Synopsis
Recognise bleeding from a low placental implantation, establish its relation to the cervix safely, and plan surveillance and birth around maternal haemorrhage risk.
- Placenta praevia reaches or covers the internal cervical os; a low-lying placenta has an edge less than 20 mm away without covering it.
- Painless bright bleeding is characteristic, but pain does not exclude praevia or concurrent abruption.
- Transvaginal ultrasound by an experienced operator safely defines the placental edge and is more accurate than a limited transabdominal view.
- A placenta reported low at the anomaly scan usually needs reassessment at 32 weeks, with further imaging determined by persistence and birth planning.
- Previous caesarean birth with anterior low placentation raises concern for placenta accreta spectrum and requires targeted expert assessment.
- RCOG 2026 supports planned birth by 37+6 weeks for uncomplicated low placentation; asymptomatic praevia without other risk factors is generally planned at 37+0–37+6.
- For a non-sensitised RhD-negative patient with bleeding after 20 weeks, give at least 500 IU anti-D within 72 hours and quantify fetomaternal haemorrhage.
Key red flags
Heavy bleeding, syncope, tachycardia or hypotension requires immediate obstetric haemorrhage resuscitation and senior review.
New pain, contractions, membrane rupture or abnormal fetal heart rate may indicate imminent birth or a second placental emergency.
Investigation priorities
Detect haemorrhagic compromise and guide urgency before detailed placental imaging.
Management branches
Bleeding is ongoing, circulation is abnormal or fetal compromise is suspected.
- Activate the obstetric haemorrhage response, obtain large-bore intravenous access, send urgent bloods and coordinate blood-product availability with the laboratory.
- Assess maternal and fetal status in parallel; avoid digital cervical examination and arrange urgent delivery when haemorrhage or compromise makes continued pregnancy unsafe.
- Involve consultant obstetrics, anaesthesia and neonatal staff early, explaining the possible need for transfusion, caesarean birth and haemorrhage-control procedures.
Ultrasound confirms low placentation and there is no immediate delivery indication.
- Record placental position, symptom history, haemoglobin, previous uterine surgery and travel circumstances, then agree hospital or outpatient care individually.
- Arrange localisation around 32 weeks after a low anomaly-scan result; if low lying or praevia persists, reassess transvaginally around 36 weeks to guide birth planning.
- Provide a direct maternity contact and explicit return advice for any bleeding, contractions, pain or membrane rupture; treat identified iron deficiency and review transfusion preferences.
Key medicines
Anti-D immunoglobulin after antepartum bleedingFor non-sensitised RhD-negative patients after 20 weeks, administer at least 500 IU within 72 hours, intramuscularly or intravenously according to the licensed preparation; give extra doses according to quantified fetomaternal haemorrhage.Routine antenatal prophylaxis does not replace event-related treatment. Confirm product route, previous immune anti-D and laboratory advice for recurrent or large haemorrhage.
Antenatal betamethasone when preterm birth is likelyFor the betamethasone sodium phosphate/acetate mixture, give 12 mg intramuscularly twice, 24 hours apart. UK phosphate-only preparations differ; confirm the unit’s formulation-specific course when preterm birth is anticipated.Select eligibility using current obstetric guidance, increase glucose surveillance with diabetes, and never postpone urgently indicated birth to complete the course.