abortion

**Definition:** Pregnancy loss before viability (<20 weeks gestation by LMP in the US, or <500 g). After 20 weeks, a loss is termed stillbirth/fetal demise (IUFD) or preterm delivery.

**Types of spontaneous abortion (miscarriage):** - **Threatened:** Vaginal bleeding, closed cervical os, viable fetus on US. Pregnancy may continue. Management is expectant. - **Inevitable:** Bleeding with a dilated cervical os; products of conception (POC) not yet expelled. - **Incomplete:** Dilated os with partial expulsion of POC; heavy bleeding, retained tissue on US. Management: expectant, misoprostol, or D&C/suction curettage. - **Complete:** All POC expelled, closed os, empty uterus on US, bleeding and pain resolving. Usually needs only follow-up (confirm declining β-hCG). - **Missed (early pregnancy loss):** Fetal demise with a retained, closed os and often no symptoms. US shows no cardiac activity (CRL ≥7 mm without heartbeat, or mean sac diameter ≥25 mm without embryo). Management: expectant, misoprostol (± mifepristone), or D&C. - **Septic:** Infection of retained POC or after an unsafe procedure. Fever, uterine tenderness, foul discharge. Treat with broad-spectrum IV antibiotics (e.g., clindamycin + gentamicin) and uterine evacuation. - **Recurrent pregnancy loss:** ≥2 (ASRM) or ≥3 (classic definition) consecutive losses.

**Etiology of spontaneous abortion:** - *First trimester:* Chromosomal abnormalities (~50%), mostly trisomies (esp. trisomy 16), then monosomy X (45,XO), and triploidy. - *Second trimester:* Anatomic causes, such as cervical insufficiency (painless cervical dilation; treat with cerclage), uterine septum or fibroids, and Asherman syndrome. Also infections and maternal disease. - *Recurrent loss:* Antiphospholipid syndrome (the most important treatable cause; treat with low-dose aspirin + heparin), parental balanced translocations, uterine anomalies, thrombophilias, uncontrolled diabetes, and thyroid disease. - *Other risk factors:* Advanced maternal age, smoking, alcohol, cocaine, trauma, and infections (e.g., Listeria, Toxoplasma, CMV, Brucella).

**Workup:** Quantitative β-hCG, transvaginal US, CBC, blood type and Rh status. Give **Rh immunoglobulin (RhoGAM)** to Rh-negative, unsensitized women. Rule out ectopic pregnancy (always consider it in first-trimester bleeding with pain) and molar pregnancy.

**Induced abortion:** - *Medical (≤10–11 weeks):* Mifepristone (progesterone receptor antagonist) followed by misoprostol (PGE1 analog) 24–48 hours later. Contraindications: ectopic pregnancy, chronic adrenal failure, long-term steroid use, bleeding disorders or anticoagulation, and an IUD in place. - *Surgical:* Suction aspiration/D&C in the first trimester; dilation and evacuation (D&E) in the second trimester. - *Complications:* Hemorrhage, uterine perforation, infection, retained POC, cervical injury, and Asherman syndrome (intrauterine adhesions causing secondary amenorrhea).

**Other high-yield points:** - Methotrexate is used for ectopic pregnancy, not for routine abortion. It is a teratogen and abortifacient. - Teratogens or drugs causing loss: misoprostol, methotrexate, warfarin, ACE inhibitors, isotretinoin. - Gestational trophoblastic disease can present as first-trimester bleeding with a very high β-hCG and a "snowstorm" appearance on US. - Cervical insufficiency vs. threatened abortion: the former is painless dilation in the second trimester, with no contractions or bleeding initially.