Interval between pregnancies.
D001824:Body Constitution; D002648:Child; D002657:Child Development; D005193:Family Planning Services; D005260:Female; D006801:Humans; D007223:Infant; D007226:Infant Mortality; D007231:Infant, Newborn; D010298:Parity; D011247:Pregnancy; D012846:Singapore; D013997:Time Factors