Background: Maternal mortality remains a major problem in many parts of the world including Nigeria.Understanding the causes of maternal mortality is crucial in confronting the challenge of unyielding high rates. The aim of this study was to determine the direct and indirect causes of maternal mortality in Lagos State, Nigeria. Materials and Methods: The study is a descriptive cross-sectional survey. The study population consisted of adults residing in Lagos State, Nigeria. The sample size used for this study was 29,988. The respondents were selected by multistage sampling from all the local government areas in the state. Data were collected using a structured interviewer-administered questionnaire. Data entry, cleaning, validation and analysis were done using Statistical Package for Social Sciences version 15.0. Results: Among the 29,988 respondents, 306 (1.0%) gave a history of married sisters who died during pregnancy, childbirth or during the postpartum period. Of the 306, 138 (45.1%) died during pregnancy; 107 (34.9%) died during childbirth, and 61 (19.9%) died during the postpartum period. Abortion, ectopic pregnancies and hypertension were the most commonly mentioned cause of death during pregnancy, while anemia, prolonged labor and obstructed labor were the common causes during childbirth. Human immunodeficiency virus/acquired immunodeficiency syndrome , infection and malaria were the common causes of maternal death during the 6 weeks after end of pregnancy/childbirth. Conclusions and Recommendation: Over half of the maternal deaths in Lagos State occurred during labor and immediately postpartum. Community education on the importance of having skilled attendants at delivery must be provided. Emergency obstetric care should be available, accessible and affordable at health facilities, and efforts must be made to prevent unwanted pregnancies and unsafe abortions by increasing contraceptive use. The malaria control efforts should be intensified.
Keywords: Childbirth, maternal mortality, postpartum, pregnancy
In the year 2000 member countries of the United Nations agreed on 8 millennium development goals (MDGs) to improve the health and socio-economic wellbeing of the people in their countries in the 21 st century. MDG 5 – to improve maternal health – set a target of reducing maternal mortality by three-fourth by 2015 (Target 5.A). Unfortunately, of all the MDGs, MDG 5 has made the least progress. ,, The number of women dying due to complications during pregnancy and childbirth decreased by 34% from 1990 to 2008.The progress is notable, but the annual rate of decline is less than half of what is needed to achieve the MDG target. This will require an annual decline of 5.5%. The 34% decline since 1990 translates into an average annual decline of just 2.3%. 
A woman dies every 90 s from complications of pregnancy – over 500,000 every year. Majority (90%) of these deaths are preventable. , A total of 99% of all maternal deaths occurs in developing countries, where 85% of the population lives. More than half of these deaths occur in sub-Saharan Africa. The maternal mortality ratio in developing countries is 450 maternal deaths/100,000 live births versus 9 in developed countries. , A woman in sub-Saharan Africa has a 1 in 16 chance of dying in pregnancy or childbirth, compared to a 1 in 4000 risk in a developed country – the largest difference between poor and rich countries of any health indicator.  Different interactive factors contribute to maternal mortality. The range is wide and includes the behavior of families and communities, social status, education, income, nutritional status, age, parity, and availability of health services. Non health sector activities, such as education, water and sanitation, roads and communication, agriculture, and internal security, also influence maternal outcome. In sub-Saharan Africa, some of the highest MMRs have been recorded in countries that are in conflict or have large refugee populations. 
Women die from a wide range of complications in pregnancy, childbirth or the postpartum period. Most of these complications develop because of their pregnant status, and some because pregnancy aggravated an existing disease. The five major killers are: Severe bleeding, infections, hypertensive disorders in pregnancy (eclampsia), obstructed labor and complications following unsafe abortion. , Globally, about 80% of maternal deaths are due to these causes and every day, about 1000 women die due to them. Among the indirect causes (20%) of maternal death are diseases that complicate pregnancy or are aggravated by pregnancy, such as malaria, anemia and human immunodeficiency virus (HIV). Women also die because of poor health at conception and a lack of adequate care needed for the healthy outcome of the pregnancy for themselves and their babies. 
Maternal mortality remains a severe problem in many parts of the world, despite efforts to reach MDG 5.  More than two decades into the war against maternal deaths, Nigeria still has one of the worst maternal mortality statistics in the world and is second only to India in the global estimates of maternal mortality.  The maternal mortality ratio in Nigeria is estimated to be 545/100,000 live births.  The maternal mortality rates in Nigeria vary in the regions and states of the country and are higher in the rural areas than the urban areas. Lagos State that is one of the most urban states in the country has an estimated maternal mortality ratio of 450/100,000 live births.  The majority of these maternal deaths, as in the rest of the world, are preventable, while the causal factors can be multiple and complex.
Understanding the causes of maternal mortality is crucial in confronting the challenge of unyielding high rates in sub-Saharan Africa. Knowledge about the causes of the problem will inform and guide strategies to address the problem.  The Nigerian and state government have adopted several policies aimed at reducing maternal mortality.  However, without details on the causes of mortality, it is difficult to identify effective strategies for curbing it. The aim of this study was to determine the direct and indirect causes of maternal mortality in Lagos State. This provides data which can be used to guide programming on safe motherhood and develop effective interventions to improve the quality of maternal health care as we work towards ending the many needless deaths occurring among women of childbearing age in Nigeria.
Lagos State is located in the South-western part of Nigeria. It is one of the most populous states in Nigeria and has the nation’s largest urban area. Lagos State is divided into 20 local government areas (LGAs).
The study is a descriptive cross-sectional survey. The study population consisted of adults residing in Lagos State, Nigeria.
Sampling size and method
The sample size used for this study was 29,988. The respondents were selected by multistage sampling from all the LGAs in the state. Each LGA is made up of enumeration areas (EAs). Three EAs were selected from each LGA by simple random sampling (using the table of random numbers). Streets were selected by balloting, and identified on the maps of the EAs. Respondents were consecutively recruited from households on selected streets. Where a household had more than one eligible respondent, one respondent was selected by balloting.
Data collection and management
Data were collected using a structured interviewer-administered questionnaire. The questionnaire consisted of the four standard questions used in the indirect sisterhood method for estimating maternal mortality plus questions on the cause of reported deaths. Respondents were asked about how many sisters they had, how many of their sisters reached adulthood, how many died, whether those who died were pregnant around the time of death and the cause of death. All the interviewers used are skilled in taking medical history. The respondents gave a description of the circumstances surrounding the death of their sisters. Data entry, cleaning, validation and analysis were done using Statistical Package for Social Sciences (SPSS) is manufactured by IBM.
Ethical approval was obtained from Ethical Research Committee of the Lagos University Teaching Hospital, Idi-Araba, and Lagos. Informed consent was obtained from all respondents.
There was a total of 29,988 respondents. Their mean age was 31.5 ± 9. 4 years. About two-fifth of the respondents (41.9) had completed secondary education. Those who had no formal education constituted 7.3% of the study population. Majority of the respondents (64.8%) were married. There were more Christians (67.0%) than Moslems (31.3%).
Among the 29,988 respondents, 306 (1.0%) gave a history of married sisters who died during pregnancy, childbirth or during the postpartum period. Of the 306 who died, 138 (45.1%) died during pregnancy, 107 (34.9%) died during childbirth, and 61 (19.9%) died during the postpartum period. Abortion, ectopic pregnancies and hypertension were the most commonly mentioned cause of death during pregnancy, while anemia, prolonged labor and obstructed labor were the common causes during childbirth. HIV/acquired immunodeficiency syndrome (AIDS), infection and malaria were the common causes of maternal death during the postpartum period [Table 1],[Table 2] and [Table 3].
In sub-Saharan Africa, about 60% of the maternal deaths occur during childbirth and the immediate postpartum period, with 50% of these deaths occurring within the first 24 h of delivery.  Similarly in this study, the greatest proportion (45.1%) of deaths were reported to have occurred during pregnancy and 54.6% during childbirth and the postpartum period. A previous study done in Lagos State had also found that 31.5% of deaths occurred during pregnancy while 68.4% occurred during delivery and the postpartum period.  The majority of these deaths and disabilities are preventable. Crucial to preventing avoidable maternal deaths is quality maternal health care that is accessible to all women.  About 15% of pregnancies and childbirths need emergency obstetric care because of complications that are difficult to predict. Access to skilled care during pregnancy, childbirth and the 1 st month after delivery is key to saving these women’s lives.  In Nigeria, only 58% of women receive some antenatal care from a skilled provider and about one-third of births occur in health facilities. 
In this study, abortion, ectopic pregnancies and hypertension were the most commonly mentioned cause of death during pregnancy, while anemia, prolonged labor and obstructed labor were the commonest causes during childbirth and HIV/AIDS, infection and malaria were the common causes postpartum. This is similar to reports in previous studies on the causes of maternal mortality. , Central to the efforts to reduce maternal mortality worldwide is making emergency obstetric care available to all women. The five major causes of maternal mortality-hemorrhage, sepsis, unsafe abortion, hypertensive disorders (including preeclampsia and eclampsia), and obstructed labor, are all treatable. What this means is that no woman should be denied access to appropriate and well-functioning health facilities.  We need to address barriers that prevent women from getting the emergency care they need.
Unsafe abortion is a major contributor to maternal mortality. Unsafe abortion deserves special mention in Africa, the only region where complications of abortion are the most common cause of maternal mortality.  The consequences of the low rate of use of family planning methods in Nigeria include a high occurrence of unplanned and unwanted pregnancies.  The study reported that more than 3000 Nigerian women being treated in hospitals for complications from unsafe abortions die each year.  Access to contraceptive methods is an important strategy in reducing maternal mortality.  Abortion was the most commonly mentioned cause of death during pregnancy by respondents in this study. Similarly, pregnancies with abortive outcome were reported as a major cause of maternal mortality in Ghana.  Living in countries where induced abortions are legally restricted, women resort to back street abortionists or quacks. Crude methods used in the pregnancy termination, delay in seeking medical attention when and if there is a problem, and the poor quality of post abortion care lead to a significant proportion of the victims sustaining serious injuries with life-threatening complications, resulting in either death or disability. 
Anemia was reported by respondents in this study as a major cause of death during childbirth. As documented by several demographic and health surveys, many African women enter pregnancy in a state of nutritional deficit and therefore are unprepared to cope with the extra physiological demands of pregnancy.  This can result in severe anemia. Some practices such as food taboos put pregnant women at risk.  Nutritional deficiencies contribute to low birth weight and birth defects as well.  Another contributory factor to the high level of deaths due to anemia may be the lack of use of hematinics. Only half (54%) of Nigerian women take iron tablets during pregnancy. 
Bleeding was mentioned by respondents as a cause of death during pregnancy, during labor and also postpartum. Ignorance of danger signs may prevent women seeking care in time for their lives to be saved. In a previous study in Nigeria, knowledge was reported as lacking about the warning signs for hemorrhage and the potential danger for bleeding after delivery. Women did not know about when to seek help from modern obstetric services.  Some believed that supernatural forces caused some forms of hemorrhage in pregnancy and delivery. Use of modern facilities for treatment of hemorrhage was constrained by continued use of traditional birth attendants, transportation difficulties, and negative perceptions of quality of care in modern obstetric institutions.  There is a need to put in place health education programs to educate women about the potential danger of bleeding. Efficient blood transfusion services are needed to save lives when women have hemorrhage. Although the Nigerian policy on blood donation requires that all donations be voluntary, social norms and the screening and administrative charges levied on blood recipients deters voluntary donors and has led to “family replacement donation” as a principal means of blood collection. 
Sepsis is one of the most frequent causes of maternal death. It can be eliminated if aseptic techniques are respected and if early signs of infection are recognized and treated in a timely manner.  In this study the sepsis was reported as a cause of mortality during pregnancy, childbirth and postpartum. Most of the deaths from infection occurred in the postpartum period.
In this study, obstructed labor and prolonged labor accounted for over a third (35.6%) of the deaths that were reported to have occurred during childbirth. Skilled practitioners can recognize and deal with slow progress before labor becomes obstructed and if necessary, ensure that caesarean section is performed on time to save the mother and the baby. For women to benefit from those cost-effective interventions, they must have antenatal care in pregnancy, and in childbirth they must be attended by skilled health providers. 
The growing HIV/AIDS pandemic is also having a severe impact on women’s health.  HIV is becoming a major cause of maternal mortality in highly affected countries in Southern Africa.  Another risk to expectant women is malaria. It can lead to anemia, which increases the risk for maternal and infant mortality and developmental problems for babies.  Malaria remains a major killer of women in pregnancy and a leading indirect cause of maternal mortality. There are effective interventions, such as intermittent preventive treatment and insecticide-treated bednets that are affordable, but often not available where they are most needed.  Malaria was the major indirect cause of maternal mortality reported in this study. This is different from the findings from a study in Ghana in which sickle cell crisis was the main indirect cause of maternal mortality.  Hypertension was one of the commonest causes of maternal death during pregnancy and childbirth reported by respondents in this study. Eclampsia is a major direct cause of maternal mortality. Although preeclampsia cannot be completely cured before the delivery, administering drugs can lower a woman’s risk of developing eclampsia, which can be fatal. 
Over half of the maternal deaths in Lagos State occur during labor and immediately postpartum. The major direct causes of maternal mortality are abortion and prolonged labor/obstructed labor while the major indirect causes of death are malaria and anemia. Community education on the importance of having skilled attendants at delivery must be provided. Emergency obstetric care should be available, accessible and affordable at health facilities and efforts must be made to increase contraceptive use and prevent malaria in pregnancy.
Source of Support: The Lagos State Government of Nigeria funded this research. The fi ndings and Conclusions are those of the authors and do not necessarily represent the views of the State Government. The support of the state Commissioner for Health, Dr. Jide Idris and Governor Babatunde Fashola, facilitated the conduct of this study, Conflict of Interest: None
[Table 1], [Table 2], [Table 3]