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Table of Contents
Year : 2021  |  Volume : 26  |  Issue : 2  |  Page : 123-127

Correlates of inter-rectus distance in Nigerian parous women

1 Department of Medical Rehabilitation, Faculty of Health Sciences and Technology, University of Nigeria, Enugu Campus, Nigeria
2 Department of Physiotherapy, Nnamdi Azikiwe University Teaching Hospital Nnewi, Anambra State, Nigeria
3 Department of Physiotherapy, Enugu State University Teaching Hospital, Parklane, Enugu, Nigeria

Date of Submission03-Aug-2020
Date of Decision26-Aug-2020
Date of Acceptance07-Sep-2020
Date of Web Publication29-Jan-2021

Correspondence Address:
Anne Uruchi Ezeigwe
Department of Medical Rehabilitation, Faculty of Health Sciences and Technology, University of Nigeria, Enugu Campus.
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijmh.IJMH_52_20

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Background: Diastasis Recti Abdominis (DRA) or increased inter-rectus distance (IRD) is among the most common pregnancy-related physical disorders in women. Studies are scarce on its correlates in an African population. Objectives: The aim of this study was to determine anthropometric and maternal correlates of DRA in Nigerian parous women. Materials and Methods: Eighty nine (89) consenting parous women (20–45 years) participated in this observational study. The IRD was measured with an electronic digital caliper at the umbilical level alongside other anthropometric measurements (weight, height, waist circumference (WC), hip circumference (HC)). Information on participants’ age, mode of delivery (MOD), parity, and age of last child (AOLC) was obtained. Data were analyzed with descriptive statistics and inferential statistics of Pearson’s and Spearman’s rank correlations, respectively, with subsequent linear regression analysis at an alpha level of P < 0.05. Results: The IRD significantly correlated with WC (r= 0.213, P = 0.045) and waist-to-hip ratio (WHR), (r = 0.357, P = 0.001). Significant regression equations were determined for the prediction of IRD based on WC and WHR. However, the other variables studied showed no significant (P > 0.05) correlation with IRD. Conclusion: WC and WHR are predictors of IRD in parous women, and these should be considered as important variables in the management of DRA associated with pregnancy.

Keywords: Body anthropometry, diastasis recti abdominis, inter-rectus distance, Nigeria, postpartum women

How to cite this article:
Ojukwu CP, Ezeigwe AU, Ezeigwe CF, Onuchukwu CL, Agwagu IM. Correlates of inter-rectus distance in Nigerian parous women. Int J Med Health Dev 2021;26:123-7

How to cite this URL:
Ojukwu CP, Ezeigwe AU, Ezeigwe CF, Onuchukwu CL, Agwagu IM. Correlates of inter-rectus distance in Nigerian parous women. Int J Med Health Dev [serial online] 2021 [cited 2022 Aug 10];26:123-7. Available from: https://www.ijmhdev.com/text.asp?2021/26/2/123/308253

  Introduction Top

Alterations in the structure and function of the abdominal muscles are common pregnancy-related changes. Increased IRD, an abnormal separation of the rectus abdominis muscle in the midline at the linea alba, is one of the commonly observed physical changes during pregnancy. The IRD refers to the width of the linea alba between the connective tissue sheaths surrounding the paired rectus abdominis muscles[1]; an abnormal increase in its dimension results in DRA, RAD, or Divarication of Rectus Abdominal Muscles (DRAM).[2],[3] Its normal dimensions are 15 mm at the xiphoid process, 22 mm at the reference point of 3 cm above the umbilicus, and 16 mm at the reference point of 2 cm below the umbilicus.[4] Pregnancy-related hormonal and biomechanical changes have been implicated as common etiologic factors of DRA in women.[5],[6] The DRA negatively impacts the biomechanics of the abdominal wall, compromising its integrity.[7]

The abdominal muscles are stabilizers, aiding posture and engaging in various activities of daily living (ADLs); as such, the presence of DRA may lead to trunk and pelvic instability, poor posture, physical activity limitations, lumbo pelvic and hip pain,[7],[8],[9] as well as pelvic floor dysfunction.[10] This defect occurs at the linea alba, a meshwork of connective tissue in which the tendinous insertions of the external oblique, internal oblique, and transversus abdominis muscles intermingle, providing structure and stability to the abdominal wall and trunk.[11] As is common in parous women, the DRA is centered at the level of the umbilicus, but it can extend to and encompass the supraumbilical or infraumbilical regions occasionally.[12]

Several risk factors have been reportedly associated with DRA in pregnant and postpartum women, some of which include multiparity, multiple gestations, older maternal age, excessive weight gain in pregnancy, cesarean section and fetal macrosomia,[13] polyhydramnios,[14] as well as genetically conditioned defects in collagen structure (including congenital disproportion of the collagen III/I ratio).[8],[11],[15] Others include a history of bariatric surgeries and abdominal surgical procedures.[8],[11],[15] However, opinions are varied on the associations between body anthropometric variables and IRD. Fernandes Mota et al.[16] reported no differences in the maternal body mass index (BMI), gestational weight gain and abdominal circumference, as well as infant birth weight in two groups of women with and without DRA at 6 months postpartum. Waist girth above 102 cm, female gender, abdominal scarring, and increased WHR have also been reported as predictors of IRD in cadavers.[17] Adequate understanding of the risk and/or associated factors of DRA will enhance early and easy identification of women at risk of DRA as well as guide clinical decision making in the management of DRA. In the African populace, studies are limited on the associated factors of DRA in women of childbearing age. As a result, this study sought to determine the body anthropometric and maternal correlates of DRA in Nigerian parous women.

  Subjects and Methods Top

This study was carried out at Enugu State University Teaching Hospital Park Lane (ESUTHP), Enugu, south-eastern Nigeria from April to June 2019. This was an observational study using the purposive sampling technique.

A priori power analysis for a significant Pearson product-moment correlation at a 0.05 level of significance, a power of 0.90, and a medium effect size of 0.30 showed that 92 participants were needed for this study (Cohen).[18] A total of 94 parous women were consecutively recruited from among those who presented for postpartum checkup or routine infant immunization at ESUTHP, Enugu; however, only 89 completed the study.

Parous women aged 20–45 years and who had experienced 1–4 childbirths were included in this study. Pregnant women were excluded from this study to rule out hormonal-related changes in the musculoskeletal system. In addition, women with a recent history of neck and/ or low back pain were excluded as these conditions may likely interfere with the protocols of the IRD measurement.

This study was approved by the Research, Education and Training Committee (RET) of the ESUTHP, Enugu and all participants gave written informed consent before their participation in the study. Subsequent to participant recruitment, information on their age, MOD, number of children (NOCH), and AOLC were obtained; HC and WC as well as standing height and body weight were measured. The IRD measurement was taken at the level of the umbilicus by the researcher (a physiotherapist with > 12years of clinical experience) with the participants’ privacy ensured and in accordance with the procedures recommended in previous studies.[10],[19],[20] The protocol included the participant adopting a crook lying position while being asked to perform partial curl up as the palpating fingers of the examiner were placed between the medial borders of the right and left rectus abdominis muscles, parallel to the linea alba. The IRD size was determined by indicating the number of fingers that fitted between the two muscle bellies. The inside measurement jaws of the digital caliper were positioned at the locations of the palpating fingers, perpendicular to the direction of the muscles, and adjusted to the perceived IRD width with the measurement value read in millimeters.

The DRA was categorized based on finger breadth: < 2 finger breadths indicates no DRA; 2–3 finger breadths, mild; 3–4 finger breadths, moderate; and ˃ 4 finger breadths, severe.[21]

Data analysis

Descriptive statistics of mean, standard deviation, frequency, and percentage were used to summarize data. Inferential statistics of bivariate correlation (Pearson’s correlation was used for parametric data, i.e. IRD and participants’ anthropometry characteristics; whereas Spearman’s rank correlation was used for nonparametric data, i.e. IRD and maternal characteristics) and multivariate analysis (linear regression) were used to determine associations among IRD and each of the WC and WHR. Alpha level was set at P < 0.05. Data were analyzed with SPSS version 21.0.

  Results Top

The mean age of the participants is 32.57 ± 5.13. The descriptive statistics of the participants’ anthropometric characteristics (weight, height, BMI, WC, HC, and WHR) are presented in [Table 1]. [Table 2] presents the maternal characteristics (MOD, parity, and AOLC) of the participants. The majority of the women had spontaneous vaginal deliveries (73.0%) and 2–4 children (59.6%); 44.9% were within 0–24 weeks from their last childbirth.
Table 1: Anthropometric characteristics of participants

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Table 2: Maternal characteristics of participants (n = 89)

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Participants’ mean IRD was 42.15 ± 9.69 mm. The categorization of their DRA severity based on the finger breadth measurements of IRD shows that a greater percentage (82.02%) of the women had mild DRA.

Pearson’s correlation test results of associations between IRD and participants’ anthropometric characteristics are presented in [Table 3]. Significant correlations existed between the IRD and each of the WC (r = 0.213, P = 0.045) and WHR (r = 0.357, P = 0.001). However, there were no significant correlations (P > 0.05) between the IRD and each of the age, height, weight, BMI, and HC. Similarly, there were no significant correlations (P > 0.05) between the IRD and the participants’ maternal characteristics [Table 4].
Table 3: Pearson’s correlation result showing associations between IRD and anthropometric characteristics of the participants

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Table 4: Correlation test results showing associations between IRD and maternal characteristics

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Further, a simple linear regression was calculated to predict the IRD based on WC. A significant regression equation was found (F(1,87)= 4.127; P = 0.045), with an R2 of 0.045. Participants’ predicted IRD is equal to 25.647+0.180(WC) mm when WC is measured in cm. Therefore, the IRD increased by 0.180 mm for every 1 cm change in WC. Specifically, the following linear regression equation was derived:

In addition, a simple linear regression was calculated to predict the IRD based on WHR. A significant regression equation was also found (F(1,87)= 12.676; P = 0.001), with an R2 of 0.127. Participants’ predicted IRD is equal to -6.485+56.198(WHR) mm when WHR is measured in cm. Therefore, the IRD increased by 56.198 for every 1 cm change in WHR. Specifically, the following regression equation was derived:

  Discussion Top

This study examined the relationships between IRD, body anthropometry, and maternal characteristics. The results showed that both WC and WHR were each positively correlated with the participants’ IRD. This means that there is a direct relationship between both anthropometric measures and IRD. Therefore, increased WC and/ or WHR can lead to increased IRD. This finding agrees with previous studies,[14],[17],[22],[23] which showed associations between IRD, WC, and WHR. Given that WC and WHR are clinical measures of obesity, it is not surprising that they are positively correlated with IRD as obesity has previously been implicated as one of the risk factors of DRA in both genders.[22],[24] Despite the fact that other anthropometric variables assessed in this study are markers of obesity, WC and WHR have been shown to be more precise markers of truncal obesity; therefore, they are more relevant to the development of DRA.[25] In obese individuals, the accumulation of abdominal fat and distension of the abdomen tend to contribute to the structure and integrity of the abdominal musculature, with resultant physical disorders, including DRA. Further, inflammatory changes due to the truncal obesity increase the susceptibility to metabolic and immune system changes.[26]

The maternal age of the participants did not indicate a significant relationship with DRA; this corroborates the results of Bobowik et al.,[22] who studied a similar age range. However, an association was found between age and the IRD in 40 primigravida aged 18 to 25 years.[27] Similarly, older maternal age (>34years) has been documented as a risk factor for DRA.[13] The reason for this lack of association between the IRD and maternal age in this study may be attributable to the fact that most participants were within a similar age bracket with a mean age of 32 years and marginal variability in age range, as opposed to the aforementioned studies that found an association between maternal age and the IRD.

Further, this study found that some maternal anthropometric variables, including height, weight, BMI, and HC, held no associations with IRD. This agrees with the works of Mota et al.[20] and Gitta et al.[28] which found no significant difference between BMI and DRA. However, a report of a statistically significant correlation between the IRD and BMI has been documented.[22] This correlation is indicated as a contributor to separation of the rectus abdominis muscles.[27] The BMI is a function of weight and height, and it is determined by a combination of genetic and environmental factors. Weight refers to general body fat, lean body mass (muscles, bone, and organs), and water. However, it is unspecific to truncal obesity, which may explain its lack of association with IRD, as reflected in the study.

In addition, this study found no correlation between the IRD and maternal characteristics (MOD, AOLC, and parity). This finding is in line with the studies of Bhandiwad et al.[27] and Sancho et al.[29] who found no relationship between the IRD and MOD. The DRA development is expected to have been completed at term, with a higher prevalence occurring in the third trimester of pregnancy as well as immediate postpartum.[30],[31] Therefore, the MOD has no relationship with DRA. Again, significant relationships between the number of deliveries and the IRD have been documented.[22],[28],[32] This is expected, as the biomechanical and physiological changes that occur during pregnancy weaken the linea alba, which results in DRA. This could infer that without postpartum rehabilitation, an increasing number of parity will further compound the weakness. The failure to observe a similar trend in this study may be possibly due to measurement instruments and the composition of the study population, which comprised about 37.1% primiparous women. Finally, this study found no correlation between the IRD and AOLC. This is at variance with findings from a previous study that suggested that the IRD resolves naturally until 12 months postpartum.[33] If this is true, we would have expected a significant relationship in the women in this study.


There was a 3.3% attrition rate.

  Conclusion Top

The WC and WHR are predictors of IRD in parous women. Appropriate consideration of these attributes will aid early detection, enable an effective assessment of DRA in women, as well as guide clinical decision making in its management.


The authors wish to acknowledge the invaluable contribution of the study center and all the participants.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

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  [Table 1], [Table 2], [Table 3], [Table 4]


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