Baseline characteristics of 121 mothers and 129 infants participating in the Latte Dosage Trial
| Placebo | Caffeine citrate 5 mg/kg/day | Caffeine citrate 10 mg/kg/day | Caffeine citrate 15 mg/kg/day | Caffeine citrate 20 mg/kg/day | Any dose of caffeine | |
| Number of mothers (% of total) | 24 (19.8) | 23 (19.0) | 24 (19.8) | 25 (20.7) | 25 (20.7) | 97 (80.2) |
| Age (years) | 31.1 (6.0) | 31.6 (5.3) | 30.6 (5.5) | 32.1 (5.8) | 31.3 (6.3) | 31.4 (5.7) |
| Primiparous | 9 (37.5) | 11 (47.8) | 16 (66.7) | 15 (60.0) | 13 (52.0) | 55 (56.7) |
| Body mass index (kg/m2) | 26.1 (23.5, 30.7) | 27.9 (24.2, 31.5) | 26.3 (23.3, 30.6) | 24.9 (21.9, 28.4) | 28.6 (23.4, 32.5) | 26.5 (23.2, 30.1) |
| Multiple pregnancy | 0 (0.0) | 1 (4.3) | 3 (12.5) | 2 (8.0) | 2 (8.0) | 8 (8.2) |
| Antenatal events | ||||||
| Maternal diabetes | 5 (20.8) | 3 (13.0) | 9 (37.5) | 2 (8.0) | 7 (28.0) | 21 (21.6) |
| Preterm prelabour rupture of membranes | 12 (50.0) | 13 (56.5) | 8 (33.3) | 15 (60.0) | 8 (32.0) | 44 (45.4) |
| Preterm labour | 20 (83.3) | 18 (78.3) | 13 (54.2) | 19 (76.0) | 17 (68.0) | 67 (69.1) |
| Hypertension in pregnancy | 3 (12.5) | 1 (4.3) | 4 (16.7) | 2 (8.0) | 5 (20.0) | 12 (12.4) |
| Antepartum haemorrhage | 1 (4.2) | 6 (26.1) | 1 (4.2) | 5 (20.0) | 2 (8.0) | 14 (14.4) |
| Suspected fetal growth restriction | 3 (12.5) | 3 (13.0) | 6 (25.0) | 4 (16.0) | 6 (24.0) | 19 (19.6) |
| Antenatal glucocorticosteroids | 5 (20.8) | 4 (17.4)* | 8 (33.3) | 8 (32.0)* | 4 (16.0) | 24 (24.7) |
| Number of infants (% of total) | 24 (18.6) | 24 (18.6) | 27 (20.9) | 27 (20.9) | 27 (20.9) | 105 (81.5) |
| Gestational age (weeks) | ||||||
| 34 | 6 (25.0) | 5 (20.8) | 6 (22.2) | 5 (18.5) | 6 (22.2) | 22 (21.0) |
| 35 | 7 (29.2) | 8 (33.3) | 9 (33.3) | 10 (37.0) | 9 (33.3) | 36 (34.3) |
| 36 | 11 (45.8) | 11 (45.8) | 12 (44.4) | 12 (44.4) | 12 (44.4) | 47 (44.8) |
| Sex (male) | 14 (58.3) | 17 (70.8) | 12 (44.4) | 18 (66.7) | 16 (59.3) | 63 (60.0) |
| Singleton† | 24 (100.0) | 22 (91.7) | 21 (77.8) | 23 (85.2) | 23 (85.2) | 89 (84.8) |
| Ethnicity (prioritised) | ||||||
| Māori | 2 (8.3) | 6 (25.0) | 1 (3.7) | 2 (7.4) | 7 (25.9) | 16 (15.2) |
| Pacific Islander | 7 (29.2) | 5 (20.8) | 2 (7.4) | 5 (18.5) | 5 (18.5) | 17 (16.2) |
| Asian | 7 (29.2) | 5 (20.8) | 13 (48.1) | 11 (40.7) | 7 (25.9) | 36 (34.3) |
| Other | 1 (4.2) | 1 (4.2) | 1 (3.7) | 1 (3.7) | 1 (3.7) | 4 (3.8) |
| NZ European | 7 (29.2) | 7 (29.2) | 10 (37.0) | 8 (29.6) | 7 (25.9) | 32 (30.5) |
| Birth weight (g) | 2566.5 (272.2) | 2674.6 (480.6) | 2523.9 (603.7) | 2641.9 (432.5) | 2393.3 (515.1) | 2555.1 (517.3) |
| Z-score‡ | −0.0 (0.7) | 0.2 (1.1) | −0.1 (1.3) | 0.1 (1.0) | −0.5 (1.1) | −0.1 (1.1) |
| Length (cm) | 47.8 (2.0) | 48.9 (2.5) | 47.2 (3.4) | 47.8 (2.1) | 46.8 (3.2) | 47.6 (2.9) |
| Z-score‡ | 0.5 (0.6) | 1.0 (1.0) | 0.3 (1.3) | 0.5 (0.9) | 0.1 (1.1) | 0.5 (1.1) |
| Head circumference (cm) | 32.4 (1.2) | 33.8 (1.5) | 32.5 (1.8) | 33.1 (1.5) | 32.3 (1.7) | 32.9 (1.7) |
| Z-score‡ | 0.2 (0.8) | 1.0 (1.0) | 0.2 (1.2) | 0.6 (1.1) | −0.0 (1.0) | 0.4 (1.1) |
| Caesarean delivery | 8 (33.3) | 10 (41.7) | 15 (55.6) | 12 (44.4) | 10 (37.0) | 47 (44.8) |
| Apgar score (5 min) | 9.0 (9.0, 10.0) | 9.0 (8.0, 10.0) | 10.0 (9.0, 10.0) | 9.0 (9.0, 10.0) | 9.0 (9.0, 10.0) | 9.0 (9.0, 10.0) |
| Admitted to neonatal intensive care | 12 (50.0) | 12 (50.0) | 13 (48.1) | 13 (48.1) | 17 (63.0) | 55 (52.4) |
| Positive pressure respiratory support prior to enrolment | 8 (33.3) | 7 (29.2) | 6 (22.2) | 9 (33.3) | 6 (22.2) | 28 (26.7) |
| Oxygen prior to enrolment | 2 (8.3) | 3 (12.5) | 4 (14.8) | 4 (14.8) | 3 (11.1) | 14 (13.3) |
Data are mean (SD), median (IQR) or n (%).
*N=1 with missing data in this group.
†In some cases, only one infant was eligible for the trial or a twin pregnancy resulted in a single live birth.
‡Z-scores were calculated from the revised Fenton growth charts for preterm infants.42