Master the board step 3

Section 6
Obstetrics
contributing author Elizabeth August, MD
The Uncomplicated Pregnancy
Diagnosing Pregnancy
Pregnancy is suggested in a patient with amenorrhea, enlargement of the
uterus, and a (+) urinary β-hCG. Pregnancy is confirmed with the following:
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Presence of a gestational sac: This is seen by transvaginal ultrasound at 4 to
5 weeks. This corresponds to a serum β-hCG level of about 1,500 mIU/mL.
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Fetal heart motion: Seen by ultrasound at 5 to 6 weeks.
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Fetal heart sounds: Heard with Doppler ultrasonography at 8 to 10 weeks.
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Fetal movements: Felt by the examining physician after 20 weeks.
CCS Tip: Order pregnancy counseling (e.g., “Avoid alcohol and tobacco.”) in
newly diagnosed pregnant patients via the ORDER icon. Type in, “Counsel patient,
pregnancy.”
Gravidity: number of
pregnancies
Parity: number of births
with a gestational age
> 24 weeks
Routine Prenatal Screening Tests
First Trimester
A 21-year-old primigravida, para 0 (G1 P0) presents for her first prenatal visit at
11 weeks’ gestation, which is confirmed by obstetric sonogram. She has no risk
factors. What screening tests will you perform?
Answer: See the following chart.
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