Ma. Klebanoff et al., Maternal serum paraxanthine, a caffeine metabolite, and the risk of spontaneous abortion, N ENG J MED, 341(22), 1999, pp. 1639-1644
Citations number
20
Categorie Soggetti
General & Internal Medicine","Medical Research General Topics
Background: Whether the consumption of caffeine during pregnancy increases
the risk of spontaneous abortion is controversial. Prior studies have deter
mined caffeine consumption by questionnaire. We used a biologic marker, ser
um paraxanthine, a metabolite of caffeine, to measure the dose of caffeine.
Methods: In a nested case-control study, we measured serum paraxanthine in
591 women who had spontaneous abortions at less than 140 days' gestation an
d in 2558 matched women from the same clinic who gave birth to live infants
at 28 weeks' gestation or later and who had serum drawn on the same day of
gestation as the women who had abortions. The women were enrolled in the C
ollaborative Perinatal Project during the period from 1959 to 1966, and ser
um paraxanthine was measured over 30 years later.
Results: A total of 487 women who had spontaneous abortions (82 percent) an
d 2087 controls (82 percent) had quantifiable serum paraxanthine concentrat
ions. However, the mean serum paraxanthine concentration was higher in the
women who had spontaneous abortions than in the controls (752 vs. 583 ng pe
r milliliter, P<0.001). The odds ratio for spontaneous abortion was not sig
nificantly elevated in the women who had serum paraxanthine concentrations
of 1845 ng per milliliter or lower, corresponding to the 95th percentile of
the matched women. However, the adjusted odds ratio for spontaneous aborti
on among women with serum paraxanthine concentrations higher than 1845 ng p
er milliliter, as compared with women who had concentrations below 50 ng pe
r milliliter, was 1.9 (95 percent confidence interval, 1.2 to 2.8).
Conclusions: Only extremely high serum paraxanthine concentrations are asso
ciated with spontaneous abortion. This suggests that moderate consumption o
f caffeine is unlikely to increase the risk of spontaneous abortion. (N Eng
l J Med 1999;341:1639-44.) (C) 1999, Massachusetts Medical Society.