Outcome | (i) | (ii) | (iii) | (iv) | (v) |
Risk (%) per 100 mg* (95% CI) | Risk (%) at 200 mg† (column (i) ×2) | Incidence of events (%) | Total number of events | Caffeine-related events (product of columns (ii) and (iv)) | |
Miscarriage | 14 (10 to 19) | 28 | 16.67‡ | ∼1 000 000‡ | 280 000 |
Stillbirth | 19 (5 to 35) | 38 | 0.6§ | 24 000¶ | 9120 |
LBW | 7 (1 to 12) | 14 | 8.28** | 331 200¶ | 46 368 |
SGA | 10 (6 to 14) | 20 | 1.5†† | 60 000¶ | 12 000 |
1 415 200 | 347 488 |
The contents of this table are a compilation of statistics from different sources and are broadly representative of the more than 60 million women in the USA between the ages of 15 and 44 years.128 129
*Greenwood et al57 as part of dose–response associations having no threshold of caffeine intake below which negative events were absent.
†Extrapolating from Greenwood et al,57 estimated risk for maternal caffeine consumption at the widely endorsed 'safe' level of 200 mg per day.
‡Estimates of incidence of pregnancy 'loss' are inevitably approximate. Among roughly 6 million pregnancies per year in the USA, an estimated one-third end in loss comprised of 1 million each of miscarriages and induced abortions.123 130
§Percentage of all births.131
¶Product of column (iii) and the approximate total of 4 million births.
**Percentage of all births.129
††Percentage of all births.132
LBW, low birth weight; SGA, small for gestational age.