PLAB 1 Obstetrics and Gynaecology 2 — Questions and Answers
Question 1: A 22-year-old woman presents with heavy, regular periods (menorrhagia) but no structural abnormality on ultrasound. She does not wish to conceive. According to NICE, what is the first-line treatment?
- Combined oral contraceptive pill
- Levonorgestrel intrauterine system (Mirena IUS) (Correct answer)
- Tranexamic acid
- Endometrial ablation
Correct answer: Levonorgestrel intrauterine system (Mirena IUS)
NICE guidelines (NG88) recommend the levonorgestrel intrauterine system (LNG-IUS/Mirena) as first-line treatment for heavy menstrual bleeding. It reduces blood loss by up to 96% and provides contraception. If declined, alternatives include tranexamic acid, NSAIDs, or combined hormonal contraception.
Question 2: A woman at 28 weeks' gestation has a routine blood test showing she is Rhesus D negative. What is the recommended prophylactic management?
- No action needed until after delivery
- Routine antenatal anti-D immunoglobulin prophylaxis at 28 weeks (Correct answer)
- Immediate delivery to prevent sensitisation
- Weekly blood tests for antibodies until delivery
Correct answer: Routine antenatal anti-D immunoglobulin prophylaxis at 28 weeks
NICE recommends routine antenatal anti-D prophylaxis (RAADP) at 28 weeks for all RhD-negative women (single dose of 1,500 IU or two doses at 28 and 34 weeks). This prevents sensitisation and haemolytic disease of the newborn. Additional anti-D is given after sensitising events.
Question 3: A 40-year-old woman presents with a 3 cm complex ovarian cyst found incidentally on ultrasound. Her CA-125 is 85 U/mL (normal <35). Using the Risk of Malignancy Index (RMI), which factors are included in the calculation?
- Age, BMI, and family history
- Ultrasound score, menopausal status, and CA-125 level (Correct answer)
- Tumour size, blood pressure, and parity
- Ethnicity, smoking status, and hormone use
Correct answer: Ultrasound score, menopausal status, and CA-125 level
The Risk of Malignancy Index (RMI) = Ultrasound score (U) x Menopausal status (M) x CA-125 level. An RMI ≥250 warrants referral to a specialist gynaecological oncology centre. This woman's elevated CA-125 and postmenopausal status increase her RMI significantly.
Question 4: A primigravida at 41+3 weeks' gestation is offered a membrane sweep. She asks about the evidence. What should you tell her about the purpose of a membrane sweep?
- It guarantees labour will start within 24 hours
- It can help stimulate the onset of spontaneous labour by releasing prostaglandins, reducing the need for formal induction (Correct answer)
- It has no evidence base and is not recommended by NICE
- It is a form of artificial rupture of membranes
Correct answer: It can help stimulate the onset of spontaneous labour by releasing prostaglandins, reducing the need for formal induction
Membrane sweeping involves separating the membranes from the lower uterine segment, which stimulates local prostaglandin release. NICE recommends offering sweeps from 40 weeks in nulliparous women and 41 weeks in multiparous women to reduce the need for formal induction of labour.
Question 5: A 32-year-old woman in established labour has a cervical dilatation rate of 0.3 cm/hour after 4 hours despite adequate contractions. According to NICE intrapartum care guidelines, what is this called and what is the next step?
- Normal progress — continue observation
- Delay in the first stage — consider amniotomy if membranes are intact, and/or oxytocin augmentation (Correct answer)
- Failure to progress — immediate caesarean section
- Precipitate labour — slow down contractions with tocolytics
Correct answer: Delay in the first stage — consider amniotomy if membranes are intact, and/or oxytocin augmentation
NICE defines delay in the first stage as cervical dilatation of less than 0.5 cm/hour over 4 hours. Management includes amniotomy (ARM) if membranes are intact, followed by oxytocin augmentation if progress remains slow. Caesarean section is considered if these measures fail.
Question 6: A woman has a primary postpartum haemorrhage (PPH) with estimated blood loss of 1,200 mL. According to UK guidelines, what are the four 'T' causes of PPH?
- Temperature, Thrombosis, Trauma, Tissue
- Tone, Trauma, Tissue, Thrombin (Correct answer)
- Tachycardia, Tension, Torsion, Toxins
- Transfusion, Tocolysis, Traction, Tamponade
Correct answer: Tone, Trauma, Tissue, Thrombin
The four T's of PPH are: Tone (uterine atony — the commonest cause, ~70%), Trauma (genital tract lacerations), Tissue (retained placenta or membranes), and Thrombin (coagulation disorders). Systematic assessment of all four causes guides management.
PLAB 1 Obstetrics and Gynaecology 2
A 22-year-old woman presents with heavy, regular periods (menorrhagia) but no structural abnormality on ultrasound.
She does not wish to conceive.
According to NICE, what is the first-line treatment?