Interpregnancy interval in lower versus higher human development index countries: a hypothesis about pregnancy spacing

BACKGROUND: A secondary analysis was conducted of two separate datasets to observe the association between maternal age and interpregnancy interval (IPI). METHODS: The IPI in a middle-income country (Guatemala) was compared with that of a very-high-income country (USA) among women with two pregnancies. RESULTS: A regression model found that with each increasing year of age, the IPI increases by 1.26 months (p<0.001) in Guatemala. A regression model found that IPI decreased as women aged in the USA. CONCLUSIONS: It is hypothesized that as countries progress in their development indices, women may delay childbearing, which may result in reduced IPI, as was the case in the USA compared with Guatemala in these datasets.