R T Kambic1, V Lamprecht. 1. Department of Population Dynamics, Johns Hopkins School of Hygiene and Public Health, Baltimore, MD 21205, USA.
Abstract
OBJECTIVE: To estimate the unplanned pregnancy rate of calendar rhythm. DESIGN: Meta-analysis of eight studies of calendar rhythm published between 1940 and 1989. RESULTS: There exist few studies of the calendar rhythm method. Analysis of the best of these studies resulted in a conservative estimated Pearl rate of 18.5 +/- 1.8, and a less conservative estimate of 15.0 +/- 4.0, standardized to 12 months' observation; these results are in the range of other natural and barrier methods. DISCUSSION: We need properly done clinical trials of the calendar rhythm method to scientifically establish its effectiveness.
OBJECTIVE: To estimate the unplanned pregnancy rate of calendar rhythm. DESIGN: Meta-analysis of eight studies of calendar rhythm published between 1940 and 1989. RESULTS: There exist few studies of the calendar rhythm method. Analysis of the best of these studies resulted in a conservative estimated Pearl rate of 18.5 +/- 1.8, and a less conservative estimate of 15.0 +/- 4.0, standardized to 12 months' observation; these results are in the range of other natural and barrier methods. DISCUSSION: We need properly done clinical trials of the calendar rhythm method to scientifically establish its effectiveness.