Miscarriage

Spontaneous pregnancy loss before 24 weeks gestation (definitions vary by country, some use 20 weeks), occurring in roughly 15 to 20% of clinically recognized pregnancies, the majority in the first trimester and the majority attributable to chromosomal abnormality.

Classified as threatened, inevitable, incomplete, complete, or missed (delayed, sometimes asymptomatic and identified incidentally on scan).

Vaginal bleeding and cramping lower abdominal pain, with or without passage of tissue.

The cervical os is closed in threatened, complete, and missed miscarriage, and open in inevitable and incomplete miscarriage.

Transvaginal ultrasound is central: absence of cardiac activity with a crown-rump length of 7 mm or greater, or an empty gestational sac with a mean sac diameter of 25 mm or greater, confirms miscarriage per most current criteria (RCOG/ASRM); findings below these thresholds require a repeat scan in 7 to 14 days rather than immediate diagnosis, to avoid misclassifying a viable early pregnancy. In a pregnancy of unknown location, serial serum beta-hCG at 48 hours helps distinguish a viable pregnancy (expected rise of at least 53 to 66%) from a failing one.

• Expectant management is first line for incomplete miscarriage, generally allowed up to 2 weeks, with a success rate around 80%; a urine pregnancy test at 3 weeks confirms completion
• Medical management: misoprostol 800 mcg PV (per vaginum) as a single dose, repeated if needed; for missed miscarriage, pretreatment with mifepristone 200 mg PO 24 to 48 hours before misoprostol improves efficacy
• Surgical management (manual vacuum aspiration or evacuation of retained products of conception under anesthesia): indicated for hemorrhage, infection, patient preference, or failed medical or expectant management
• Anti-D prophylaxis for Rh negative women undergoing surgical management (regardless of gestation in many protocols), and for medical or expectant management beyond 12 weeks
• Recurrent miscarriage (3 or more consecutive losses) warrants specialist workup: antiphospholipid antibody screen, parental karyotyping and/or products of conception karyotyping, pelvic ultrasound for uterine anomaly, and thrombophilia screening

Referral: early pregnancy unit for all suspected miscarriage; recurrent miscarriage clinic after 3 losses.