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Year : 2019  |  Volume : 21  |  Issue : 2  |  Page : 62-66

Estimation of maternal mortality by sisterhood method in two rural communities in Kaduna State, Nigeria

1 Department of Community Medicine, College of Medicine, Kaduna State University, Kaduna, Nigeria
2 Department of Community Medicine, Aminu Kano University Teaching Hospital/Bayero University, Kano, Nigeria
3 Department of Community Medicine, College of Medicine, Usman Dan Fodio University Teaching Hospital, Sokoto, Nigeria

Date of Submission25-Oct-2018
Date of Decision03-Jun-2019
Date of Acceptance28-Jun-2019
Date of Web Publication13-Dec-2019

Correspondence Address:
Nafisat Ohunene Usman
Department of Community Medicine, College of Medicine, Kaduna State University, Kaduna
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jomt.jomt_34_18

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Background: One of the sustainable development goals is reducing the global maternal mortality burden with maternal mortality ratio (MMR) being one of the indicators to track the progress. Unfortunately, there is paucity of MMR data, especially at subnational levels. Standard household survey methods used in maternal mortality estimation are very resource intensive. The indirect sisterhood method offers a cheaper alternative. Although the results may be retrospective and not very useful in tracking progress, it provides useful information for advocacy. Objective: This article determines the proportion of deaths that was due to maternal causes, lifetime risk of maternal death, and MMR in two rural communities in northwestern Nigeria. Methodology: The indirect sisterhood method for estimation of maternal mortality was used to collect information from a sample of 1905 women within the reproductive age group in two rural communities, in Kaduna state, northwestern Nigeria. Results: There were a total of 416 deaths among ever married sisters of the respondents, of which 50% were due to maternal causes. The lifetime risk of maternal death is one in 11, whereas the MMR was 1400 per 100,000 live births. Conclusion: The maternal mortality indicators in these two communities are higher than the national rates and this underscores the need for the generation of subnational data and the scaling up of maternal mortality indicators. It also underpins the need to focus on social determinants like maternal education and early marriage in the course of reducing maternal mortality.

Keywords: Maternal mortality, northwest nigeria, rural community, sisterhood method

How to cite this article:
Usman NO, Abdullahi HM, Nmadu AG, Omole VN, Ango JT. Estimation of maternal mortality by sisterhood method in two rural communities in Kaduna State, Nigeria. J Med Trop 2019;21:62-6

How to cite this URL:
Usman NO, Abdullahi HM, Nmadu AG, Omole VN, Ango JT. Estimation of maternal mortality by sisterhood method in two rural communities in Kaduna State, Nigeria. J Med Trop [serial online] 2019 [cited 2023 Feb 5];21:62-6. Available from:

  Introduction Top

Maternal mortality that refers to the death of a woman during pregnancy, childbirth, or within 42 days after birth[1] remains a major global health problem with countries in sub-Saharan Africa and South Asia being the worst affected.[2] It is unfortunate that the countries with the highest burden have made the least progress toward preventing maternal mortality.[3] It is the health indicator showing the highest disparity between developed and developing countries with 99% of maternal death occurring in developing countries.[2] Despite some concerted efforts to address this largely preventable problem, maternal mortality is still a major challenge in resource-poor settings like Nigeria. The maternal mortality ratio (MMR) in Nigeria is 814 per 100,000 live births that implies that one woman dies every 10 minutes from causes related to pregnancy or childbirth.[4] This figure is a national average and does not reflect the regional disparities across the country. Zones like the north-east and north-west have higher MMRs of 1549 and 1026, respectively.[5] This disparity reflects inequities in access to health services and highlights the cultural and socioeconomic dissimilarities.[2]

The causes of maternal death include the direct and indirect medical causes together with nonmedical causes that include socioeconomic, religious, cultural and legal factors, reproductive health factors, and health systems/health services factors.[6] Maternal death mainly occurs due to complications during and following pregnancy and childbirth. These complications include postpartum and antepartum hemorrhage, infections, preeclampsia, eclampsia, unsafe abortions, and others.[2] A study in Kano observed that eclampsia, ruptured uterus, and anemia were responsible for about 50% of maternal deaths in the area.[7] Despite this, maternal health services are still greatly underutilized likely due to poor educational status, low socioeconomic status, geographical barriers, etc.[8] The Nigerian healthcare system is poorly developed and, as such, it lacks adequate and functional surveillance systems.[9] Consequently, maternal and child healthcare are inadequate and inequitably distributed. There is paucity of data on maternal mortality due to poor documentation of the pregnancy status of the woman at the time of death.[10] This can be particularly difficult to obtain in low-income settings where vital statistics are often incomplete or do not exist. Estimates are frequently based on hospital data, which often do not reflect the maternal risk within communities.[10] In spite of the difficulty faced in measuring maternal mortality, monitoring of maternal death is still of utmost importance. Estimates of maternal mortality are essential for planning and monitoring the outcomes or impact of maternal health interventions.[11]

The sisterhood method is an indirect technique for deriving population-based estimates of maternal mortality in high-fertility populations.[12] The adult respondents are asked four questions about the survival of all their adult sisters born to the same mother. The method reduces the need for large sample sizes because there may be more than one respondent per household, more than one sister per respondent, and the time period of death that is not restricted.[12] Minimal time is required to carry out this method. However, data collection procedures for this method are retrospective (a period of about 10–12 years before the survey) and therefore cannot be used to measure progress but data obtained can be used for advocacy purposes and to stimulate greater awareness.[11]

This study aims to use the indirect sisterhood method to estimate the MMR, the percentage of death due to maternal causes, and the lifetime risk of maternal death in two rural communities in Kaduna state, in an effort to provide credible data that will inform local maternal and newborn healthcare improvement.

  Materials and methods Top

Study setting

This survey was carried out in two rural areas in Kaduna State, namely Richifa and Kwasallo wards of Soba Local Government Area (LGA) of Kaduna State. The total fertility rate of this region is 6.7 with the median age at first birth being 17.9 years.[13] The languages spoken here are Hausa and Fulfulde. Most of the people are farmers and traders. The wards have health posts and primary health centers. There is a general hospital about 25 km away.

Study design and population

It was a cross-sectional descriptive survey to estimate the MMR among women of reproductive age in two rural communities in Soba LGA. The respondents were permanent residents of the study areas. A total of 1905 respondents were randomly selected after a line listing was done of all households in the communities. There were 860 households in Kwasallo and 1107 households in Richifa. One female of reproductive age was randomly selected from each household.

Data collection

Data were collected from a total of 1905 women of reproductive age using a structured questionnaire translated to Hausa, the local language, focused on maternal and child health. There were 10 Hausa-speaking research assistants who collected data using paper-based questionnaires over 12 days. The questionnaire also included the four standard indirect Sisterhood Method questions to estimate MMR in the state. The specific questions included were as follows: (1) How many sisters (born to the same mother) have you ever had who reached the age of 15 (including those who are now dead)? (2) How many of these sisters are alive now? (3) How many of these sisters are dead? (4) How many of the dead sisters died during pregnancy, labor, or within 42 days after delivery. It should be noted that the term sister “born to the same mother” was used to help to forestall some of the ambiguities in the term “sister” which in some populations may be used to refer to a wide variety of relations.

Data processing and analysis

Data collected were entered, validated, and analyzed using Statistical Package for Social Sciences (SPSS, IBM Corporation, IL, USA) software version 21. Descriptive statistics were conducted using frequencies and proportions. Total fertility rate, lifetime risk, and MMR were calculated. The overall lifetime risk of dying of maternal causes was calculated using the following formula:

q (w) = ∑ri/∑Bi

where ri equals the number of maternal deaths and Bi is the “sister units of risk of exposure” that is the number of ever married sisters multiplied by the adjustment factor. The adjustment factor is a constant, reported in the standard guidelines for the sisterhood method calculations.[12] To convert this to the more conventional measure of maternal mortality, the MMR (deaths per 100,000 live births), the probability of survival was calculated from the inverse of the lifetime risk of dying.

Probability of survival = 1−∑ri/∑Bi

From that, MMR was calculated using the following formula:

MMR = 1−(probability of survival) 1/TFR

Ethical consideration

Approval to carry out this study was obtained from the Research and Ethics Committee of Ahmadu Bello University Teaching Hospital. Permission to conduct the study was also sought from the Soba LGA authorities and the ward heads of the study communities. The study participants were informed about the purpose of the study and also that they could voluntarily withdraw from the study at any time. Written and verbal consent was obtained from all the participants before the questionnaires were administered to them.

  Results Top

A total of 1905 female respondents within the reproductive age group participated in the study. All the respondents were Muslims and 96.1% of them were Hausa. Regarding the level of education, 47.9% of the respondents had Quranic education whereas only 0.9% had up to tertiary level of education [Table 1]. There were a total of 416 deaths among ever married sisters of the respondents, of which 50% were due to maternal causes. The lifetime risk of maternal death is one in 11, whereas the MMR was 1400 per 100,000 live births [Table 3].
Table 1: Sociodemographic characteristics (n = 1905)

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Table 2: ASFRs of the respondents

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Table 3: Analytical framework used to estimate maternal mortality and lifetime risk of maternal death

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  Discussion Top

This survey showed that the MMR was 1400 maternal deaths per 100,000 live births, which is similar to other results obtained from the previous studies in this subregion. This is higher than the national estimates of 576 maternal deaths per 100,000 live births that used the same method.[13] This disparity is likely due to the fact that this (national) result was not disaggregated to highlight subregional differences.[13] The results are consistent with two other studies of MMR estimated by the sisterhood method in northern Nigeria. The first study reported an MMR of 1400 maternal deaths per 100,000 live births in three communities in Zaria, Kaduna State.[14] The second study estimated a MMR of 1271 maternal deaths per 100,000 live births in four states in northern Nigeria (Zamfara, Jigawa, Katsina, and Yobe).[11]

Despite the fact that most maternal deaths are preventable with well-known healthcare solutions to prevent or manage complications, maternal mortality is still a major challenge in developing countries like Nigeria. Regardless of the fact that the result obtained is retrospective, it is still unacceptably high in view of the fact that there have been several effective, evidence based, inexpensive interventions set up to prevent maternal mortality such as the integrated maternal, newborn, and child strategy and safe motherhood initiative.

Maternal deaths accounted for 50% of the deaths reported in this study among the respondents’ sisters. This could be due to the fact that women in this area, more often than not, deliver at home without a skilled birth attendant.[13] This could also point to the fact that the health facilities in these areas were understaffed, underutilized, and ill-equipped.[15] The largest proportion of respondents (47.9%) had received only Quranic education, with only 0.9% attaining tertiary level education. This is not entirely unusual for rural areas in this region.[13] However, if this low educational level of these respondents is similar to those of their deceased sisters, it will imply that illiteracy was a contributory factor to their demise. Previous studies have shown that there is a relationship between maternal education and maternal mortality, with maternal literacy being a predictor for maternal mortality.[16],[17],[18] A World Health Organization global survey observed that women with no education and those with between 1 and 6 years of education had 2.7 times and 2 times, respectively, the risk of maternal mortality relative to women with more than 12 years of education. This included those with access to health facilities providing intrapartum care.[19] Educated women are more likely to adopt simple and low-cost practices to maintain hygiene, respond to symptoms such as bleeding or high blood pressure, and access the information on abortion and place of abortion, and more willing to accept treatment and birth attendance.[19] Female education may plausibly cause declines in maternal mortality.

  Conclusion Top

Motherhood is expected to a joyful and gratifying experience; however, for a lot of women in developing countries, this is not the case. This study showed that the estimate of MMR among women in this community was unacceptably high and social determinants for maternal mortality like early marriage and poor educational status were prevalent. More emphasis should be given to the wider social determinants of health when devising strategies to reduce maternal mortality and to achieve the sustainable development goals (SDG) for maternal mortality.


The authors wish to express their gratitude to the Soba LGA Chairman and ward heads of Richifa and Kwasallo wards for their support and cooperation. They would also like to thank the research assistants for their time and effort. Finally, they wish to thank the women for consenting to participate in this study.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

WHO. Maternal mortality ratio (per 100 000 live births) [Internet]. 2014. Available at [Accessed October 10, 2018]  Back to cited text no. 1
Blencowe H, Cousens S, Jassir FB, Say L, Chou D, Mathers C et al. National, regional, and worldwide estimates of stillbirth rates in2015, with trends from 2000: a systematic analysis. Lancet Glob Health 2016;4:e98-108.  Back to cited text no. 2
WHO. The safe motherhood initiative and beyond [Internet]. 2011. Available at [Accessed October 20, 2018]  Back to cited text no. 3
WHO, UNICEF, UNFPA WBG and U and UNPD. Nigeria: maternal mortality in 1990-2015. Lancet 2015;(15):838-7.  Back to cited text no. 4
Mother, newborn and child health and mortality in nigeria-general facts [Internet]. Available at [Accessed October 10, 2018]  Back to cited text no. 5
Society of Gynaecology and Obstetrics of Nigeria. B-D, Adinma E. Trop J Obstet Gynaecol [Internet]. Vol. 28, pp. 5-13. Available at [Accessed October 18, 2018]  Back to cited text no. 6
Adamu YM, Salihu HM, Sathiakumar N, Alexander GR. Maternal mortality in Northern Nigeria: a population-based study. Eur J Obstet Gynecol Reprod Biol 2003;109:153-9.  Back to cited text no. 7
McNamee P, Ternent L, Hussein J. Barriers in accessing maternal healthcare: evidence from low-and middle-income countries. Expert Rev Pharmacoecon Outcomes Res 2009;9:41-8.  Back to cited text no. 8
Welcome MO. The Nigerian health care system: need for integrating adequate medical intelligence and surveillance systems. J Pharm Bioallied Sci 2011;3:470-8.  Back to cited text no. 9
Sharma V, Brown W, Kainuwa MA, Leight J, Nyqvist MB. High maternal mortality in Jigawa State,Northern Nigeria estimated using the sisterhood method. BMC Pregnancy Childbirth 2017;17:163.  Back to cited text no. 10
Doctor HV, Findley SE, Afenyadu GY. Estimating maternal mortality level in rural Northern Nigeria by the sisterhood method. Int J Popul Res 2012;2012:1-5.  Back to cited text no. 11
Graham W, Brass W, Snow RW. Estimating maternal mortality: the sisterhood method. Stud Fam Plann 2006;20:125-35.  Back to cited text no. 12
NDHS. Nigeria Demographic and Health Survey 2013. Natl Popul Comm Fed Repub Niger [Internet]. 2014;1-400. Available at  Back to cited text no. 13
Idris H, Tyoden C, Ejembi C, Taylor K. Estimation of maternal mortality using the indirect sisterhood method in three communities in Kaduna State, Northern Nigeria Résumé [Internet]. Afr J Reprod Health 2010;14(Special Issue). Available at [Accessed October 18, 2018]  Back to cited text no. 14
Abdulraheem I, Olapipo AR, Amodu MO. Primary health care services in Nigeria: critical issues and strategies for enhancing the use by the rural communities. J Public Heal Epidemiol 2012;4:5-13.  Back to cited text no. 15
Mcalister C, Baskett TF. Female education and maternal mortality: a worldwide survey. J Obstet Gynaecol Canada 2006;28. Available at [Accessed October 20, 2018]  Back to cited text no. 16
Bhalotra S, Clarke D. Background paper prepared for the Education for All Global Monitoring Report 2013/4 teaching and learning: achieving quality for all. Educational Attainment and Maternal Mortality [Internet]. 2014. Available at [Accessed October 20, 2018]  Back to cited text no. 17
Pillai VK, Maleku A, Wei F. Maternal mortality and female literacy rates in developing countries during 1970-2000: a latent growth curve analysis. Int J Popul Res 2013;2013:1-11.  Back to cited text no. 18
Karlsen S, Say L, Souza J-P, Hogue CJ, Calles DL, Gülmezoglu AM et al. The relationship between maternal education and mortality among women giving birth in health care institutions: analysis of the cross sectional WHO Global Survey on Maternal and Perinatal Health. BMC Public Health 2011;11:606.  Back to cited text no. 19


  [Table 1], [Table 2], [Table 3]


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