children of which 14 701 were alive at one year of age (Table 1). Table 1ALSPAC eligible sample pregnancy size and birth outcomesALSPAC enrolled pregnancies n = 15 247Non-enrolled pregnancies n = 5001ALSPAC eligible sample n = 20 248 pregnancies Pregnancy size n (%) Singletons14 971 (98.2)a4909 (98.2)b Sets of Twins204 (1.3)a43 (0.9)b Sets of Triplets3 (<0.1)a1 (<0.1)b Sets of Quads1 (<0.1)a0 (<0.1)b No known birth outcome68 (0.4)a48 (1.0)bALSPAC eligible sample n = 20 390 children/foetuses Outcomes (numbers of foetuses/offspring) n (%) Foetal loss <20 weeks547 (3.6)c138 (2.8)d Foetal death/sb 20+ weeks68 (0.4)c37 (0.7)d Neonatal death <7 days45 (0.3)c11 (0.2)d Neonatal death 7–27 days8 (<0.1)c2 (<0.1)d Post-neonatal death 28 days–1 year21 (0.1)c15 (0.3)d Alive > 1 year14 701 (95.5)c4797 (96.0)d Total15 390e (100)c5000e (100)daPercentage of 15 247 enrolled pregnancies.bPercentage of 5001 non-enrolled pregnancies.cPercentage of 15 390 enrolled children (foetal).dPercentage of 5000 non-enrolled children (foetal).eThe sample contains two twin pregnancies where only one child enrolled (recruitment phases II and III). These are reported as an enrolled twin pregnancy with birth outcomes of a single enrolled and a single non-enrolled child.
