Effect of early detection and treatment on malaria related maternal mortality on the north-western border of Thailand 1986-2010

Abstract

Introduction: Maternal mortality is high in developing countries, but there are few data in high-risk groups such as migrants and refugees in malaria-endemic areas. Trends in maternal mortality were followed over 25 years in antenatal clinics prospectively established in an area with low seasonal transmission on the north-western border of Thailand.

Methods and findings: All medical records from women who attended the Shoklo Malaria Research Unit antenatal clinics from 12(th) May 1986 to 31(st) December 2010 were reviewed, and maternal death records were analyzed for causality. There were 71 pregnancy-related deaths recorded amongst 50,981 women who attended antenatal care at least once. Three were suicide and excluded from the analysis as incidental deaths. The estimated maternal mortality ratio (MMR) overall was 184 (95%CI 150-230) per 100,000 live births. In camps for displaced persons there has been a six-fold decline in the MMR from 499 (95%CI 200-780) in 1986-90 to 79 (40-170) in 2006-10, p<0.05. In migrants from adjacent Myanmar the decline in MMR was less significant: 588 (100-3260) to 252 (150-430) from 1996-2000 to 2006-2010. Mortality from P. falciparum malaria in pregnancy dropped sharply with the introduction of systematic screening and treatment and continued to decline with the reduction in the incidence of malaria in the communities. P. vivax was not a cause of maternal death in this population. Infection (non-puerperal sepsis and P. falciparum malaria) accounted for 39.7 (27/68) % of all deaths.

Conclusions: Frequent antenatal clinic screening allows early detection and treatment of falciparum malaria and substantially reduces maternal mortality from P. falciparum malaria. No significant decline has been observed in deaths from sepsis or other causes in refugee and migrant women on the Thai-Myanmar border.

Figure 1. Study area sites of migrant and refugee clinics on the Thai-Myanmar border.

Sites for migrants denoted by circles (orange) and refugee by squares (blue).

Figure 2. Maternal mortality ratio (95%CI) per 100,000 live births 1986 to 2010.

Note the first data point (filled circle) for refugees in the year prior to 1986 is only P.falciparum as the sole documented contributor to maternal mortality. Subsequent refugee data (open circles) and all migrant data (open squares) and the 95% confidence intervals (bars) are all cause mortalities, summarized for year blocks. Frequent screening and early detection and treatment at antenatal care commenced in 1986 in refugees and in 1998 in migrants. The data for Thailand (all cause mortality) is referenced for discrete years 1986, 1990, 2000 and 2008 (blue bars) and the 95% CI are plotted although they are very narrow .

Figure 3. Trends in maternal mortality from P.falciparum malaria. Figure 3a

Refugees: Prior to 1994 the proportion of homebirths was not systematically recorded but was estimated at 90% (right axis). From 1994 the place of birth was systematically recorded and a significant decline can be observed. The fall in maternal mortality due to P.falciparum (left axis) occurred with the introduction of weekly screening in May 1986 and before the decline in home birth and the decrease of maternal P.falciparum malaria (right axis). From 2005–2010 the proportion of women infected with P.falciparum and the proportion of home births have been at their lowest with no maternal deaths in the last 5 years. Figure 3b Migrants: Systematic screening in migrant women started in 1998 and the proportion of women with home births (right axis) has reduced markedly as well as the proportion of women with P.falciparum infection (right axis). There does not appear to be a relation between home birth and P.falciparum related maternal deaths (left axis).

Figure 4. Three major causes of maternal mortality in refugees and migrants on the Thai-Myanmar border.

Maternal mortality rates for haemorrhage (black square), sepsis (open square) and P.falciparum (grey square) are presented in year blocks for Figure 4a refugees and Figure 4b migrants. The 1996–2000 year block in migrants represents data collection commencing in 1998.