Table 2.
Average Maternal Caffeine Consumption Reported for the Year prior to Pregnancy for Case-Infants and Control-Infants in the National Birth Defects Prevention Study, United States, 1997–2002
| Controls (N = 4143) | NTD (N = 768) | Spina bifida (N = 459) | Anencephaly (N = 218) | Encephalocele (N = 91) | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| N | (%)a | N | (%)a | N | (%)a | N | (%)a | N | (%)a | |
| Total caffeine (mg/day) | ||||||||||
| None (0–9) | 635 | (15.5) | 97 | (12.8) | 55 | (12.0) | 31 | (14.5) | 11 | (12.2) |
| Very low (10–99) | 1438 | (35.0) | 285 | (37.5) | 169 | (37.0) | 80 | (37.4) | 36 | (40.0) |
| Low (100–199) | 958 | (23.3) | 190 | (25.0) | 117 | (25.6) | 52 | (24.3) | 21 | (23.3) |
| Moderate (200–299) | 557 | (13.6) | 99 | (13.0) | 58 | (12.7) | 30 | (14.0) | 11 | (12.2) |
| High (≥300) | 520 | (12.7) | 90 | (11.8) | 58 | (12.7) | 21 | (9.8) | 11 | (12.2) |
| Caffeinated coffee | ||||||||||
| Never or ≤1 cup/month | 2232 | (54.3) | 415 | (54.3) | 245 | (53.6) | 125 | (57.9) | 45 | (50.0) |
| 1 cup/month–6 cups/week | 536 | (13.0) | 116 | (15.2) | 69 | (15.1) | 35 | (16.2) | 12 | (13.3) |
| 1 cup/day | 581 | (14.1) | 115 | (15.1) | 71 | (15.5) | 25 | (11.6) | 19 | (21.1) |
| 2 cups/day | 410 | (10.0) | 59 | (7.7) | 35 | (7.7) | 18 | (8.3) | 6 | (6.7) |
| ≥3 cups/day | 355 | (8.6) | 58 | (7.6) | 37 | (8.1) | 13 | (6.0) | 8 | (8.9) |
| Caffeinated tea | ||||||||||
| Never or <1 cup/month | 2140 | (52.0) | 415 | (54.3) | 267 | (58.4) | 111 | (51.4) | 37 | (41.1) |
| 1 cup/month–6 cups/week | 1155 | (28.1) | 204 | (26.7) | 111 | (24.3) | 64 | (29.6) | 29 | (32.2) |
| 1 cup/day | 437 | (10.6) | 82 | (10.7) | 40 | (8.8) | 24 | (11.1) | 18 | (20.0) |
| 2 cups/day | 206 | (5.0) | 28 | (3.7) | 17 | (3.7) | 9 | (4.2) | 2 | (2.2) |
| ≥3 cups/day | 175 | (4.3) | 34 | (4.5) | 22 | (4.8) | 8 | (3.7) | 4 | (4.4) |
| Caffeinated soda (mg)/day | ||||||||||
| None (0) | 1322 | (32.2) | 204 | (26.8) | 113 | (24.7) | 63 | (29.4) | 28 | (30.8) |
| >0–<½ (1–16) | 746 | (18.2) | 136 | (17.9) | 82 | (17.9) | 35 | (16.4) | 19 | (20.9) |
| ½–<1 (17–33) | 673 | (16.4) | 122 | (16.0) | 72 | (15.9) | 31 | (14.5) | 19 | (20.9) |
| 1–<2 (34–67) | 277 | (6.7) | 68 | (8.9) | 41 | (9.0) | 21 | (9.8) | 6 | (6.6) |
| 2–<3 (68–101) | 454 | (11.0) | 99 | (13.0) | 64 | (14.0) | 26 | (12.2) | 9 | (9.9) |
| ≥3 (≥102) | 639 | (15.5) | 133 | (17.5) | 85 | (18.6) | 38 | (17.8) | 10 | (11.0) |
| Chocolate | ||||||||||
| Never or <1 oz./month | 807 | (19.6) | 169 | (22.1) | 105 | (22.3) | 42 | (19.5) | 22 | (24.2) |
| ≥1 oz./month | 3311 | (80.4) | 594 | (77.9) | 352 | (77.7) | 173 | (80.5) | 69 | (75.8) |
| Caffeine-containing medicationsb | ||||||||||
| None | 4066 | (99.0) | 753 | (99.2) | 448 | (98.7) | 216 | (100.0) | 89 | (100.0) |
| Any | 42 | (1.0) | 6 | (0.8) | 6 | (1.3) | 0 | (0.0) | 0 | (0.0) |
a
Numbers of cases and controls may vary because of missing or incomplete data. Percentages may not sum to 100 due to rounding.
b
Medications reported for one month before through the third month of pregnancy. Caffeine from medications not included in estimate of total caffeine.
NTD, neural tube defect.