USMLE Step 2 CK Lecture Notes 2019: Obstetrics/Gynecology (Kaplan Test Prep)

(Kiana) #1

INTRAUTERINE CONTRACEPTION


A   30-year-old woman   with    Crohn's disease who periodically    requires
steroid therapy seeks advice regarding long-term contraception. She has had
3 pregnancies. A subserosal, fundal fibroid was noted at the time of her
previous cesarean section delivery. She states that she is in a mutually
monogamous relationship. She was treated for a chlamydia infection 2
months ago but does not like the idea of hormonal contraception and is
asking about the risks associated with an IUS.

Intrauterine system (IUS) contraception is a long-acting reversible contraceptive
method that involves placement of a small T-shaped object inside the uterus.
Failure rate is <1%. Continuation rates at 1 year are almost 80%.


Mechanisms of action include the following:


Absolute contraindications include a confirmed or suspected pregnancy, known
or suspected pelvic malignancy, undiagnosed vaginal bleeding, and known or
suspected salpingitis. Relative contraindications include abnormal uterine size
or shape, medical condition (e.g., corticosteroid therapy, valvular heart disease,


Decreased   sperm   transport
Increased tubal motility (causing failure of implantation of immature zygote)
Decreased implantation secondary to endometrial inflammation
Phagocytic destruction of sperm and blastocyst
Alteration of cervical mucus (only progesterone IUSs)
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