Risk of Adverse Pregnancy Outcomes among Women Practicing Poor Sanitation in Rural India: A Population-Based Prospective Cohort Study

Background: The importance of maternal sanitation behaviour during pregnancy for birth outcomes remains unclear. Poor sanitation practices can promote infection and induce stress during pregnancy and may contribute to adverse pregnancy outcomes (APOs). We aimed to assess whether poor sanitation practices were associated with increased risk of APOs such as preterm birth and low birth weight in a population-based study in rural India. Methods and Findings: A prospective cohort of pregnant women (n = 670) in their first trimester of pregnancy was enrolled and followed until birth. Socio-demographic, clinical, and anthropometric factors, along with access to toilets and sanitation practices, were recorded at enrolment (12th week of gestation). A trained community health volunteer conducted home visits to ensure retention in the study and learn about study outcomes during the course of pregnancy. Unadjusted odds ratios (ORs) and adjusted odds ratios (AORs) and 95% confidence intervals for APOs were estimated by logistic regression models. Of the 667 women who were retained at the end of the study, 58.2% practiced open defecation and 25.7% experienced APOs, including 130 (19.4%) preterm births, 95 (14.2%) births with low birth weight, 11 (1.7%) spontaneous abortions, and six (0.9%) stillbirths. Unadjusted ORs for APOs (OR: 2.53; 95% CI: 1.72–3.71), preterm birth (OR: 2.36; 95% CI: 1.54–3.62), and low birth weight (OR: 2.00; 95% CI: 1.24–3.23) were found to be significantly associated with open defecation practices. After adjustment for potential confounders such as maternal socio-demographic and clinical factors, open defecation was still significantly associated with increased odds of APOs (AOR: 2.38; 95% CI: 1.49–3.80) and preterm birth (AOR: 2.22; 95% CI: 1.29–3.79) but not low birth weight (AOR: 1.61; 95% CI: 0.94–2.73). The association between APOs and open defecation was independent of poverty and caste. Even though we accounted for several key confounding factors in our estimates, the possibility of residual confounding should not be ruled out. We did not identify specific exposure pathways that led to the outcomes. Conclusions: This study provides the first evidence, to our knowledge, that poor sanitation is associated with a higher risk of APOs. Additional studies are required to elucidate the socio-behavioural and/or biological basis of this association so that appropriate targeted interventions might be designed to support improved birth outcomes in vulnerable populations. While it is intuitive to expect that caste and poverty are associated with poor sanitation practice driving APOs, and we cannot rule out additional confounders, our results demonstrate that the association of poor sanitation practices (open defecation) with these outcomes is independent of poverty. Our results support the need to assess the mechanisms, both biological and behavioural, by which limited access to improved sanitation leads to APOs. Pinaki Panigrahi and colleagues examine the association between adverse pregnancy outcomes and sanitation practices in pregnant women in rural India.Background: Pregnancy is usually a happy time for women and their families. But, for some women, pregnancy ends unhappily. Some women lose their baby during early pregnancy (spontaneous abortion or miscarriage) or during late pregnancy (stillbirth). Others have their baby earlier than expected (preterm birth) or have a baby with low birth weight, two outcomes that adversely affect the baby’s survival and long-term health. The burden of adverse pregnancy outcomes (low birth weight, preterm birth, stillbirth, and spontaneous abortion) is substantial across the world but is particularly high in resource-limited settings. More than 60% of all preterm births take place in Asia and sub-Saharan Africa, and in India alone nearly 13 million babies (47% of all births) had a low birth weight in 2010. Many risk factors for adverse pregnancy outcomes have been identified, including infection, diabetes, poor antenatal care, and other socio-economic factors, but a clear causal mechanism for adverse pregnancy outcomes has not been established. Why Was This Study Done?: One potential risk factor for adverse pregnancy outcomes, particularly in resource-limited settings, is poor sanitation—the inadequate provision of facilities and services for the safe disposal of human urine and feces. The WHO/UNICEF Joint Monitoring Programme for Water Supply and Sanitation estimates that, globally, 1.1 billion people defecate in the open, a practice that can expose individuals to contact with human feces containing infectious organisms and that can contaminate food and water. Poor sanitation might contribute to adverse pregnancy outcomes by promoting infection or by causing stress during pregnancy. Women might, for example, limit their intake of food and water to avoid having to use inadequate toilet facilities, thereby adversely affecting the health of their unborn child. Here, the researchers assess whether poor sanitation practices are associated with an increased risk of adverse pregnancy outcomes by undertaking a population-based prospective study in two rural areas of Odisha state, India. Odisha has a high infant death rate (57 deaths per 1,000 live births), only 18.2% of households have access to an improved latrine (a facility such as a flush toilet that hygienically prevents human contact with human excreta), and 75% of households practice open defecation. What Did the Researchers Do and Find?: For their study, the researchers enrolled 670 women during the first trimester of their pregnancy. They recorded socio-demographic data (for example, age, level of education, and household assets), clinical data, weight and height, and toilet access and sanitation practices for each woman at enrollment and followed them through pregnancy until birth. Nearly two-thirds of the women practiced open defecation, and a quarter experienced an adverse pregnancy outcome, most commonly a preterm birth and/or having a baby with low birth weight. After adjustment for potential confounding factors (factors that might affect outcomes, such as socio-demographic characteristics), open defecation was significantly associated with adverse pregnancy outcomes (all four adverse outcomes considered together) and with preterm birth, but not with low birth weight (a significant association is one that is unlikely to have happened by chance). Specifically, the adjusted odds ratios (an indicator of the strength of association between an exposure and an outcome; an odds ratio of more than one indicates that an exposure increases the risk of an outcome) of adverse pregnancy outcomes and preterm birth among women practicing open defecation compared with women with access to a latrine were 2.38 and 2.22, respectively. Notably, these associations were independent of poverty, caste, and religion. What Do These Findings Mean?: These findings indicate that, among women in Odisha, defecation in the open (poor sanitation) during pregnancy is associated with a higher risk of any adverse pregnancy outcome and of preterm birth than the use of a latrine. Counterintuitively, these findings also suggest that the association between open defecation and adverse pregnancy outcomes is not explained by poverty. Although the researchers adjusted for numerous confounding factors in their analysis, the women who defecated in the open may have shared some other unknown characteristic (residual confounding) that was actually responsible for their increased risk of an adverse pregnancy outcome. Further studies are now needed to determine the socio-behavioral and/or biological basis of the association between poor sanitation and adverse pregnancy outcomes. Appropriate public health interventions can then be designed to reduce the burden of adverse pregnancy outcomes among women living in settings where there is limited access to adequate sanitation. Additional Information: This list of resources contains links that can be accessed when viewing the PDF on a device or via the online version of the article at http://dx.doi.org/10.1371/journal.pmed.1001828.