Why and when do RFMs occur or are perceived to occur?
Clearly when stillbirth occurs, movements stop and this will usually, but not invariably, be perceived. Paradoxically, there may be a transient increase in movements. However, in the vast majority with RFMs, the movements pick up again and the pregnancy proceeds to term without adverse outcome 1,7.
Accepting that perceived and actual movements are different, there is little evidence on why reduced movements occur. Perception is altered by placental site, fetal position, fetal sleep and maternal activity. The data from biophysical profiles suggest a poor score is a late event. It is the largely undocumented but nevertheless clear experience of ultrasound that babies with severe FGR usually move normally and are perceived to do so. This, and the abrupt presentation of stillbirth with RFMs 8, suggests that where pathological it is a preterminal symptom. This is occasionally identified by a preterminal cardiotocograph. The implication is that the time window to expedite birth before disaster is short. Indeed, if RFMs do occur late in the sequence of different events that lead to stillbirth, fetal movements initiatives are akin to screening for ovarian cancer by looking for ascites.