (51.3) 18 (46.2) 1 (2.6) Placenta Percreta ( n  = 1) 0 (0) 1 (100) 0 (0) Δ: Fisher’s exact test was used for this comparison. Bold font signified statistically significant P values Management strategies for different PAS subtypes Singleton ( n  = 783) Twin ( n  = 101) Δ: Fisher’s exact test was used for this comparison. Bold font signified statistically significant P values Table 7 Concordance rate of clinical PAS subtypes and pathological diagnosis Group PAS Subtypes Histopathological Examination Pathologically Confirmed Cases Concordance Rate (95% CI) Singleton ( n  = 714) Placenta Accreta 486 9 1.9% (0.9% − 3.5%) Placenta Increta 198 16 8.1% (4.9% − 12.7%) Placenta Percreta 30 15 50.0% (32.9% − 67.1%) Total 714 40 5.6% (4.1% − 7.5%) Twin ( n  = 95) Placenta Accreta 56 4 7.1% Placenta Increta 38 8 21.1% Placenta Percreta 1 1 100.0% Total 95 13 13.68% Concordance rate of clinical PAS subtypes and pathological diagnosis Singleton ( n  = 714) Twin ( n  = 95) Neonates in the twin group had significantly lower birth weights and a higher rate of transfer to the Pediatric Department than those in the singleton group. No significant intergroup differences were observed in neonatal sex or the proportion of low Apgar scores (Table  8 ). Table 8 Comparison of neonatal outcomes Variable Singleton ( n  = 783) Twin ( n  = 202) Statistic P P -adj Neonatal weight (g) 2891.46 ± 642.95 2217.32 ± 458.81 t  = 17.01 < 0.001 < 0.001 Newborn gender χ2  = 2.06 0.151 0.189  Male 401(51.21) 92(45.54)  Female 382(48.79) 110(54.46) Low Apgar score 15(1.92) 5(2.48) χ2  = 0.25 0.615 0.652 Neonatal transfer to pediatric department 334(42.71) 136(67.33) χ2  = 38.99 < 0.001 < 0.001 Bold font signified statistically significant P values Comparison of neonatal outcomes Bold font signified statistically significant P values

This study included women diagnosed with PAS during cesarean delivery at the Women and Children’s Hospital affiliated to Ningbo University from December 2018 to November 2023. Inclusion criteria were: (1) gestational age ≥ 28 weeks; (2) cesarean delivery; (3) intraoperative clinical diagnosis and/or postoperative pathological diagnosis of PAS. Exclusion criteria were: (1) incomplete medical records; (2) multifetal pregnancies with more than two fetuses. While pathological diagnosis is the gold standard for PAS, the hysterectomy rates have decreased with advancements in clinical management. The FIGO guidelines [ 7 ] emphasize clinical description as the most important diagnostic and classification criterion for PAS. The clinical grading criteria for 2019 are as follows: Grade 1: Abnormally adherent placenta (placenta accreta), with no or minimal neovascularization on the uterine surface; Grade 2: Abnormally invasive placenta (placenta increta) where a placental “bulge” is visible, with significant vascular proliferation, but the placental tissue does not invade the uterine serosa. Gentle traction on the umbilical cord causes the uterus to pull inward, and the placenta does not separate (dimple sign); Grade 3: Abnormally invasive placenta (placenta percreta): Grade 3a: Limited to the uterine serosa; Grade 3b: Involving the bladder, with unclear anatomical boundaries between the bladder and uterus; Grade 3c: Involving other pelvic tissues/organs, such as the broad ligament, vaginal wall, pelvic sidewall, or any other pelvic organ. Thus, either intraoperative clinical diagnosis or postoperative pathological diagnosis was accepted as the diagnostic criterion for PAS in this study. A retrospective cohort study was conducted using electronic medical records. From December 2018 to November 2023, 26,617 singleton and 2,124 twin pregnancies with gestational age  ≥  28 weeks were delivered. PAS was diagnosed in 783 singleton and 101 twin pregnancies (83 dichorionic diamniotic, 17 monochorionic diamniotic, and 1 monochorionic monoamniotic). The twin PAS group was compared to the singleton PAS group regarding demographic characteristics, obstetric clinical features, and perioperative maternal and neonatal outcomes. A total of 376 women had a history of uterine surgery, including 362 who underwent cesarean section, 9 with a history of myomectomy, 2 with a history of cornual pregnancy surgery, and 2 with a history of rudimentary uterine horn surgery. History of intrauterine procedures encompassed procedures such as induced abortion, dilation and curettage (D&C), and hysteroscopic surgery. Postpartum hemorrhage was commonly defined as blood loss of 1000 mL after cesarean delivery. According to Chinese guidelines, prophylactic antibiotics after cesarean section are usually stopped within 24 h. However, given that all participants in this study had PAS, which involved greater intraoperative and postoperative complexity than routine cesarean delivery, the duration of antibiotic administration was determined individually based on the patient’s postoperative recovery. A low Apgar score was defined as a score of ≤ 7 at either 1 or 5 min. Data were analyzed using SPSS 26.0. Normally distributed continuous variables were presented as mean ± standard deviation (SD) and compared using independent sample t tests. Nonnormally distributed variables were expressed as median and interquartile range (IQRs), and compared using rank-sum tests. Categorical variables were described as frequencies with corresponding percentages, and compared using Pearson’s chi-square test or Fisher’s exact test. To control the false positive risk from multiple testing, all reported p-values were adjusted for the false discovery rate (FDR) using the Benjamini–Hochberg procedure. Univariable and multivariable logistic regression analyses were used to investigate the association between PAS and multiple gestation. The OR and 95% CI were reported. The Cochran-Armitage trend test was used for analyzing trends in clinical-pathological concordance rates. A two-sided P -value < 0.05 was considered statistically significant.

In summary, twin pregnancies with PAS have fewer high-risk factors and lower preoperative diagnosis rates but worse maternal and neonatal outcomes compared to singleton pregnancies, necessitating more clinical interventions and longer treatment durations. Improving the accuracy of prenatal diagnosis of PAS in twin pregnancies for twin PAS is crucial, as it enables optimized surgical planning and strategies to mitigate severe obstetric complications.

We found that twin gestation was associated with a 1.53-fold increase in the risk of PAS compared to singleton gestation, a finding consistent with Miller et al. [ 8 ] and Guo et al. [ 9 ], but contrary to Matsuzaki et al. [ 10 ]. Previous studies have identified several risk factors for PAS, including a history of uterine surgery, intrauterine procedures, ART, prior PAS, bicornuate uterus, submucosal uterine fibroids, adenomyosis, advanced maternal age, and smoking. Furthermore, placenta previa has been established as an independent risk factor for PAS [ 11 , 12 ]. Notably, the twin group lacked typical risk factors associated with PAS, such as advanced maternal age, multiparity, multigravidity, repeated uterine surgeries, multiple intrauterine manipulations, and placenta previa, but still had a higher PAS incidence. This may be attributed to several factors: firstly, twin pregnancies have larger placental areas, increasing the likelihood of implantation and invasion into the lower uterine segment or previous cesarean scars [ 13 ]. Secondly, multiple gestation is identified as an independent risk factor for PAS [ 8 , 9 , 14 ]. Finally, ART, commonly used in twin pregnancies, is a known risk factor for PAS [ 15 ]. Potential infertility, intrinsic characteristics of infertile patients, and a hyperhormonal environment may enhance the invasion of trophoblast cells, leading to placental abnormalities [ 15 – 17 ]. DI Girolamo et al. reported the prenatal detection rate of PAS in twin pregnancies was achieved in only about one-third of cases [ 13 ]. Our study suggested a significantly lower preoperative diagnosis rate in the twin group than in the singleton group (2.97% vs. 23.37%), which is consistent with the findings of Shamshirsaz et al. [ 18 ]. Ultrasound and magnetic resonance imaging (MRI) are commonly used auxiliary examinations for detecting PAS. The challenges in imaging diagnosis may be due to larger placental volumes and acoustic shadows from the fetuses. Even for experienced teams, the prenatal detection rate of PAS is lower [ 19 – 21 ]. If the majority of the placenta is located on the posterior wall and is not a placenta previa, prenatal detection may be further complicated by the acoustic shadows cast by the twins themselves. Antenatal diagnosis of PAS is crucial as it allows for multidisciplinary planning, optimal delivery timing, and prophylactic interventions, thereby reducing maternal and neonatal morbidity and mortality [ 22 ]. Therefore, close collaboration between clinicians and imaging specialists is essential to enhance the prenatal diagnostic accuracy of twin pregnancy with PAS, thereby facilitating early multidisciplinary planning of safe management strategies. The twin PAS group had consistently poorer outcomes, including higher rates of preterm delivery, invasive PAS, postpartum hemorrhage, intrauterine tamponage, blood transfusion, longer antibiotic use, longer hospital stays, lower neonatal birth weights, and higher rates of neonatal transfer to the Pediatric Department ( P < 0.05). The management strategies of PAS varied significantly based on disease severity. Our data also revealed a clear progression in management strategies with increasing PAS severity (Table 6 ), shifting from conservative approaches (manual removal) for PA to more radical procedures (localized resection and hysterectomy) for PI and PP. These findings align with previous studies reporting higher rates of severe maternal complications in twin PAS pregnancies. Miller et al. [ 8 ] reported that multiple pregnancies with PAS had significantly higher rates of blood transfusion, hysterectomy, amniotic fluid embolism, and disseminated intravascular coagulation compared to singleton pregnancies. Shamshirsaz et al. [ 18 ] conducted a multicenter study showing that PAS patients with multiple pregnancies received more red blood cell transfusions during surgery and within 24 h postoperatively. However, GUO et al. [ 9 ] reported no significant difference in the incidence of perioperative adverse events between twin and singleton PAS patients. Contrasting with Miller et al. [ 8 ] who suggested invasive PAS is more common in singletons, our study found a higher rate in twins. This discrepancy highlights the need for future prospective studies to confirm this association and explore the underlying biological mechanisms. Furthermore, a striking difference was observed in the indications for preterm delivery. In singletons, PAS itself was the leading cause (45.8%), often necessitating iatrogenic delivery. Conversely, in twins, spontaneous preterm labor (34.1%) and preeclampsia (15.9%) were the primary drivers, with PAS directly accounting for only 6.1% of cases. This disparity underscores distinct clinical management priorities: for singleton PAS, the focus is on elective delivery timing, weighing maternal and fetal safety against fetal maturity; for twin PAS, the emphasis shifts towards preventing and managing spontaneous preterm birth and preeclampsia. These findings suggest that singleton and twin PAS may represent distinct clinical entities. PAS is histologically characterized by the absence of decidua between the placental chorionic tissue and the uterine myometrium [ 23 ]. Miller et al. [ 8 ] reported concordance rates of 13.8% in twins and 18.3% in singletons. In contrast, our study found even lower rates (13.68% in twins vs. 5.60% in singletons), with an overall concordance rate of 6.55%. The concordance rate significantly increased with PAS severity. The low accuracy for PA/PI is likely because most patients underwent manual removal, which precludes obtaining myometrial tissue for pathological confirmation, leading to clinical overdiagnosis. The highest concordance rate was observed in the PP group, where hysterectomy provided complete pathological specimens for definitive diagnosis. This finding may underscore the role of histopathology (particularly hysterectomy specimens) as the gold standard for diagnosing PAS, especially in PP cases. Although PAS increases the risk of uterine wall injury, chorionic villi invasion is often unevenly distributed within the myometrium. Placental tissue may not remain in the decidua and myometrium, leading to potential false-negative results in pathological diagnosis. For patients undergoing uterine preservation, attempts to manually remove the placenta during surgery may disrupt the gross and microscopic pathological features, making it challenging to accurately grade the severity of PAS [ 24 ]. Several deficiencies in our workflow contributed to this low concordance: Firstly, insufficient communication between pathologists and obstetricians led to inadequately detailed pathology requisitions, lacking crucial intraoperative findings. Secondly, incomplete tissue specimens (e.g., placenta without adjacent myometrium) were often submitted. Thirdly, pathologist experience in diagnosing PAS was limited. We have since initiated optimizations to address these issues. The notable clinical-pathological discrepancy highlights the need to refine clinicians’ sampling techniques and enhance pathologists’ expertise. While histopathological examination remains the gold standard for diagnosing many conditions, clinical description continues to serve as a crucial reference for defining and grading PAS. Pathologists play a decisive role in distinguishing between different PAS grades. Furthermore, immunohistochemistry can more accurately assess the depth of myometrial invasion, offering a reliable method for consistent PAS grading [ 25 ]. A limitation of this study is the small sample size of twin pregnancies with placenta accreta spectrum (PAS), particularly for cases of placenta percreta. Our findings warrant validation in prospective, large-scale, multi-center studies. Future research should prioritize enrolling more twin PAS cases, especially severe ones, to establish more robust and definitive clinical evidence.