Clinical overview
Antepartum haemorrhage (APH) is bleeding from the genital tract from 24 weeks of gestation until the birth of the baby. It complicates roughly 3–5% of pregnancies (standard teaching) and is one of the great obstetric emergencies: it threatens the mother through exsanguination and disseminated intravascular coagulation (DIC), and the fetus through abruption-related hypoxia and the consequences of iatrogenic preterm birth. In South Africa, obstetric haemorrhage — antepartum and postpartum combined — sits among the leading direct causes of maternal death in every triennium of the Saving Mothers report (NCCEMD), and a large proportion of those deaths are judged avoidable: late recognition, under-resuscitation, delayed transfer between levels of care, and failure to deliver in time.
The registrar's task in APH is fundamentally one of simultaneous triage: decide in the first minutes whether this is a stable, minor "spotter" who can be investigated calmly, or a haemodynamically compromising bleed that demands resuscitation and delivery now. The two diagnoses that kill — placenta praevia and placental abruption — must be actively excluded or confirmed, and the single most important rule of APH is burned into every obstetric curriculum: never perform a digital vaginal examination until placenta praevia has been excluded, because you can provoke catastrophic haemorrhage. This chapter treats APH as the HOTS-level integrative problem it is — recognise, resuscitate, diagnose the cause, and deliver or expectantly manage by gestation, maternal stability and fetal condition. See also Postpartum haemorrhage, Pre eclampsia and HELLP (abruption association) and Shock management.
Core knowledge
Definition and causes
Figure J7.1 — Antepartum haemorrhage cause map contrasting abruption, praevia/PAS, vasa praevia and local causes, with the central safety rule to avoid digital vaginal examination until praevia is excluded.
APH = bleeding from or into the genital tract from 24⁺⁰ weeks until delivery. Bleeding before 24 weeks is classed as threatened miscarriage or early-pregnancy bleeding. The causes are conventionally grouped:
- Placental causes (the dangerous two):
- Placenta praevia — placenta wholly or partly implanted in the lower uterine segment. RCOG (GTG 27a) now favours describing the placenta as low-lying when the placental edge is <20 mm from the internal os on transvaginal scan after 16 weeks, and praevia when it covers the os.
- Placental abruption — premature separation of a normally sited placenta.
- Vasa praevia — fetal vessels running through the membranes over the internal os, unsupported by placenta or cord (RCOG GTG 27b). Rare but lethal to the fetus: rupture causes fetal exsanguination, classically painless bleeding with acute fetal compromise at membrane rupture.
- Local / lower genital tract causes — cervical ectropion, cervicitis, cervical polyp, cervical carcinoma, vaginal trauma, and infection. These are common and benign-to-serious; cervical cancer must be considered in any unexplained APH (link to Cervical screening SA).
- Uterine rupture — see Uterine rupture; bleeding may be revealed or concealed, with pain, fetal compromise and collapse.
- "Indeterminate" / unexplained APH — a large group where no cause is found; still associated with adverse outcome and warrants surveillance.
A "heavy show" (blood-stained mucus at the onset of labour) is physiological and is a diagnosis of exclusion, not a label to apply prematurely.
Placental abruption
Abruption is haemorrhage at the decidua–placenta interface. Bleeding may be revealed (tracks down and out through the cervix), concealed (retained behind the placenta — the abdomen distends, the uterus is tense, and the visible blood loss grossly underestimates true loss), or mixed. The cardinal feature is pain: a continuously painful, tense, "woody-hard" uterus, often with uterine irritability and a non-reassuring or absent fetal heart. Concealed abruption is the trap — a woman can be in hypovolaemic shock with DIC and only a trickle of external bleeding.
Risk factors (standard teaching): previous abruption (the strongest), hypertensive disorders and pre-eclampsia, abdominal trauma (including assault/GBV — relevant in the SA setting), smoking and cocaine use, polyhydramnios with sudden decompression, multiple pregnancy, advanced maternal age and multiparity, thrombophilia, and preterm prelabour rupture of membranes. Abruption is a leading cause of DIC in pregnancy because thromboplastin from the disrupted decidua enters the circulation.
Placenta praevia and the spectrum of accreta
Classically painless, causeless, recurrent fresh red bleeding, often with the fetal head high or a malpresentation because the placenta occupies the lower segment. Risk factors include previous caesarean section, previous praevia, advanced maternal age, multiparity, multiple pregnancy and assisted reproduction.