Abstract
The aim of this study was to investigate the prevalence of diastasis recti abdominis (DRA) and to find the possible risk factors for DRA based on two diagnostic criteria among women in long-term postpartum period. A cross-sectional study was conducted on 1000 postpartum women at five different time points (3, 5, 10, 20, and 30 years after partum, respectively). Inter-recti distance (IRD) was assessed using ultrasound imaging, while basic data were collected through self-reported questionnaires. Two diagnostic criteria, IRD > 2 cm and IRD > 3 cm, were used to present the prevalence of DRA. Univariate and multivariate analyses were employed to explore the risk factors for DRA. When using the diagnostic criterion of IRD > 2 cm for DRA, the prevalence was 36%, 31%, 22%, 26%, and 30% at 3, 5, 10, 20, and 30 years postpartum, respectively. When using the diagnostic criterion of IRD > 3 cm for DRA, the prevalence was 13%, 8%, 6%, 8%, and 10%, respectively. The results revealed that higher body mass index (BMI) was a risk factor for DRA at 10 years postpartum (p = 0.000), bigger number of parturitions was a risk factor at 3, 5, and 10 years postpartum (p = 0.000, 0.004 and 0.000), twins was a risk factor at 3 years postpartum (p = 0.001), and diabetes was a risk factor at 20 and 30 years postpartum (P = 0.000 and 0.004). (1) The prevalence of DRA in the long-term postpartum period was high, especially when IRD > 2 cm was used as the diagnostic criterion. (2) Higher BMI, bigger number of parturitions, twins and diabetes were independently associated with higher odds of DRA at different long-term postpartum time points. (3) The diagnostic criterion for DRA should be further improved to avoid excessive clinical diagnosis and treatment. (1) This study elucidated the prevalence and risk factors associated with long-term postpartum DRA, thereby enhancing clinical awareness and advocating for early intervention and prevention measures to mitigate serious adverse outcomes. (2) This study presented the research results using two diagnostic criteria, increasing comparability with existing studies. In addition, discussions on reasonable diagnostic criterion for DRA were also conducted to avoid excessive clinical diagnosis and treatment.
Keywords: Diastasis recti abdominis, Postpartum, Prevalence, Risk factor, Diagnostic criteria
Subject terms: Diseases, Medical research
Introduction
Diastasis recti abdominis (DRA) refers to an abnormal separation of the two rectus abdominis along the middle of linea alba1. DRA commonly occurred during the last second and third trimester of pregnancy and in the early postpartum period2. With the increasing attention paid to the issue of DRA, many scholars studied the prevalence of this condition, but the conclusions varied among the studies3–5. A study used palpation to measure inter-recti distance (IRD), use a separation of ≥ 2 fingerbreadths as the diagnostic criterion for DRA, and found that the prevalence of DRA at gestation week 21, 6 weeks, 6 months and 12 months postpartum was 33.1%, 60.0%, 45.4%, and 32.6%, respectively5. Another study used ultrasound to detect IRD in women in the first year after childbirth, with IRD ≥ 2 cm as the diagnostic criterion for DRA. The incidence of DRA was reported to be 82.6%6. In addition, one more study also investigated DRA by measuring IRD using ultrasound, with a diagnostic criterion of over 16 mm at 2 cm below the umbilicus. It was found that the prevalence of DRA decreased from 100% at gestational week 35 to 39% at 6 months postpartum4. The incidence of DRA reported in various studies was significantly inconsistent, mainly due to the different stages of pregnancy or childbirth in which the selected study samples were located, the different methods of measuring IRD, and the inconsistent diagnostic criteria for DRA.
The risk factors for DRA had also not been consistently confirmed. Hui Fei et al. studied the DRA of women during the first postpartum year, using IRD ≥ 2 cm as the diagnostic criterion. After analysis, they concluded that the risk factors for DRA were cesarean section and multiple parturitions6. Alberto Sartori et al. selected ordinary women who had completed the post-delivery rehabilitation stage as the research subjects, using > 3 cm as the diagnostic criterion, and found that increasing BMI and number of pregnancies were risk factors for DRA7. Lina Wu et al. selected 644 adult women from different age stages to study DRA. They used the diagnostic criterion of Rath et al.8 and found that Age, the number of pregnancies, BMI and diabetes were risk factors for DRA9. There was significant inconsistency in the risk factors for DRA reported in various studies, mainly due to the different postpartum stages and age stages of the selected study samples, as well as inconsistent diagnostic criteria for DRA.
Searching for literatures on DRA from PubMed, it was found that the majority of its study population were women within one year after childbirth, with little involvement of women in the long-term postpartum period. From the understanding of pregnancy status and the incidence of DRA in late pregnancy and one year after delivery, DRA is an inevitable phenomenon in late pregnancy and a common phenomenon shortly after delivery. Furthermore, based on the results of numerous existing studies, the presence of DRA after one year postpartum did not necessarily lead to adverse outcomes3,10. This reduced the necessity of studying early postpartum DRA. However, we believed that studying the long-term DRA after childbirth was still necessary and long-term existence was likely to lead to adverse results including abnormal condition, lumbopelvic pain and external defects11,12.
The diagnostic criteria for DRA were still inconsistent. Various studies adopted different diagnostic criteria for DRA, which inevitably led to inconsistent research results. It was difficult to directly compare the results of various studies. Therefore, it was necessary to unify the diagnostic criteria for DRA. But this could be a complex and lengthy process. Prior to this, presenting research results with different diagnostic criteria in the same study is also of positive significance, as it can increase comparability with existing researches and provide a basis for exploring a reasonable diagnostic criterion for DRA.
This study aimed to investigate the prevalence of DRA and to find the possible risk factors for DRA in long-term postpartum period. Two diagnostic criteria, IRD > 2 cm and IRD > 3 cm, were used to present the prevalence of DRA.
Materials and methods
Study design and participants
This cross-sectional study was conducted at Wenzhou Hospital of Integrated Traditional Chinese and Western Medicine, Zhejiang. Participants who were 3, 5, 10, 20, or 30 years after partum were recruited using a quota sampling method. In actual recruitment, the length of postpartum time was relaxed by plus or minus 10%, i.e. 3 ± 0.3 years, 5 ± 0.5 years, 10 ± 1.0 years, 20 ± 2.0 years, and 30 ± 3.0 years after partum. The participants were sequentially enrolled from a physical examination center of the hospital from September 2020 to September 2022. The inclusion criteria for the participants were as follows: (1) women aged 18 years and above; (2) a history of childbirth; (3) possessing the ability to understand and communicate. The exclusion criteria for the participants were as follows: (1) serious medical conditions; (2) history of abdominal surgery (excluding caesarean section); (3) congenital abdominal muscle dysplasia; (4) severe impairment of abdominal muscles.
We set a sample size of 200 at 3, 5, 10, 20, and 30 years postpartum, respectively. During the implementation process, 20 cases, 26 cases, 19 cases, 16 cases, and 18 cases rejected at 3, 5, 10, 20, and 30 years postpartum, respectively. The main reasons for rejection were lack of interest in the research content and insufficient time to cooperate. The actual number of participants is 1,000 including 200 in each of the five postpartum periods. Please see Fig. 1 for CONSORT Flow Diagram.
Fig. 1.
CONSORT flow diagram.
Measurements
Measurement of IRD
In this study, IRD was measured using ultrasound imaging. During data acquisition, the participants were positioned supine with bent legs and arms alongside the body. The participant was asked to lie on their back in a hook-lying position (knees bent, feet flat on the table) with their arms resting on the table. The measurement sites on the abdomen were marked 4.5 cm above, at and 4.5 cm below the umbilicus6. Finally, the maximum value among them was taken. The sonographers received training on the measurement method before data collection. Additionally, IRD assessments for all participants were conducted using the same ultrasound equipment (Philips EPIQ5). The diagnostic criteria for DRA are IRD > 2 cm and IRD > 3 cm. And, IRD was classified into ≤ 2 cm, >2–3 cm, >3–5 cm, and > 5 cm according to the guidelines of the European Hernia Society13.
Risk factors and questionnaires
The possible risk factors were identified based on existent literatures and clinical practice. The chosen variables included age, height, weight, the number of parturitions, caesarean section, twins, diabetes, chronic nephrosis, chronic cough, chronic constipation (more than 3 months) and occupation type. The information was collected through self-reported questionnaires. After the ultrasound examination, the participants were invited to a lounge to complete the aforementioned questionnaires. Throughout this process, three trained investigators accompanied the participants and provided explanations for questionnaire items if needed. Additionally, investigators checked each questionnaire immediately after the participants completed them and reminded the respondents to fill in any missing information if necessary.
The sonographers, investigators and participants were unaware of the grouping of the participants. Specifically, the sonographers didn’t know the DRA diagnostic criterion used in this study. The investigators were unaware of the participants’ IRD values. And, the participants didn’t know their own IRD values and whether they had been diagnosed with DRA until their surveys ended.
Data analysis
Firstly, the participants were stratified based on differing postpartum periods, including 3, 5, 10, 20, and 30 years after partum. The prevalence of DRA was presented as percentage. Secondly, univariate comparisons were conducted to compare the risk factors for DRA. Rank data were analyzed using the Kruskal-Wallis H test. Categorical data were analyzed using the chi-square test. Subsequently, ordinal multivariate logistic regression was employed to determine the risk factors for DRA. All statistical analyses were performed using SPSS 26.0. A p-value < 0.05 was considered statistically significant. Bonferroni correction was adopted in multivariate analysis, the corresponding P-value was taken as < 0.05/10 = 0.005, as there was a total of 10 independent variables.
Ethical considerations
The study was approved by the Ethics Committee of Wenzhou Hospital of Integrated Traditional Chinese and Western Medicine (2022-L093). All research procedures were conducted in accordance with relevant guidelines and regulations. Informed consent was obtained from all participants and/or their legal guardians, and the study was conducted in compliance with the Declaration of Helsinki.
Results
Prevalence of DRA
According to the definition of IRD over 2 cm, the prevalence of DRA at 3, 5, 10, 20, 30 years postpartum was 36%, 31%, 22%, 26% and 30%, as shown in Fig. 2. According to the definition of IRD over 3 cm, the prevalence of DRA was 13%, 8%, 6%, 8% and 10%, as shown in Fig. 2.
Fig. 2.
The prevalence of DRA.
The number of participants in each IRD classification section was detailed in Table 1.
Table 1.
Classification of IRD at five time points.
| Time point | ≤ 2 cm | > 2–3 cm | > 3–5 cm | > 5 cm | Total |
|---|---|---|---|---|---|
| 3 years after partum | 129(64.5%) | 46(23.0%) | 25(12.5%) | 0 | 200 |
| 5years after partum | 138(69.0%) | 47(23.5%) | 15(7.5%) | 0 | 200 |
| 10 years after partum | 156(78.0%) | 32(16.0%) | 12(6.0%) | 0 | 200 |
| 20 years after partum | 149(74.5%) | 36(18.0%) | 15(7.5%) | 0 | 200 |
| 30 years after partum | 141(70.5%) | 40(20.0%) | 17(8.5%) | 2(1.0%) | 200 |
Data were presented as numbers (percentage). IRD = Inter-recti distance.
Univariate analysis of DRA
At 3 years postpartum, the differences of the number of parturitions and twins between the women in different classification sections were statistically significant (P = 0.000 and 0.001). At 5 years postpartum, the difference of the number of parturitions was statistically significant (p = 0.020). At 10 years postpartum, the differences of BMI and the number of parturitions were statistically significant (P = 0.006 and 0.002). At 20 years postpartum, the differences of BMI, the number of parturitions and diabetes were statistically significant (P = 0.036, 0.021 and 0.000). At 30 years postpartum, the differences of BMI, the number of parturitions, diabetes and chronic cough were statistically significant (P = 0.000, 0.011, 0.000 and 0.034). Please see Tables 2, 3, 4, 5 and 6 for details.
Table 2.
Univariate analysis of DRA at 3 years postpartum.
| Variable | IRD | Total (n = 200) |
H/χ2 | p-value | ||
|---|---|---|---|---|---|---|
| ≤ 2 cm (n = 129) | > 2–3 cm (n = 46) | > 3–5 cm (n = 25) | ||||
| *Age(years) | ||||||
| ≤ 33 | 57 | 28 | 10 | 95 | 5.556 | 0.062 |
| 34–38 | 69 | 18 | 12 | 99 | ||
| ≥ 39 | 3 | 0 | 3 | 6 | ||
| *BMI (kg/m2) | ||||||
| ≤ 18.4 | 23 | 4 | 0 | 27 | 3.849 | 0.146 |
| 18.5–23.9 | 70 | 31 | 17 | 118 | ||
| 24-27.9 | 36 | 11 | 3 | 50 | ||
| ≥ 28 | 0 | 0 | 5 | 5 | ||
| *The number of parturitions | ||||||
| 1 | 67 | 18 | 4 | 89 | 17.788 | 0.000 |
| 2 | 62 | 28 | 16 | 106 | ||
| 3 | 0 | 0 | 5 | 5 | ||
| #Caesarean | ||||||
| Yes | 46 | 13 | 8 | 67 | 0.862 | 0.650 |
| No | 83 | 33 | 17 | 133 | ||
| Twins | ||||||
| Yes | 1 | 0 | 4 | 5 | 11.841 | 0.001 |
| No | 128 | 46 | 21 | 195 | ||
| Diabetes | ||||||
| Yes | 1 | 1 | 1 | 3 | 2.506 | 0.288 |
| No | 128 | 45 | 24 | 197 | ||
| Chronic nephrosis | ||||||
| Yes | 0 | 0 | 0 | 0 | 1 | |
| No | 129 | 46 | 25 | 200 | ||
| Chronic cough | ||||||
| Yes | 9 | 1 | 1 | 11 | 1.231 | 0.654 |
| No | 120 | 45 | 24 | 189 | ||
| Chronic constipation | ||||||
| Yes | 13 | 6 | 2 | 21 | 0.525 | 0.782 |
| No | 116 | 40 | 23 | 179 | ||
| #Occupation | ||||||
| Mental labor | 44 | 20 | 9 | 73 | 1.287 | 0.525 |
| Physical labor | 85 | 26 | 16 | 127 | ||
Data were presented as numbers. BMI = body mass index, IRD = Inter-recti distance. *Rank data were compared using Kruskal-Wallis test. #Categorical variables were compared using Person chi-square test. Categorical variables were compared using Fisher chi-square test.
Table 3.
Univariate analysis of DRA at 5 years postpartum.
| Variable | IRD | Total (n = 200) |
H/χ2 | p-value | ||
|---|---|---|---|---|---|---|
| ≤ 2 cm (n = 138) |
> 2–3 cm (n = 47) |
> 3–5 cm (n = 15) |
||||
| *Age(years) | ||||||
| ≤ 35 | 72 | 26 | 7 | 105 | 1.055 | 0.590 |
| 36–40 | 52 | 19 | 5 | 76 | ||
| ≥ 41 | 14 | 2 | 3 | 19 | ||
| *BMI (kg/m2) | ||||||
| ≤ 18.4 | 11 | 0 | 2 | 13 | 1.538 | 0.463 |
| 18.5–23.9 | 84 | 32 | 6 | 122 | ||
| 24-27.9 | 37 | 10 | 5 | 52 | ||
| ≥ 28 | 6 | 5 | 2 | 13 | ||
| *The number of parturitions | ||||||
| 1 | 73 | 20 | 4 | 97 | 7.857 | 0.020 |
| 2 | 65 | 25 | 8 | 98 | ||
| 3 | 0 | 2 | 2 | 4 | ||
| 4 | 0 | 0 | 1 | 1 | ||
| #Caesarean | ||||||
| Yes | 59 | 20 | 8 | 87 | 0.639 | 0.727 |
| No | 79 | 27 | 7 | 113 | ||
| Twins | ||||||
| Yes | 0 | 0 | 1 | 1 | 5.924 | 0.075 |
| No | 138 | 47 | 14 | 199 | ||
| Diabetes | ||||||
| Yes | 4 | 2 | 1 | 7 | 1.465 | 0.520 |
| No | 134 | 45 | 14 | 193 | ||
| Chronic nephrosis | ||||||
| Yes | 0 | 0 | 0 | 0 | 1 | |
| No | 138 | 47 | 15 | 200 | ||
| Chronic cough | ||||||
| Yes | 12 | 3 | 3 | 18 | 2.590 | 0.234 |
| No | 126 | 44 | 12 | 182 | ||
| #Chronic constipation | ||||||
| Yes | 16 | 6 | 3 | 25 | 0.878 | 0.645 |
| No | 122 | 41 | 12 | 175 | ||
| #Occupation | ||||||
| Mental labor | 57 | 20 | 8 | 85 | 0.801 | 0.670 |
| Physical labor | 81 | 27 | 7 | 115 | ||
Data were presented as numbers. BMI = body mass index, IRD = Inter-recti distance. *Rank data were compared using Kruskal-Wallis test. #Categorical variables were compared using Person chi-square test. Categorical variables were compared using Fisher chi-square test.
Table 4.
Univariate analysis of DRA at 10 years postpartum.
| Variable | IRD | Total (n = 200) |
H/χ2 | p-value | ||
|---|---|---|---|---|---|---|
| ≤ 2 cm (n = 156) |
> 2–3 cm (n = 32) |
> 3–5 cm (n = 12) |
||||
| *Age(years) | ||||||
| ≤ 40 | 70 | 14 | 5 | 89 | 0.190 | 0.909 |
| 41–45 | 59 | 13 | 7 | 79 | ||
| ≥ 46 | 27 | 5 | 0 | 32 | ||
| *BMI (kg/m2) | ||||||
| ≤ 18.4 | 11 | 0 | 1 | 12 | 10.102 | 0.006 |
| 18.5–23.9 | 105 | 18 | 4 | 127 | ||
| 24-27.9 | 35 | 13 | 3 | 51 | ||
| ≥ 28 | 5 | 1 | 4 | 10 | ||
| *The number of parturitions | ||||||
| 1 | 98 | 18 | 3 | 119 | 12.387 | 0.002 |
| 2 | 55 | 14 | 4 | 73 | ||
| 3 | 2 | 0 | 3 | 5 | ||
| 4 | 1 | 0 | 2 | 3 | ||
| #Caesarean | ||||||
| Yes | 63 | 13 | 3 | 79 | 1.124 | 0.570 |
| No | 93 | 19 | 9 | 121 | ||
| Twins | ||||||
| Yes | 0 | 0 | 0 | 0 | 1 | |
| No | 156 | 32 | 12 | 200 | ||
| Diabetes | ||||||
| Yes | 14 | 4 | 2 | 20 | 1.563 | 0.400 |
| No | 142 | 28 | 10 | 180 | ||
| Chronic nephrosis | ||||||
| Yes | 1 | 1 | 1 | 3 | 5.227 | 0.064 |
| No | 155 | 31 | 11 | 197 | ||
| Chronic cough | ||||||
| Yes | 14 | 4 | 2 | 20 | 1.563 | 0.400 |
| No | 142 | 28 | 10 | 180 | ||
| Chronic constipation | ||||||
| Yes | 19 | 5 | 2 | 26 | 0.837 | 0.667 |
| No | 137 | 27 | 10 | 174 | ||
| #Occupation | ||||||
| Mental labor | 76 | 15 | 3 | 94 | 2.517 | 0.284 |
| Physical labor | 80 | 17 | 9 | 106 | ||
Data were presented as numbers. BMI = body mass index, IRD = Inter-recti distance. *Rank data were compared using Kruskal-Wallis test. Categorical variables were compared using Person chi-square test. Categorical variables were compared using Fisher chi-square test.
Table 5.
Univariate analysis of DRA at 20 years postpartum.
| Variable | IRD | Total (n = 200) |
H/χ2 | p-value | ||
|---|---|---|---|---|---|---|
| ≤ 2 cm (n = 149) |
> 2–3 cm (n = 36) |
> 3–5 cm (n = 15) |
||||
| *Age(years) | ||||||
| ≤ 50 | 67 | 20 | 4 | 91 | 4.139 | 0.126 |
| 51–55 | 31 | 8 | 4 | 43 | ||
| ≥ 56 | 51 | 8 | 7 | 66 | ||
| *BMI (kg/m2) | ||||||
| ≤ 18.4 | 10 | 1 | 0 | 11 | 6.626 | 0.036 |
| 18.5–23.9 | 85 | 24 | 5 | 114 | ||
| 24-27.9 | 39 | 6 | 6 | 51 | ||
| ≥ 28 | 15 | 5 | 4 | 24 | ||
| *The number of parturitions | ||||||
| 1 | 86 | 21 | 4 | 111 | 7.729 | 0.021 |
| 2 | 60 | 13 | 8 | 81 | ||
| 3 | 3 | 1 | 2 | 6 | ||
| 4 | 0 | 1 | 1 | 2 | ||
| #Caesarean | ||||||
| Yes | 49 | 11 | 8 | 68 | 2.771 | 0.250 |
| No | 100 | 25 | 7 | 132 | ||
| Twins | ||||||
| Yes | 1 | 0 | 1 | 2 | 3.930 | 0.176 |
| No | 148 | 36 | 14 | 198 | ||
| #Diabetes | ||||||
| Yes | 17 | 7 | 8 | 32 | 18.210 | 0.000 |
| No | 132 | 29 | 7 | 168 | ||
| Chronic nephrosis | ||||||
| Yes | 9 | 4 | 3 | 16 | 4.333 | 0.080 |
| No | 140 | 32 | 12 | 184 | ||
| Chronic cough | ||||||
| Yes | 18 | 5 | 2 | 25 | 0.331 | 0.872 |
| No | 131 | 31 | 13 | 175 | ||
| #Chronic constipation | ||||||
| Yes | 23 | 7 | 2 | 32 | 0.432 | 0.806 |
| No | 126 | 29 | 13 | 168 | ||
| #Occupation | ||||||
| Mental labor | 68 | 13 | 7 | 88 | 1.115 | 0.573 |
| Physical labor | 81 | 23 | 8 | 112 | ||
Data were presented as numbers. BMI = body mass index, IRD = Inter-recti distance. *Rank data were compared using Kruskal-Wallis test. #Categorical variables were compared using Person chi-square test. Categorical variables were compared using Fisher chi-square test.
Table 6.
Univariate analysis of DRA at 30 years postpartum.
| Variable | IRD | Total (n = 200) |
H/χ2 | p-value | |||
|---|---|---|---|---|---|---|---|
| ≤ 2 cm (n = 141) |
> 2–3 cm (n = 40) |
> 3–5 cm (n = 17) |
> 5 m (n = 2) |
||||
| *Age(years) | |||||||
| ≤ 60 | 31 | 6 | 3 | 1 | 41 | 1.148 | 0.765 |
| 61–65 | 44 | 14 | 4 | 0 | 62 | ||
| ≥ 66 | 66 | 20 | 10 | 1 | 97 | ||
| *BMI (kg/m2) | |||||||
| ≤ 18.4 | 5 | 2 | 0 | 0 | 7 | 23.420 | 0.000 |
| 18.5–23.9 | 70 | 17 | 1 | 0 | 88 | ||
| 24-27.9 | 48 | 19 | 8 | 0 | 75 | ||
| ≥ 28 | 18 | 2 | 8 | 2 | 30 | ||
| *The number of parturitions | |||||||
| 1 | 88 | 25 | 8 | 0 | 121 | 11.193 | 0.011 |
| 2 | 49 | 12 | 4 | 0 | 65 | ||
| 3 | 4 | 3 | 3 | 1 | 11 | ||
| 4 | 0 | 0 | 2 | 1 | 3 | ||
| Caesarean | |||||||
| Yes | 47 | 12 | 2 | 2 | 63 | 6.910 | 0.055 |
| No | 94 | 28 | 15 | 0 | 137 | ||
| Twins | |||||||
| Yes | 1 | 1 | 1 | 0 | 3 | 5.500 | 0.140 |
| No | 140 | 39 | 16 | 2 | 197 | ||
| Diabetes | |||||||
| Yes | 22 | 11 | 8 | 2 | 43 | 15.134 | 0.000 |
| No | 119 | 29 | 9 | 0 | 157 | ||
| Chronic nephrosis | |||||||
| Yes | 13 | 5 | 2 | 1 | 21 | 3.880 | 0.269 |
| No | 128 | 35 | 15 | 1 | 179 | ||
| Chronic cough | |||||||
| Yes | 17 | 7 | 6 | 1 | 31 | 8.170 | 0.034 |
| No | 124 | 33 | 11 | 1 | 169 | ||
| Chronic constipation | |||||||
| Yes | 29 | 9 | 4 | 1 | 43 | 1.688 | 0.633 |
| No | 112 | 31 | 13 | 1 | 157 | ||
| Occupation | |||||||
| Mental labor | 53 | 20 | 7 | 1 | 81 | 2.385 | 0.519 |
| Physical labor | 88 | 20 | 10 | 1 | 119 | ||
Data were presented as numbers. BMI = body mass index, IRD = Inter-recti distance. *Rank data were compared using Kruskal-Wallis test. Categorical variables were compared using Fisher chi-square test.
Multivariate analysis of DRA
At 3 years postpartum, bigger number of parturitions and twins were risk factors (p = 0.000 and 0.001). At 5 years postpartum, bigger number of parturitions was a risk factor (p = 0.004). At 10 years postpartum, higher BMI and bigger number of parturitions were risk factors (p = 0.000 and 0.000). At 20 and 30 years postpartum, diabetes was a risk factor (P = 0.000 and 0.004). Please see Table 7 for details.
Table 7.
Multivariate analysis of DRA at five time points.
| Time point | Variable | Estimate | S.E | Wald | df | p-value | 95%CI | |
|---|---|---|---|---|---|---|---|---|
| 3 years after partum | The number of parturitions | 0.921 | 0.257 | 12.862 | 1 | 0.000 | 0.418 | 1.424 |
| Twins | ||||||||
| No | -1.983 | 0.609 | 10.603 | 1 | 0.001 | -3.176 | -0.789 | |
| Yes | 0 | . | . | 0 | . | . | . | |
| 5 years after partum | The number of parturitions | 0.432 | 0.151 | 8.140 | 1 | 0.004 | 0.135 | 0.729 |
| 10 years after partum | BMI | 0.476 | 0.138 | 11.949 | 1 | 0.000 | 0.206 | 0.747 |
| The number of parturitions | 0.563 | 0.154 | 13.296 | 1 | 0.000 | 0.260 | 0.865 | |
| 20 years after partum | Diabetes | |||||||
| No | -0.825 | 0.238 | 11.972 | 1 | 0.000 | -1.292 | -0.358 | |
| Yes | 0 | 0 | ||||||
| 30 years after partum | Diabetes | |||||||
| No | -1.070 | 0.368 | 8.467 | 1 | 0.004 | -1.790 | -0.349 | |
| Yes | 0 | 0 | ||||||
Multivariate analysis was conducted by ordinal multivariate logistic regression. BMI = body mass index. Bonferroni correction was adopted in multivariate analysis, the corresponding P-value was taken as < 0.05/10 = 0.005, as there was a total of 10 independent variables.
Discussion
To date, the majority of DRA research efforts have concentrated on pregnant women and those in the early postpartum period3–5, with relatively little attention given to women in the long-term postpartum phase. This study represented an inaugural attempt to examine the prevalence and risk factors of DRA among women in the long-term postpartum period. This study revealed a trend that the prevalence of DRA initially decreases with increasing postpartum time, followed by a slight increase. Additionally, the women reporting higher BMI, bigger number of parturitions, twins, and diabetes exhibited a heightened risk of DRA. In particular, diabetes mainly affected women 20 and 30 years after delivery.
Prevalence of DRA
The diagnostic criteria directly affected the prevalence of DRA. The stage of pregnancy and delivery could also affect the prevalence of DRA. In general, the prevalence of DRA was highest in late pregnancy, and it gradually decreased after delivery. Especially in the first year after childbirth, the prevalence of DRA showed the most significant downward trend4,5,11. As for the long-term trend of postpartum changes, it was not clear before. This study focused on postpartum women in the long term and displayed the prevalence of DRA using two diagnostic criteria: IRD > 2 cm and IRD > 3 cm. According to the diagnostic criterion of IRD > 2 cm, the prevalence of DRA was 36%, 31%, 22%, 26%, and 30% 3 years, 5 years, 10 years, 20 years, and 30 years after partum, respectively. Concurrently, when the diagnostic criterion was elevated to IRD > 3 cm, the corresponding prevalence of DRA was 13%, 8%, 6%, 8%, and 10%, respectively.
From the research results, it could be seen that from 3 years postpartum to 10 years postpartum, the prevalence of DRA was gradually decreasing. It might indicate a slow recovery of DRA after childbirth. In addition, from 10 years postpartum to 30 years postpartum, the prevalence of DRA was on the contrary showing an increasing trend. On the one hand, this increase could be attributed to factors such as aging or entering the elderly stage, which might lead to elevated intra-abdominal pressure due to obesity, chronic cough, and other abdominal pressure related factors14. On the other hand, this might be due to the reduction of collagen in linea alba during the aging stage, making it easier to stretch and thin linea alba15,16.
Possible risk factor for DRA
Some studies suggested that higher BMI was a risk factor for DRA9,17, while others held the opposite view4,5. The potential mechanism by which higher BMI was a risk factor for DRA could be attributed to the increased adipose tissue within the abdominal cavity in individuals with long-term obesity, such as omentum and mesentery. This led to an increase in intra-abdominal contents, exerting pressure on the abdominal wall, which might contribute to the occurrence of DRA in obese patients. This study found that higher BMI was a risk factor for DRA 10 years after partum. However, 3 and 5 years after partum, higher BMI was not a risk factor for DRA. This could be associated with the relatively short duration of high BMI. Some reports suggested that obesity was a risk factor for DRA in older women but not in younger women9. In other words, the influence of high BMI on DRA appeared to be a gradual process. As for whether BMI was a risk factor for DRA at 20 and 30 years postpartum, it was before Bonferroni correction and not after Bonferroni correction. This indicated that BMI was not a stable risk factor for DRA at these two time points, which might be due to the increasing number of factors affecting DRA as the body aged, leading to a decrease in the proportion of high BMI’s impact on DRA or confusion.
Some studies suggested that bigger number of parturitions was a risk factor for DRA6,18,19, but another research had found similar rates of DRA occurrence between primiparous and multiparous women, indicating that multiple parturitions might not be a risk factor20. We found that bigger number of parturitions was a risk factor for DRA at most time points. Affected by relaxin during pregnancy, the maternal rectus abdominis muscle relaxed and became thin21,22, leading a weak resistance to the increasing intra-abdominal pressure. With the growth of the fetus, rectus abdominis muscle was constantly pushed to both sides, and linea alba would also be stretched to both sides accordingly, which led to the generation of DRA23. When the women who had not fully recovered from last pregnancy became pregnant again, their already damaged rectus abdominis muscle and linea alba would once again experience pulling or even separation. This indicated that the incidence of DRA might increase as the number of parturitions increased18.
This study found that twins was a risk factor for DRA 3 years after partum. This was consistent with the findings of Wu et al.9. One possible reason was that compared to singleton pregnancies, twin pregnancies exerted higher pressure on the rectus abdominis muscle, which could damage the integrity of abdominal tissues20,24. Consequently, the rectus abdominis muscle might be passively pulled to the sides, leading to destruction of its fibers14,15. However, this study did not conclusively identify twins as a risk factor for DRA at the other four time points. The main reason for this was sampling error. The number of mothers with twins in the sample was too small at the other four time points, making it statistically unfeasible to determine the impact of twins on DRA through analysis. And the sample size needs to be expanded for further verification in the future. Therefore, after comprehensive consideration, it is concluded that twin pregnancies may not a stable and reliable risk factor for DRA.
This study found that diabetes was a risk factor for DRA 20 and 30 years after partum, which was consistent with the finding of Wu et al.9. Some studies suggested that diabetes-induced changes in the rectus abdominis muscle might occur through two mechanisms: diabetes might lead to impaired mitochondrial oxidative phosphorylation and supercomplex assembly in rectus abdominis muscle fibers16, or it might induce changes in muscle structure by reducing fast fibers and increasing slow fibers25, resulting in a higher likelihood of muscle mass and function loss in diabetic individuals26,27. This would cause linea alba to face more intra-abdominal pressure, leading to the occurrence of DRA. In this study, diabetes was not identified as a risk factor for DRA at 3, 5, and 10 years postpartum. This could be due to the lower prevalence of diabetes in younger individuals compared to older adults28, as well as the relatively short duration of diabetes in these patients, which might not have manifested its impact on DRA yet. In other words, the effect of diabetes on DRA might require a longer-term process to become evident.
No significant differences were found for age, cesarean section, or occupation form as risk factors in different long-term postpartum periods. Mota et al. and Sperstad et al. did not consider age as a risk factor for DRA4,5. Conversely, Spiznagle et al. found that patients with DRA were older compared to those without DRA, suggesting age as a risk factor11. One study indicated that cesarean section was a risk factor29. There was currently no article exploring whether physically demanding work was related to the incidence of DRA. However, a study indicated that women who lifted weights 20 times or more per week were more likely to develop DRA5. In this study, these factors were not statistically correlated with the occurrence of DRA, indicating the need for further research and exploration.
Diagnostic criteria for DRA
Although researches on DRA had only gradually increased in recent years, it was likely that DRA had existed since ancient times. The main reason why DRA did not become a clinical research hotspot earlier was that it did not easily lead to serious adverse outcomes, as observed clinically. Additionally, based on the common understanding of clinical disease patterns, adverse outcomes related to disease are likely to be associated with the severity and duration of disease30,31. Similarly, only when DRA is severe enough and exists for a long enough time, can it potentially lead to adverse outcomes. This study suggested that IRD > 2 cm was too low as a diagnostic criterion for DRA, firstly because it resulted in a very high prevalence rate of DRA, and secondly because an IRD exceeding 2 cm might not be sufficient to cause adverse outcomes32. Moreover, as one of the methods for detecting DRA, the finger-width method typically used a criterion of 2 fingers5, which was close to 3 cm. In addition, 3 cm as an integer is very convenient for clinical use. Therefore, we believe that IRD > 3 cm may be a more appropriate diagnostic criterion.
Strengths and limitations
The strengths of this study included: (1) being the first to investigate the prevalence and risk factors for DRA in the long-term postpartum period; (2) a large sample size; (3) the utilization of ultrasound as a precise and dependable method for measuring IRD; and (4) using two standards to display the results, which increased comparability with other studies, and discussing the diagnostic criteria of DRA. However, several limitations should also be acknowledged. Firstly, this study was cross-sectional in nature, which might lead to inevitable unmeasured residual confounding. Therefore, further cohort studies are warranted to ascertain the risk factors for DRA in the long-term postpartum period. Secondly, the sample was drawn from a restricted geographical area, potentially limiting the generalizability of the findings to other populations. Thus, future studies should aim to validate these findings across diverse populations.
Conclusion
1) The prevalence of DRA in the long-term postpartum period was high, especially when IRD > 2 cm was used as the diagnostic criterion. Given that, Healthcare providers and professionals should closely monitor and assess whether postpartum women experience DRA, not only in the early stages but also in the long term. 2) Higher BMI, bigger number of parturitions, twins, and diabetes were independently associated with higher odds of DRA at different long-term postpartum time points. Therefore, some preventive measures can be considered. Giving birth to a child is very important for both a family and society, and should not be stopped due to DRA, which can also be treated. Twin pregnancy is a natural event and isn’t an adjustable risk factor either. We believe that active weight control and treatment of diabetes are the correct measures to prevent the occurrence of DRA, delay its development, and promote its rehabilitation. 3) The diagnostic criterion for DRA should be further improved to avoid excessive clinical diagnosis and treatment.
Acknowledgements
The authors want to express sincere gratitude to all the participants.
Author contributions
Conception and design of the research, acquisition of data, and writing of the manuscript: S-SL and J-JL and H-B X and Y-CG. Analysis and acquisition of the data: L-LW, Y-YZ and S-SL. Analysis and critical revision of the manuscript for intellectual content: C-XZ and S-ZQ. All authors have read and approved the final draft.
Funding
This study was supported by the science and technology plan project of Wenzhou (Grant No. Y2020047).
Data availability
The raw/processed data required to reproduce these findings cannot be shared at this time as the data also form part of an ongoing study. If any additional information or materials are required, please do not hesitate to contact the corresponding author.
Declarations
Competing interests
The authors declare no competing interests.
Footnotes
Publisher’s note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Saisai Lin, Jinjin Lu, and Lilu Wang contributed equally to thiswork and share first authorship.
Hongbo Xu, and Yechun Gu contributed equally to thiswork and share corresponding authorship.
Contributor Information
Hongbo Xu, Email: xhb@wmu.edu.cn.
Yechun Gu, Email: guyechun@126.com.
References
- 1.Gluppe, S., Engh, M. E. & Bø, K. What is the evidence for abdominal and pelvic floor muscle training to treat diastasis recti abdominis postpartum? A systematic review with meta-analysis. Braz J. Phys. Ther.25(6), 664–675. 10.1016/j.bjpt.2021.06.006 (2021). [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Boissonnault, J. S. & Blaschak, M. J. Incidence of diastasis recti abdominis during the childbearing year. Phys. Ther.68(7), 1082–1086. 10.1093/ptj/68.7.1082 (1988). [DOI] [PubMed] [Google Scholar]
- 3.Tuominen, R., Jahkola, T., Saisto, T., Arokoski, J. & Vironen, J. The prevalence and consequences of abdominal rectus muscle diastasis among Finnish women: An epidemiological cohort study. Hernia26(2), 599–608. 10.1007/s10029-021-02484-8 (2022). [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Fernandes da Mota, P. G., Pascoal, A. G., Carita, A. I. & Bø, K. Prevalence and risk factors of diastasis recti abdominis from late pregnancy to 6 months postpartum, and relationship with lumbo-pelvic pain. Man. Ther.20(1), 200–205. 10.1016/j.math.2014.09.002 (2015). [DOI] [PubMed] [Google Scholar]
- 5.Sperstad, J. B., Tennfjord, M. K., Hilde, G., Ellström-Engh, M. & Bø, K. Diastasis recti abdominis during pregnancy and 12 months after childbirth: Prevalence, risk factors and report of lumbopelvic pain. Br. J. Sports Med.50(17), 1092–1096. 10.1136/bjsports-2016-096065 (2016). [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6.Fei, H. et al. The relationship of severity in diastasis recti abdominis and pelvic floor dysfunction: A retrospective cohort study. BMC Womens Health21(1), 68. 10.1186/s12905-021-01194-8 (2021). [DOI] [PMC free article] [PubMed] [Google Scholar]
- 7.Sartori, A. et al. Rectus muscle diastasis in Italian women: Determinants of disease severity, and associated disorders. Front. Surg.11, 1360207. 10.3389/fsurg.2024.1360207 (2024). [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8.Rath, A. M. et al. The abdominal linea Alba: An anatomo-radiologic and biomechanical study. Surg. Radiol. Anat.18(4), 281–288. 10.1007/bf01627606 (1996). [DOI] [PubMed] [Google Scholar]
- 9.Wu, L. et al. Diastasis recti abdominis in adult women based on abdominal computed tomography imaging: Prevalence, risk factors and its impact on life. J. Clin. Nurs.30(3–4), 518–527. 10.1111/jocn.15568 (2021). [DOI] [PubMed] [Google Scholar]
- 10.Benjamin, D. R., Frawley, H. C., Shields, N., van de Water, A. T. M. & Taylor, N. F. Relationship between diastasis of the rectus abdominis muscle (DRAM) and musculoskeletal dysfunctions, pain and quality of life: A systematic review. Physiotherapy105(1), 24–34. 10.1016/j.physio.2018.07.002 (2019). [DOI] [PubMed] [Google Scholar]
- 11.Spitznagle, T. M., Leong, F. C. & Van Dillen, L. R. Prevalence of diastasis recti abdominis in a urogynecological patient population. Int. Urogynecol. J. Pelvic Floor. Dysfunct.18(3), 321–328. 10.1007/s00192-006-0143-5 (2007). [DOI] [PubMed] [Google Scholar]
- 12.Parker, M. A., Millar, L. A. & Dugan, S. A. Diastasis Rectus Abdominis and lumbo-pelvic pain and dysfunction-are they related? J. Women’s Pelvic Health Phys. Therapy33(2), 15–22. 10.1097/01274882-200933020-00003 (2009). [Google Scholar]
- 13.Hernández-Granados, P. et al. European Hernia Society guidelines on management of rectus diastasis. Br. J. Surg.108(10), 1189–1191. 10.1093/bjs/znab128 (2021). [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14.Zhu, Y. et al. Risk factors and patient-reported outcomes in Chinese women with Postpartum Diastasis Recti Abdominis: An observational study. Int. J. Womens Health16, 179–192. 10.2147/ijwh.S437088 (2024). [DOI] [PMC free article] [PubMed] [Google Scholar]
- 15.Wang, Q., Yu, X., Chen, G., Sun, X. & Wang, J. Does diastasis recti abdominis weaken pelvic floor function? A cross-sectional study. Int. Urogynecol. J.31(2), 277–283. 10.1007/s00192-019-04005-9 (2020). [DOI] [PubMed] [Google Scholar]
- 16.Antoun, G. et al. Erratum to: Impaired mitochondrial oxidative phosphorylation and supercomplex assembly in Rectus Abdominis muscle of diabetic obese individuals. Diabetologia59(2), 396–397. 10.1007/s00125-015-3821-3 (2016). [DOI] [PubMed] [Google Scholar]
- 17.Doubkova, L. et al. Diastasis of Rectus Abdominis muscles in low back pain patients. J. Back Musculoskelet. Rehabil.31(1), 107–112. 10.3233/bmr-169687 (2018). [DOI] [PubMed] [Google Scholar]
- 18.Liaw, L. J., Hsu, M. J., Liao, C. F., Liu, M. F. & Hsu, A. T. The relationships between inter-recti distance measured by ultrasound imaging and abdominal muscle function in postpartum women: A 6-month follow-up study. J. Orthop. Sports Phys. Ther.41(6), 435–443. 10.2519/jospt.2011.3507 (2011). [DOI] [PubMed] [Google Scholar]
- 19.Kaufmann, R. L. et al. Normal width of the linea Alba, prevalence, and risk factors for diastasis recti abdominis in adults, a cross-sectional study. Hernia26(2), 609–618. 10.1007/s10029-021-02493-7 (2022). [DOI] [PMC free article] [PubMed] [Google Scholar]
- 20.Rett, M., Braga, M., Bernardes, N. & Andrade, S. Prevalence of diastasis of the rectus abdominis muscles immediately postpartum: Comparison between primiparae and multiparae. Braz. J. Phys. Ther.13, 275–280. 10.1590/S1413-35552009005000037 (2009). [Google Scholar]
- 21.Ormsbee, M. J. et al. Osteosarcopenic obesity: The role of bone, muscle, and fat on health. J. Cachexia Sarcopenia Muscle5(3), 183–192. 10.1007/s13539-014-0146-x (2014). [DOI] [PMC free article] [PubMed] [Google Scholar]
- 22.Grossi, J. V. et al. Arq. Bras. Cir. Dig.29, 8–11. 10.1590/0102-6720201600s10003 (2016).
- 23.Axer, H., von Keyserlingk, D. G. & Prescher, A. Collagen fibers in linea Alba and rectus sheaths. J. Surg. Res.96(2), 239–245. 10.1006/jsre.2000.6071 (2001). [DOI] [PubMed] [Google Scholar]
- 24.Turan, V., Colluoglu, C., Turkyilmaz, E. & Korucuoglu, U. Prevalence of diastasis recti abdominis in the population of young multiparous adults in Turkey. Ginekol. Pol.82(11), 817–821 (2011). [PubMed] [Google Scholar]
- 25.Vesentini, G. et al. Morphological changes in rat rectus abdominis muscle induced by diabetes and pregnancy. Braz. J. Med. Biol. Res.51(4), e7035. 10.1590/1414-431x20177035 (2018). [DOI] [PMC free article] [PubMed] [Google Scholar]
- 26.Al-Ozairi, E. et al. Skeletal Muscle and Metabolic Health: How do we increase muscle Mass and function in people with type 2 diabetes?. J. Clin. Endocrinol. Metab.106(2), 309–317. 10.1210/clinem/dgaa835 (2021). [DOI] [PubMed] [Google Scholar]
- 27.Guerrero, N. et al. Premature loss of muscle mass and function in type 2 diabetes. Diabetes Res. Clin. Pract.117, 32–38. 10.1016/j.diabres.2016.04.011 (2016). [DOI] [PubMed] [Google Scholar]
- 28.Li, Y. et al. Prevalence of diabetes recorded in mainland China using 2018 diagnostic criteria from the American Diabetes Association: National cross sectional study. Bmj369, m997. 10.1136/bmj.m997 (2020). [DOI] [PMC free article] [PubMed] [Google Scholar]
- 29.Cardaillac, C. et al. Diastasis of the rectus abdominis muscles in postpartum: Concordance of patient and clinician evaluations, prevalence, associated pelvic floor symptoms and quality of life. Eur. J. Obstet. Gynecol. Reprod. Biol.252, 228–232. 10.1016/j.ejogrb.2020.06.038 (2020). [DOI] [PubMed] [Google Scholar]
- 30.Martinez-De Jesús, F. R. et al. Validation of the Ischaemia Severity Scale (ISS) based on non-invasive vascular assessments (SEWSS) for Predicting outcomes of Diabetic Foot Attack. J. Clin. Med.11(23). 10.3390/jcm11237195 (2022). [DOI] [PMC free article] [PubMed]
- 31.Hitha, B. et al. Microalbuminuria in patients with essential hypertension and its relationship to target organ damage: An Indian experience. Saudi J. Kidney Dis. Transpl.19(3), 411–419 (2008). [PubMed] [Google Scholar]
- 32.Beer, G. M. et al. The normal width of the linea Alba in nulliparous women. Clin. Anat.22(6), 706–711. 10.1002/ca.20836 (2009). [DOI] [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
The raw/processed data required to reproduce these findings cannot be shared at this time as the data also form part of an ongoing study. If any additional information or materials are required, please do not hesitate to contact the corresponding author.