Mirena Use In Pregnancy & Lactation

Pregnancy: The use of Mirena during an existing or suspected pregnancy is contraindicated (see Contraindications). In case of an accidental pregnancy with Mirena in situ, ectopic pregnancy should be excluded (see Precautions) and the system must be removed and termination of the pregnancy should be considered. Removal of Mirena or probing of the uterus may result in spontaneous abortion. Should these procedures not be possible, the woman should be informed about increased risk of spontaneous abortion or premature labour observed during the use of copper and plastic IUDs. Accordingly, such pregnancies should be closely monitored. The woman should be instructed to report all symptoms that suggest complications of the pregnancy, like cramping abdominal pain with fever.
Because of the intrauterine administration and the local exposure to the hormone, teratogenicity (especially virilisation) cannot be completely excluded. It can be expected that the systemic hormone exposure of the foetus through the maternal circulation is lower than with any other hormonal contraceptive method. Clinical experience of the outcomes of pregnancies with Mirena in situ is limited. However, the woman should be informed that, to date, there is no evidence of birth defects caused by Mirena use in cases where pregnancy continues to term with Mirena in place.
Lactation: Levonorgestrel has been identified in the breast milk. About 0.1% of the levonorgestrel dose is transferred during breast-feeding, but it is not likely that there will be a risk for the child with the dose released from Mirena, when it is inserted in the uterine cavity.
There appear to be no deleterious effects on infant growth or development when using any progestogen-only method after six weeks postpartum. Progestogen-only methods do not appear to affect the quantity or quality of breast milk. Uterine bleeding has rarely been reported in women using Mirena during lactation.
Fertility: Studies have suggested that in women who discontinue Mirena for planned pregnancy the pregnancy rate at one year is similar to those who do not use contraception.