Vessey M P, McPherson K, Johnson B
Lancet. 1977 Oct 8;2(8041):731-3. doi: 10.1016/s0140-6736(77)90236-7.
43 deaths are known to have occurred among the 17 032 participants in the Oxford/Family Planning Association contraceptive study up to the end of April, 1977. 9 deaths from cardiovascular causes have been observed among the women in the oral-contraceptive entry group (49 681 woman-years of observation) while no such deaths have been observed among the women who entered the study while using a diaphragm or an intrauterine device (39 146 woman-years of observation). These findings are consistent with the results presented in the accompanying report from the Royal College of General Practitioners Oral Contraception Study.