Resting Heart Rate Variability and the Effects of Biofeedback Intervention in Women with Low-Risk Pregnancy and Prenatal Childbirth Fear.

Anxiety about labor in women at the end of pregnancy sometimes reaches levels that are clinically concerning. We investigated whether low-risk pregnant women with childbirth fear during the last trimester demonstrate specific findings with regard to resting heart rate variability (HRV) and examined whether HRV biofeedback can reduce this fear and alter resting HRV. We measured the levels of childbirth fear (Wijma delivery expectancy/experience questionnaire, W-DEQ) and resting HRV indexes in 97 low-risk pregnant women in their 32nd-34th week of gestation and advised women with W-DEQ scores of ≥ 66 (n = 40) to practice HRV biofeedback (StressEraser) at home. We then reassessed these measures 3-4 weeks later in the 36th-37th week of gestation regardless of whether the women practiced the method. We found that childbirth fear had no significant effect on resting HRV indexes when the W-DEQ cutoff was conventionally set at ≥ 66. However, women with W-DEQ scores of ≥ 90 (n = 5) had a significantly lower high-frequency power than their counterparts (p = 0.028). The W-DEQ scores reduced significantly in women who performed HRV biofeedback (n = 18, p < 0.001), but there was no change in those who did not perform the method (n = 20). These findings suggested that very high W-DEQ scores (≥ 90), but not the conventional criteria (W-DEQ score ≥ 66), of the fear of childbirth were associated with low parasympathetic activity among low-risk pregnant women and that HRV biofeedback intervention can effectively decrease the fear of childbirth in these women.