Reply to letter to the Editor regarding "Counting fetal movement frequency to prevent adverse fetal outcomes".

概要

We appreciate the response to our article, "Fetal movement frequency and the effect of associated perinatal factors: Multicenter study" 1.
　First, we agree that it is important to encourage pregnant women to report changes in their perception of the fetal movement (FM) quality, such as the strength and pattern, in order to prevent adverse fetal outcomes, as the comment on our article stated. It has been reported that decreased fetal movement (DFM) is associated with adverse fetal outcomes2, and an excessive delay in maternal reporting of DFM is related to perinatal death3. We previously showed that only 11% of mothers with stillbirths visited the outpatient department within 24 h of perceiving DFM 4. We therefore aimed to evaluate the normal range of FM frequency in the current study so that pregnant women could immediately report their perception of DFM. In addition, we could not establish a cut off level for the onset of adverse perinatal outcomes due to the fact that we did not factor in the FM frequency of fetal cases with a poor outcome in this study.
　Next, we are also concerned that pregnant women might mistake DFM in late pregnancy as normal for the term, according to the widespread myth that FM normally decreases toward the end of a pregnancy. Kuwata et al. showed a similar result to ours that the FM counting time based on the modified 'count to 10 method' gradually increased toward 40 weeks of gestation5, whereas several other studies found that pregnant women perceived strong and frequent FMs of healthy fetuses up to the birth.6 Although it is difficult to conclude whether or not FMs decrease toward the end of pregnancy, informing pregnant women of the normal range of FM counting time might help them report their perception of DFM more expediently and thus prevent adverse fetal outcomes.