The Human Cost of Tobacco Chewing Among Pregnant Women in India: A Systematic Review and Meta-analysis.

BACKGROUND: In India, smokeless tobacco (SLT) use among pregnant women is high and its adverse effects on pregnancy outcomes have not been properly documented in.

OBJECTIVES: To collate available evidence on the association between SLT use and three adverse pregnancy outcomes, i.e. low birth weight, preterm birth and stillbirth among women in India.

SEARCH STRATEGY: A systematic search was conducted in MEDLINE, IndMed, Web of Science, Google Scholar and major journals. Two authors independently reviewed the studies and extracted data.

SELECTION CRITERIA: Inclusion criteria were English articles published till December 2014, case control, case cohort or cohort, and exposure and outcome variables meeting predefined criteria. Exclusion criteria were case series, case reports, cross-sectional designs, risk estimate not restricted/adjusted for smoking with or without adjustment for other factors and duplicate data. Qualitative synthesis was followed by meta-analysis. Attributable burden was estimated using the population attributable fraction method.

MAIN RESULTS: Pooled odds ratio was significant for all three outcomes: low birth weight (1.88, 95 % CI 1.38, 2.54), preterm birth (1.39: 1.01, 1.91) and stillbirth (2.85: 1.62, 5.01). We found that 0.87 million low birth weight babies, 0.19 million preterm births and 0.12 million stillbirths occurring annually in India could be attributed to maternal SLT use.

CONCLUSION: There was a suggestive evidence of SLT use associated with adverse pregnancy outcomes among women in India. Further studies in this field are required to generate more conclusive evidence.