Evidence
Surveillance decision
Surveillance decision
We propose to update the section on morbidly adherent placenta in the NICE guideline on caesarean birth. The term morbidly adherent placenta will be editorially amended to placenta accreta spectrum (PAS) with committee input.
Exceptional surveillance review summary
Reason for considering this area
NICE received feedback that the section of the NICE guideline on morbidly adherent placenta may be out of date with regards to terminology and that a number of the recommendations within it need reviewing and may need updating in light of more recent guidance from the Royal College of Obstetrics and Gynaecology (RCOG) on Placenta Praevia and Placenta Accreta: Diagnosis and Management.
Methods
To review the impact of this enquiry on NICE guidance we took the following approach:
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Considered the information submitted by the stakeholder.
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Considered the evidence used to develop the NICE guideline on caesarian birth related to the section on morbidly adherent placenta.
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Discussed the issues raised with the NICE clinical adviser.
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Considered feedback from topic experts.
It was concluded that full updated literature searches were not needed because the information we obtained was enough to establish whether an amendment to the guideline was needed.
For further information see ensuring that published guidelines are current and accurate in developing NICE guidelines: the manual.
Information considered in this exceptional surveillance review
How the guideline was developed
The section on morbidly adherent placenta dates back to 2011 and includes 6 recommendations:
Recommendation 1.2.7: For women who have had a previous caesarean birth, offer colour-flow Doppler ultrasound at 32 to 34 weeks as the first diagnostic test for morbidly adherent placenta if low-lying placenta is confirmed.
Recommendation 1.2.8: If a colour-flow Doppler ultrasound scan result suggests morbidly adherent placenta:
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discuss with the woman how MRI in addition to ultrasound can help diagnose morbidly adherent placenta and clarify the degree of invasion, particularly with a posterior placenta
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explain what to expect during an MRI procedure
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inform the woman that current experience suggests that MRI is safe, but that there is a lack of evidence about any long-term risks to the baby
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Offer MRI if this is acceptable to the woman.
Recommendation 1.2.9: Discuss birth options (for example, timing of birth, operative interventions including possibility of hysterectomy, need for blood transfusion) with a woman suspected to have morbidly adherent placenta. This discussion should be carried out by a consultant obstetrician, or with a consultant obstetrician present.
Recommendation 1.2.10: When performing a caesarean birth for a woman suspected to have a morbidly adherent placenta, ensure that:
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a consultant obstetrician and a consultant anaesthetist are present in the operating theatre
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a paediatric registrar, consultant, or equivalent, is present
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a haematology registrar, consultant, or equivalent, is available for advice
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a critical care bed is available
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sufficient cross-matched blood and blood products are readily available.
Recommendation 1.2.11: Before performing a caesarean birth for women suspected to have morbidly adherent placenta, the multidisciplinary team should agree which other healthcare professionals need to be consulted or present, and the responsibilities of each team member.
Recommendation 1.2.12: All hospitals should have a locally agreed protocol for managing morbidly adherent placenta that sets out how these elements of care should be provided.
In the 2011 guideline the section on morbidly adherent placenta was fully updated from the original 2004 version. The update focused on the diagnosis and management of morbidly adherent placenta and included an economic analysis to compare different diagnostic strategies for morbidly adherent placenta in praevia.
Previous surveillance
The 2017 surveillance review prompted an update of the guideline in 2020/21. However, the section on morbidly adherent placenta was not updated, as although during the surveillance review experts highlighted this section as an important one, no new evidence was identified that would impact on recommendations.
Five of the recommendations within the section on morbidly adherent placenta were editorially refreshed for sense and style during the 2021 update of the guideline. There was no update to the content of the recommendations or evidence base underpinning them.
New intelligence
NICE received feedback that the section of the guideline on morbidly adherent placenta may be out of date and explained that the terminology of morbidly adherent placenta is no longer used and instead the term PAS is preferred. The feedback also highlighted that recommendations 1.2.7 to 1.2.9 and 1.2.12 within this section may need reconsidering as they differ from more recent guidance from RCOG on Placenta Praevia and Placenta Accreta.
In particular, the following suggestions were made:
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Recommendation 1.2.7 needs to consider the role of screening for PAS at the mid-pregnancy routine scan.
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Recommendation 1.2.8 should reconsider the role of MRI in diagnosis of PAS.
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Recommendation 1.2.9 needs to consider the need for delivery in a specialist centre with access to blood products and intensive care unit.
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Recommendation 1.2.12 should consider the role of nationally agreed protocols.
Expert feedback
We contacted 5 experts with backgrounds in obstetrics, operational department practice and midwifery to determine if the term PAS had replaced morbidly adherent placenta. Two experts replied and agreed that PAS is the preferred term, however 1 expert explained that morbidly adherent placenta is still in use and that students may need to be aware of both terms. As such, it was deemed that morbidly adherent placenta should be editorially amended to PAS with committee input.
How we will handle this
We propose to update the section on morbidly adherent placenta in the NICE guideline on caesarean birth taking into consideration the guidance from RCOG. There are several aspects to this update. Firstly, the term morbidly adherent placenta needs to be integrated or replaced with the newer term PAS but with committee consideration to ensure any replacement is helpful to practice.
The evidence base identified in the RCOG guidance on MRI compared with colour-flow Doppler ultrasound for diagnosing PAS needs reviewing as the RCOG guidance includes new evidence that was not considered during NICE guideline development.
Issues around when to screen for PAS, the role of specialist centres for birth, and nationally agreed protocols also need committee consideration. Furthermore, NICE's guideline on antenatal care may need to be cross referred to, particularly as it provides useful advice on screening during routine antenatal scans.
Overall decision
We propose to update the section on morbidly adherent placenta in the NICE guideline on caesarean birth. The term morbidly adherent placenta will be editorially amended to PAS with committee input.
ISBN: 978-1-4731-4318-0
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