Avaliação do efeito de intervenções de proteção social e de saúde na mortalidade materna entre as mulheres de baixa renda do Brasil.

Abstract

Backgroud: Although efforts have been made in the last 20 years, maternal mortality is still an important public health problem. Extremes of health care coexist, with the persistence of inequalities in access to health care and the excessive medicalization of delivery and the increase in caesarean sections and invasive interventions. Caesarean can save lives of the mothers and the newborns when needed, but studies have been showed that this mode of delivery can also expose women to an increased risk of morbidity and mortality. Alleviating poverty, promoting health education practices and investing in quality services are considered priorities actions for reducing maternal deaths. The Bolsa Família Programme (BFP), a conditional cash transfer programme (CCT), has impacted on improving social determinants and expanding access to healthcare for the Brazilian population. There are references in the literature about positive impacts of CCT on maternal health and its determinants, but the effect of the BFP on maternal mortality has not yet been investigated in Brazil. Overall objective: Evaluate the effect of health and social protection interventions on maternal mortality among low-income women in Brazil. Specific objectives: i) To assess the medium and long-term association between the coverage of the Bolsa Família Programme and the Maternal Mortality Ratio in Brazilian municipalities; ii) Assess the impact of the Bolsa Família Programme on maternal mortality, in the cohort of 100 million Brazilians; iii) To investigate the association between caesarean section and maternal mortality, according to Robson's classification, in the poor and extremely poor women in Brazil. Methods: The thesis was presented in 3 articles according to each specific objective. For the first objective, we conducted an ecological longitudinal design and used all 2,548 Brazilian municipalities with vital statistics of adequate quality during the period 2004–14. BFP municipal coverage was classified in four levels, from low to consolidated, and its duration effects were measured using the average municipal coverage of previous years. We used negative binomial multivariable regression models with fixed-effects specifications, adjusted for all relevant demographic, socioeconomic, and healthcare variables. For the second objective, we conducted a longitudinal population-based study of women of reproductive age (10-49 years old) who had at least one live birth, using data from Brazilian National Health and administrative databases linked to the 100 Million Brazilian Cohort for the period 2004 to 2015. We utilized propensity score kernel weighting to control for socio-demographic and economic confounders in the association between BFP receipt and overall maternal mortality, stratified by different subgroups. We also analysed the effect of the time of BFP receipt. For the third objective, we conducted a population-based cohort study in Brazil by linking routine data, departing from 100 million Brazilian Cohort between 2011 and 2015, Brazilian Live Birth Information System (SINASC) and Mortality Information System (SIM). Women with at least one live birth were classified into one of ten Robson groups based on pregnancy and delivery characteristics. We used propensity scores to match CD with vaginal deliveries (1:1) and prelabour CD with unscheduled CD (1:1) and estimated associations with maternal mortality using Cox regression. We also conducted analyzes with deaths more related to CS and excluding deaths that suggest prenatal morbidities. Results for the first objective: BFP was significantly associated with reductions of maternal mortality proportionally to its levels of coverage and years of implementation, with a Rate Ratio (RR) reaching 0.88(95%CI:0.81- 0.95), 0.84(0.75-0.96) and 0.83(0.71-0.99) for intermediate, high and consolidated BFP coverage over the previous 11 years. The BFP duration effect was stronger among young (<30 years) mothers (RR 0.77;95%CI:0.67-0.96). BFP was also associated with reductions in the proportion of pregnant women with no prenatal visits (RR 0.73;95%CI:0.69-0.77), reductions in hospital case-fatality rate for delivery (RR 0.78;95%CI:0.66-0.94), and increases in the proportion of deliveries in hospital (RR 1.05;95%CI:1.04-1.07). Results for the second objective: We included 6,677,273 women aged between 10 and 49, 4,056 of whom had died from a maternal-related cause. BFP beneficiaries had an 18% lower risk of maternal death (ORadj: 0.82, 95%CI=0.73-0.96). Increased BFP exposure (1 to 4, 5-9 or ≥9 years) was associated with a higher reduction of maternal deaths (OR: 0.85; 95%CI: 0.75-0.97; OR:0.70;95%CI:0.60-0.82,OR: 0.69 95%CI:0.53-0.88, respectively). The BFP also has led to substantial increases in prenatal appointments and inter-birth intervals, and had the greatest impact on the most vulnerable groups. Results for the thrid objective: 5,239,086 women were analysed. After propensity score matching, CS were associated with an increasing risk of maternal mortality, even in groups with low expected rates of caesarean: Overall (HR= 1.95 IC95% 1.77-2.15); Robson 1-4 (HR= 1.99 IC95% 1.63-2.43), Robson 6-10 (HR= 2.69 IC95% 2.29-3.16). There was no statistically significant difference in mortality risk in groups 5 (HR= 1.02 IC95% 0.74-1.42). The mortality risk was markedly lower excluding causes attributed to antenatal morbidities and substantially higher for thromboembolism death, which reinforces the control for indication bias and suggests the independent risk of these mode of delivery for maternal mortality. Conclusions: Our results showed that the PBF has a role in reducing maternal mortality, both at the municipal coverage level and among the poorest Brazilian women, and these associations remained strong even after adjusting for health care, pregnancy and childbirth characteristics. Increasing the exposure time, the greater the effect of the PBF, suggesting that the sustainability of social protection actions have an effect throughout the life of the beneficiaries. The BFP has also led to substantial increases in antenatal visits and the interval between births, with a greater contribution to more vulnerable women. These findings highlight the possible long-term effect of PTCRs and their potential value in reducing maternal mortality. Regarding the evaluation of caesarean section, the present study suggests that the excessive use of caesarean section may be a risk factor for maternal mortality compared to vaginal delivery. Maternal mortality remains high in lowincome countries, and the route of delivery is one of the main modifiable risk factors for maternal death among several global initiatives aimed at reducing it. Our results reinforce the importance of better monitoring and management of cesarean sections, optimizing interventions and increasing the allocation of resources to the women most in need. Furthermore, social policies must be improved and extended to the greatest possible number of families in poverty, as social development is a fundamental priority to reduce maternal mortality among low-income women.