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Difficulty: MediumNormal Pregnancy and Prenatal Care

Match each normal obstetrical finding or clinical milestone to the earliest gestational age at which it is typically expected during a normal, uncomplicated pregnancy.

  • Transvaginal ultrasound visualization of a gestational sac containing a yolk sac5 to 6 weeks gestation
  • Fetal heart tones become reliably audible via a handheld Doppler device10 to 12 weeks gestation
  • Uterine fundus becomes palpable midway between the pubic symphysis and the maternal umbilicus16 weeks gestation
  • Uterine fundus becomes palpable precisely at the level of the maternal umbilicus20 weeks gestation

Answer

Yolk sac on transvaginal ultrasound: 5 to 6 weeks. Fetal heart tones via Doppler: 10 to 12 weeks. Fundus midway to umbilicus: 16 weeks. Fundus at umbilicus: 20 weeks.
In a normal pregnancy, clinical dating utilizes well-established milestones. A gestational sac containing a yolk sac is the earliest definitive sonographic evidence of an intrauterine pregnancy, reliably visible via transvaginal ultrasound at 5 to 6 weeks gestation. By 10 to 12 weeks, the uterus begins to rise out of the protective bony pelvis, which allows fetal heart tones to be auscultated externally with a handheld Doppler device. Physical examination of uterine growth follows a predictable pattern: by 12 weeks, the fundus is palpable at the pubic symphysis; by 16 weeks, it is palpable midway between the pubic symphysis and the maternal umbilicus; and by 20 weeks, it reaches the level of the umbilicus.

Step-by-Step Solution

1
Identify the timeline for early sonographic landmarks.
The yolk sac appears within the gestational sac at 5 to 6 weeks gestation.
This early sonographic finding confirms an intrauterine pregnancy before physical examination changes are prominent.
2
Determine the timeline for clinical auscultation of fetal heart tones.
A handheld Doppler can reliably detect fetal heart tones by 10 to 12 weeks gestation.
The uterus must grow enough to become an abdominal organ (rising above the pelvic brim) to allow the Doppler signal to easily penetrate the maternal abdomen.
3
Track second-trimester anatomical fundal height progression.
The fundus reaches midway between the symphysis pubis and umbilicus at 16 weeks, and reaches the umbilicus at 20 weeks.
Uterine growth follows a highly predictable anatomical trajectory in the second trimester, serving as a reliable bedside marker for appropriate fetal growth.

Key Concept

Normal obstetrical milestones and gestational dating landmarks
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Topics

Normal Pregnancy and Prenatal Care

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