Intrauterine Devices (IUDs): Mechanisms of Action

Intrauterine Devices (IUDs): Mechanisms of Action
Authors: Danielle Chang Reviewers: Mirna Matta Crystal Liu Aysah Amath* * MD at time of publication
Intrauterine Device (IUD)
Contraceptive device that sits in the fundus of the uterus
Two Types
T-shaped polyethylene with fine copper wrapped around the vertical stem and arms
Releases copper in the uterus
Progesterone Releasing
IUD made of plastic containing levorgestrel (synthetic progesterin, progesterone receptor agonist)
Releases levorgestrel in the uterus Stimulate progesterone receptors
May inhibit ovulation through negative feedback on hypothalamus (not consistent evidence)
Foreign body reaction in endometrium
IUD creates local lysosomal activation and uterine inflammatory response Mechanism not fully understood
High copper concentrations toxic to sperm
Alters sperm mobility
Decreases chance of fertilization
Suppresses endometrium
Thickening of the cervical mucus
Barrier to sperm penetration
Disturbs function of endometrium
Changes uterine environment
Thins the endometrium
Decreases number of blood vessels to the endometrium
Suppresses proliferation
Atrophies endometrial glands
Sloughing of the endometrium
Inflammatory reaction against blastocyst if fertilization occurred
Hostile environment for implantation
Decreased menstrual blood loss and eventual amenorrhea
Sign/Symptom/Lab Finding
Published October 12, 2019 on