Pregnancy changes the rules, and the exam knows it. The same numbers that would reassure you in any other patient — a normal D-dimer, a heart rate that is “only” mildly up, a blood loss that looks modest — can be quietly lethal here, and the candidate who treats a pregnant woman like everyone else walks into the trap.

It tests whether you can hold two patients in mind at once and still pick the correct immediate step, when the definitive management usually belongs to obstetrics, anaesthetics or gynaecology. You lead the resuscitation. The SBA may still ask for the definitive step — but that treatment decision isn’t yours to own; what counts is knowing what it is and exactly who to call to make it happen: a fast bleep to obstetrics, a category-1 caesarean, the on-call gynaecology registrar for theatre.

Three habits earn the marks:

• Split immediate from definitive. Your job is the ED stabilisation — resuscitate, the first drug, the first manoeuvre, the right referral. The definitive step (delivery, theatre, methotrexate) is often someone else’s, and the SBA usually asks for the one you own.
• Read the clues in the stem. Gestation, the character of the pain, the colour of the bleeding, the pulse that is slow rather than fast, the rhesus status — these are planted deliberately and each one points somewhere specific.
• Respect pregnant physiology. A normal D-dimer doesn’t exclude a PE; a young fit woman compensates until she crashes; the “normal” observations are shifted. The trap is treating her like a non-pregnant adult.

Run a standard ALS arrest with two pregnancy-specific modifications and a hard four-minute clock. Per Resuscitation Council UK, the defibrillation energy, the drug doses and the compressions are all unchanged — do not dose-adjust anything. What changes is the mechanical obstruction of the gravid uterus and the airway:

• Manual uterine displacement — from around 20 weeks, or once the fundus is at the umbilicus, displace the uterus up and to the left to take it off the inferior vena cava and aorta. Aortocaval compression is why CPR alone often won’t generate an output in a pregnant woman. Per Resuscitation Council UK, left lateral tilt is no longer recommended: keep her supine and use manual displacement, because tilting the patient compromises the quality of chest compressions.
• Anticipate a difficult airway and intubate early — pregnant women desaturate fast and are at high aspiration risk.

Then work the reversible causes — they carry an obstetric flavour, and the aide-memoire BEAU-CHOPS keeps them in order:

Amniotic fluid embolism (AFE) is the one to flag: a rare but often fatal reaction around labour or delivery where amniotic fluid enters the maternal circulation, triggering sudden cardiovascular collapse, hypoxia and DIC. There is no antidote — management is high-quality supportive resuscitation.

Drug doses are for reference only — confirm against the current BNF.

For the resuscitation framework these scenarios are built on, see our guide to cardiac arrest in the FRCEM Final.

Resuscitative hysterotomy (perimortem caesarean)

If there is no return of spontaneous circulation, start the resuscitative hysterotomy by four minutes and aim to deliver by five minutes — the timings are what the exam tests. The rationale still matters: it is done for the mother, because emptying the uterus relieves aortocaval compression and restores venous return — the most effective intervention you have to achieve ROSC. A live baby is a welcome bonus, not the goal.

The technique is crude but you need to be able to describe it:

1. Bedside, no anaesthesia — do not move to theatre and do not wait for anaesthetic cover; she is in arrest and CPR continues throughout.
2. A large scalpel (e.g. a size-10 blade) is all you need — do not wait for a full surgical set or for the obstetrician to arrive.
3. Vertical midline incision from the pubic symphysis up to the umbilicus, cutting through skin, fat, the linea alba between the recti, and the peritoneum into the abdomen.
4. Reflect the bladder downward if it is in the way, then make a vertical incision in the lower uterus and extend it upward — with scissors or fingers, shielding the fetus — until you reach the cavity and amniotic fluid.
5. Deliver the baby, clamp and cut the cord, hand to the neonatal team, then deliver the placenta.
6. CPR continues throughout and after delivery — pack the uterus and manage haemorrhage as you go.

Pre-eclampsia is new hypertension (≥140/90) after 20 weeks plus proteinuria or maternal organ dysfunction, per NICE NG133. It sits on a spectrum, and where a woman falls on it decides whether she needs magnesium — which prevents and treats seizures but is not an antihypertensive:

Whichever class she is in, your ED shortlist is the same: control the blood pressure, give magnesium when it is indicated, do not drown her with fluid, and remember that delivery is the only cure — organised by the obstetric team.

Take the symptoms and risk factors seriously, because they are how the stem signposts the diagnosis before the BP is even quoted:

• Symptoms: severe headache, visual disturbance, epigastric or right-upper-quadrant pain, vomiting, clonus. HELLP — haemolysis, elevated LFTs, low platelets — is the dangerous variant.
• High-risk factors: previous pre-eclampsia, chronic hypertension, chronic kidney disease, diabetes, autoimmune disease (SLE, antiphospholipid syndrome).
• Moderate-risk factors: first pregnancy, age ≥40, BMI ≥35, family history, multiple pregnancy, an interval over 10 years since the last pregnancy.

The numbers to know:

Treat on clinical suspicion before imaging with a therapeutic low-molecular-weight heparin, and do not use a D-dimer to exclude it. PE is the leading direct cause of maternal death, with the risk highest in the postpartum period, so the threshold to investigate and treat is low. Per RCOG GTG37b and the MBRRACE data, the diagnostic pathway is deliberately different from the non-pregnant one:

• D-dimer is out. It is physiologically raised in pregnancy and is not used to rule out VTE. The usual decision rules — Wells, PERC, and the pregnancy-adapted YEARS pathway from the ARTEMIS study — are not endorsed by RCOG or NICE for this purpose. Image on suspicion.
• If there are DVT signs, scan the legs first. Bilateral leg Dopplers: confirming a DVT confirms the VTE, so you can start anticoagulation without a chest study to make the diagnosis. It doesn’t always end the imaging question, though — if the size or extent of the PE would change management (e.g. a haemodynamically significant PE being considered for thrombolysis), you may still want chest imaging. Both V/Q and CTPA are low-dose radiation in any case.
• Chest imaging is a shared decision. Both V/Q and CTPA are low-dose radiation. CTPA gives a higher maternal breast radiation dose; V/Q a higher fetal dose. Counsel her and gain informed consent. Choose CTPA first-line if the chest X-ray is abnormal.

Maternal sepsis is one of the top five direct causes of maternal death, and the catch is the physiology. Normal pregnancy already shifts the numbers — a faster heart rate, a lower blood pressure, a higher respiratory rate, a physiological leucocytosis — so they overlap with the usual sepsis triggers and a single raw value misleads in either direction. What really catches people out is reserve: a young, fit woman compensates well and looks deceptively stable, then deteriorates suddenly. So treat any unwell pregnant or recently delivered woman as septic until proven otherwise, lean on a pregnancy-specific MEOWS chart rather than raw thresholds, and start the Sepsis Six within the hour.

The sources are the obstetric ones — chorioamnionitis, endometritis, a urinary tract infection or pyelonephritis, a caesarean wound, mastitis — plus the non-obstetric (pneumonia, appendicitis). The organism the exam wants is Group A Streptococcus (Streptococcus pyogenes), which can cause a fulminant, rapidly fatal sepsis and is treated aggressively; E. coli is the other common culprit.

Management is sepsis management, done fast: high-flow oxygen, blood cultures and a lactate, broad-spectrum IV antibiotics within one hour (the quality marker), IV fluids, and a catheter to track urine output. Use a MEOWS chart to pick up the deterioration the raw numbers hide, get source control (evacuate retained products, deliver if the uterus is the source), and involve obstetrics, microbiology and critical care early.

Antepartum haemorrhage (APH) is bleeding from the genital tract from 24 weeks until delivery; postpartum haemorrhage (PPH) is bleeding after the baby is born. Both are resuscitate-first scenarios. APH then carries one rule the exam loves: no digital vaginal examination until placenta praevia is excluded.

Antepartum haemorrhage

Per RCOG GTG63, the character of the bleed and the uterus tells you the cause:

The ED steps are the same regardless of cause: resuscitate (large-bore access, crossmatch, major haemorrhage protocol if needed), give anti-D if she is RhD-negative, and get the obstetric team for steroids and delivery decisions. The digital exam stays away until a scan has cleared praevia.

Postpartum haemorrhage

Per RCOG GTG52, primary PPH is ≥500 mL within 24 hours (minor 500–1000 mL, major >1000 mL); secondary PPH is from 24 hours to 12 weeks. Find the cause with the four Ts:

Resuscitate alongside, and because tone is the usual culprit, work its stepwise pathway:

• Resuscitate: two 14G cannulae, crossmatch four units, activate the major haemorrhage protocol. Give tranexamic acid 1 g IV.
• Mechanical first: rub up the fundus, empty the bladder, bimanual compression.
• Uterotonic ladder: oxytocin 5 units → ergometrine 500 mcg (avoid in hypertension) → carboprost 250 mcg (avoid in asthma) → misoprostol.
• Surgical escalation: intrauterine balloon → B-Lynch suture → arterial ligation → hysterectomy as the last resort.

First decide whether delivery is imminent, because that decides whether you deliver in the ED or transfer. Crowning, an irresistible urge to push, or contractions less than two minutes apart mean it is happening now — deliver in the department, call the obstetric and neonatal teams, and assign someone solely to the baby. If it is not imminent (not fully dilated, head not visible), transfer to the labour ward with an escort, IV access and a call ahead.

A normal delivery

• Deliver the head slowly: encourage panting, guard the perineum, check for a nuchal cord.
• Shoulders: gentle traction down for the anterior shoulder, then up for the posterior.
• Third stage: oxytocin 10 units IM, then controlled cord traction only after the signs of separation (a gush of blood, the cord lengthens, the fundus rises). Never pull on the cord before separation — you can cause uterine inversion.
• The newborn (Resuscitation Council UK): dry and keep warm, defer cord clamping for ≥60 seconds if well. Not breathing or HR <100 → five inflation breaths. HR <60 after 30 seconds of effective ventilation → chest compressions at 3:1.

Shoulder dystocia — HELPERR

The anterior shoulder is stuck behind the symphysis after the head delivers. Work through HELPERR, and never apply fundal pressure (it impacts the shoulder further and risks a brachial plexus injury and Erb’s palsy):

Risk factors (often unpredictable) include a previous dystocia, macrosomia, diabetes, obesity, and an induced or prolonged labour.

Cord prolapse

Per RCOG GTG50, the cord drops below the presenting part and the part compresses it. The aim is to take pressure off the cord until delivery:

• Elevate the presenting part with a hand in the vagina, and put the mother knee–chest or head-down.
• Fill the bladder (it lifts the presenting part off the cord).
• Minimal cord handling — don’t keep touching it (vasospasm).
• Terbutaline 250 mcg SC for tocolysis if the fetal heart rate is abnormal.
• Category-1 caesarean is the definitive answer.

Breech

Per RCOG GTG20b, the cardinal rule is hands off — do not pull. Traction extends the arms up behind the head (nuchal arms) and provokes head entrapment — both obstruct delivery and are what kills the baby. Let the breech deliver spontaneously to the scapula, then assist only if needed:

• Types: frank (bum first, legs extended — commonest), complete (cross-legged), footling (foot first — highest cord-prolapse risk).
• Løvset manoeuvre — rotate the trunk to deliver the arms, freeing nuchal arms.
• Mauriceau–Smellie–Veit — flex the after-coming head; deliver it within minutes.

Do a pregnancy test in every reproductive-age woman with abdominal pain or collapse, and read the βhCG alongside the scan, never alone. Per NICE NG126, a ruptured ectopic is a haemorrhagic emergency that can look like almost anything, so the test is what stops you from missing it. Risk factors include a previous ectopic, pelvic inflammatory disease or tubal damage, an IUCD in situ, IVF, previous sterilisation and smoking. The red flags are collapse, tachycardia, hypotension and shoulder-tip pain.

The βhCG only means something alongside a scan (ideally transvaginal), never on its own:

• A high βhCG (above the discriminatory level, ~1500 IU/L) with an empty uterus on scan → suspect an ectopic.
• “Pregnancy of unknown location” (PUL) is a specific term — a positive test with no intrauterine and no extrauterine pregnancy seen on a transvaginal scan. A woman who simply hasn’t been scanned yet isn’t formally a PUL — but she may already have two serial βhCGs on the system (a prior visit or GP) to interpret.
• The percentage the exam wants: over 48 hours a rise of >63% suggests an intrauterine pregnancy and a fall of >50% a failing pregnancy — anything in between (a suboptimal rise) is the red flag for a possible ectopic. The stem will often just quote two βhCG values and expect you to read the change.
• A single βhCG cannot exclude an ectopic.

Your ED job is to stratify by stability:

The definitive treatment is gynaecology’s call, but it helps to know the logic: methotrexate suits the well, stable woman with hCG <1500, a mass <35 mm, no fetal heartbeat and no significant pain; surgery (salpingectomy as default, salpingotomy if the other tube is damaged) for a mass ≥35 mm, a fetal heartbeat, hCG ≥5000, or pain and rupture. Give anti-D if she is RhD-negative and managed surgically.

Classify miscarriage by the cervical os and what is left in the uterus, then manage by stability. Per NICE NG126, the os open or closed is the discriminator the exam tests:

The ED pathway:

• Unstable (heavy ongoing bleeding, severe pain, sepsis or cervical shock) → resuscitate: two large-bore cannulae, FBC and crossmatch, IV fluids and the major haemorrhage protocol; if there is cervical shock, remove the products from the os with forceps; then refer to acute gynaecology for urgent evacuation/theatre.
• Stable → refer to EPAU, who offer expectant, medical or surgical management.
• Septic miscarriage → IV antibiotics plus urgent evacuation.

Advise that bleeding and cramping are expected, to return if soaking pads, feverish, in severe pain or faint, and to do a urine pregnancy test in around three weeks to confirm completion. Give anti-D only if managed surgically and RhD-negative.

Rehydrate with 0.9% saline plus potassium — not dextrose first — give thiamine, and step through the antiemetic ladder. Hyperemesis gravidarum is the severe end of nausea and vomiting of pregnancy, affecting 0.3–3.6% of pregnancies and interfering with the ability to eat and drink. The 2024 update of RCOG Green-top Guideline No. 69 shifts the emphasis to a patient-focused assessment using the PUQE score rather than strict weight-loss and electrolyte thresholds. Onset is in the first trimester, symptoms peak around 9 weeks and usually settle by 16–20 weeks.

The PUQE (Pregnancy-Unique Quantification of Emesis) score grades severity over the last 24 hours. It sums three items, each scored 1–5 (total 3–15):

• Hours of nausea — not at all (1) → >6 hours (5)
• Vomiting episodes — none (1) → ≥7 (5)
• Retching episodes — none (1) → ≥7 (5)

The total places her on the severity scale:

Investigations: U&E (looking for hyponatraemia and hypokalaemia, and acute kidney injury), FBC, a venous gas, and exclude a urinary tract infection. Note one 2024 change: ketonuria is no longer recommended by RCOG as a marker of severity, having proved an unreliable indicator. Because the disease is driven by hCG, there is an association with molar and multiple pregnancy — arrange a pelvic ultrasound to look for both, and for a non-viable pregnancy.

ED management:

• Fluids: 0.9% sodium chloride with potassium chloride replacement. Do not give dextrose first — it risks precipitating Wernicke’s encephalopathy and over-rapid sodium correction.
• Thiamine for all admitted with prolonged vomiting, to prevent Wernicke’s (oral or IV).
• VTE thromboprophylaxis with LMWH for admitted patients (unless contraindicated, e.g. active bleeding), with a pregnancy-specific VTE risk assessment.
• Antiemetic ladder (below).
• Corticosteroids are reserved for refractory cases and are specialist (obstetric) initiated, not an ED step.

Admission is for continued nausea and vomiting with an inability to tolerate oral fluids or oral antiemetics, clinical dehydration, ketonaemia or electrolyte disturbance not responding to outpatient or ambulatory treatment, or a comorbidity (such as diabetes) that the vomiting is destabilising.

OHSS is the one to think of in a woman who has had recent IVF or ovarian stimulation and now presents with abdominal distension, pain and breathlessness. It is an iatrogenic, hCG-driven syndrome: vascular permeability rises, fluid shifts out of the circulation into the abdomen and chest, and she becomes intravascularly deplete and haemoconcentrated — despite looking fluid-overloaded with ascites. Pregnancy makes it worse and more prolonged, because endogenous hCG keeps driving it.

Grade it on the haematocrit and the clinical picture. Severe OHSS = clinical ascites, oliguria, haematocrit >45%, hypoproteinaemia and ovaries usually over 12 cm; critical OHSS = tense ascites or large effusions, haematocrit >55%, white cells over 25, oliguria/anuria, thromboembolism or ARDS — and warrants critical care.

In the ED: send bloods (FBC and haematocrit, U&E, LFTs, coagulation), give analgesia with paracetamol (avoid NSAIDs — renal) and antiemetics, and use careful IV crystalloid to refill the intravascular space, with albumin/colloid if the haemoconcentration persists. Thromboprophylaxis with LMWH is essential — OHSS is a strongly prothrombotic state and the clot can be in unusual sites (the neck veins, for example). Ultrasound-guided paracentesis relieves tense ascites causing pain, breathlessness or oliguria. Avoid diuretics until the intravascular volume is replaced, and remember the enlarged ovaries can tort or rupture.

Only RhD-negative women need anti-D, and only after a potentially sensitising event, given within 72 hours of it. Per BSH guidance and NICE NG126, the gestation and the type of event decide whether it is indicated at all:

The dose depends on gestation:

• Before 20 weeks: 250 IU.
• At or after 20 weeks: 500 IU plus a Kleihauer test to quantify the feto-maternal haemorrhage and check whether more is needed.

A point that orients the whole topic: EPAU manages early pregnancy (roughly up to 14–16 weeks, locally defined); beyond that, problems go to maternity and obstetric services; and APH is bleeding from 24 weeks. Knowing which service owns the patient is half of choosing the right referral in an SBA.

When do you perform a resuscitative hysterotomy? By four minutes into the arrest, delivering by five, if there is no ROSC and the uterus is at or above the umbilicus. It is done for the mother — to relieve aortocaval compression — at the bedside, with CPR continuing.

What is the magnesium dose for eclampsia? 4 g IV over 5–15 minutes, then 1 g/hr for 24 hours; a recurrent seizure gets a further 2–4 g IV. Toxicity (reflexes fade first) is reversed with calcium gluconate 10 mL of 10%. Magnesium is not an antihypertensive.

Can a D-dimer rule out PE in pregnancy? No — it is physiologically raised and is not used to exclude VTE. Image on suspicion and treat with therapeutic LMWH before imaging; DOACs and warfarin are contraindicated.

How do you separate abruption from praevia? Abruption is painful with a woody, tender uterus and often concealed bleeding; praevia is painless and bright red. No digital vaginal exam until a scan excludes praevia.

What is cervical shock? Bradycardia and hypotension from products in the cervical os stimulating the vagus — a slow pulse, not fast. Removing the products with sponge forceps reverses it immediately.

Who needs anti-D? Only RhD-negative women, within 72 hours of a sensitising event. Before 12 weeks only for surgical management, ectopic, molar or termination; from 12 weeks for any sensitising event. 250 IU before 20 weeks, 500 IU plus a Kleihauer at or after 20 weeks.

For how these fit the wider blueprint, see our FRCEM Final high-yield topics for 2026, and for the toxicological reversal agents that surface in maternal arrest (magnesium, calcium, Intralipid), our guide to toxidromes and the unknown poisoning.

Sources and further reading

• Resuscitation Council UK — maternal cardiac arrest and newborn life support
• NICE NG133 — hypertension in pregnancy
• RCOG Green-top 37b — thromboembolism in pregnancy (PE)
• RCOG Green-top 64 — identification and management of maternal sepsis
• RCOG Green-top 63 — antepartum haemorrhage
• RCOG Green-top 52 — postpartum haemorrhage
• RCOG Green-top 50 — umbilical cord prolapse
• RCOG Green-top 20b — management of breech presentation
• NICE NG126 — ectopic pregnancy and miscarriage
• RCOG Green-top 69 (2024) — nausea/vomiting of pregnancy and hyperemesis
• RCOG Green-top 5 — ovarian hyperstimulation syndrome (OHSS)
• BSH — anti-D immunoglobulin (with NICE NG126); plus MBRRACE-UK and RCEM Learning

Drug doses are for reference only — confirm against the current BNF.