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 children'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 children'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 children'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.