Determinants of uterovaginal prolapse in Western Ethiopia

Uterovaginal prolapse is a significant public health concern in developing countries like Ethiopia where access to health care is limited. It significantly affects women’s health and productivity. Thus, it is very important to identify determinant factors and take preventive actions. A hospital-based unmatched case-control study was conducted on 86 cases and 258 controls who attended gynecologic outpatient departments in Nekemte town from May 1 to July 30, 2019. Cases were women with grade II, III and IV uterovaginal prolapse while controls were women free from uterovaginal prolapse but with other gynecologic diseases. Data were collected using pretested interviewer-administered questionnaires, and measurements on height and weight were taken to calculate the women’s body mass index. Data were entered using Epi Data version 3.1, and analysis was carried out by SPSS version 20. Descriptive, bivariate and multivariable logistic regressions were performed. The adjusted odds ratio with a 95% confidence interval was used, and statistical significance was declared at p < 0.05. This study revealed age ≥ 40 years (AOR = 10.49; 95% CI: 4.03, 27.35), duration of labor ≥ 24 h (AOR = 8.32; 95% CI: 3.58, 19.33), instrumental delivery (AOR = 7.40; 95% CI: 1.21, 45.28), non- utilization of family planning (AOR = 3.14; 95% CI: 1.32, 7.47) and underweight (BMI < 18.5 kg/m2) (AOR = 5.30; 95% CI: 1.83, 15.33) were determinants of uterovaginal prolapse. Age ≥ 40 years, prolonged labor, instrumental delivery, non-utilization of family planning and underweight were identified as determinant factors of uterovaginal prolapse. Thus, family planning service utilization and appropriate and timely obstetric care are advisable.


Introduction
Uterovaginal prolapse (UVP) is the descent of the uterus through the vaginal canal due to defects in the support structures of the uterus and vagina because of different factors such as high parity, strenuous activities, birth trauma, malnutrition and and increased intraabdominal pressure. It is manifested by a protruding mass per vagina and urinary and rectal complaints [1,2].
Uterovaginal prolapse is a common pelvic floor disorder among women of reproductive age and postmenopausal women. It occurs in both developed and developing countries with an overall global prevalence of 2-20%. For instance, it is 3.4% in Nigeria, 20.4% in the UK, 14% in the USA and 27.1% in Turkey [3][4][5][6]. In Ethiopia, gynecologic problems are important health problems affecting maternal health outcomes, sexual function and women's productivity. Earlier studies in Ethiopia revealed that pelvic organ prolapse (POP) accounted for 40.7% and 15% of all gynecologic surgeries, respectively [7][8][9].
A review of the world literature revealed different factors related to the development of uterovaginal prolapse. The most important ones are factors that increase intra-abdominal pressure, difficult labor and delivery, malnutrition, old age, connective tissue disorders, heavy exercise and pelvic trauma [7,[10][11][12]. However, what factors lead to the occurrence of UVP are not well studied in Ethiopia. There are only a few studies in the country that relied on patient records, which might be subject to information bias because of the incompleteness and poor quality of secondary data [7,8]. Also, to the best of the authors' knowledge, there has been no study on determinants of uterovaginal prolapse in Western Ethiopia. Thus, the current study assessed the determinant factors of UVP in Western Ethiopia using primary data.

Study area and period
A hospital-based unmatched case-control study was conducted among women attending the gynecologic outpatient department (OPD) in Nekemte town from May 1 to July 30, 2019. Nekemte town, the capital city of the East Wollega zone, is located 331 km west of Addis Ababa. According to the 2018 Nekemte town Health Office Report, the total population of Nekemte town was 127,380, of which 51.03%, 49.97%, 16.4% and 3.47% were male, female, children under 5 years and pregnant women, respectively. The dominant ethnic group is Oromo [13]. There are two public hospitals in the town: Nekemte Specialized Hospital and Wollega University Referral Hospital. These hospitals provide services including obstetric and gynecologic services to nearly 5 million people in western Ethiopia and adjacent areas. They have wellorganized gynecology and obstetrics departments, which are led by 7 gynecologists and 15 general practitioners. These two hospitals provide uterovaginal prolapse and other surgical interventions.

Study population
All women attending gynecologic OPD at public hospitals in Nekemte town during the study period comprised the study population. Cases were women with grade II, III and IV uterovaginal prolapse. Controls were women free from uterovaginal prolapse but with some other gynecologic disease during the same study period. All women aged > 18 years attending OPD during the study period were included in the study. However, women with grade I UVP, women with cervical elongation, women with a total abdominal hysterectomy and vaginal hysterectomy, critically ill women and women with mental problems were excluded from the study.

Sample size determination and sampling procedure
The sample size was calculated using Epi-info software version 7 using sample size determination for unmatched casecontrol studies. The parameters that were used to calculate sample size were: 95% confidence level, 80% power, control-to-case ratio of 3: 1, proportion of controls with exposure 6.2%, proportion of cases with exposure 18.5% and odds ratio of 3.1. This was calculated from the study conducted in Bahir Dar town, northwest Ethiopia, by taking BMI (< 18.5 kg/m 2 ) as one of the main exposure variables for pelvic organ prolapse that provide the maximum sample size [14]. This yielded 78 cases and 232 controls. Adding a 10% nonresponse rate, the final sample size was 341 (86 cases and 258 controls).
Two hospitals in Nekemte town were included because they provide surgical interventions for cases of UVP. Then, based on the number of clients who had visited the gynecologic OPD of these two hospitals during the previous 3 months (60 cases and 358 controls for Wollega University Referral Hospital and 45 cases and 308 controls for Nekemte Specialized Hospital), the sample size was proportionally allocated to each hospital. Finally, cases in the two hospitals were included consecutively, and three controls for each case were selected using a systematic sampling method.

Measurements
Inter-pregnancy interval was defined as the interval between the most recent previous childbirth and the starting time of pregnancy for the current child as reported by the mother at the time of the interview. In this study, a woman faced laborintensive work if she reported frequent engagement in work like lifting and carrying heavy objects. Chronic cough was defined as a cough that lasted ≥ 2 months. Chronic constipation was defined as a stool frequency of less than three per week that lasts several months or having difficulty passing stools. In this study, abortion was defined as either spontaneous or induced termination of pregnancy before fetal viability (before 28 weeks of gestational age according to the Ethiopian context).

Data collection tools and procedures
Data on socio-demographic, obstetric, gynecologic and medical history were collected by using a pre-tested structured interviewer-administered questionnaire, which was developed by reviewing different works in the literature . Four BSc nurses and two MSc supervisors were recruited and trained for data collection. All questionnaires were checked for completeness daily by the supervisors.
Physical measurement was used to obtain data on the weight and height of women. The weight of each woman was measured using a balanced beam in kg to the nearest 0.1 kg, and height was measured using a measuring tape to the nearest 0.1 cm. Diagnosis of uterovaginal prolapse was made by gynecologists working in the outpatient department. A pelvic examination was done after a woman had emptied her bladder. The examination was done in a lithotomy position. To avoid intra-and inter-rater reliability, the authors had a thorough discussion with attending gynecologists on finding documentation.
Shaw's classification system of uterovaginal prolapse was used for grading the disease. In this classification system, the descent is classified into four grades: first grade is the descent of the cervix into the vagina, second grade is the descent of the cervix into the introitus, third grade is the descent of the cervix outside the introitus, and fourth grade is when the entire uterus is outside introitus [1].

Data quality assurance
The questionnaire was first prepared in English and then translated to the local language (Afan Oromo). The data collectors and supervisors were trained for 2 days on data collection and details of the study. A pretest was conducted on 4 cases and 12 controls at Mettu Karl Hospital, which is located in southwest Ethiopia.

Data processing and analysis
After checking for completeness, data were entered using Epi Data version 3.1. They were then cleaned and exported to SPSS version 20 for analysis. Frequency distribution and percentage were used to describe predictor variables. Also, descriptive statistics including mean and standard deviation were conducted to describe continuous variables. Bivariate analysis was used to examine the association between dependent and independent variables; odds ratios (ORs) and their 95% confidence intervals (CIs) were calculated. All variables with a P value < 0.2 in the bivariate analysis were included in the multivariate logistic regression analysis model to identify determinant factors of uterovaginal prolapse. Statistical significance was set at a p value of < 0.05. In the model development process, the existence of multi-collinearity was assessed to rule out the interaction among independent variables using the variance inflation factor (VIF). Accordingly, the result of VIF was close to one, which showed minimal collinearity. The model was assessed for goodness of fit using the Hosmer-Lemeshow test. Since the p value for the Hosmer-Lemeshow chi-square was > 0.05 (P = 0.965), the model estimate was adequate to fit the data at an acceptable level.

Ethical considerations
Ethical clearance was obtained from Wollega University Institute of Health Sciences Ethical Review Board. Additionally, a letter of cooperation was written to respective hospitals by Wollega University Institute of Health Sciences. To obtain permission, hospital administrations were informed before starting data collection. All participants were given adequate information regarding the purpose, risks and benefits, and confidentiality of the study was described in the information sheet. Participation was fully voluntary, and written informed consent was taken from each participant. Confidentiality of the patient was kept, and the information was only used for this study.

Socio-demographic characteristics of study participants
Out of the total sample, 325 respondents (82 cases and 243 controls) participated in the interview with a response rate of 95.3%. The mean ages of cases and controls were 45.9 (± 10.4 SD) years and 31.2 (± 7.6 SD) years, respectively. The proportion of older age women (≥ 40 years) was found to be higher among cases (65.9%) than controls (8.6%) (p = 0.001). The majority of study participants, both cases and controls, were Oromo by ethnicity, Protestants and married. Forty-seven (57.3%) cases and 122 (50.2%) controls had no formal education (p = 0.01). More than half of participants among cases 47 (57.3%) and controls 140 (57.6%) were housewives (p = 0.022). Of the total women involved, 54(65.9%) cases and 135 (55.6%) controls were rural residents (Table 1).

Determinants of uterovaginal prolapse among study participants
The odds of developing UVP according to different characteristics of women were estimated by odds ratio using binary logistic regression analysis. Variables having a p value < 0.2 at bivariate analysis were taken for multivariable analysis. In the final model, the odds of having UVP across each independent variable were adjusted for confounding effects. Accordingly, age, duration of labor, mode of delivery, family planning use, family history of UVP and low BMI were predictor variables that remained significantly associated with UVP at a p value < 0.05.
Multivariable logistic regression analysis indicated that women aged >40 years had 10.5 times greater odds of experiencing uterovaginal prolapse compared to those aged < 40 years (AOR = 10.49; 95% CI: 4.03, 27.35). Women who had a duration of labor ≥ 24 h during the last childbirth had 8.32 times higher odds of developing UVP compared to those who stayed < 24 h (AOR = 8.32; 95% CI: 3.58, 19.33). Women who gave birth by instrumental delivery had 7.40 times higher odds of developing UVP compared to women who gave birth by cesarean section (AOR = 7.40; 95% CI: 1.21, 45.28). Women who did not ever use family planning had 3.14 times higher odds of developing UVP compared to  However, the effects of residence, gravidity, parity, place of delivery, menopausal status, history of chronic cough, chronic constipation and carrying heavy objects were no longer significant after adjusting for confounders (Table 4).

Discussion
The main objective of the study was to identify the determinant factors of UVP among women attending gynecologic OPD at public hospitals in Western Ethiopia. Accordingly, many modifiable factors were identified to affect the occurrence of UVP.
Different studies reported that the risk of UVP increases with age [7,14,16,27,29]. This study also revealed that women aged ≥ 40 years had 10.49 times higher odds of experiencing UVP compared to women aged < 40 years. This might be due to age-related weakening of pelvic supportive structures, decreased levels of estrogen and high parity in this age group. However, a study conducted in Gondar Dabat district, Ethiopia, reported a contradictory finding [34].
Duration of labor ≥ 24 h was significantly associated with the development of uterovaginal prolapse. This finding is consistent with previous reports from India [26], Nepal [31], Tanzania [36], Nigeria [20] and Ethiopia [7]. This could be because prolonged labor causes more damage to supportive structures of the uterus and other pelvic organs. Prolonged labor can also be complicated by obstructed labor, which might need aggressive interventions like operative deliveries that might worsen damage already weakened structures.
Previous studies indicated a controversial association between instrumental deliveries and pelvic prolapse. A study in Greater Baltimore Medical Center in Towson has suggested that operative delivery (forceps or vacuum) substantially increases the odds for pelvic organ prolapse [37] while a population-based study in Sweden [38] failed to show this association. Interestingly, this study identified a significant association between instrumental delivery and UVP. Women who delivered by either forceps or vacuum had 7.4 times  higher odds of developing UVP compared to women who delivered by cesarean section. A possible explanation could be due to stretching and tearing as a result of excessive traction applied during difficult instrumental deliveries [32]. Women who did not use family planning had 3.14 times higher odds of developing UVP compared to their counterparts. This finding is similar to the study conducted at Wolaita Sodo University Referral Hospital [33]. This is because mothers who do not use family planning have repeated deliveries during which cumulative effects of pushing down pain might damage the pelvic support structures. However, a study conducted in England [3] did not show an association between the utilization of family planning and the development of UVP.
In this study, family history was found to be a predictor for UVP. Women with a family history of UVP had 3.77 times higher odds of developing UVP compared to their counterparts. This is consistent with studies conducted in Addis Ababa, Ethiopia [8], and Nepal [34]. Similarly, a study conducted in Italy reported that the risk of urogenital prolapse was higher in women with a family history of prolapse compared to women without a family history of prolapse [18]. This could be due to the presence of congenital connective tissue disorders in these families.
Like a report from Bahir Dar, Ethiopia [14], underweight (BMI <18.5 kg/m 2 ) was also found to be a determinant of UVP in this study. This is due to the possibility of deficiencies of micronutrient, which are necessary for connective tissue strength. On the other hand, other studies showed that obesity (BMI ≥ 25 kg/m 2 ) is a risk factor for UVP [16,24,31].
In conclusion, age ≥ 40 years, prolonged labor, instrumental delivery, non-utilization of family planning, family history of UVP and underweight were identified as determinant factors of uterovaginal prolapse. Therefore, creating awareness among women regarding possible risk factors and preventive measures regarding uterovaginal prolapse, training of health professionals on how to manage prolonged labor and how to use instrumental delivery cautiously, and further study that utilizes strong designs are recommended.

Strengths and limitations of this study
This is the first case-control study in Western Ethiopia aimed to identify determinant factors of uterovaginal prolapse. We hope that the findings of this study will bring much needed attention to this serious condition and provide information to help those who are most likely to develop a uterovaginal prolapse. This study also had limitations. Due to its inherent nature, associations could only be made from the analysis of the data, and no cause and effect could be firmly established. It is also subject to recall bias. Besides, the wider confidence intervals due to the small number of cases in some variables might affect the precision of association in these variables.