Foetal heart rate can be auscultated with a fetoscope at:

Appeared in: DSSSB 12 August 2024

Explanation

A fetoscope is a non-electronic, horn-shaped or stethoscope-like instrument used to listen to fetal heart sounds.
For a fetoscope to work, the fetus must be large enough and the heart strong enough for the sounds to travel through the amniotic fluid and maternal abdominal wall.
This is typically possible around 18 to 20 weeks of gestation.
By 20 weeks, the fetal heart sounds are clearly audible in most pregnancies using a fetoscope.

Option A: At 4 weeks, the fetal heart is just beginning to form and beat. It is microscopic and its sounds cannot be detected by any external device, not even sensitive ultrasounds.
Option B: At 12 weeks, the fetal heart sounds can be detected, but it requires an electronic Doppler device which amplifies the sound. A fetoscope is not sensitive enough at this stage.
Option D: At 8 weeks of gestation, cardiac activity can be visualized on a transvaginal ultrasound, but the sounds are not audible with any external listening device, including a fetoscope.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Fetal heart rate auscultation milestones based on the instrument used as background academic context rather than a clinical decision trigger.
Understanding the correct timing for using different auscultation tools is crucial for accurate prenatal assessment and managing parental expectations.
Using a fetoscope before 18-20 weeks and failing to hear a heartbeat can cause unnecessary anxiety for the parents. Nurses must educate parents on when to expect to hear the heartbeat with different methods.
In low-resource settings where Doppler ultrasound may not be available, the fetoscope remains a vital tool for monitoring fetal well-being.

How to Approach the Question

First, identify the key terms in the question: 'Foetal heart rate', 'auscultated', and 'fetoscope'.
The question asks for the specific gestational age when a 'fetoscope' can be used.
Recall or look up the different methods for detecting fetal heart rate and their corresponding timelines.
Differentiate between electronic devices (like Doppler ultrasound) that amplify sound and non-electronic devices (like a fetoscope).
Recognize that non-electronic devices require the fetus to be larger and the heartbeat stronger, which occurs later in pregnancy.
Compare the options provided with the known timeline for fetoscope use (18-20 weeks) to select the most appropriate answer.

Concept Tested & Keywords

Concept Tested: Fetal heart rate auscultation milestones based on the instrument used.
Stem keywords: Foetal heart rate, auscultated, fetoscope, gestation
Lead-in keywords: BEST, MOST RELEVANT CLUE
Negative lead-in flag: false

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E6 Obstetrics Williams p. 19-36

E6 Midwifery Obstetrics and Gynecology Nursing Sandeep Kaur p. 50-60

E6 Parks TextBook of Preventive & Social Medicine part 2 — Subpart A (pp 1-232 of 464) p. 19-21

Practise the full DSSSB 12 August 2024

Attempt every question from this paper in a timed mock, then review the full solution for each one.