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.