Oral contraception, coital frequency, and the time required to conceive

Using data from the 1965 National Fertility Study (NFS) and from the 1957-1967 Princeton Fertility Study (PFS) the relationship between oral contraceptive use coital frequency and time required for conception is studied. Using NFS data mean monthly coital frequency (calculated by contraceptive method for women classified by age race education and religion) for women aged 25-44 was increased 18-20% for pill users compared to those using other methods a finding consistent with the PFS which observed a 7.5 monthly frequency rate for pill users compared to a theoretical 6.3 rate had they not shifted to pill use. Using data confined to women of similar age who discontinued contraception between June 1961 and September 1965 in order to conceive and adjusting coital frequency by age no difference was found in the time required to conceive between women who have used the pill and women who have used other methods of contraception. 85-87% of all women were pregnant within the first 6 months with a mean waiting time of 2.1-2.3 months; similar knowledge of the ovulatory cycle was found for both groups. Limitations to study results including reliability of measurement of coital frequency and problems of selectivity including age and memory bias are discussed.