Master Obstetrics & Gynecology
for DHA

What the DHA Tests in Obstetrics & Gynecology

The DHA Obstetrics & Gynecology exam tests the ability to manage common and emergency presentations in antenatal, intrapartum, and postnatal care, as well as gynaecological disorders. Candidates must demonstrate knowledge of evidence-based screening (e.g., combined first-trimester screening, GBS prophylaxis), diagnostic criteria (e.g., pre-eclampsia, gestational diabetes per IADPSG), and first-line medical and surgical management (e.g., oxytocin for PPH, methotrexate for ectopic). Emphasis is on UK/international guidelines (RCOG, NICE, WHO) for conditions like placenta praevia, preterm labour, and ovarian hyperstimulation. Decision-making around mode of delivery, emergency obstetric interventions (e.g., Kielland’s forceps, internal podalic version), and gynaecological oncology staging (FIGO) is heavily tested.

High-Yield Concepts

• Pre-eclampsia diagnosis and management: Diagnosis: BP ≥140/90 mmHg after 20 weeks with proteinuria (≥0.3 g/24h) or other end-organ dysfunction. Severe: BP ≥160/110 mmHg. First-line treatment: oral labetalol 200 mg, nifedipine MR 10 mg, or IV hydralazine 5 mg. For seizure prophylaxis in severe pre-eclampsia: IV magnesium sulfate 4 g bolus then 1 g/hour for 24 hours. Delivery recommended at 37 weeks for mild, 34 weeks for severe with steroids.
• Gestational diabetes mellitus (GDM) screening and criteria: Screen at 24–28 weeks with 75 g OGTT. IADPSG criteria: fasting ≥5.1 mmol/L, 1-hour ≥10.0 mmol/L, 2-hour ≥8.5 mmol/L (any one abnormal). First-line management: dietary modification and metformin 500 mg BD, titrated to 2 g daily. Insulin (e.g., isophane) if targets not met. Target glucose: fasting <5.3 mmol/L, 1-hour postprandial <7.8 mmol/L.
• Postpartum haemorrhage (PPH) protocol: Primary PPH: blood loss >500 mL vaginal or >1000 mL caesarean. First-line: oxytocin 5 IU slow IV, then 40 IU in 500 mL normal saline at 125 mL/hour. Second-line: ergometrine 0.5 mg IM (contraindicated in hypertension), carboprost 250 mcg IM (asthma caution), or misoprostol 800 mcg PR. If ongoing: intrauterine balloon (Bakri) or compression sutures (B-Lynch). Massive transfusion protocol: 4 units RBC, 4 units FFP, 1 pool platelets.
• Ectopic pregnancy diagnosis and management: Diagnosis: transvaginal ultrasound showing empty uterus with adnexal mass, β-hCG >1500 IU/L with no intrauterine pregnancy. First-line surgical: laparoscopic salpingectomy (if contralateral tube healthy). Medical: methotrexate 50 mg/m² IM single dose if unruptured, mass <35 mm, no fetal cardiac activity, β-hCG <5000 IU/L. Follow β-hCG days 4 and 7; if decline <15%, repeat dose.
• Cervical cancer screening and FIGO staging: Screening: HPV primary testing every 5 years from age 25 (UK). If HPV positive, cytology triage. FIGO 2018 staging: Stage IA1 (microinvasive <3 mm depth), IA2 (3–5 mm), IB1 (≥5 mm but <2 cm). Treatment: IA1 – cone biopsy; IA2 – radical trachelectomy or hysterectomy; IB1 – radical hysterectomy with pelvic lymphadenectomy. For stage IB3 or higher: chemoradiation (cisplatin weekly).
• Preterm labour management: Definition: regular contractions with cervical change at 24+0 to 36+6 weeks. Tocolysis: nifedipine MR 20 mg orally stat, then 20 mg TDS for 48 hours (to allow steroids). Alternative: atosiban IV. Antenatal corticosteroids: betamethasone 12 mg IM two doses 24 hours apart. Magnesium sulfate for neuroprotection if <30 weeks. Antibiotics: if PPROM, erythromycin 250 mg QDS for 10 days (co-amoxiclav contraindicated).
• Polycystic ovary syndrome (PCOS) diagnosis and management: Rotterdam criteria: 2 of 3 – oligo/anovulation, clinical/biochemical hyperandrogenism, polycystic ovaries on ultrasound (≥12 follicles per ovary or volume >10 mL). First-line for anovulatory infertility: letrozole 2.5–7.5 mg daily for 5 days (or clomiphene 50–150 mg). For hirsutism: combined oral contraceptive (e.g., ethinylestradiol 30 mcg + drospirenone 3 mg). Metformin 1.5–2 g daily if glucose intolerance.
• Shoulder dystocia management algorithm: McRoberts’ manoeuvre (hyperflexion of thighs) + suprapubic pressure (not fundal). If fails: internal rotation (Rubin II, Woods’ screw). Next: deliver posterior arm (sweep elbow across chest). If still undelivered: roll patient to all-fours (Gaskin manoeuvre). Last resort: Zavanelli manoeuvre (push head back, emergency caesarean). Document head-to-body interval, episiotomy, and neonatal injury (brachial plexus, clavicle fracture).

Common Traps in Obstetrics & Gynecology Questions

• Confusing pre-eclampsia with chronic hypertension: pre-eclampsia requires new-onset proteinuria or end-organ dysfunction after 20 weeks, not just elevated BP.
• Using oral hypoglycaemics like glibenclamide first-line in GDM: metformin is first-line; glibenclamide has higher rates of neonatal hypoglycaemia and is not preferred.
• Forgetting that magnesium sulfate is given for 24 hours in severe pre-eclampsia, not just a single bolus, and checking for toxicity (absent patellar reflexes, respiratory rate <12/min).
• Assuming a positive urine pregnancy test in a woman with an IUD always means ectopic: intrauterine pregnancy with IUD in situ is possible, so ultrasound is mandatory.
• Thinking that all postmenopausal bleeding is endometrial cancer: while it requires investigation (TVS, biopsy), atrophic vaginitis or endometrial atrophy is more common.
• Misinterpreting Kleihauer test: in Rh-negative women with trauma, the dose of anti-D is 500 IU for <20 weeks and 1500 IU for >20 weeks, not based on fetal blood volume alone.

How to Revise Obstetrics & Gynecology for the DHA

Prioritise high-stakes obstetric emergencies (PPH, eclampsia, shoulder dystocia, cord prolapse) and their stepwise algorithms, as these are common in DHA scenarios. Gynaecology questions often frame a presentation (e.g., irregular bleeding, pelvic pain) and ask for the next diagnostic step (e.g., saline infusion sonography, hysteroscopy) or first-line treatment according to NICE/RCOG. Practice applying FIGO staging to cervical and endometrial cancer cases, and memorise key drug doses (oxytocin, methotrexate, magnesium). Questions are often clinical vignettes requiring you to choose the most appropriate management from a list of interventions; avoid over-investigating when simple tests (e.g., urine dip, TVS) suffice. Focus on UK-style guidelines, not US-based ones (e.g., no routine use of 17-OHPC for preterm labour prevention).

Practise it: MedLumen has 110 Obstetrics & Gynecology questions for the DHA, each with a full explanation and references.