Factors associated with unintended pregnancy in Yamagata, Japan.

Data on unintended pregnancy are scarce in Japan. The purpose of this study is to examine the association of sociodemographic, reproductive, and other health behavioral factors with unintended pregnancy. A survey was conducted from May through November 1999 in Yamagata, Japan. We distributed anonymous self-administered questionnaires to cervical and breast cancer screening participants aged 35-49 years. There were 564 eligible women, and the number of respondents was 421 (74.6%). The proportion of women who had experienced unintended pregnancy was 46.2%, and 40.1% of them had repeated experiences. Among 312 pre-menopausal married women who did not want to become pregnant, 15.4% were not using any contraception. Factors that were significantly associated with the experience of unintended pregnancy were age of husband being 4 or more years older [Odds ratio (OR) = 1.83], and age at initiation of sexual intercourse (OR = 1.86) and marriage during teens (OR = 11.14). Analysis of 1255 pregnancies that the subjects had experienced showed that 51.2% and 25.9% of mistimed and unwanted pregnancies occurred as a result of no contraceptive use, and 39.5% and 71.1% of these ended in abortions. The number of past unintended pregnancies was significantly (p < 0.001) correlated with the number of pregnancies (r(s) = 0.49), live births 0.20) and abortions (r(s) = 0.63). This is the first epidemiological study in Japan to examine factors associated with unintended pregnancy, and also contraceptive use and pregnancy outcome for each of the unintended pregnancy women had experienced. Unintended pregnancy is not a rare event among our target population, and many unintended pregnancies leading to abortion could be prevented by effective contraceptive use. Results suggest that Yamagata's family planning strategies need to target both the younger and older generations, and address the role of men. A woman's pregnancy history reflecting her past experience of unintended pregnancy could be used as an indicator for recognizing the woman's need for appropriate contraceptive counseling for the prevention of repeated unintended pregnancies.