総説、診療ガイドライン
等の名称

EMERGENCY
CONTRACEPTIVE PILLS Medical and Service
Delivery Guidance
Forth Edition

著者、団体名等

ICEC/ FIGO

記載内容（抜粋）
LNG-ECP use versus non-use of LNG-ECP; adverse pregnancy
very low
outcomes:
7. EFFECTS ON PREGNANCY
Studies of women who became pregnant despite using the LNG regimen or who used
it inadvertently after becoming pregnant indicate that this regimen does not
harm either a pregnant woman or her fetus. It does not increase rates of
miscarriage, ectopic pregnancy, low birth weight, congenital malformations, or
pregnancy complications. Postmarketing pharmacovigilance data collection for
UPA ECPs also confirm the safety of this regimen. LNG and UPA ECPs are not
indicated for women with a known or suspected pregnancy; however, there is no
known harm to the woman, the course of her pregnancy, or the fetus if ECPs are
accidentally used.
8. PRECAUTIONS AND CONTRAINDICATIONS
ECPs are not indicated for a woman who has a confirmed pregnancy because they
will have no benefit. However, if an evaluation for pregnancy has not been
performed or if pregnancy status is unclear, ECPs may be used as there is no
evidence to suggest harm to a developing fetus.

Fact sheet on the
safety
of
levonorgestrel-alone
emergency
contraceptive
pills
(LNG ECPs)

WHO

Can LNG ECPs harm a developing fetus?
LNG ECPs do not harm a developing fetus if they are mistakenly taken early in
pregnancy. A study that compared pregnancy outcomes in women who used LNG ECPs
during their conception cycle with women who had not used LNG ECPs found no
differences in rates of miscarriage, birth weight, malformations, or in the
sex ratio at birth.
Can LNG ECPs cause an abortion?
LNG ECPs do not interrupt an established pregnancy or harm a developing embryo.
The evidence available to date shows that LNG ECP use does not prevent a
fertilized egg from attaching to the uterine lining. The primary mechanism of
action is to stop or disrupt ovulation; LNG ECP use may also prevent the sperm
and egg from meeting.
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