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Planned earlier delivery for late pre-eclampsia may be better for mothers

BMJ 2020; 368 doi: (Published 15 January 2020) Cite this as: BMJ 2020;368:l6779


NIHR’s research signals in The BMJ

  1. Rob Cook, clinical director1,
  2. Johnny Lyon-Maris, clinical adviser2,
  3. Peter Davidson, clinical adviser1
  4. on behalf of NIHR Dissemination Centre
  1. 1Bazian, Economist Intelligence Unit healthcare, London UK
  2. 2Wessex Institute, University of Southampton, Southampton, UK
  1. Correspondence to R Cook rob.cook{at}

The study

Chappell LC, Brocklehurst P, Green ME, et al. Planned early delivery or expectant management for late preterm pre-eclampsia (PHOENIX): a randomised controlled trial. Lancet 2019;394:1181-90.

This project was funded by the NIHR Health Technology Assessment Programme (project number 12/25/03).

To read the full NIHR Signal, go to:

Why was this study needed?

Mild pre-eclampsia affects up to 6% of pregnancies, with severe cases developing in 1% to 2%. Early signs include high blood pressure and having protein in the urine. Symptoms such as ankle swelling and headaches can occur if the condition progresses. In rare cases, there can be serious complications such as convulsions and stroke as well as stillbirth.

The cause is not yet fully understood, but it is thought to be linked to problems with the placenta. Delivering the baby is the only cure. Less urgent cases are usually monitored with the intent of progressing the pregnancy as far as possible to avoid complications associated with prematurity in the baby. The aim of this study was to determine whether inducing delivery earlier reduces the chance of harm to the mother without harming the baby despite the baby being born before they are considered fully developed.

What did this study do?

The PHOENIX randomised controlled trial allocated 448 women to a planned delivery, such as an induction or caesarean section, and 451 women to expectant management (usual care). All had late pre-eclampsia.

The trial took place in 46 consultant led maternity units across England and Wales. Those in the intervention group were scheduled for initiation of delivery within 48 hours of randomisation to enable preparations such as neonatal lung maturity acceleration to take place. Delivery was by induction of labour unless a caesarean section was necessary. Expectant management involved delivery at 37 weeks or sooner, as in the recommendations from the National Institute for Health and Care Excellence (NICE).

Longer term results from this trial are still being collected. For example, it will be useful to know if those infants in the intervention group have a higher incidence of developmental delay.

What did it find?

● Babies in the planned delivery arm were born on average five days earlier than controls, according to their gestational age.

● The primary outcome for the baby was either death or neonatal unit admission. This was higher in the planned delivery group affecting 196 (42%) infants compared with 159 (34%) infants in the expectant management group (adjusted relative risk 1.26, 95% confidence interval 1.08 to 1.47). However, admission was mainly attributed to prematurity, without excessive respiratory or other morbidity, intensity of care, or length of stay, and there were no deaths.

● The primary maternal outcome was either a recorded high systolic blood pressure of at least 160 mm Hg after randomisation or any of the fullPIERS model outcomes (Pre-eclampsia Integrated Estimate of RiSk). This includes specific outcomes such as death, stroke, and acute renal failure. The incidence of any of these outcomes was lower in the planned delivery group, affecting 289 (65%) women compared with 338 (75%) women in the expectant management group (adjusted relative risk 0.86, 95% confidence interval 0.79 to 0.94).

● Progression to severe pre-eclampsia was the main adverse outcome for both maternal groups, affecting 287 (64%) women in the planned delivery group compared with 334 (74%) women in the expectant management group (adjusted relative risk 0.86, 95% confidence interval 0.79 to 0.94). There were no strokes, a low incidence of other complications, and one death that was thought to be unrelated to the trial.

● Total maternal and infant costs were lower in the planned delivery group compared with the expectant management group, with an adjusted cost saving of £1478 (95% confidence interval £2354 to £605).

What does current guidance say on this issue?

Recent NICE guidance on the diagnosis and management of hypertension in pregnancy recommends that women diagnosed before 34 weeks should be monitored until they reach 37 weeks unless the condition worsens. Intravenous magnesium sulphate and a course of antenatal corticosteroids should be offered in line with the NICE guideline on preterm labour and birth.

The advice for women between 34 and 37 weeks is the same, but in addition, it states that if considering a planned delivery, it is important to take into account the condition of woman and baby. A course of antenatal corticosteroids should be considered, in line with the NICE guideline on preterm labour and birth. At 37 weeks and above, birth should be initiated within 24 to 48 hours.

What are the implications?

The results of this trial suggest that early planned delivery for late preterm pre-eclampsia is better for the mother and does no harm to the baby, though at the cost of more admissions to the neonatal unit. If, as the authors of the trial suggest, alternative care strategies could be put in place, such as transitional care to enable mother and child to stay together, then this disadvantage could be minimised. Further long term results are awaited.


  • Competing interestsThe BMJ has judged that there are no disqualifying financial ties to commercial companies. The authors declare the following other interests: none.

  • Further details of The BMJ policy on financial interests is here:

  • Contributor Joelle Kirby.

  • All authors contributed to development and review of this summary, as part of the wider NIHR Signals editorial team ( RC is guarantor.

  • Disclaimer NIHR Signals are owned by the Department of Health and Social Care and are made available to the BMJ under licence. NIHR Signals report and comment on health and social care research but do not offer any endorsement of the research. The NIHR assumes no responsibility or liability arising from any error or omission or from the use of any information contained in NIHR Signals.

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