A transvaginal ultrasound scan shows no fetal heartbeat or fetal activity

A 24 year old woman who is 15 weeks pregnant presents with pain in her lower abdomen for the past couple of hours. She has some vaginal spotting. On examination, abdomen is tender, and cervical os is closed. A transvaginal ultrasound scan shows no fetal heartbeat or fetal activity. What is the SINGLE most likely diagnosis?

A. Threatened miscarriage
B. Inevitable miscarriage
C. Incomplete miscarriage
D. Missed miscarriage
E. Spontaneous miscarriage

It is important to note that missed miscarriage may present with heavy vaginal bleeding or none at all. But if there is no fetal heart seen, at this stage of pregnancy, it is a missed miscarriage. Note that in normal pregnancy the fetal heart is seen usually at 6 weeks. So you should not be diagnosing a missed miscarriage if a 4 week pregnant lady has no fetal heartbeat seen on a transvaginal ultrasound. There are more specific ultrasound criterias to diagnose missed miscarriage but are beyond what will be asked in PLAB part 1.

A short summary of types of miscarriages that are commonly asked in PLAB Threatened miscarriage → Vaginal bleeding + fetal heart seen. Cervical os is closed Missed miscarriage (delayed miscarriage) → Dead fetus before 20 weeks without the symptoms of expulsion. May or may not have vaginal bleeding. Cervical os is closed. Inevitable miscarriage → Cervical os opened and bleeding Incomplete miscarriage - Not all products of conception have been expelled Complete miscarriage - Everything has been expelled