Master Obs & Gyn
for PMDC NLE Step 1

What the PMDC NLE Step 1 Tests in Obs & Gyn

Obs & Gyn on the PMDC NLE Step 1 tests the candidate's ability to manage common obstetric emergencies (e.g., eclampsia, postpartum haemorrhage, shoulder dystocia), interpret antenatal screening (e.g., OGTT for GDM, anomaly scans), and apply evidence-based intrapartum care (e.g., partogram use, induction of labour). Gynaecology focuses on menstrual disorders (e.g., PCOS, endometriosis), pelvic infections (PID, Bartholin's abscess), contraception (COC, IUCD, implant), and menopause management (HRT risks/benefits). Candidates must recall diagnostic criteria (e.g., Rotterdam for PCOS, FIGO for abnormal uterine bleeding), first-line treatments (e.g., tranexamic acid for heavy menstrual bleeding, metformin for GDM), and surgical indications (e.g., ectopic pregnancy – salpingectomy vs. salpingostomy). Emphasis is on clinical decision-making, not pure recall.

High-Yield Concepts

• Eclampsia & Severe Pre-eclampsia: First-line anticonvulsant is IV magnesium sulphate (loading dose 4g over 5-10 minutes, then 1g/hour for 24 hours). Severe pre-eclampsia: BP ≥160/110 mmHg with proteinuria ≥300 mg/24h; treat with oral labetalol or IV hydralazine. Deliver after 34 weeks; before 34 weeks, give corticosteroids (betamethasone 12mg IM x2, 24h apart) for fetal lung maturity.
• Postpartum Haemorrhage (PPH): Primary PPH: blood loss >500 mL (vaginal) or >1000 mL (caesarean) within 24 hours. Active management: IV oxytocin (10 IU slow IV/IM) first-line; if refractory, ergometrine (0.5mg IM) or carboprost (250mcg IM q15min, max 8 doses). Uterine balloon tamponade (Bakri balloon) or B-Lynch suture if medical fails.
• Gestational Diabetes Mellitus (GDM): Screen at 24-28 weeks with 75g OGTT; diagnostic thresholds: fasting ≥5.1 mmol/L, 1-hour ≥10.0, 2-hour ≥8.5 mmol/L (WHO 2013). First-line treatment: lifestyle modification + metformin (500mg BD, max 2500mg/day); if inadequate, add insulin (e.g., NPH). Target fasting glucose <5.3 mmol/L, 2-hour postprandial <6.7 mmol/L.
• Ectopic Pregnancy: Triad: amenorrhoea, unilateral pelvic pain, vaginal bleeding. Diagnosis: transvaginal ultrasound (empty uterus + adnexal mass) + serial β-hCG (rise <66% in 48 hours). First-line: laparoscopic salpingectomy if contralateral tube normal; salpingostomy if desired fertility. Medical: methotrexate (50mg/m² IM) if unruptured, mass <35mm, no fetal cardiac activity, β-hCG <5000 IU/L.
• Polycystic Ovary Syndrome (PCOS): 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 (2.5-7.5mg cycle days 3-7) over clomiphene. For hirsutism: COC (e.g., ethinylestradiol + cyproterone acetate) or spironolactone (50-100mg BD).
• Abnormal Uterine Bleeding (AUB) – PALM-COEIN: FIGO classification: structural (Polyp, Adenomyosis, Leiomyoma, Malignancy) and non-structural (Coagulopathy, Ovulatory, Endometrial, Iatrogenic, Not classified). Heavy menstrual bleeding: first-line tranexamic acid (1g TDS for 5 days) or mefenamic acid (500mg TDS). If fails, consider LNG-IUS (Mirena) or endometrial ablation.
• Shoulder Dystocia: Risk factors: macrosomia, diabetes, prolonged second stage. Management: McRoberts' manoeuvre (hyperflexion of thighs) + suprapubic pressure (not fundal). If fails: delivery of posterior arm (Woods' screw) or Zavanelli manoeuvre (last resort). Document: head-to-body interval >60 seconds, use of manoeuvres, neonatal injury (e.g., Erb's palsy, clavicle fracture).
• Cervical Cancer Screening & HPV: Screening: cervical cytology (Pap smear) every 3 years (ages 25-49) then every 5 years (ages 50-64) in NHS; HPV primary screening (HPV test first, cytology if positive for 16/18). Abnormal results: colposcopy + biopsy. Treatment: CIN1 – observe; CIN2/3 – LLETZ excision. HPV vaccine (Gardasil 9) for ages 12-13, covers 9 types including 16/18/6/11.

Common Traps in Obs & Gyn Questions

• Confusing pre-eclampsia with gestational hypertension: pre-eclampsia requires proteinuria or end-organ dysfunction, not just hypertension.
• Using oxytocin before delivery of the placenta in PPH: it is given after placental delivery to avoid retained placenta or uterine inversion.
• Forgetting that magnesium sulphate is the first-line for eclampsia, not diazepam or phenytoin (which are second-line in resource-limited settings).
• Assuming all ectopic pregnancies require surgery: methotrexate is appropriate for stable, unruptured cases with low β-hCG (<5000) and no fetal cardiac activity.
• Misinterpreting PCOS ultrasound criteria: polycystic ovaries alone (without hyperandrogenism or anovulation) are not diagnostic; also, the follicle count threshold is ≥12 per ovary (not 10).
• Neglecting to check renal function before starting metformin in GDM: contraindicated if eGFR <30 mL/min/1.73m².

How to Revise Obs & Gyn for the PMDC NLE Step 1

Focus on clinical scenarios where you must choose between two similar management options (e.g., oxytocin vs. ergometrine for PPH; methotrexate vs. surgery for ectopic). Memorise exact diagnostic cut-offs (OGTT values, β-hCG thresholds, BP targets) and drug doses (magnesium sulphate, metformin, tranexamic acid). Practice interpreting partogram abnormalities (e.g., prolonged latent phase, arrest of descent) and deciding when to intervene (e.g., augmentation with oxytocin vs. caesarean for fetal distress). Gynae questions often test stepwise management of AUB or PCOS — know first-line, second-line, and surgical options. Review FIGO staging for cervical and endometrial cancer briefly, but prioritise screening protocols and HPV vaccination schedules. Use past PMDC-style MCQs to build speed in identifying the one correct step in a clinical algorithm.

Practise it: MedLumen has 50 Obs & Gyn questions for the PMDC NLE Step 1, each with a full explanation and references.