Association of Maternal Factors with Twin Births: Evidence from Bangladesh Demographic Health Survey

Aims: To investigate which maternal factors are associated with the multiple birth status of a child in a developing country like Bangladesh where neonatal mortality, child nutrition and maternal health are matters of concern.

Study Design: This is a cross-sectional study that collects information through several questionnaires including a women’s questionnaire that provides demographic and health information on mothers and their children.

Place and Duration of Study: The nationally representative health survey “Bangladesh Demographic and Health Survey (BDHS)” was conducted between November 2010 and April 2011.

Methodology: Information on 45842 live births of which 780 were twins and 45062 were singletons were extracted from the database of the Bangladesh Demographic Health Survey (BDHS). The associations between risk factors and the outcome were assessed using crude and adjusted logistic regression models. Statistically significant associations were identified and the strengths of the associations were measured and compared through odds ratios.

Results: The rate of twinning was 17 per 1000 live births. The association between a child’s birth order and twin birth status appears to be very strong in the data. The crude logistic regression analysis indicates that children from seventh order pregnancies are 7.03 times more likely than first order pregnancies to be twins. Furthermore, adjusted estimates show that an increase of one level of birth order is accompanied by a 1.362 times higher likelihood of being a twin. Although birth interval was significantly associated with the outcome in the bivariate analysis, it was no longer significant after adjusting for other factors in a multivariable model. Moderate to severe maternal anemia and higher maternal education are also found to be associated with increased risk of being a multiple birth.

Conclusion: Birth order is an important correlate of twin birth status in Bangladesh. Higher order pregnancies are more likely to be twin births compared to lower order pregnancies. Among other factors, age of mother, level of maternal anemia and maternal education are associated with the outcome. These factors must therefore be taken into account in any future study aimed at determining the causes of twin births in Bangladesh.