Birth Small Talk

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If fetal movement monitoring on its own doesn’t work, will adding a blood test to it improve outcomes?

A team from Nottingham University have just published results from a pilot study (Armstrong et al., 2020), conducted to decide whether it might be possible and useful to run a full scale randomised controlled trial. The paper is free to access. The research team acknowledged that preventing stillbirth is important and that using fetal movement monitoring alone doesn’t seem to work. The goal of the full-sized trial will be to see if adding a blood test to the assessment of women with reduced fetal movements might reduce the rate of stillbirth.

For this pilot trial, researchers recruited women who presented to hospital with reduced fetal movements between 36 and 41 weeks of gestation and asked them to have blood taken to measure placental growth factor (PlGF). Women were then randomised to either a group where the results of this test remained unavailable to clinicians caring for them, or to a group where the results of the test were used to support decision making. For women in the second group, induction of labour was recommended if this result was abnormal, while all other women had standard care. The primary outcomes examined were stillbirth, neonatal death, low Apgar score at 5 minutes, cord blood acidosis, and admission to the neonatal unit.

PlGF (as the name suggests) is produced by the placenta. Previous research has shown that women with low levels of PlGF are more likely to develop pre-eclampsia, and that testing PlGF reduces the time to make a diagnosis of pre-eclampsia (Duhig, et al., 2019). PlGF is also lower in women who experience stillbirth or who have a small for gestational age baby (Heazell, et al., 2019), so it seems a logical step to ask whether testing for PlGF is a useful addition to the workup of women with reduced fetal movements.

61% of women approached to participate in the trial agreed to take part, with 216 women enrolled. The most common reason for not agreeing was wanting to avoid have a blood test. In the 109 women where the results of the test were known, 16 had an abnormal test result, and all but one was offered early birth as per the protocol. The induction of labour (45%) and caesarean section (9%) rates were the same in both groups. The rate of babies having at least one of the outcomes measured was 8% in the known test result group, and 4% in the unknown group, a statistically significant difference. Most of this difference was due to a higher rate of acidosis in cord blood taken at birth. 

The researchers suggest that a large-scale trial is now warranted. So many interventions in maternity care have been introduced because they seemed like a good idea at the time. The same could be possible for PlGF testing. It is heartening to see that care is being taken to ensure that rigorous research is being done first. It will be interesting to see whether the worsening of outcomes seen in the pilot trial persists in a properly powered trial. 

Armstrong-Buisseret, L., Godolphin, P. J., Bradshaw, L., Mitchell, E., Ratcliffe, S., Storey, C., & Heazell, A. E. P. (2020). Standard care informed by the result of a placental growth factor blood test versus standard care alone in women with reduced fetal movement at or after 36(+0) weeks’ gestation: a pilot randomised controlled trial. Pilot Feasibility Stud, 6, 23. doi:10.1186/s40814-020-0561-z

Duhig, K., Myers, J., Seed, P., Sparkes, J., Low, J., Hunter, R., et al. (2019). Placental growth factor testing to assess women with suspected pre-eclampsia: A multicentre, pragmatic, stepped-wedge cluster-randomised controlled trial. Lancet, 393(10193), 1807-1818. doi:10.1016/S0140-6736(18)33212-4

Heazell, A., Hayes, D., Whitworth, M., Takwoingi, Y., Bayliss, S., & Davenport, C. (2019). Biochemical tests of placental function versus ultrasound assessment of fetal size for stillbirth and small-for-gestational-age infants. Cochrane Database Syst Rev, 5, Cd012245. 

Categories: New research, Stillbirth

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