The generalizability of trial data; a comparison of beta-blocker trial participants with a prospective cohort of women taking beta-blockers in pregnancy

Eur J Obstet Gynecol Reprod Biol. 2001 Feb;94(2):205-10. doi: 10.1016/s0301-2115(00)00331-6.


Objective: To evaluate the generalizability of randomized controlled trial (RCT) data to obstetric practice, using the example of beta-blocker therapy.

Study design: Descriptive comparison of characteristics of participants, interventions, and outcomes assessed between a meta-analysis of trials of beta-blocker therapy in pregnancy, and a prospective cohort of beta-blocker exposed callers to Motherisk, a Teratology Information Service.

Results: 72 women (cohort) and 34 trials with 2474 participants (meta-analysis) were compared. The generalizability of trials was limited by an inadequate description of maternal demographics and indications for beta-blockers, and a focus on the effectiveness of beta-blockers as antihypertensives rather than on reproductive risks.

Conclusions: Some of these limitations could be rectified. Others cannot, such as evaluation of teratogenicity (for ethical reasons) or all indications for a drug (for practical reasons). Reference to observational literature is, and will likely remain, necessary to address the 'harm' side of the therapeutic equation in pregnancy.

Publication types

  • Comparative Study
  • Meta-Analysis
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adrenergic beta-Antagonists / adverse effects
  • Adrenergic beta-Antagonists / therapeutic use*
  • Adult
  • Cohort Studies
  • Databases as Topic
  • Diabetes, Gestational / drug therapy
  • Female
  • Gestational Age
  • Humans
  • Hydralazine / therapeutic use
  • Hypertension / drug therapy*
  • Infant, Newborn
  • Labetalol / therapeutic use
  • Pregnancy
  • Pregnancy Complications / drug therapy
  • Pregnancy Complications, Cardiovascular / drug therapy*
  • Prospective Studies
  • Racial Groups
  • Randomized Controlled Trials as Topic*
  • Treatment Outcome


  • Adrenergic beta-Antagonists
  • Hydralazine
  • Labetalol