Talking straight about emergency contraception

The timing of sexual intercourse in relation to ovulation strongly influences the chance of conception, although the actual number of fertile days in a woman's menstrual cycle is uncertain. The timing of intercourse may also be associated with the sex of the baby. We recruited 221 healthy women who were planning to become pregnant. At the same time the women stopped using birth-control methods, they began collecting daily urine specimens and keeping daily records of whether they had sexual intercourse. We measured estrogen and progesterone metabolites in urine to estimate the day of ovulation. In a total of 625 menstrual cycles for which the dates of ovulation could be estimated, 192 pregnancies were initiated, as indicated by increases in the urinary concentration of human chorionic gonadotropin around the expected time of implantation. Two thirds (n = 129) ended in live births. Conception occurred only when intercourse took place during a six-day period that ended on the estimated day of ovulation. The probability of conception ranged from 0.10 when intercourse occurred five days before ovulation to 0.33 when it occurred on the day of ovulation itself. There was no evident relation between the age of sperm and the viability of the conceptus, although only 6 percent of the pregnancies could be firmly attributed to sperm that were three or more days old. Cycles producing male and female babies had similar patterns of intercourse in relation to ovulation. Among healthy women trying to conceive, nearly all pregnancies can be attributed to intercourse during a six-day period ending on the day of ovulation. For practical purposes, the timing of sexual intercourse in relation to ovulation has no influence on the sex of the baby.

A single 10 mg dose of mifepristone, and two 0.75 mg doses of levonorgestrel 12 h apart, are effective for emergency contraception. Because no studies had compared the efficacies of both compounds, or investigated a single dose of 1.5 mg levonorgestrel, we undertook this three-arm trial. We did a randomised, double-blind trial in 15 family-planning clinics in 10 countries. We randomly assigned 4136 healthy women with regular menstrual cycles, who requested emergency contraception within 120 h of one unprotected coitus, to one of three regimens: 10 mg single-dose mifepristone; 1.5 mg single-dose levonorgestrel; or two doses of 0.75 mg levonorgestrel given 12 h apart. The primary outcome was unintended pregnancy; other outcomes were side-effects and timing of next menstruation. Analysis was by intention to treat, but we did exclude some patients from the final analyses. Of 4071 women with known outcome, pregnancy rates were 1.5% (21/1359) in those given mifepristone, 1.5% (20/1356) in those assigned single-dose levonorgestrel, and 1.8% (24/1356) in women assigned two-dose levonorgestrel. These proportions did not differ significantly (p=0.83). The relative risk of pregnancy for single-dose levonorgestrel compared with two-dose levonorgestrel was 0.83 (95% CI 0.46-1.50), and that for levonorgestrel (the two regimens combined) compared with mifepristone, 1.05 (0.63-1.76). Side-effects were mild and did not differ greatly between groups, and most women menstruated within 2 days of the expected date. Women who took levonorgestrel had earlier menses than did those who took mifepristone. The three regimens studied are very efficacious for emergency contraception and prevent a high proportion of pregnancies if taken within 5 days of unprotected coitus. Mifepristone and levonorgestrel do not differ in efficacy. A 1.5 mg single levonorgestrel dose can substitute two 0.75 mg doses 12 h apart.

It is estimated that half of unintended pregnancies could be averted if emergency contraception (EC) were easily accessible and used. To evaluate the effect of direct access to EC through pharmacies and advance provision on reproductive health outcomes. A randomized, single-blind, controlled trial (July 2001-June 2003) of 2117 women, ages 15 to 24 years, attending 4 California clinics providing family planning services, who were not desiring pregnancy, using long-term hormonal contraception or requesting EC. Participants were assigned to 1 of the following groups: (1) pharmacy access to EC; (2) advance provision of 3 packs of levonorgestrel EC; or (3) clinic access (control). Primary outcomes were use of EC, pregnancies, and sexually transmitted infections (STIs) assessed at 6 months; secondary outcomes were changes in contraceptive and condom use and sexual behavior. Women in the pharmacy access group were no more likely to use EC (24.2%) than controls (21.0%) (P = .25). Women in the advance provision group (37.4%) were almost twice as likely to use EC than controls (21.0%) (P<.001) even though the frequency of unprotected intercourse was similar (39.8% vs 41.0%, respectively, P = .46). Only half (46.7%) of study participants who had unprotected intercourse used EC over the study period. Eight percent of participants became pregnant and 12% acquired an STI; compared with controls, women in the pharmacy access and advance provision groups did not experience a significant reduction in pregnancy rate (pharmacy access group: adjusted odds ratio [OR], 0.98; 95% confidence interval [CI], 0.58-1.64; P = .93; advance provision group: OR, 1.10; 95% CI, 0.66-1.84, P = .71) or increase in STIs (pharmacy access group: adjusted OR, 1.08, 95% CI, 0.71-1.63, P = .73; advance provision group: OR, 0.94, 95% CI, 0.62-1.44, P = .79). There were no differences in patterns of contraceptive or condom use or sexual behaviors by study group. While removing the requirement to go through pharmacists or clinics to obtain EC increases use, the public health impact may be negligible because of high rates of unprotected intercourse and relative underutilization of the method. Given that there is clear evidence that neither pharmacy access nor advance provision compromises contraceptive or sexual behavior, it seems unreasonable to restrict access to EC to clinics.