Use of various contraceptive methods and time of conception in a community-based population

To investigate the association between method of contraception and time to conception in a normal community-based population.

Prospective, cross-sectional, survey.

Large comprehensive ambulatory women's health center.

One thousand pregnant women at their first prenatal obstetrics visit were asked to complete a self-report questionnaire. The return to fertility was analyzed by type of contraceptive method, duration of use, and other sociodemographic variables.

Response rate was 80% (n=798). Mean age of the patients was 29.9+/-5 years. Seventy-five percent had used a contraceptive before trying to conceive: 80% oral contraceptives, 8% intrauterine device, and 7% barrier methods. Eighty-six percent conceived spontaneously. Contraceptive users had a significantly higher conception rate than nonusers in the first 3 months from their first attempt at pregnancy. Type of contraception was significantly correlated with time to conception. Pregnancy rates within 6 months of the first attempt was 60% for oral contraceptive users compared to 70 and 81% for the intrauterine device and barrier method groups, respectively. There was no correlation between time to conception and parity or duration of contraceptive use. Other factors found to be significantly related to time to conception were older age of both partners and higher body mass index.

Contraception use before a planned pregnancy does not appear to affect ease of conception. Type of method used, although not duration of use, may influence the time required to conceive.