Introduction
Global demographic transitions driven by rapid population aging and unprecedented declines in fertility rates have raised substantial concerns regarding future population sustainability and health system challenges. Women of reproductive age with disabilities represent an important yet frequently overlooked demographic group within this broader context. Globally, the prevalence of disability among women of reproductive age has been estimated to range from approximately 6% to 15% [1,2]. In Korea, registered persons with disabilities accounted for 5.1% of the total population based on the most recent 2024 data [3]. Among them, the proportion of women with disabilities of reproductive age is estimated to have declined from 0.77% of the total female population in 2013 to 0.58% in 2024, representing an approximately 25% reduction over 11 years [4].
Despite clear evidence that women with disabilities experience significantly greater barriers to reproductive and perinatal health care-stemming from physical, social, and systemic limitations-research investigating perinatal outcomes in this population remains limited, particularly studies utilizing nationally representative, long-term datasets. Most existing studies have focused on single disability types or have employed small sample sizes, resulting in limited generalizability and reduced policy relevance [5-7].
Against this backdrop of rapid demographic transformation and sharply declining fertility rates, maternal health has emerged as a pivotal factor influencing population well-being. According to the World Health Organization (WHO), population-level trends in women of reproductive age and maternal health indicators represent central pillars for evaluating public health sustainability. In Korea, the total fertility rate (TFR) reached historically low levels, recording 0.78 in 2022, 0.72 in 2023, and 0.75 in 2024, which are significantly below the Organisation for Economic Co-operation and Development (OECD) average [8-10]. Across OECD member countries, the TFR declined by half, from 3.3 in 1960 to 1.5 in 2022 [11]. Maternal mortality and morbidity are essential indicators of global maternal health. Although global maternal mortality has declined over time, recent estimates indicate more than 222 maternal deaths per 100,000 live births, underscoring the ongoing severity of the challenge. Meanwhile, severe maternal morbidity has continued to increase, as growing numbers of women experience critical perinatal complications, including major hemorrhage, severe cardiopulmonary events, renal failure, and acute respiratory distress syndrome.
Given these demographic and clinical challenges, understanding reproductive trends and perinatal outcomes among women with disabilities has become increasingly urgent, particularly in countries experiencing extreme fertility decline. Therefore, this study aims to analyze nationwide, population-level trends in fertility and maternal morbidity among women with disabilities in Korea using 10 years of National Health Insurance Service (NHIS) data. Specifically, we examine differences in total fertility rates, disability-specific perinatal characteristics, and cumulative mortality among live-born infants at 1 and 5 years after birth, as well as long-term trends in reproductive outcomes among women with disabilities. In addition, we compare the burden of major perinatal complications affecting maternal health between women with and without disabilities.
The primary outcome was nationwide fertility patterns and birth trends among women with disabilities. The secondary outcomes were cumulative mortality among infants at 1 and 5 years after birth and maternal morbidity occurring during pregnancy, delivery, and the postpartum period, based on International Classification of Diseases, 10th Revision (ICD-10) O-code diagnoses. This was a descriptive, non-causal study using linked administrative health data. The study aimed to describe nationwide differences in fertility patterns, infant mortality, and maternal morbidity between women with and without disabilities using linked administrative health data and to provide evidence to inform equity-centered maternal health care and guide future research and policy discussions supporting women with disabilities.
Materials and methods
1. Study design
This nationwide population-based descriptive study evaluated fertility outcomes and perinatal health disparities between women with and without disabilities in the Republic of Korea. The study population comprised women of reproductive age (15-49 years) who delivered between January 2013 and December 2022 and were enrolled in the NHIS. Mothers were identified if they had medical records containing a primary diagnosis related to pregnancy, childbirth, or the puerperium (ICD-10 codes O00-O99) or if delivery was confirmed in the maternal-neonatal linked database.
2. Data sources
The study utilized insurance eligibility, mortality, and morbidity data, along with the maternal-neonatal linked database, provided by the NHIS. The NHIS operates a universal, single-payer health insurance system that covers more than 99% of the South Korean population. As part of its administrative claims process, the NHIS maintains comprehensive beneficiary-level demographic and health care utilization data, including age, residential region, socioeconomic status, diagnostic and procedure codes, medical expenditures, and mortality records. The maternal-neonatal linked database integrates maternal and neonatal records using delivery information derived from the NHIS administrative system. Although it does not capture all births nationwide, it has been reported to represent the majority of deliveries in Korea, and previous validation studies have confirmed its suitability for population-based research [11-14].
3. Study population
All eligible births in Korea during the study period were included; therefore, no sample size calculation was required. Individuals were included if they met at least one of the following criteria: 1) medical records containing ICD-10 codes O00-O99 during the study period or 2) confirmed delivery in the maternal-neonatal linked database.
Records with missing or incompletely linked data were excluded from the analytic sample.
Although the number of excluded cases was small, we cannot rule out the possibility that women with disabilities were disproportionately represented among the excluded observations. The mid-year population by disability status and age group was used to calculate crude birth rates (CBR). The mid-year population of persons with disabilities was derived from year-end disability registration statistics from the Ministry of Health and Welfare, and the mid-year population without disabilities was calculated by subtracting this value from the total mid-year resident population reported by Statistics Korea. Fig. 1 presents an overview of the study population selection process.
4. Classification of disability
Disability status was identified based on official disability registration and categorized according to the 15 legal classifications defined by the Welfare of Persons with Disabilities Act. To ensure statistical stability, disability categories were regrouped into three analytical classifications: 1) physical disability (including physical impairment, brain lesion disorders, visual impairment, hearing impairment, language impairment, and facial disfigurement), 2) internal disability (including cardiac, respiratory, and hepatic impairment, intestinal or urinary fistula, and epilepsy), and 3) mental disability (including intellectual disabilities, autism spectrum disorder, and mental disorders).
Detailed classification criteria are provided in Supplementary Table 1.
5. Measures and outcomes
Fertility outcomes were assessed using the annual number of live births and CBR. Women aged 15-49 years were grouped into 5-year age categories (15-19, 20-24, … 45-49 years) for age-specific fertility analyses. Neonatal survival outcomes were evaluated using cumulative mortality probabilities calculated at 1 and 5 years after birth. Maternal health conditions were defined as major pregnancy-related complications occurring within 1 year before or after delivery and were presented as prevalence per 100,000 individuals.
6. Statistical analysis
All analyses were performed using SAS version 9.4 (SAS Institute Inc., Cary, NC, USA). Because key confounding variables were limited in the administrative dataset, the analyses were descriptive and unadjusted. Descriptive statistics were used to examine annual trends in fertility outcomes and to compare differences between women with and without disabilities. Cumulative mortality among live-born infants at 1 and 5 years after birth was calculated as the cumulative probability of death during each follow-up period. This measure differs from conventional neonatal mortality (death within 28 days) and early neonatal mortality (death within 7 days). Maternal complications were summarized as prevalence estimates per 100,000 individuals.
Although this study utilized nationwide administrative data, selection bias may have persisted because the linked dataset did not capture births or maternal events that did not generate claims and because health care utilization patterns may have differed between women with and without disabilities. However, the potential impact of selection bias was minimized by including all eligible individuals identified in nationwide administrative records.
Results
A total of 2,861,120 mothers and 2,861,080 neonates were included in this analysis between 2013 and 2022. In 2022, 773 mothers with disabilities gave birth. A minor discrepancy of 40 cases between the total number of mothers (2,861,120) and neonates (2,861,080) over the 10-year period resulted from technical linkage failures during the NHIS administrative data merging process. Throughout the study period, the number of births among women with disabilities steadily decreased, while births among women without disabilities also declined, although to a lesser extent.
1. Birth and fertility trends
From 2013 to 2022, a consistent and widening disparity in fertility was observed between women with and without disabilities (Table 1).
2. Birth numbers
The number of births among women with disabilities declined sharply over the study period, decreasing from 1,988 births in 2013 to 773 births in 2022, representing a 61.1% reduction. In comparison, births among women without disabilities declined from 372,716 to 174,553, representing a 53.2% reduction. The disparity between the two populations widened progressively. The ratio of births between mothers without disabilities and mothers with disabilities increased from 187.5 in 2013 to 225.8 in 2022, indicating that the fertility gap expanded over time.
3. CBR
The CBR was consistently lower among women with disabilities across all years. In 2013, the CBR was 0.8 per 1,000 population among women with disabilities, compared with 7.8 among women without disabilities. By 2022, the corresponding CBRs were 0.3 and 3.6, respectively. The CBR ratio between groups also increased, rising from 9.8 in 2013 to 12.3 in 2022, highlighting a progressively widening disparity in fertility patterns between the two groups.
4. Trend comparison
Both groups experienced a downward trend in fertility over the past decade; however, the decline was more pronounced among women with disabilities. A temporary increase was observed in 2017, when births among women with disabilities rose to 2,834; however, this peak was followed by a sustained decline in subsequent years. In contrast, women without disabilities experienced a more gradual decline in fertility rates.
5. Interpretation of age-specific fertility rates
Analysis of age-specific fertility rates demonstrated notable differences in fertility distribution and temporal trends between women with and without disabilities (Fig. 2). In both populations, fertility rates declined across most age groups from 2013 to 2022.
Among women with disabilities, fertility peaked at ages 30-34 in 2013 but shifted to ages 35-39 in 2022, indicating accelerated maternal population aging. In contrast, the peak fertility age among women without disabilities remained at 30-34 years throughout the study period. The age-specific fertility rate in the peak age group decreased markedly from approximately 60 births per 1,000 women in 2013 to fewer than 30 births per 1,000 women in 2022. Fertility levels also declined across all other age categories, reflecting an accelerated downward trend over the decade.
Among women without disabilities, the fertility peak consistently remained in the 30-34-year age group, although the rate decreased substantially, from approximately 120 births per 1,000 women in 2013 to about 50 births per 1,000 women in 2022. Compared with women with disabilities, the decline in peak fertility was more moderate, with the overall level remaining significantly higher across all age groups.
Overall, the widening gap in age-specific fertility distribution suggests that fertility decline and maternal aging progressed more rapidly among women with disabilities during the study period. The shift in peak fertility to older maternal ages among women with disabilities further supports concerns regarding reduced reproductive opportunities and increased barriers to timely family planning in this population.
6. Cumulative mortality after birth
Analysis of cumulative post-birth mortality revealed persistently higher mortality among infants born to women with disabilities than among those born to women without disabilities (Table 2). Although mortality gradually declined in both groups over time, the gap remained evident and widened during follow-up, with infants of women with disabilities consistently experiencing more than two- to three-fold higher mortality across the 1-year and 5-year follow-up periods. Taken together, these trends demonstrate sustained and widening survival disparities between infants born to women with and without disabilities.
7. Distribution of mothers with disabilities by disability type
Analysis of births by disability type showed a substantial decline across all subgroups over the study period (Table 3).
Physical disabilities accounted for the largest proportion of births among women with disabilities throughout the decade and experienced the sharpest decline. Births among women with mental and internal disabilities also decreased; however, these groups remained numerically smaller and contributed a relatively modest proportion of total deliveries. Compared with women without disabilities, who also experienced a marked reduction in births over time, the pace of decline was consistently steeper among women with disabilities, further widening the gap between the two populations.
8. Distribution of mothers with disabilities by age and disability type (pooled 2020-2022)
Analysis of data from 2020 to 2022 showed clear age-related differences in childbirth patterns among women with disabilities (Table 4). To provide stable estimates for small disability subgroups and to minimize year-to-year fluctuations-particularly during the coronavirus disease 2019 pandemic-birth data were pooled across the most recent 3 years. Childbirth in this group was most concentrated at ages 35-39 years, indicating a peak fertility window approximately one age band older than that of women without disabilities, whose births were predominantly among those aged 30-34 years.
Across nearly all age strata, physical disabilities accounted for the largest proportion of births. In contrast, women with mental disabilities contributed a relatively greater proportion of births at younger maternal ages, whereas internal disabilities remained the smallest subgroup across the age distribution.
Unlike women without disabilities-whose childbirth declined sharply beyond age 40-women with disabilities demonstrated a higher concentration of births at advanced maternal ages, including ≥40 years. Taken together, these patterns illustrate accelerated maternal aging and delayed childbearing among women with disabilities relative to women without disabilities.
9. Prevalence of maternal morbidity
Women without disabilities exhibited higher recorded maternal morbidity across nearly all antepartum and intrapartum diagnostic categories (Table 5). During the antepartum and intrapartum periods, the overall prevalence of maternal morbidity was lower among women with disabilities than among women without disabilities (247.3 vs. 694.4 per 100,000 women of reproductive age). Within the disability group, women with physical disabilities accounted for the largest proportion of maternal morbidity across most diagnostic categories. In both groups, a substantial proportion of antepartum and intrapartum morbidity was classified as other maternal disorders predominantly related to pregnancy and maternal care related to the fetus and amniotic cavity.
In the postpartum period, overall maternal morbidity remained lower among women with disabilities than among women without disabilities (99.4 vs. 255.2 per 100,000 women of reproductive age). In both groups, puerperium-related conditions constituted the largest category of postpartum morbidity. Variation by disability type was observed within the disability group, with pregnancy-related disorders more frequently recorded among women with mental disabilities and fetal-related care conditions more commonly observed among women with physical disabilities, respectively.
Discussion
To our knowledge, this is the first study using nationwide linked data among women with disabilities in the Republic of Korea to investigate fertility patterns, neonatal mortality, and maternal morbidity. Previous research addressing reproductive or maternal health among women with disabilities in Korea has been limited and has often relied on small regional samples or focused on specific disability groups rather than the complete national population [2,7]. International studies have similarly reported a lack of large-scale epidemiologic evidence addressing reproductive health inequities among women with disabilities [5,15,16]. By including both women with and without disabilities and examining 10-year longitudinal trends, this study provides new insight into emerging disparities in maternal and neonatal outcomes.
Our findings indicate a marked decline in birth counts and CBR among women with disabilities over the past decade, exceeding the reductions observed among women without disabilities, and a clear shift in peak fertility age from 30-34 to 35-39 years. Because advanced maternal age is strongly associated with increased obstetric and neonatal risks, the accelerated maternal aging observed among women with disabilities represents an important demographic shift with potential health implications [17-22]. While Korea provides disability-related maternal support through existing systems-including public health center case management, home-visiting services, and subsidized care through disability registration frameworks-access remains variable and fragmented. Strengthening the integration and continuity of these programs may improve perinatal outcomes. Taken together, these findings illustrate accelerated maternal aging and delayed childbearing among women with disabilities compared with women without disabilities.
Neonatal outcomes indicate persistent inequities; infants born to women with disabilities showed higher cumulative mortality risks over 1-year and 5-year follow-up, and these gaps widened over time. Similar patterns of elevated neonatal risk have been reported in prior studies [23-25]. Several mechanisms may contribute to the elevated cumulative mortality observed among infants born to women with disabilities. Previous studies have documented higher risks of preterm birth, low birth weight, and maternal medical comorbidities in this population, which are established predictors of infant mortality. In addition, socioeconomic disadvantage, reduced access to prenatal and pediatric care, and barriers to postnatal follow-up may further affect infant survival. Although the present study was not designed to identify causal pathways, these findings highlight the importance of continued monitoring and targeted support for infants born to women with disabilities.
Maternal morbidity was lower among women with disabilities than among women without disabilities. Because morbidity rates were calculated using a population-based denominator (women of reproductive age), these estimates reflect population-level prevalence rather than individual risk per delivery episode. Accordingly, the lower observed prevalence should not be interpreted as evidence of better underlying health status among women with disabilities. Because the NHIS comprises nationwide population data, the observed lower morbidity rates likely reflect underutilization of health care services and diagnostic underrecording due to access barriers rather than true clinical protection. Prior studies have also reported disparities in health care utilization and diagnostic coding practices among women with disabilities [1,5,26], which may influence recorded morbidity in administrative datasets. The overall distribution of postpartum morbidity was broadly similar between groups; however, variation by disability type was observed within the disability group. These subgroup patterns warrant further investigation in future studies incorporating more detailed clinical information.
Social determinants, including lower income, reduced employment, and lower marriage rates among women with disabilities, may further intensify delays in family formation and medical vulnerability [27-30]. International policy frameworks emphasize disability-informed maternal care as a priority for advancing health equity [11,31]. Our findings do not imply specific policy prescriptions but instead highlight areas in which strengthened care coordination and monitoring may be beneficial, particularly in postpartum care, where morbidity appears disproportionately concentrated.
This study has notable strengths, including the use of nationwide linked administrative data and decade-long longitudinal coverage. However, several limitations should be acknowledged. Claims data do not capture disability severity, functional capacity, or social context, and maternal morbidity is likely underestimated among women with disabilities for the reasons outlined above [32]. Additionally, the absence of covariates such as gestational age, parity, and socioeconomic indicators limited the ability to conduct adjusted analyses. Future work may incorporate analytic methods such as multivariable regression or propensity score adjustment using available variables and, where feasible, linkage to external datasets containing information on disability severity or socioeconomic indicators; however, such approaches are not possible within the current NHIS-only framework because of limited clinical and social data availability. Accordingly, all differences should be interpreted as descriptive associations rather than causal effects. Nevertheless, this study provides foundational descriptive evidence that may inform future research and support efforts to address reproductive health inequities. Women with disabilities may have reduced contact with obstetric services or may seek care outside reimbursed pathways, leading to selective underrepresentation of complications. Continued work integrating both administrative and clinical datasets, as well as qualitative exploration of lived experiences, will be essential to understand the mechanisms underlying these disparities. Furthermore, future research should incorporate multivariable regression models to adjust for critical confounders, including maternal age, parity, and socioeconomic status, to better elucidate the independent association between disability status and maternal and infant outcomes.
In conclusion, women with disabilities in Korea face substantial disparities in reproductive outcomes, including declining fertility, accelerated maternal aging, higher neonatal mortality, and distinct patterns of maternal morbidity. These findings underscore the importance of disability-inclusive maternal health approaches and improved continuity of care to support equitable outcomes for mothers and infants.
Furthermore, this study is the first in Korea to quantitatively characterize maternal and child health inequities among women with disabilities by simultaneously presenting fertility indicators, maternal morbidity profiles, and neonatal survival within a unified, full-cycle analytical framework.
Future research should incorporate more sophisticated analytic approaches that account for important confounding factors, including disability severity, socioeconomic disadvantage, and caregiving environments, and should integrate qualitative methods to elucidate underlying mechanisms and lived experiences. Policy development may be considered to support the reproductive health rights of women with disabilities.
Potential priorities include expanding support systems for high-risk pregnancies, strengthening access to prenatal and postpartum care, and building integrated care pathways to help reduce preventable inequities across the maternal life course.
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