60 Usha Verma and Neil Verma
(i.e., nausea was reduced from 50.5% with Yuzpe to 23.1% with Plan B;
vomiting was reduced from 18.8% to 5.6%). There are only three
contraindications to the use of LNG EC: existing pregnancy, undiagnosed
vaginal bleeding or a known allergy to any ingredient in the product. There is
only one report in the literature of a potential drug interaction with LNG-only
EC; this was an apparent interaction with warfarin [162].
There were some concerns initially regarding the increase in ectopic
pregnancy rate when emergency contraception fails. In a systemic review that
included 136 studies, there was no increase in the rate of ectopic pregnancies
when the treatment failed. In the LNG studies, 3 of 307 (1%) were ectopic
while the incidence of ectopic pregnancy in the general population is around
2%. Because emergency contraceptive pills are effective in lowering the risk
of pregnancy, their use will reduce the chance that an act of intercourse will
result in ectopic pregnancy [163].
Safety in Pregnancy
There is no evidence that LNG would harm a pregnant woman or would
harm a developing fetus if the product is taken accidentally during early
pregnancy. Use in pregnant women is contraindicated because the product
would be ineffective, not because it has been shown to be unsafe [164–166].
No studies have examined potential teratogenic effects of LNG-EC. However,
there have also been no reports of adverse birth outcomes in safety and
efficacy studies of the drug covering over 6000 women. Only one adverse
birth outcome has been reported to Women’s Capital Corporation (the
distributors of Plan B) since Plan B has been on the market, and this was
following the use of another brand of LNG-only emergency contraception in
the UK.
Jatloui et al. reported on the safety of emergency contraceptives. This was
based on a PubMed and Cochrane database search for articles published from
the date of inception until May 2015 pertaining to the safety of LNG, ulipristal
acetate or Yuzpe ECP use. Four studies examined LNG or Yuzpe use among
pregnant or breastfeeding women, and one reported the risk of ectopic
pregnancy among women repeatedly using LNG ECPs. Poor pregnancy
outcomes were rare among pregnant women who used LNG or Yuzpe ECPs
during the conception cycle or early pregnancy. Breastfeeding outcomes did
not differ between women exposed to LNG ECP and those unexposed, and
there was no increased risk of ectopic pregnancy versus intrauterine pregnancy
after repeated use of ECPs compared with nonuse. One study demonstrated
that LNG passes into breastmilk but in minimal quantities. Studies suggest that