Fetal acoustic stimulation in early labor and pathological fetal acidemia: a preliminary report.
OBJECTIVE
To determine if a nonreactive response to fetal acoustic stimulation in early labor can predict a significantly higher risk of umbilical arterial pH <7.10 or <7.00.


METHODS
Fetal acoustic stimulation was applied to the fetuses of term parturients (gestational age > or =37 weeks) with cervical dilation of < or =5 cm. The responses to stimulation were correlated with cesarean delivery for fetal distress and umbilical arterial pH. Student's t-test, Chi-square, and Fisher exact test were used; P < 0.05 was considered significant. Relative risks (RR) and 95% confidence intervals (CI) were calculated.


RESULTS
The study population contained 271 subjects, of which 90% (244) had a reactive response following acoustic stimulation and 10% (27) a nonreactive response. The maternal demographics, time interval from stimulation to delivery (8.3 +/- 8.7 vs. 8.3 +/- 8.4 h; P = 1.00) were similar in the two groups. Compared to those with a reactive response, patients with a nonreactive response had a significantly greater risk for: 1) cesarean delivery for fetal distress (2.0% vs. 11.1%; P = 0.03, RR 4.1, 95% Cl 1.5, 60.5), 2) umbilical arterial pH <7.10 (2.0% vs. 14.8%; P = 0.007, RR 5.0, 95% CI 2.2, 11.6), and 3) umbilical arterial pH <7.00 (0.8% vs. 7%; P = 0.05, RR 5.0, 95% CI 1.8, 15.2).


CONCLUSIONS
A nonreactive response to fetal acoustic stimulation in early labor is associated with a significantly increased risk for cesarean delivery for fetal distress and neonatal acidosis. This finding extends the potential value of acoustic stimulation as an intrapartum admission screening test.
Chauhan
S P
SP
Maternal-Fetal Medicine Section at Spartanburg Regional Medical Center, South Carolina, USA. mfmchauhan@aol.com
Hendrix
N W
NW
Devoe
L D
LD
Scardo
J A
JA
D000138:Acidosis / Q000175:diagnosis*; D000161:Acoustic Stimulation; D000328:Adult; D002585:Cesarean Section; D005260:Female; D005316:Fetal Distress / Q000175:diagnosis; D005333:Fetus / Q000502:physiology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007231:Infant, Newborn; D007743:Labor, Obstetric; D011247:Pregnancy; D011256:Pregnancy Outcome; D012307:Risk Factors; D014469:Umbilical Arteries; D014732:Vibration