Miscarriage

Definition

Basics and definition

• A miscarriage is defined as the loss of a pregnancy before the foetus is viable, which is under 500 g weight.
• The incidence of clinically recognised miscarriages is 10–15% of all clinical pregnancies.
• By far the most common cause of early miscarriages is chromosomal abnormalities of the embryo.

Classification

Types with bleeding and an open cervix

• An Abortus incipiens is characterised by bleeding, contractions and an open cervix and can no longer be stopped.
• In an Abortus incompletus with retained products of conception in the uterine cavity, the bleeding typically not, due to retained products.
• An Abortus completus has occurred when the gestational sac has been completely expelled, the bleeding has stopped and the beta-hCG level decreases over time.

Silent and complicated courses

• A missed miscarriage is a non-viable pregnancy without symptoms with a a closed cervix.
• A definitive ultrasound criterion for a missed miscarriage is a crown-rump length of CRL ≥7 mm without cardiac activity.
• A blighted ovum (anembryonic pregnancy) refers to a gestational sac without an embryonic pole.

Diagnosis

Ultrasound correlation

• If an intrauterine gestational sac is absent at this level, there is a high suspicion of ectopic pregnancy.
• The ultrasound milestones are the gestational sac from about 4+3 to 5+0 weeks, the yolk sac from about 5+3 weeks, and the embryo with a heartbeat from about 6+0 weeks.

Typical imaging findings

• Colposcopy: The cervix is livid and otherwise smooth. Fresh dark-red blood wells out of the cervical canal and collects in the posterior fornix. The external os appears closed and no tissue lies on it.

Keep learning in the app

Further reading (selection)

1. StatPearls: Early Pregnancy Loss (Spontaneous Abortion) (NCBI Bookshelf)
2. DocCheck Flexikon, Abort
3. DocCheck Flexikon, Humanes Choriongonadotropin

Cross-references