A few months ago I mentioned a Cochrane review that found caffeine didn’t adversely affect full-term outcomes of pregnancy. However, the reviewers located only one study that met their criteria. Now, an apparently solid study provides reassurance that caffeine also is not implicated in causing miscarriage – which another study claimed in early 2008.
Caffeine consumption has been equivocally associated with miscarriage, despite an absence of prospective longitudinal measurement of caffeine intake during sensitive windows of human development. In response to this critical data gap, we analyzed daily caffeine consumption while attempting pregnancy through 12 menstrual cycles at risk for pregnancy and found that caffeine consumption did not increase the risk or hazard of miscarriage, even after adjusting for relevant covariates.
I can’t get the full text, even with my library privileges, but the crucial point is that this study was prospective, meaning it followed women over time as they attempted to conceive. Thus, it didn’t rely on people’s usually faulty memories to gauge how much coffee or Pepsi they drank and when. It’s not evident to me whether it was also a controlled study, which was one of the Cochrane criteria.
By comparison, the study by Dr. De-Kun Li that caused all the anxiety about caffeine and miscarriage was retrospective. It relied on women’s memories. Only one interview was conducted with each study participant. In most of those cases where the woman miscarried, the interviews occurred after the pregnancy loss. It seems sort of obvious how grief and hormones might lead to self-blaming. Oh, if I’d only given up my coffee! Broadsheet had a good rundown of the other blatant weaknesses of the study. The media, naturally, blew it up into yet another Rule for Pregnancy, and Dr. Li did his best to add to the guilt-tripping.
While this new study has little direct bearing on me, personally (I am so done having babies!), I’d be just delighted if there were one less realm that the Pregnancy Police saw fit to patrol.
Coffee kitteh from I Can Has Cheezburger?