How can I counsel patients about the potential complications associated with placenta accreta spectrum during their antenatal visits?

Guideline-aligned answer with reasoning, red flags and references. Clinically reviewed by Dr Kola Tytler MBBS CertHE MBA MRCGP.

Posted: 17 August 2025Updated: 17 August 2025 Guideline-Aligned (High Confidence) Clinically Reviewed
Dr Kola Tytler MBBS CertHE MBA MRCGPClinical Lead • iatroX
When counseling patients about potential complications associated with placenta accreta spectrum (PAS) during antenatal visits, it is important to discuss several key aspects of diagnosis, management, and birth options .
  • Diagnosis and Referral: If a routine 20-week ultrasound scan shows placenta praevia or a low-lying placenta in a patient with a previous caesarean or uterine scar, they will be referred for a greyscale ultrasound scan with colour Doppler to assess for PAS . This specialized scan should be performed around 28 weeks, but no later than 29 weeks, by a senior clinician with expertise in PAS diagnosis . If PAS is suspected, the patient will be referred to a specialist placenta accreta spectrum centre for ongoing care and management .
  • Further Assessment: An MRI scan may be considered to complement ultrasound findings when planning surgical management of PAS . Patients should be informed about what to expect during an MRI procedure and that it can help clarify the degree of invasion, especially with a posterior placenta . It should also be discussed that current experience suggests MRI is safe, but there is a lack of evidence about any long-term risks to the baby .
  • Birth Options and Potential Complications: A senior obstetrician will discuss birth options with the patient, including the timing of birth and operative interventions . This discussion will cover the possibility of a hysterectomy and the potential need for blood transfusion . Patients should be aware that placental adherence problems, particularly after multiple caesarean births, are a relevant risk . For planned caesarean birth in suspected PAS, a multidisciplinary team will be involved, including specialists such as gynaecological surgeons, interventional radiologists, colorectal surgeons, urologists, or vascular surgeons, depending on the nature of the PAS . During a planned caesarean birth for a woman or pregnant person suspected to have PAS, a consultant obstetrician, a consultant gynaecologist, and a consultant anaesthetist will be present in the operating theatre . A paediatric or neonatal registrar or consultant will also be present to provide immediate care for the baby . A haematology registrar or consultant should be available for advice, and a critical care bed for the patient and a neonatal cot for the baby should be available . Sufficient cross-matched blood and blood products will be readily available if blood transfusions are acceptable to the patient .

Educational content only. Always verify information and use clinical judgement.