PLAB 1 Obstetrics and Gynaecology

Question 1

A 28-year-old woman at 32 weeks' gestation presents with painless bright red vaginal bleeding. On examination, the uterus is soft and non-tender. What is the most likely diagnosis?

Accepted Answer

Placenta praevia

Answer

Painless, bright red vaginal bleeding in the third trimester is the hallmark presentation of placenta praevia. The soft, non-tender uterus distinguishes it from placental abruption, which typically presents with constant pain and a woody-hard uterus. Digital vaginal examination is contraindicated.

Question 2

A 30-year-old primigravida at 34 weeks' gestation has a blood pressure of 165/110 mmHg, proteinuria of 3+, and complains of a severe headache and visual disturbances. What is the most appropriate immediate management?

Accepted Answer

Admit, commence IV magnesium sulphate and IV labetalol, and plan urgent delivery

Answer

This presentation — severe hypertension, significant proteinuria, headache, and visual disturbances — constitutes severe pre-eclampsia with imminent risk of eclampsia. NICE guidelines (NG133) recommend IV magnesium sulphate for seizure prevention, IV labetalol for BP control, and planned delivery.

Question 3

A 25-year-old woman presents at 7 weeks' gestation with vaginal bleeding and left iliac fossa pain. Her serum beta-hCG is 1,500 IU/L and transvaginal ultrasound shows an empty uterus. What is the most likely diagnosis?

Accepted Answer

Ectopic pregnancy

Answer

An empty uterus on transvaginal ultrasound with a beta-hCG above the discriminatory level (usually 1,500-2,000 IU/L), combined with pain and bleeding, is highly suspicious for ectopic pregnancy until proven otherwise. This requires urgent gynaecological assessment.

Question 4

According to NICE guidelines, what is the recommended method of induction of labour when the cervix is unfavourable (Bishop score <6)?

Accepted Answer

Vaginal prostaglandin E2 (dinoprostone) or oral misoprostol to ripen the cervix

Answer

NICE recommends cervical ripening with vaginal prostaglandin E2 (dinoprostone) or oral misoprostol when the cervix is unfavourable (Bishop score <6). ARM and oxytocin are used once the cervix is favourable. Mechanical methods (balloon catheter) are also options.

Question 5

A 35-year-old woman presents with post-menopausal bleeding. She is on no hormone replacement therapy. What is the most appropriate initial investigation?

Accepted Answer

Transvaginal ultrasound to assess endometrial thickness

Answer

Post-menopausal bleeding requires investigation to exclude endometrial cancer. NICE recommends transvaginal ultrasound as the first-line investigation. If endometrial thickness is ≥4 mm, hysteroscopy with endometrial biopsy is indicated. All women with PMB should be referred via 2-week wait.

PLAB 1 Practice Test

PLAB 1 Practice Test

PLAB 1 Obstetrics and Gynaecology