The impact of short inter-pregnancy intervals on children's growth and cognitive development in Cebu, Philippines: a 22 year longitudinal study
A large body of evidence suggests that short inter-pregnancy intervals negatively impact birth outcomes; however, relatively little is known about the extent to which these impacts persist beyond birth or affect children's post-natal growth and cognitive development. This thesis uses data from the Cebu, Philippines Longitudinal Health and Nutrition Survey to examine the impact of short inter-pregnancy intervals (both preceding and subsequent to the index child) on the growth and development of index children from birth to 21.5 years. The following outcomes were of interest: birth weight; birth length; linear growth from 0-2, 2-11.5, and 11.5-21.5 years; attained height at 21.5 years; cognitive performance at 8.5 and 11.5 years; and educational attainment at 21.5 years. The results show that inter-pregnancy intervals of less than 12 months negatively impact birth outcomes and early linear growth. The effect sizes were as follows: 84-93 g for birth weight; 0.23-0.32 cm for birth length; 0.83-0.94 cm for attained height at 10.5 months; and 3.0-4.2 cm for attained height at 6.75 years. These effects did not generally persist later in life and did not extend so far as to negatively impact childrenâ€™s cognitive performance and educational attainment. It was sociological effects associated with sib-ship size not biological effects associated with a short inter-pregnancy interval that negatively impacted childrenâ€™s cognitive development and educational attainment, with each older sibling associated with a 0.5-1.0 point deficit in IQ score and each younger sibling associated with a 1.0-2.0 point deficit in IQ score at 8.5 and 11.5 years. These results indicate that the promotion of appropriate inter-pregnancy spacing is not sufficient alone to improve child development in developing countries. To address childrenâ€™s cognitive development also requires addressing family size. Further efforts are therefore needed to generate and meet demand for family planning in developing countries with high fertility rates.