Factors that increase reactivity during fetal nonstress testing

Area of Science:

• Obstetrics and Gynecology
• Fetal Medicine
• Maternal-Fetal Medicine

Background:

• The nonstress test (NST) is a primary method for antepartum fetal surveillance.
• Nonreactive NST results can be ambiguous, necessitating further investigation or intervention.
• Improving NST reactivity and reducing testing time are clinically significant goals.

Purpose of the Study:

• To review methods that may enhance nonstress test (NST) reactivity.
• To identify factors that can shorten the time required to achieve a reactive NST.
• To assess the clinical utility of various interventions in antepartum fetal surveillance.

Main Methods:

• Systematic review of studies investigating interventions during NST.
• Analysis of maternal intake (glucose, cocoa, caffeine) effects on fetal heart rate and activity.
• Evaluation of maternal positioning, fetal manipulation, and external stimulation techniques.

Main Results:

• Maternal glucose administration showed no significant impact on NST results.
• Maternal intake of 70% cocoa or caffeine demonstrated a stimulating effect on fetal reactivity, more pronounced with higher cocoa concentrations (80%).
• Vibroacoustic and halogen light stimulation were associated with reduced time to NST reactivity; maternal positioning yielded equivocal results, and fetal manipulation had no effect.

Conclusions:

• Certain maternal intakes (cocoa, caffeine) and external stimuli (vibroacoustic, light) can enhance NST reactivity.
• These methods offer potential to improve the efficiency and effectiveness of antepartum fetal surveillance.