Master Obstetrics and Gynecology
for SMLE

What the SMLE Tests in Obstetrics and Gynecology

The SMLE tests applied obstetric and gynecologic knowledge through clinical vignettes requiring diagnosis, risk stratification, and management decisions. In obstetrics, emphasis is on antenatal screening (e.g., combined test for Down syndrome, OGTT thresholds for GDM), management of hypertensive disorders (pre-eclampsia: BP ≥140/90 with proteinuria, MgSO4 for seizures), obstetric haemorrhage (PPH: >500 mL vaginal/ >1000 mL CS, first-line oxytocin), and fetal monitoring (CTG interpretation, category I-III). In gynaecology, focus is on abnormal uterine bleeding (PALM-COEIN classification, first-line tranexamic acid or LNG-IUS), acute pelvic pain (ectopic pregnancy: β-hCG >1500 IU/L with empty uterus on TVUS), menopause management (HRT risks: VTE, breast cancer), and cervical cancer screening (HPV primary testing, colposcopy referral for HPV16/18). Candidates must demonstrate safe prescribing in pregnancy (avoid ACEi, warfarin, isotretinoin) and knowledge of UK/BSOG guidelines.

High-Yield Concepts

• Pre-eclampsia diagnosis and management: Diagnosis: BP ≥140/90 mmHg on two occasions 4 hours apart with proteinuria (≥0.3 g/24h or PCR ≥30 mg/mmol). Severe features: BP ≥160/110, HELLP syndrome (haemolysis, elevated liver enzymes, low platelets), neurological symptoms. First-line antihypertensive: labetalol 200 mg oral; for seizure prophylaxis: IV magnesium sulfate (4 g bolus, then 1 g/hour for 24 hours). Delivery indicated at ≥37 weeks or earlier for maternal/fetal compromise.
• Gestational diabetes mellitus (GDM) screening and targets: Screen high-risk women (BMI >30, previous GDM, family history) with 75g OGTT at 24-28 weeks. Diagnostic thresholds: fasting ≥5.1 mmol/L, 1-hour ≥10.0 mmol/L, 2-hour ≥8.5 mmol/L. First-line management: dietary modification, metformin if needed. Blood glucose targets: fasting <5.3 mmol/L, 1-hour postprandial <7.8 mmol/L. Insulin added if targets not met.
• Postpartum haemorrhage (PPH) management: Primary PPH: blood loss >500 mL vaginal delivery, >1000 mL caesarean. First-line uterotonic: oxytocin 5 IU slow IV or 10 IU IM. Second-line: ergometrine 0.5 mg IM (contraindicated in hypertension) or carboprost 250 mcg IM (asthma caution). Mechanical measures: bimanual compression, intrauterine balloon (Bakri). Massive transfusion protocol: 1:1:1 ratio of RBC:FFP:platelets.
• Ectopic pregnancy diagnosis and management: Suspect in any woman of reproductive age with abdominal pain and vaginal bleeding. Diagnostic: transvaginal ultrasound showing empty uterus with β-hCG >1500 IU/L (discriminatory zone). First-line surgical: laparoscopic salpingectomy (or salpingotomy if contralateral tube absent). Medical: methotrexate 50 mg/m² IM if unruptured, β-hCG <5000 IU/L, no fetal cardiac activity, reliable patient.
• Abnormal uterine bleeding (AUB) evaluation and treatment: Use PALM-COEIN classification (Polyp, Adenomyosis, Leiomyoma, Malignancy; Coagulopathy, Ovulatory, Endometrial, Iatrogenic, Not classified). First-line investigations: FBC, TSH, coagulation screen, transvaginal ultrasound. Treatment: tranexamic acid 1 g QDS during bleeding, mefenamic acid 500 mg TDS, or LNG-IUS (Mirena) for heavy menstrual bleeding. Endometrial biopsy indicated if age >45 or risk factors for endometrial cancer.
• Cervical cancer screening guidelines: NHS Cervical Screening Programme: HPV primary screening for women aged 25-64. 25-49: every 3 years; 50-64: every 5 years. If HPV positive, cytology triage. Refer for colposcopy if HPV16/18 positive or any high-risk HPV with abnormal cytology. Treatment of CIN: LLETZ excision. HPV vaccination (Gardasil 9) recommended for girls and boys aged 12-13.
• Menopause management and HRT: Diagnosis: vasomotor symptoms (hot flushes, night sweats), vaginal atrophy, sleep disturbance. HRT first-line for significant symptoms: oestrogen (oral or transdermal) plus progestogen if uterus intact. Transdermal oestrogen preferred for VTE risk. Risks: VTE (oral HRT), breast cancer (combined HRT >5 years), stroke (oral). Contraindicated in breast cancer, unexplained vaginal bleeding, active liver disease. Alternatives: SSRIs (paroxetine), gabapentin for hot flushes.
• CTG interpretation and fetal monitoring: Three-tier classification: Category I (normal): baseline 110-160 bpm, variability 6-25 bpm, accelerations present, no decelerations. Category II (indeterminate): requires evaluation and reclassification. Category III (abnormal): absent variability with recurrent late/variable decelerations, bradycardia, or sinusoidal pattern — immediate intervention needed (intrauterine resuscitation, delivery). Key features: late decelerations indicate uteroplacental insufficiency; variable decelerations suggest cord compression.

Common Traps in Obstetrics and Gynecology Questions

• Confusing pre-eclampsia with gestational hypertension: proteinuria is required for pre-eclampsia diagnosis, not just elevated BP.
• Forgetting that methotrexate for ectopic pregnancy is contraindicated if fetal cardiac activity is present or β-hCG >5000 IU/L.
• Using oral oestrogen HRT in a woman with prior VTE — transdermal route is safer and preferred.
• Assuming a negative urine pregnancy test rules out ectopic pregnancy — serum β-hCG is more sensitive and quantitative.
• Treating heavy menstrual bleeding with norethisterone alone without investigating for structural causes (PALM-COEIN).
• Missing the need for antenatal anti-D prophylaxis in a RhD-negative woman after any sensitising event (e.g., bleeding, trauma, invasive procedure).

How to Revise Obstetrics and Gynecology for the SMLE

Prioritise high-stakes obstetric emergencies: PPH, eclampsia, shoulder dystocia, cord prolapse. Questions often present as acute scenarios requiring immediate stepwise management (e.g., 'first action' for PPH is oxytocin, not hysterectomy). Gynaecology vignettes frequently test AUB workup and cervical screening algorithms. Memorise key thresholds: β-hCG 1500 IU/L for ectopic, OGTT cut-offs, BP criteria for pre-eclampsia. Practice interpreting CTGs with category classification and linking to management. Expect questions on contraceptive counselling (COC contraindications: migraine with aura, smokers >35) and safe prescribing in pregnancy (avoid NSAIDs after 28 weeks, ACEi, warfarin). Use NICE and RCOG guidelines as references; exam answers align with these. Focus on management algorithms rather than rare conditions.

Practise it: MedLumen has 50 Obstetrics and Gynecology questions for the SMLE, each with a full explanation and references.