MODERATE TO HEAVY CAFFEINE CONSUMPTION DURING PREGNANCY AND RELATIONSHIP TO SPONTANEOUS-ABORTION AND ABNORMAL FETAL GROWTH - A METAANALYSIS

The objective was to determine the association of moderate to heavy ca ffeine consumption during pregnancy on spontaneous abortion and birth weight in humans, Data sources used included a computerized literature search of MEDLINE (1966-July 1996); EMBASE (1988-November 1996); Psyc hlit I (1974-1986); Psychlit II (1987-1996); CINAHL (1982-May 1996) an d manual search of bibliographies of pertinent articles. Inclusion cri teria were: English language research articles; pregnant human females ; case control or cohort design; documented quantity of caffeine consu mption during pregnancy; control group with minimal or no caffeine con sumption (0 to 150 mg caffeine/d); documented data regarding spontaneo us abortion and/or fetal growth, The exclusion criteria were: case rep orts; editorials; review papers. The methods section of each study was examined independently by two blinded investigators with a third inve stigator adjudicating disagreements. Two independent investigators ext racted data onto a standardized form. A third investigator adjudicated discrepancies. We compared a caffeine-exposed group (>150 mg/d) and c ontrols (0 to 150 mg/d), using Mantel-Haenszel pooling, Of the 32 stud ies meeting inclusion criteria, 12 had extractable data (6 for spontan eous abortion, 7 for low birth weight, 1 common study), Mantel-Haensze l odds ratio (CI,,,) was 1.36 (1.29-1.45) for spontaneous abortion in 42,988 pregnancies. The overall risk ratio was 1.51 (1.39-1.63) for lo w birthweight (<2500 g) in 64,268 pregnancies. Control for confounders such as maternal age, smoking, and ethanol use was not possible. We c oncluded that there is a small but statistically significant increase in the risks for spontaneous abortion and low birthweight babies in pr egnant women consuming >150 mg caffeine per d, A possible contribution to these results of maternal age, smoking, ethanol use, or other conf ounders could not be excluded. (C) 1998 Elsevier Science Inc.