Maternal and Fetal Health Research Centre, University of Manchester, St Mary's Hospital, Manchester, UK
- Maternal and Fetal Health Research Centre, University of Manchester, St Mary's Hospital, Manchester, UK
- Correspondence to Alexander E Heazell
Maternal and Fetal Health Research Centre, University of Manchester, 5th floor, St Mary's Hospital, Oxford Road, Manchester, M13 9Wl, UK;
Implications for practice and research
■ Maternal perception of an active fetus and fetal hiccups is associated with reduced likelihood of late stillbirth.
■ A sudden change in maternally perceived fetal activity, particularly reduced fetal movements (RFM), is associated with late stillbirth and women should be encouraged to seek advice if this occurs.
■ Research is needed to examine the possible link between a single period of vigorous fetal activity and risk of late stillbirth.
■ The relationship between fetal hiccups, fetal breathing movements and their loss in compromised fetuses merits deeper exploration.
There has been no reduction in stillbirth rates for over two decades in many high-income countries, with approximately 1 in 200 pregnancies being affected after 24 weeks gestation in the UK.1 2 Identification of modifiable risk factors related to stillbirth would facilitate public-health campaigns aimed at stillbirth prevention.
Stacey et al conducted a retrospective case-controlled study including 155 women with singleton, structurally-normal stillbirths (cases) and 310 gestation-matched pregnant women with live infants (controls). This study used an interviewer-administered questionnaire completed in the first 3–6 weeks after the stillbirth (cases) and at an equivalent gestation to when the stillbirth occurred (controls). Detailed methodology of this study has been published elsewhere.3
Maternal perception of increasing strength and frequency of fetal movements or hiccups in late pregnancy was associated with a lower rate of late stillbirth. Maternal perception of RFM, absence of fetal hiccups and a single episode of vigorous fetal movement were associated with late stillbirth.
This study confirms observations from many other studies that fetal activity was associated with well-being and that conversely a reduction in fetal movements was associated with an increased risk of late stillbirth, either because the fetus had died or because the fetus was compromised before death.4 These observations led to efforts from the 1970s onwards to define ‘normal’ and ‘reduced’ fetal activity.5 Stacey et al inform practitioners that it is maternal perception of RFM or reduced fetal hiccups that is associated with late stillbirth rather than a specific definition of abnormal fetal activity.
The relationship between RFM and stillbirth is hypothesised to result from attempted fetal compensation to insufficient oxygen and/or nutrient delivery by the placenta.6 The reduction in hiccups might relate to loss of fetal breathing movements as a result of decompensation of the fetus.7 The underlying reasons for the link between a single episode of vigorous fetal movement and late stillbirth are not clear. It could be speculated these events may correspond to fetal seizures or a period of fetal agitation before death. Importantly, the clinical utility of this observation is complicated by the association between ongoing vigorous fetal activity and a reduction in late stillbirth, as an assessment of whether vigorous activity was confined to a single period can only be made in retrospect.
As with all retrospective studies, this study is complicated by recall bias. Mothers may ruminate over events after a stillbirth which may alter recall of events, which may not be the case for women with an ongoing pregnancy. However, this methodology is appropriate and feasible to investigate modifiable factors associated with stillbirth, as prospective studies would be prohibitively large. The findings of this study are consistent with many other studies linking RFM with fetal demise.
Women should be encouraged to present to their maternity service following perception of a sudden change in fetal activity and particularly RFM. Staff in maternity units should be aware of the association between RFM and late stillbirth and ensure that women who present with RFM undergo assessment to exclude fetal compromise. Preliminary studies suggest that acting upon RFM by excluding acute fetal compromise by fetal heart rate monitoring, and evaluating fetal growth and liquor volume using ultrasound, can reduce perinatal mortality.8