TABLE 1

Comparison Between the Subsample and the Remaining Cohort With Regard to Maternal Characteristics

VariablesInfants Not Included in the 3-Mo Subsample (n = 3020)Infants Included in the 3-Mo Subsample (n = 885)P
Family income (quintiles).009
 1 (poorest)630 (20.9)157 (17.7)
 2587 (19.4)194 (21.9)
 3614 (20.3)147 (16.6)
 4612 (20.3)196 (22.2)
 5 (wealthiest)577 (19.1)191 (21.6)
Living with partner.739
 Yes2535 (83.9)747 (84.4)
 No485 (16.1)138 (15.6)
Schooling, y.009
 Up to 4480 (16.0)113 (13.0)
 5–81252 (41.7)335 (38.6)
 9–11976 (32.5)326 (37.5)
 ≥12293 (9.8)95 (10.9)
Maternal age, y.737
 <20570 (18.9)171 (19.3)
 20–352125 (70.4)626 (70.8)
 >35324 (10.7)87 (9.8)
Maternal skin color.190
 White2220 (73.5)638 (72.1)
 Black581 (19.2)192 (21.7)
 Other219 (7.3)55 (6.2)
Parity.004
 01151 (38.1)390 (44.1)
 1–31559 (51.6)423 (47.8)
 ≥4309 (10.2)72 (8.1)
Paid work during pregnancy.318
 No1810 (59.9)514 (58.1)
 Yes1209 (40.1)371 (41.9)
Smoking during pregnancy.522
 No2210 (73.2)638 (72.1)
 Yes810 (26.8)247 (27.9)
Daily cigarettes during pregnancy.284
 1–10526 (70.2)155 (66.5)
 >10223 (29.8)78 (33.5)
Alcohol consumption.218
 No2926 (96.9)850 (96.1)
 Yes94 (3.1)35 (3.9)
Heavy caffeine consumption in the first trimester of pregnancy.014
 No2457 (81.6)689 (77.9)
 Yes556 (18.4)196 (22.1)
Heavy caffeine consumption in the second trimester of pregnancy.019
 No2495 (82.9)703 (79.4)
 Yes516 (17.1)182 (20.6)
Heavy caffeine consumption in the third trimester of pregnancy.064
 No2533 (84.1)721 (81.5)
 Yes479 (15.9)164 (18.5)
Heavy caffeine consumption at 3 mo postpartum.186
 No2574 (85.2)770 (87.0)
 Yes446 (14.8)115 (13.0)