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Year : 2022  |  Volume : 9  |  Issue : 2  |  Page : 135-140

Estimation of maternal mortality ratio with sisterhood method in six local government areas of Oyo State, Nigeria

1 Research Department, African Health Project, Abuja, Nigeria
2 Department of Public Health, Triune Biblical University Global Extension, New York, USA
3 Obstetrics and Gynecology Department, Kogi State University Teaching Hospital, Anyigba, Kogi State, Nigeria
4 Microbiology Department, National Institute for Pharmaceutical Research and Development, Idu, Abuja, Nigeria

Date of Submission20-Oct-2021
Date of Acceptance29-Mar-2022
Date of Web Publication17-Jun-2022

Correspondence Address:
Dr. Felix O Sanni
Department of Public Health, Triune Biblical University Global Extension, New York
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/mgmj.mgmj_80_21

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Background: The reduction of maternal mortality rate has been the top priority of global health, yet its persistently high rate in Africa is a severe issue that requires the attention of both the individual and policymakers. Objective: To determine the maternal mortality rate by applying the sisterhood method in six local government areas in Oyo State. Materials and Methods: The indirect sisterhood method was used to collect data concerning maternal mortality. For study purposes, the data were collected from women in the reproductive age group between 15 and 49 years using a structured questionnaire. Statistical Package for the Social Sciences version 25.0 software was used for analyzing the collected data. Results: It has been observed that the average maternal mortality rate in the six local government areas was 489/100,000 live births ranging from 346 to 756/100,000 live births. The highest maternal mortality rate was found in Iseyin local government area (756/100,000 live births), followed by 586/100,000 from Saki, 444 from Ibadan North, 430 from Ogbomosho, 374 from Atiba, and the least value of 346/100,000 live births in Ibadan North local government area. Conclusion: The maternal mortality rate has been found lower than the previous studies but still unacceptably high, especially among adolescents aged 15–39 years. Therefore, it is advocated that policymakers employ appropriate interventions such as the release of more funds for standard family planning and childbirth spacing programs to minimize maternal mortality in the state.

Keywords: Live births, maternal death, mortality ratio, pregnancy

How to cite this article:
Onoja AJ, Sanni FO, Akogu SP, Onoja SI, Adamu I, Yaaba YO. Estimation of maternal mortality ratio with sisterhood method in six local government areas of Oyo State, Nigeria. MGM J Med Sci 2022;9:135-40

How to cite this URL:
Onoja AJ, Sanni FO, Akogu SP, Onoja SI, Adamu I, Yaaba YO. Estimation of maternal mortality ratio with sisterhood method in six local government areas of Oyo State, Nigeria. MGM J Med Sci [serial online] 2022 [cited 2022 Oct 1];9:135-40. Available from: http://www.mgmjms.com/text.asp?2022/9/2/135/347705

  Introduction Top

It is estimated that over 820 women die daily from preventable pregnancy and childbirth-related causes. Many more women are injured, infected, or face other childbirth-related complications.[1] In 2013, there were an estimated 289,000 maternal deaths and a maternal mortality ratio (MMR) of 210 maternal deaths per 100,000 live births worldwide.[1] The struggle against maternal mortality has witnessed a significant reduction in many parts of the world in the last three decades, yet it remains a major public health challenge, especially in Africa and Asia. Maternal deaths in Africa reduced by about 41% between 1990 and 2010, yet about 57% of all maternal deaths still occur in Africa, thereby placing the African continent in the top MMR in the world.[1] MMR varies from country to country, and Nigeria is ranked number four in the world with 917 (500–999) behind South Sudan, Chad, and Sierra Leone, all in Africa.[2],[3] The lifetime risk of an African woman dying a maternal death is estimated at one in 39, while it is one in 4,700 in the industrialized world.[1] This is unacceptably high, which poses a very serious challenge to Africa and demands the attention of all stakeholders to reduce this high MMR.

Compared with developed countries, Africa is characterized by many physical, economic, social, and psychological challenges, specifically in rural communities: scattered, inadequate health infrastructure, shortage of qualified healthcare personnel, poor transportation and awareness, and low levels of income and poor educational background. All these conditions need to be understood to improve the enablement of accurate directing of interventions to reduce maternal mortality to minimum levels.[4]

The reduction of maternal mortality has been the priority of global health and a major concern in the United Nations Sustainable Development Goal 3[5] and a major concern of the Global Strategy for Women’s and Children’s Health started by the UN Secretary General in 2010.[6] Several studies have documented MMR in different parts of Nigeria, ranging from 208 to 1,400 per 100,000 live births[7],[8],[9],[10],[11],[12],[13],[14] with few studies in Oyo State, which recorded 963/100,000 live births[15] and 262/100,000 live births.[16] The studies conducted in Oyo State were hospital-based studies, which might not account for the cases not presented in the hospital. This study aimed at estimating the MMR in six local government areas (LGAs) of Oyo State using the sisterhood method. The study involved both the easy-to-reach and the hard-to-reach areas. This method helps capture deaths related to pregnancy complications that are not presented in the hospital, particularly in the hard-to-reach areas where there are poor health facilities.

  Materials and methods Top

Study population

Oyo State popularly referred to as the “Pace Setter” is one of the constituent 36 states of the Federal Republic of Nigeria. It came into existence with the breakup of the old Western State of Nigeria during the state creation exercise on February 3, 1976. Oyo State is located in the South-West region of Nigeria. Latitude 8° and longitude 4° East bisect the State into four nearly equal parts. The State now covers a total of 27,249 square kilometers of landmass. The State is divided into three senatorial districts: Oyo North, Oyo Central, and Oyo South. Oyo North has 13 local governments, of which six were surveyed. The local governments studied in Oyo State are Atiba, Ibadan North East, Ibadan South East, Iseyin, Ogbomoso North, and Saki. The study design was similar to the entire study.

Study design and sampling method

The study was a cross-section that employed a descriptive survey to obtain information on both maternal deaths and deaths from other causes, involving the respondent’s sisters. A probability sampling technique was employed by collecting data related to maternal mortality using the indirect sisterhood method from women of reproductive age 14–49. Ten wards were selected from each of the six local governments surveyed. Twenty communities or clusters were also selected in each of the wards using a probability sampling method. A supervisor was appointed in each of the six LGAs to communicate with the community and local government leaders who provided guides and ensured the involvement of the primary healthcare managers that helped in community identification processes, and easy and efficient sampling. A structured questionnaire was used to collect data from women of reproductive age. Data were inputted and analyzed using SPSS version 25.0 software.

Sample size

Based on the assumption of 45% maternal deaths and 5% tolerable error, the estimated minimum sample size was 1,000 respondents from each of the six local governments (which were the selected local government). Also, 10% of the sample size was added for likely nonresponse (10% of 1,000 is 100, which was added to sort for any error, incomplete, or declined responses); this stands as a cluster sampling design effect. Therefore, the estimated minimum sample size was 1,100 from each of the six LGAs, making an estimated total minimum sample size of 6,600.

Data collection

Trained officers and staff of the African Health Project were employed in data collection using a structured questionnaire. The data collectors were selected based on predetermined academic performances and experience criteria. The questionnaire was pretested on the fields before the final administration. Supervisors and consultants were employed to provide support for the data collectors and to ensure that the data collected were quality and uncompromised. The data collection process lasted for 2 weeks in March 2017 with daily team meetings for updates and reviews of the research processes. Data were collected from 2017 because there were no recent data, which further shows the need for this study to help future studies.

Data analysis

Data collected were inspected and inputted into SPSS version 25.0 software by trained data entry clerks. The data manager was appointed to supervise data entry and to actively participate in the data entry process. Descriptive statistics were performed, and adjusted factors and lifetime risk of dying a maternal death were calculated.

The MMR was calculated using a standard set of questions established in previous studies.[9],[14],[17] Such questions include “the number of respondent’s maternal sisters, ever attained age 15 or ever married, including the living and the dead, applying the equation below to calculate the MMR (deaths per 100,000 live births).”[9]

Probability of survival = 1−Σri/ΣNiAi,[18] where ri = number of maternal deaths, Ni = number of ever-married sisters, and Ai = adjustment factor. The probability of survival was calculated from the inverse of the lifetime risk of dying. From that, MMR was calculated using the formula: MMR = 1−(probability of survival)1/TFR,[18] where TFR = total fertility rate.

Ethical issue

The approval to conduct the study was received from the National Health Research Ethics Committee (NHREC) of the Federal Ministry of Health (NHREC/01/03/2017–20/03/2017). The study protocol was clearly explained to the respondents, and the confidentiality of their data was assured. Signed consents were obtained from the respondents before they were included in the study.

  Results Top

The results of the survey are presented in this section. The average maternal mortality in the six local governments was 489/100,000 live births with a range of 346–756 per/100,000 live births. In all six local governments, the highest number of respondents was between the ages of 30–34. In Atiba LGA, there were 1,915 respondents with a total of 4,845 ever-married sisters and a total of 368 deaths, of which 67 (18.2%) were maternal deaths. Sister unit of risk of exposure was highest among women in the age group 30–34 years (722.8), while the lifetime risk of dying a maternal death was highest among those aged 20–24 (0.12). The MMR in Atiba LGA was 374 per 100,000 live births as shown in [Table 1].
Table 1: Maternal mortality ratio in Atiba local government area, Oyo State

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The 1,927 respondents in Ibadan North had 4.974 sisters who have ever married with a total of 398 deaths, 66 (16.6%) of which were maternal deaths. The highest risk of exposure (682.05) was also found within the age group 30–34 years, while the lifetime risk of dying a maternal death was highest (0.12) among women of age 20–24 years [Table 2]. The MMR was estimated as 346 per 100,000 live births.
Table 2: Maternal mortality ratio in Ibadan North local government area, Oyo State

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The MMR in Ibadan North was 444 per 100,000 live births. This was estimated from 2,107 respondents who had 5,161 ever-married sisters. The maternal death in this LGA was 84, which is 21.3% of the total death of 393. The highest lifetime risk of dying a maternal death was 0.14 found within the age group 20–24, while the highest risk of exposure (637.3) was found among women in the age group 30–34 [Table 3].
Table 3: Maternal mortality ratio in Ibadan South local government area, Oyo State

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In Iseyin LGA, the total number of respondents was 957. These respondents had 2,250 sisters that have ever married, of which 217 have died. There were 61 (28.1%) maternal deaths with a sister risk of exposure of 1116.6 and a total lifetime risk of 0.05. Ages 20–24 had the highest lifetime risk of dying a maternal death of 0.23, while the MMR was estimated as 756 per 100,000 live births [Table 4].
Table 4: Maternal mortality ratio in Iseyin local government area, Oyo State

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The maternal mortality rate in Ogbomosho local government was 430 per 100,000 live births. There were a total of 1,707 respondents in this LGA with 4,063 ever-married sisters, 317 deaths, and 64 (20.2%) maternal deaths. The highest unit of risk of exposure (541.2) was found among women of age 30–34 years, while the highest lifetime risk of dying a maternal death of 0.16 was found within age 20–24 years [Table 5].
Table 5: Maternal mortality ratio in Ogbomosho local government area, Oyo State

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There were 2,305 respondents to Saki LGA with 5,430 ever-married sisters and 466 deaths, of which 117 (25.1%) were maternal deaths. The highest risk of exposure (589.0) and lifetime risk of dying a maternal death (0.20) were found in age 30–34 and 15–19 years, respectively. The MMR in this LGA was 586 per 100,000 live births [Table 6].
Table 6: Maternal mortality ratio in Saki local government area, Oyo State

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  Discussion Top

This study found high rates of MMR in the six LGAs from a minimum of 346/100,000 live births in Ibadan North to 756 found in Iseyin LGA with an average MMR of 489/100,000 live births. The average MMR found in this study is slightly lower than the estimated average of 917/100,000 live births in Nigeria in 2017.[2] The difference between this study and the MMR reported for Nigeria was that although this study accounted for six LGAs in Oyo State, the UNICEF survey was an average representative of MMR in Nigeria.

The average MMR found in this study is lower than 963/100,000 live births found in a study conducted about a decade ago[15] and slightly higher than 262/100,000 live births reported in a recent study.[16] However, the current values are still unacceptably high and can be attributed to “weak implementation of the family planning/child spacing programs at the state and local government levels due to insufficient funds,” a shortage of medical personnel in the State as compared to other states.[16] This calls for more interventions in minimizing maternal mortality in the State. Comparing the MMR values found in this study to findings in some other parts of Southwest, Nigeria, the average MMR found in this study is closely related to 208 and 381 reported in Ondo State in the same year.[7],[19]

Studies from other parts of the country show higher MMRs than the current study. For instance, the MMR of 1,400 per 100,000 live births was found in two different studies conducted in three LGAs in 2010[9] and in two LGAs of Kaduna State, northwestern Nigeria in 2019.[14] There is a significant decline of about 49.2% (963 in 2010 to 489 in 2017), unlike in the North where the MMR remained the same for almost a decade.[9],[14] Several other studies from the North have also reported higher MMR than found in this study. These include 2,849/100,000 deliveries found in Nguru, Borno State from 2003 to 2007[20] and 1,732 per 100,000 live births obtained in Bauchi, North-East, Nigeria.[12] Previous studies conducted in South-South, Nigeria also found higher MMR than the value found in this study; in Benin, Edo State, South-South, Nigeria, MMR was reported as 2,356/100,000 deliveries.[21] A study conducted in Enugu State, South-East also found MMR of 840/100,000 live births.[8]

The highest lifetime risk of dying a maternal death in this study was among young adults aged 20–24, and the sister unit of exposure was found higher among middle-aged women aged 30–34 years. These findings are in agreement with previous studies.[9],[14],[22] Studies have shown that young women aged 10–24 years are at higher risk of maternal mortality and pregnancy complications than other age groups.[3],[23],[24] This result may also be due to early marriage among teenagers, lacking the experience, care, and overall capacity to carry out the roles of a mother. It might also be due to poor access to standard family planning services, especially in rural and hard-to-reach areas as reported in previous studies.[16] High maternal mortality seen among women in this study might also be due to a high number of pregnancies among women in less-developed countries than women in industrialized countries, which is responsible for higher lifetime risk of death due to pregnancy.[3] Factors such as poverty, unemployment, and irresponsibility may play a role, as poor, unemployed, and irresponsible couples may have more time to make babies they have no plans for, putting their health and their neonate at risk.[3]

  Conclusion Top

This study found reduced maternal mortality rates in Oyo State compared with previous studies, yet the maternal mortality rate found in this study is still unacceptably high, especially among adolescents aged 15–39 years. Therefore, it is advocated that more funds be appropriated for standard family planning and childbirth spacing programs. This should also be backed up with legislative laws for the provision of free comprehensive maternal and child health services across the State.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

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Olopade FE, Lawoyin TO Maternal mortality in a Nigerian maternity hospital. African J Biomed Res 2008;11:267-73.  Back to cited text no. 15
Adebayo M Health: How Oyo loses 262 women out of 100,000 expectant mothers. Daily Post Nigeria published on November 18, 2017. Available from: https://dailypost.ng/2017/11/18/oyo-loses-262-women-100000-expectant-mothers/. [Last accessed on February 15, 2022].  Back to cited text no. 16
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  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]


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