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

(Kiana) #1

CESAREAN SECTION


Cesarean section is a procedure in which the fetus is delivered through incisions
in the maternal anterior abdominal and uterine walls. The overall U.S. cesarean
section rate in 2011 was ~33% (includes both primary and repeat procedures).


Risks. Maternal mortality and morbidity are higher than with vaginal delivery,
especially with emergency cesareans performed in labor. Maternal mortality is
largely anesthetic-related, with overall mortality ratio of 25 per 100,000.


Uterine Incisions


Hemorrhage: Blood   loss    is  2x  that    of  a   vaginal delivery,   with    mean    of  1,000
mL.
Infection: Sites of infection include endometrium, abdominal wall wound,
pelvis, urinary tract, or lungs. Prophylactic antibiotics can decrease infectious
morbidity.
Visceral injury: Surrounding structures can be injured (e.g., bowel, bladder,
and ureters).
Thrombosis: Deep venous thrombosis is increased in the pelvic and lower
extremity veins.

Low segment transverse. This    incision    is  made    in  the noncontractile  portion
of the uterus and is the one most commonly used. The bladder must be
dissected off the lower uterine segment. It has a low chance of uterine rupture
in subsequent labor (0.5%).
Advantages are trial of labor in a subsequent pregnancy is safe; the risk
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