FHS can be auscultated with a fetoscope as early as which of the following?

Appeared in: DHS 2018 shift 1st

Explanation

A fetoscope is a non-electronic, acoustic instrument used for auscultating fetal heart sounds.
Due to its non-amplified nature, the fetus must be sufficiently large for the heartbeat to be audible through the mother's abdomen.
This typically occurs around 18 to 20 weeks of gestation, making 20 weeks the correct answer among the choices.
By 20 weeks, the fetal heart is strong enough and the body large enough for the sound to be transmitted effectively for detection with a fetoscope.

Option A: At 5 weeks, the fetal heart is just beginning to form. It is impossible to hear the heartbeat with any instrument, although cardiac activity may be visualized on a transvaginal ultrasound around 6 weeks.
Option B: At 10 weeks, the fetal heartbeat is not audible with a fetoscope. It can, however, be detected using an electronic Doppler ultrasound device, which amplifies the sound waves.
Option C: While fetal development is advancing, 15 weeks is generally too early to reliably detect fetal heart sounds using a non-amplified fetoscope. The sound is typically not strong enough to be heard.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Timeline for Fetal Heart Sound (FHS) Auscultation as background academic context rather than a clinical decision trigger.
Detecting FHS is a positive and conclusive sign of pregnancy. It provides reassurance to the expectant parents and confirms fetal viability.
Nurses must select the appropriate assessment tool based on the gestational age. Using a fetoscope at 10 weeks would be inappropriate and could cause unnecessary anxiety if no heartbeat is found.
The normal FHS range is 110-160 bpm. A rate outside this range requires further assessment and reporting, as it can indicate fetal distress.

How to Approach the Question

First, identify the key terms in the question: 'FHS' (fetal heart sounds), 'auscultated', and 'fetoscope'.
The question asks for the earliest time FHS can be heard with a fetoscope.
Recall the different methods for detecting fetal heart activity and their respective timelines.
Differentiate between a fetoscope (an acoustic, non-electronic device like a stethoscope or Pinard horn) and a Doppler (an electronic ultrasound device).
Remember that electronic devices like Doppler can detect the heartbeat much earlier (around 10-12 weeks) because they amplify the sound.
A fetoscope relies on the unamplified sound being strong enough to travel through the maternal abdomen, which happens later in pregnancy.

Concept Tested & Keywords

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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 DHS 2018 shift 1st

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