Prevalence, Neonatal Characteristics, and First-year Mortality of Down Syndrome: a National Study

Objective: To determine the prevalence, neonatal characteristics, and first-year mortality in Down syndrome (DS) among children in The Netherlands.

Study Design: The number of DS births registered by the Dutch Paediatric Surveillance Unit (DPSU) in 2003 was compared with total live births (reference population) and perinatal registrations.

Results: The prevalence of DS was 16 per 10,000 live births. Compared with the reference population, the 182 children with trisomy 21 had a gestational age of 38 weeks versus 39.1 weeks (P < .001), a birth weight of 3119 g versus 3525 g in males (P < .001) and 2901 g versus 3389 g in females (P < .001), and mothers with a parity of > or = 4.17% versus 5% (P < .001) and a mean age of 33.6 years versus 31 years (P < .001) and 33% (n = 54) > or = 36 years). The mean age of DS diagnosis was 10.2 days in nonhospital deliveries and 1.8 days in hospital deliveries (P < .001). Children with DS were less often breast-fed (P < .05), and 86% (n = 156) were hospitalized after birth. Neonatal and infant mortality were higher in DS, 1.65% versus 0.36% (P < .02) and 4% versus 0.48% (P < 0.001), respectively.

Conclusions: The prevalence of DS in The Netherlands exceeds previously reported levels and is influenced by the mother's age. Neonatal and infant DS mortality have declined, but still exceed those in the reference population.