Nonstress testing is used more frequently for antepartum testing than contraction stress testing because contraction stress testing has a:
Higher frequency of equivocal test results
Limited reporting option for the compromised fetus
Low predictability of fetal well-being within 7 days of a negative test
Comprehensive and Detailed Explanation From Exact Extract–Based NCC C-EFM References:
NCC and AWHONN explain that Contraction Stress Testing (CST):
Has a higher rate of equivocal (“equivocal–suspicious” or “equivocal–hyperstimulation”) results
Frequently must be repeated or replaced with other tests
Requires inducing contractions, which carries risk (hyperstimulation, preterm labor, uterine rupture in scarred uterus)
NST is used more commonly because it is:
Noninvasive
Easier to perform
Has fewer contraindications
Has a lower rate of equivocal results
Why the others are incorrect:
B — CST does detect fetal compromise reliably and is NOT limited in its reporting structure.
C — A negative CST actually has very high negative predictive value for 7 days, making this answer incorrect.
Thus the correct choice is A. Higher frequency of equivocal results.
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