The relationship of maternal position to the results of brief nonstress tests: A randomized clinical trial

OBJECTIVE: This study was undertaken to determine whether maternal posture (left lateral recumbent vs semi-fowler position) had any effect on nonstres s test results when the test was performed for a shortened period (10 minut es). STUDY DESIGN: In this randomized clinical trial of 108 patients with single ton pregnancies at 32 to 42 weeks' gestation, patients were randomly assign ed to a "sitting first" (semi-Fowler position) or a "supine first" (left la teral recumbent position) group at the initial visit. The order of position was alternated at subsequent visits. Ten minutes of fetal heart rate monit oring was performed in each position at each visit. Computer analysis of th e nonstress test was used to interpret each 10-minute segment for reactivit y. Statistical analyses were performed on the paired nonstress test unit (s itting and supine). RESULTS: There were no adverse clinical outcomes among the participants. Lo gistic regression analysis showed that both the sequence of the nonstress t est and the position were significant and independent factors related to no nstress test reactivity. Tests performed during the second 10 minutes and t ests performed with the patient in the semi-fowler position were more likel y to have reactive results. CONCLUSION: The semi-fowler position is a superior position for conducting a nonstress test in a short period. Use of this position could decrease the need for prolonged monitoring, thus leading to a more time-effective evalu ation of patients at risk.