From the Guidelines
The initial step in managing a suspected miscarriage involves a thorough clinical history, physical examination, and ultrasound evaluation, as outlined in the Society of Radiologists in Ultrasound consensus conference recommendations 1. When a patient presents with suspected miscarriage, the primary goal is to determine the viability of the pregnancy and the type of miscarriage, if any, to guide appropriate management. Key points to consider in the workup include:
- Ultrasound criteria for early pregnancy loss (EPL), such as embryonic crown-rump length (CRL) <7 mm and no cardiac activity, or mean sac diameter (MSD) 16-24 mm and no embryo 1.
- The classification of EPL into categories including concerning for, diagnostic of, in progress, incomplete, and completed, which helps in deciding the management approach.
- The use of serial quantitative beta-hCG measurements to assess pregnancy viability, with the understanding that levels should approximately double every 48-72 hours in a viable pregnancy. Management strategies depend on the type of miscarriage diagnosed:
- For a complete miscarriage, typically no further intervention is required.
- For an incomplete or missed miscarriage, options include expectant management, medical management with misoprostol, or surgical management via vacuum aspiration or dilation and curettage. Medical management with misoprostol (800 mcg vaginally or 600 mcg sublingually) is often preferred due to its effectiveness and avoidance of surgical risks 1. Additional considerations include:
- Administration of anti-D immunoglobulin (RhoGAM) to Rh-negative women to prevent isoimmunization.
- Monitoring for potential complications such as excessive bleeding, infection, or incomplete evacuation.
- Providing emotional support, as miscarriage can have significant psychological impacts.
- Advising patients to wait at least one menstrual cycle before attempting conception again, primarily for accurate dating of a future pregnancy.
From the Research
Suspected Miscarriage Workup
- The diagnosis of miscarriage is typically made using transvaginal ultrasound (TVS) assessment 2
- TVS should be considered the standard test to assess viability of the pregnancy 3
- Assessment of vaginal bleeding is best made in the context of time taken to saturate a sanitary pad, with changing a pad soaked with blood and clots more than once an hour indicating heavy bleeding that requires immediate referral 3
Risk Factors and Treatment
- Advancing maternal and paternal age, being underweight or overweight, smoking, and high alcohol consumption are known risk factors for miscarriage 3
- Expectant management is the first-line approach for miscarriage, encouraged for 7-14 days after diagnosis, with most women miscarrying spontaneously during this time 3
- Medical management of miscarriage can be offered using misoprostol, while surgical management may be chosen by a woman if she has had a previous adverse or traumatic experience associated with pregnancy 3
- Anti-D prophylaxis is required for women who are rhesus negative and experiencing symptoms of bleeding if the pregnancy is 12 weeks' gestation 3
Diagnostic Criteria and Accuracy
- Evidence-based criteria should be employed for the diagnosis of delayed and incomplete miscarriage 2
- Complete miscarriage should not be diagnosed with TVS alone without serial biochemical confirmation, unless an intrauterine gestation sac has previously been visualized 2
- The sensitivity, specificity, predictive value, and overall diagnostic accuracy of ultrasound are calculated, with transvaginal ultrasound being nondiagnostic in 17.7% of cases 4
- The use of three-dimensional ultrasound has not improved the diagnosis of miscarriage 2