A longitudinal study of contraception and pregnancies in the same women followed for a quarter of a century.

BACKGROUND

There is a need to improve our understanding of contraceptive use over the long term. The aims of this study were to describe contraceptive use and pregnancies in the same women followed prospectively from 19 to 44 years of age.

METHODS

In 1981, a postal questionnaire about contraception, pregnancies and reproductive health was sent to a random sample (n = 656) of 19-year-old women resident in Gothenburg, Sweden. The responders were contacted again every fifth year.

RESULTS

At 19 years of age, 74% of the women had already used contraception and this increased to 98% at 44 years. Combined oral contraception was the commonest method currently used up to 29 years of age (48/51/22% at 19/24/29 years of age, respectively) and thereafter an intrauterine device (IUD: 34/39/38% at 34/39/44 years of age, respectively). Condom use alone during the 25-year study period was: 14/12/24/21/21/15% and non-use of contraception was: 35/24/26/20/21/26%. The mean number of pregnancies/children increased from 0.2/0.1 at 19 years of age to 3.1/2.1 at 44 years. Women who had been pregnant and women who had not been pregnant <or=19 years of age were compared up to 44 years of age (months of OC use: 69/107, P < 0.01; months of IUD use: 126/91, P < 0.01; 4.2/2.9 pregnancies, P < 0.001; 2.5/2.1 children, P< 0.09).

CONCLUSIONS

Choice of contraception was strongly related to age and parity, and the cumulative total number of pregnancies at 44 years of age, and contraceptive choice was related to age at first pregnancy.