Fecundity in Thai and European regions: results based on waiting time to pregnancy.

Very little is known about the frequency of subfecundity in different cultures, ethnic groups and regions. To fill this gap, the European Study Group on Infertility and Subfecundity established data on the prevalence of infertility and subfecundity in five European regions. In this study, a comparison of fecundity was made between 4035 Caucasian women from five European countries and 1496 Asian women from southern Thailand. Fecundity was measured using 'time to pregnancy', i.e. the time women took to conceive after stopping contraceptive methods. The Thai primigravid women had a shorter time to pregnancy than European women, whereas time to pregnancy was found to be longer among Thai multigravidae, although this was not statistically significant. This study has illustrated that cross-culture comparison of subfecundity is difficult despite using a common protocol and questionnaire because of differences in the use of contraceptive methods and a different concept of pregnancy planning. The distribution of time to pregnancy for the Thai women was not outside the variation found within the European samples.