For women whose emergency contraception failed, one study of 332 pregnant women who had used levonorgestrel found no teratogenic effect or risk of birth defects.5 Although it is not contraindicated in breastfeeding mothers, it was recommended that patients discontinue breastfeeding for 8 hours post ingestion. Recognized contraindications to oral contraceptives do not apply to levonorgestrel, given the temporary and relative low exposure to the hormone.3
As for efficacy, timing is of the essence. As stated previously, if not taken before ovulation has occurred, it is ineffective. If taken within 72 hours of unprotected intercourse, one study showed levonorgestrel would prevent 85% of pregnancies that otherwise might have occurred.3 Although the package insert says it must taken within 72 hours, studies have shown protection up to 120 hours post coitus, but that efficacy declines with every hour. Body mass index also may play a role in effectiveness, but the studies have been varied and more research is required before a determination is made.2
Dr. Francine Pearce
The annual well visit is the opportune time to educate parents and teens about abstinence, sex, sexually transmitted infections, and emergency contraception. Parents need to know the statistics of teen pregnancy and rates of STIs so they can be informed and further these conversations at home. should they find themselves in this dilemma. The websites not-2-late.com and bedsider.org are excellent sources of information on emergency contraception.