Influence of migration status on hysterectomy surgical approach and indications for benign conditions-a nationwide cohort register study

Over the past few decades, surgical techniques have evolved significantly, shifting from open abdominal procedures to a variety of minimally invasive approaches, including laparoscopic, robotic, or vaginal [ 1 , 2 ]. This evolution in surgery has led to improved surgical outcomes, including reduced postoperative morbidity, shorter hospital stays, and faster recovery [ 3 ]. Despite these improvements, disparities in access to minimally invasive surgery among patients from lower socioeconomic backgrounds and migrant populations, have been reported in numerous studies from the United States and other non-European countries [ 4–6 ]. The evidence from European countries and in the field of gynaecology remains limited. Hysterectomy is one of the most commonly performed gynaecological surgeries worldwide, with almost 5000 procedures conducted annually in Norway [ 2 ]. The choice of surgical approach is influenced by multiple factors, including surgical indications, uterine size, comorbidities, prior surgeries, geographic distribution, and surgeon experience. US and Canadian studies have shown that racial minority women are less likely to receive minimally invasive hysterectomy compared with white Caucasian women [ 7–10 ]. A review on health disparities in access to minimally invasive surgery highlighted the lack of European research on benign gynaecological conditions [ 11 ]. In the Nordic countries, a positive correlation between hysterectomy rate and income has been found in Finland [ 12 ]. In Denmark, a higher proportion of unemployed women had open hysterectomy [ 13 ], and those with a low socioeconomic position had higher odds of complications following hysterectomy [ 14 ]. However, few of these studies have simultaneously taken migrant status into account. Migrant populations are highly diverse [ 15 ]. According to the International Organization for Migration, a migrant is anyone who moves from their usual place of residence—within a country or across borders—either temporarily or permanently, and for a wide range of reasons [ 16 ]. Despite universal health coverage in the Nordic countries, persistent disparities in reproductive health remain a major public health concern [ 17 ]. Studies from Norway indicate that migrants participate less frequently in the cervical cancer-screening program compared with Norwegian-born women [ 18 ]. Furthermore, higher educational levels correlate with increased access to specialist care for gynaecological cancer symptoms in Norway [ 19 ]. Previous reports have also shown substantial geographical variation in hysterectomy rates across different regions of Norway [ 20 ]. Furthermore, age [ 9 ] and indication [ 21 ] are known determinants of surgical approach, while temporal [ 2 ] and regional [ 20 ] factors may reflect changes in practice patterns and resource availability. Few studies have simultaneously assessed the combined effects of migration and socioeconomic status on hysterectomy provision in a context of universal health care. This nationwide register-based cohort study examines how migration status and socioeconomic factors influence the choice of surgical approach in hysterectomies and explores differences in hysterectomy indications for benign conditions, using nationwide data between 2008 and 2020. Sub-analyses were performed after excluding fibroid indications to assess whether observed differences persisted independently of a condition known to influence uterine size and surgical approach, and restricted to a single tertiary centre to examine whether disparities remained after reducing variation in institutional practice patterns and surgical expertise.

We used individually linked data from the Norwegian Patient Registry (NPR) covering all hysterectomies performed in Norway from 2008 to 2020, in addition to sociodemographic variables from Statistics Norway. The NPR is a compulsory registry that records demographic, administrative, and clinical health data for all patients treated by public and private specialist healthcare services. Statistics Norway is the official national statistical institute and contains information on a number of socioeconomic variables. Our study sample included women with a registered hysterectomy procedure code, using the NOMESCO Classification of Surgical Procedures, as the primary procedure code. We identified 62 648 individuals who underwent hysterectomy in Norway between 2008 and 2020. If duplicate procedures were recorded for the same individual, we considered only the last reported hysterectomy. We excluded cases with malignant, pre‑malignant, or uncertain malignant diagnoses, obstetric indications, individuals registered as men, women under 18 years, and those missing education or income data (S2). We categorized the procedure codes by surgical approach; laparoscopic (including robotically assisted), vaginal and open surgery (S1). Laparoscopic (keyhole) hysterectomy involves entry into the abdominal cavity through small trocar ports, using a video camera for visualization and electrosurgical instruments inserted through these ports. The uterus is removed either intact or morcellated, typically via the vagina or, if necessary, through a small abdominal incision. Vaginal hysterectomy is carried out entirely through the vaginal canal without abdominal incisions and is generally suitable for smaller, mobile uteri. Open abdominal hysterectomy is performed through a transverse or midline laparotomy, allowing direct manual access to the uterus. We also included the International Statistical Classification of Diseases, 10th Revision (ICD-10) diagnosis codes recorded for the hysterectomy procedure in the NPR. These codes were used to define the indication for hysterectomy and were subsequently grouped into clinically relevant categories. Migrant status was categorized as Norwegian-born for individuals registered as born in Norway, regardless of parental migration status (S1). Due to the small number of Norwegian-born individuals with migrant parents ( n  = 91), this group was included in the Norwegian-born reference category. Region of birth was classified according to the Statistics Norway Standard for World Regions and Countries [ 22 ] and categorized into: ‘EU/European Economic Area (EEA), USA, Canada, Australia, New Zealand’, ‘Europe except EU/EEA’, ‘Asia’, ‘Africa’, and ‘Latin America’. Education level was reported as the highest level of completed education for each woman annually from 2008 to 2020, categorized into five categories, from least to highest educational level. Household income was defined as the total income from wages, self-employment, capital income, pensions, and social benefits received by the household. Household income was aggregated across the years preceding surgery, and the median value was used and thereafter divided into five equally sized groups with increasing income levels. Data were analysed using Stata version 18.0 (StataCorp, College Station, TX, USA). Descriptive statistics were calculated for patient and procedure characteristics, with categorical variables presented as frequencies (%) and continuous variables as means (standard deviations). Differences in categorical variables between migration groups and region of birth groups were assessed using Pearson’s chi-square test. We used multinomial logistic regression to examine associations between migration and hysterectomy surgical approach. Results are reported as crude and adjusted odds ratios (ORs) with 95% confidence intervals (CIs). Statistical significance was defined as P  < .05, and all tests were two-sided. Covariates included age, year of surgery, indication, and county. These were selected a priori based on their relevance to surgical decision making and access to care. Although these variables showed significant interactions with the outcome, none interacted significantly with the socioeconomic variables. We conducted correlation analyses between education and income, which was weak (Spearman’s ρ  = 0.297), indicating no concern for multicollinearity. To assess effect modification, interaction terms between migration status and socioeconomic variables were included. The migration × income interaction was statistically significant and retained in the model. We performed a sub-analysis where we excluded cases with fibroids as the surgical indication as fibroids can enlarge the uterus, often necessitating an abdominal approach, and are known to have a higher prevalence in some ethnic groups, and assessed whether differences by migration status persisted among women without fibroid as indications for hysterectomy. To further account for variation in surgical practice and expertise, thereby isolating potential disparities not explained by system-level difference, we performed a sub-analysis restricted to Oslo University Hospital, the only gynaecological department in Oslo County and a high-volume centre with advanced surgical expertise.

After exclusions, the final cohort included 38 913 women who underwent hysterectomy for benign conditions. Among the women studied, 17 387 (44.7%) had a laparoscopic procedure, 9288 (23.9%) underwent a vaginal hysterectomy, and 12 238 (31.4%) had an open abdominal hysterectomy ( Table 1 ). The most common indication for hysterectomy was fibroids, followed by abnormal uterine bleeding, and genital prolapse. Indications varied by surgical approach: fibroids were most common among women undergoing open and laparoscopic hysterectomy, whereas genital prolapse was the leading indication for vaginal hysterectomy. Women undergoing laparoscopic hysterectomy were younger on average compared with those undergoing vaginal or open abdominal hysterectomy (mean age 46, 54, and 50 years, respectively). The use of laparoscopic hysterectomy increased over time, with a greater proportion of procedures being performed laparoscopically in the later years of the study period (2018–20) than in earlier years. Characteristics of women undergoing hysterectomy by surgical approach ( n  = 38 913), with n (%) and mean (±SD). Born in Norway with two Norwegian-born parents + Norwegian-born to immigrant parents + Norwegian-born with one foreign-born parent. Oceania excluding Australia and New Zealand is excluded. Most women were Norwegian born (86.7%), and migrants comprised 13.2% of the sample. Among migrants, the largest proportion were born in EU/EEA countries, USA, Canada, Australia, or New Zealand (38.6%), followed by Asia (37.4%), Europe outside EU/EEA (8.9%), Africa (7.9%), and Latin America (7.1%). Laparoscopic hysterectomy was the predominant approach across most groups, although women born in Africa had a higher proportion of open hysterectomy (52.3%). Vaginal hysterectomy was least frequent among women born in Africa (4.2%) compared with Norwegian-born women (25.5%). Regarding socioeconomic characteristics, 42.8% of women had completed upper secondary education and 33.5% had higher education. Multinomial logistic regression showed that migrants had lower odds of undergoing laparoscopic (OR 0.66, 95% CI: 0.57–0.77) and vaginal hysterectomy (OR 0.60, 95% CI: 0.49–0.75) compared with open hysterectomy ( Table 2 ). Within the migrant group, migrants with higher income levels (levels 4 and 5) had increased odds of laparoscopic hysterectomy, with OR 1.28 (95% CI: 1.01–1.63) for income level 4 and OR 1.34 (95% CI: 1.05–1.70) for income level 5, compared with income level 1. The migration × income interaction was statistically significant, indicating that the association between migration status and surgical approach varied across income levels. When considering income regardless of migration status, only the highest income level (level 5) was associated with increased odds of laparoscopic hysterectomy (OR 1.14, 95% CI: 1.03–1.27), while income level 4 showed a near-significant trend (OR 1.11, 95% CI: 1.00–1.23). None of the education levels showed significant associations, although levels 2 (OR 1.14, 95% CI: 0.86–1.51), 3 (OR 1.19, 95% CI: 0.90–1.57), and 4 (OR 1.17, 95% CI: 0.89–1.55) all suggested a possible trend towards increased odds of laparoscopic, as compared with open hysterectomy. For vaginal hysterectomy, none of the educational or income levels showed significant associations. Adjusted a multinomial regression with OR, 95% CI, P values, and ARD for surgical approach of hysterectomy (open hysterectomy as base outcome vs. laparoscopic or vaginal hysterectomy). Adjusted for age, year of surgery, indication, and county. Norwegian-born includes women born in Norway regardless of parental migration status, including women born in Norway to migrant parents. Income level 1 represents the lowest household income quintile and income level 5 the highest. Open hysterectomy occurred in 31.4% of the study population (>10%). Because the outcome is common, ORs may overestimate relative risks. Absolute risk differences were, therefore, also calculated assuming a baseline probability of 30% for open hysterectomy. The regression model also showed associations with surgical indication, region, year, and age ( Table S3 ). The odds of laparoscopic hysterectomy increased over time (OR 1.25, 95% CI 1.24–1.26), while increasing age was associated with reduced odds (OR 0.96, 95% CI 0.96–0.97). Compared with fibroids, women with genital prolapse had higher odds of vaginal hysterectomy (OR 473.42, 95% CI: 372.41–601.84). Compared with the reference hospital (Oslo), all other counties showed higher odds of vaginal hysterectomy. In sub-analyses, findings were consistent with the main results. In the single-centre analysis of hysterectomies performed at Oslo University Hospital ( n  = 4657), migrant women had lower odds of undergoing laparoscopic hysterectomy compared with open surgery (OR = 0.79, 95% CI 0.65, 0.96) (S4). Women in the highest income group had higher odds of laparoscopic hysterectomy compared with those in the lowest group (OR 1.38, 95% CI 1.07, 1.78). In the analysis restricted to cases with fibroids as the sole indication at Oslo University Hospital ( n  = 2220), migrant status remained associated with reduced odds of laparoscopic hysterectomy (OR 0.76, 95% CI: 0.62–0.94, P  = .012). In the nationwide sub-analysis excluding fibroids indications ( n  = 22 931), migrant women had lower odds of both laparoscopic (OR 0.69, 95% CI 0.54, 0.88) and vaginal hysterectomy (OR 0.51, 95% CI 0.38, 0.68), compared with Norwegian-born women (S5). Women in the highest income group again had higher odds of undergoing laparoscopic hysterectomy compared with those in the lowest income group (OR 1.28, 95% CI 1.10, 1.50). The distribution of hysterectomy indications differed significantly between Norwegian-born women and migrants ( P  < .001) and across region-of-birth groups ( P  < .001) ( Table 3 ). Fibroids were the most common indication for hysterectomy among migrants compared with Norwegian-born women (56.3% vs. 38.7%). Fibroids were also the most common indication across all migrant region-of-birth groups, particularly among women born in Africa (75.9%). Over time, the proportion of hysterectomies performed for fibroids declined among Norwegian-born women, but increased across all migrant region-of-birth groups. The steepest increase was observed among African-born women ( Fig. 1 ). Abnormal uterine bleeding was more common among Norwegian-born women than migrants (31.0% vs. 24.3%). Conversely, hysterectomy due to genital prolapse was substantially less common among migrants (5.7% vs. 14.1%) and was particularly rare among African-born women. The prevalence of prolapse as an indication for hysterectomy remained low across all migrant region of birth groups throughout the study period, while for Norwegian-born women we observed a slight downward trend. Endometriosis and pelvic pain as indications for hysterectomy were more evenly distributed between the groups, with both groups showing an upward trend, particularly after 2016. Educational attainment and household income by migration status and region of birth are presented in Table S6 . Temporal changes in the distribution of hysterectomy indications, expressed as the percentage of all hysterectomies per year attributable to each indication, stratified by region of birth and migration status. Hysterectomy indications by migration status and region of birth, n (%). Differences assessed using Pearson’s chi-square tests. Overall difference between Norwegian-born and migrant women: Pearson’s χ ²(4) = 712.5, P  < .001. Overall difference across region-of-birth groups: Pearson’s χ ²(20) = 862.1, P  < .001.

In this cohort of 38 913 women who underwent hysterectomy for benign conditions in Norway from 2008 to 2020, migrant women had significantly lower odds of undergoing minimally invasive hysterectomy. The adjusted risk difference was −8 percentage points for laparoscopic hysterectomy, and −10 percentage points for vaginal hysterectomy, compared with open surgery. Higher income levels were associated with an increased likelihood of laparoscopic surgery, for both migrants and non-migrants. Sub-analyses on single-centre and non-fibroid diagnoses, potentially controlling for variation in clinical culture, surgical skill set and uterine size, showed similar results. Significant differences in surgical indications were observed between Norwegian-born women and migrants, and across region-of-birth groups, with fibroids being consistently more common among migrants—particularly African-born women. These findings suggest that, despite universal health coverage, disparities in access to minimally invasive hysterectomy persist, particularly among migrant women. Our finding of lower odds of laparoscopic and vaginal hysterectomy among migrant women likely reflects a combination of patient-related and healthcare system-related factors. Patient-related factors may include differences in disease presentation, health literacy, symptom perception, and healthcare-seeking behaviour [ 23 ]. The higher prevalence of fibroids among migrant women may influence the choice of surgical approach, as fibroids can increase uterine size and make minimally invasive surgery more challenging. It is well established that both the incidence and clinical presentation of fibroids vary by ethnicity, with women of African descent having the highest risk [ 24 ]. The higher proportion of fibroids as an indication for hysterectomy among migrant women may also reflect changes in the composition of the migrant population in Norway over time, with an increasing proportion of women born in African countries [ 25 ]. More broadly, differences in indications between migrants and Norwegian-born women may reflect underlying variations in reproductive health, healthcare-seeking behaviour, or diagnostic patterns. This interpretation is supported by findings from a UK audit, which showed that women from more socioeconomically deprived areas were more likely to present with severe symptoms of heavy menstrual bleeding, suggesting potential delays in care-seeking or differences in symptom perception [ 26 ]. The observed increase in endometriosis and pelvic pain as indications for hysterectomy may reflect growing awareness and improved diagnosis of these conditions over time [ 27 ]. The substantially lower proportion of genital prolapse as an indication for hysterectomy among migrant women compared with Norwegian-born women may be partly explained by the younger age profile of the migrant population, as the prevalence of pelvic organ prolapse increases with age [ 28 ]. Healthcare system–related factors are also likely to play an important role. These include communication barriers, differences in access to specialist care, variation in referral pathways, and differences in the availability of minimally invasive surgical expertise across hospitals. Provider-level factors, including surgeons’ training, experience, and treatment preferences, may also influence surgical decision-making. Our sub-analyses restricted to a single, tertiary level hospital and to non-fibroid indications, yielded similar results of lower odds of laparoscopic and vaginal hysterectomy among migrant women, suggesting that these disparities are not solely explained by clinical factors or uterine size, consistent with previous findings [ 8 , 29 , 30 ]. For instance, one US study found that Black women had twice the odds of undergoing open hysterectomy compared with white women, even after adjusting for uterine size, BMI, and prior pelvic surgery [ 29 ]. Similarly, Bougie et al . [ 8 ] found that Black women undergoing hysterectomy for non-fibroid indications had lower odds of receiving minimally invasive hysterectomy compared with white women (aOR 0.77, 95% CI 0.69–0.86). Interestingly, a recent US study showed that non-English speaking women were significantly less likely to receive a minimally invasive hysterectomy [ 27 ], further underscoring the impact of communications barriers on healthcare access and treatment options. A growing body of literature recognizes migration as an important social determinant of health, influencing healthcare access, utilization, and health outcomes through multiple pathways. These include language barriers, differences in health literacy, unfamiliarity with healthcare systems, socioeconomic disadvantage, and experiences of exclusion or discrimination. The disparities observed in our study may therefore reflect broader structural determinants operating across the healthcare pathway rather than differences in clinical need alone. Numerous papers on migrant women’s health in the Nordic countries have demonstrated disparities in healthcare use and adverse reproductive outcomes among migrant women [ 31 , 32 ]. Although it is challenging to determine the underlying mechanisms—given that large registry-based studies often lack detailed migration-specific variables—some research has explored the role of sociocultural factors. For example, a foreign‑born father has been associated with an increased risk of adverse neonatal outcomes and migrants with shorter residence have been shown to have a higher risk of obstetric anal sphincter injury [ 33 , 34 ]. These findings suggest that part of the observed risk differential may reflect broader structural and interpersonal influences, including communication barriers, limited familiarity with the healthcare system, lower health literacy, and potential discrimination within healthcare services. Although our study does not provide evidence for this, similar underlying mechanisms could plausibly be involved. In accordance with our findings on income levels, several US studies have reported that women with lower income are at increased risk of undergoing open hysterectomy [ 9 , 10 ]. For instance, payment by private insurance was associated with laparoscopic hysterectomy compared with payment by Medicare. However, in the US context, the choice of surgical approach may be influenced by the type of insurance coverage. Thus, given the substantial differences in healthcare financing between the United States and Norway, direct comparisons may be challenging. Furthermore, we did not identify comparable data from other European countries, which may reflect the assumption that universal healthcare systems inherently mitigate socioeconomic disparities in access to care. One Danish study with data from 2004 to 2008, found a higher proportion of unemployed women undergoing open hysterectomy [ 13 ], however, the distribution of the different approaches of hysterectomy were not comparable to our data with only 6% having a laparoscopic procedure. Regarding educational status, one Canadian study reported no association between the minimally invasive approach and neighbourhood educational attainment, suggesting that education may not uniformly influence surgical options across different healthcare contexts [ 35 ]. In summary, our study provides novel evidence of disparities in access to minimally invasive hysterectomy among migrant women within a universal healthcare system. The observed higher prevalence of fibroids among women of African origin and the association between higher income and greater use of laparoscopic hysterectomy are consistent with findings from previous international studies. The major strength of our study is the use of individual data from various population-based registries, covering the total population of women who underwent hysterectomy. The NPR is known for its high-quality data, and Statistics Norway compiles statistics based on multiple nationwide administrative registries [ 36 ]. These data are widely used in epidemiological research and are generally considered to be of high quality. However, information on migrants’ educational attainment, particularly when obtained abroad, may be less precise, as it is partly based on survey data and incomplete registry information. Since 2014, Statistics Norway has applied statistical methods to estimate missing educational levels at the aggregate level. However, these estimates are not available at the individual level, which may affect data accuracy in our study. While our analysis adjusted for the most common indications for hysterectomy, we were unable to include additional clinical covariates that may influence surgical approach. For instance, this study’s database did not give us an opportunity to examine differences by surgeon, as it may be possible that results differed by surgeon characteristics such as surgical volume and physician training. However, we performed a sub-analysis within a single hospital to account for variations in institutional culture and clinical practices. Furthermore, our dataset did not include information on uterine size, which may influence choice of approach. To account for uterine size, we performed a sub-analysis where we excluded fibroid indications, as fibroids typically have the greatest impact on uterine size and weight [ 37 ]. Another limitation is the categorization of migration status and regions of birth, as it does not capture heterogeneity within migrant groups, which may obscure important subgroup differences, potentially underestimating or misinterpreting disparities. We lacked information on key migration-related characteristics such as reason for migration, duration of residence, and age at migration, which may be important determinants of health and healthcare use. Moreover, although individuals born in Norway to migrant parents may differ from other Norwegian-born individuals with respect to migration-related characteristics, including this small group in the Norwegian-born reference category may introduce some heterogeneity. Furthermore, the categorization of region of birth may further mask differences between subgroups. While disparities in obstetric outcomes have received increasing attention, inequities in gynaecological care, particularly regarding access to minimally invasive hysterectomy, remain insufficiently documented in European countries. To ensure that all women receive high-quality, evidence-based treatment, equity must be explicitly integrated into the organization and delivery of gynaecological care. This includes systematic monitoring of surgical approaches by migration status and socioeconomic indicators to identify, track, and address disparities in access to minimally invasive procedures. In addition, implementation of national clinical guidelines to promote equitable access to minimally invasive hysterectomy is important. Targeted interventions to improve communication and health literacy are also needed, including interpreter services and culturally adapted patient information. Our study is an important first step in addressing the underexplored relationship between migration status, socioeconomic background and provision of surgical care for benign gynaecological conditions in Norway. Further research is needed to investigate the underlying mechanisms behind this association, exploring the social, cultural, and institutional factors that influence surgical decision-making. This includes examining clinician bias, variation in surgical training, and access to high-volume centres. Qualitative studies involving both patients and clinicians could provide valuable insights into patient preferences, trust in healthcare providers, and perceived barriers to care, which could be crucial for understanding the mechanisms driving these disparities. Additionally, outcome-based research comparing recovery, complications, and satisfaction across surgical approaches and demographic groups would help inform strategies for more equitable and patient-centred care.