Early Pregnancy & Complications
Let beta-hCG and ultrasound sort the empty uterus from the viable one
First-trimester bleeding: hCG and ultrasound logic
A fixed reflex. Any first-trimester bleeding gets a quantitative β-hCG, a transvaginal ultrasound, blood type and Rh, and an assessment of hemodynamic stability. The differential is ectopic pregnancy; threatened, inevitable, incomplete, complete, or missed abortion; and molar pregnancy (plus benign causes such as cervical lesions or subchorionic hemorrhage).
- Intrauterine sac seenectopic is essentially excluded (except rare heterotopic pregnancy with assisted reproduction)
- No sac, hCG above the zoneectopic or nonviable pregnancy until proven otherwise
- No sac, hCG below the zone, stablepregnancy of unknown location—repeat hCG in 48 hours
- Slow rise or plateauabnormal pregnancy (ectopic or failing IUP); a normal early IUP rises at least ~35–53%
A single hCG cannot locate a pregnancy; pair it with ultrasound and, if indeterminate, serial values 48 hours apart.
Ectopic pregnancy
Where and who. An ectopic pregnancy implants outside the uterine cavity, most often in the ampulla of the fallopian tube. Risk factors reflect tubal damage: prior PID (chlamydia) or ectopic pregnancy, tubal surgery, and smoking, plus assisted reproduction. An IUD lowers absolute ectopic risk, but a pregnancy that occurs with an IUD in place is more likely to be ectopic.
Presentation. The classic triad—amenorrhea, unilateral pelvic pain, and vaginal bleeding—appears at 6–8 weeks. Rupture causes hemoperitoneum, peritoneal signs, shoulder pain, and shock; an unstable patient goes straight to surgery.
| Feature | Methotrexate | Surgery |
|---|---|---|
| Hemodynamics | Stable, unruptured | Ruptured or unstable |
| β-hCG | Below ~5,000 | High |
| Mass | <3.5–4 cm | Large |
| Fetal cardiac activity | Absent | Present |
| Other | Reliable follow-up | Methotrexate contraindicated (renal, hepatic, or hematologic disease, breastfeeding) or failed |
| Follow-up | hCG on days 4 and 7: expect ≥15% drop; then weekly to zero | Salpingostomy (tube spared; follow hCG) or salpingectomy |
Methotrexate is a folate antagonist that stops trophoblast growth. If hCG falls by less than 15% from day 4 to day 7, a second dose is given; failure of medical therapy leads to surgery. Patients avoid folate-containing vitamins, NSAIDs, and alcohol during treatment.
Spontaneous and recurrent pregnancy loss
Cause. Most first-trimester losses result from fetal chromosomal abnormalities, chiefly autosomal trisomies. The cervical os and the retained tissue name the type:
| Type | Bleeding | Cervical os | Uterine contents |
|---|---|---|---|
| Threatened | Yes | Closed | Viable pregnancy |
| Inevitable | Yes | Open | Products not yet passed |
| Incomplete | Yes | Open | Some products passed, some retained |
| Complete | Resolving | Closed | All passed; empty uterus |
| Missed | None | Closed | Fetal demise retained |
Management. A threatened abortion is observed. Early pregnancy loss can be managed expectantly, medically (misoprostol, often after mifepristone), or surgically (suction curettage/D&C), depending on stability, bleeding, and patient preference; heavy bleeding or instability favors suction curettage. A septic abortion (fever, uterine tenderness, foul discharge) needs broad-spectrum antibiotics and prompt evacuation. If the mother is Rh(D)-negative, anti-D is standard at 12 weeks or later; ACOG (2024) allows omitting it after abortion or pregnancy loss before 12 weeks.
Recurrent pregnancy loss (≥2–3 losses) prompts a workup: antiphospholipid syndrome (lupus anticoagulant, anticardiolipin, anti-β2-glycoprotein I), uterine anomalies such as a septate uterus, parental balanced translocations (karyotype both partners), and thyroid and diabetes control. Painless second-trimester cervical dilation instead suggests cervical insufficiency, treated with cerclage.
Antiphospholipid syndrome is the most important treatable cause of recurrent loss: low-dose aspirin plus heparin improves live-birth rates.
Gestational trophoblastic disease
| Feature | Complete mole | Partial mole |
|---|---|---|
| Karyotype | 46,XX, all paternal (sperm fertilizes an empty egg) | Triploid, e.g., 69,XXX or 69,XXY (two sperm, one egg) |
| Fetal parts | None | Present |
| Trophoblast | Diffuse proliferation | Focal |
| β-hCG | Markedly high | Lower |
| Ultrasound | "Snowstorm" / cluster of grapes | Fetus with abnormal placenta |
| Progression to neoplasia | ~15–20% | Low |
The exaggerated pregnancy. Molar pregnancy classically causes first-trimester bleeding, a uterus large for dates, hyperemesis, early preeclampsia before 20 weeks, theca-lutein cysts, and hyperthyroidism, because hCG shares an α subunit with TSH and cross-stimulates its receptor.
Preeclampsia before 20 weeks should always trigger a search for a mole.
Management. Evacuate by suction dilation and curettage (hysterectomy is an option if childbearing is complete), then follow serial β-hCG until undetectable to detect gestational trophoblastic neoplasia (invasive mole or choriocarcinoma). Use reliable contraception and avoid pregnancy during surveillance so a new pregnancy does not mask a rising hCG. A rising or plateauing hCG signals neoplasia, which is highly chemosensitive; get a chest X-ray (lungs are the usual metastatic site) and treat persistent low-risk disease with methotrexate.
Hyperemesis gravidarum and Rh prophylaxis
Hyperemesis gravidarum is severe nausea and vomiting with >5% weight loss, dehydration, ketosis, and hypokalemic hypochloremic metabolic alkalosis. It is linked to high hCG (molar or multiple gestation), so ultrasound is part of the workup. First-line drug therapy is pyridoxine (vitamin B6) with doxylamine, plus IV fluids and additional antiemetics (ondansetron, metoclopramide, promethazine) as needed.
Give thiamine before dextrose-containing fluids to prevent Wernicke encephalopathy.
Rh prophylaxis. An Rh(D)-negative mother receives anti-D immunoglobulin (RhoGAM) after any sensitizing event—first-trimester bleeding, ectopic pregnancy, miscarriage, abortion, molar evacuation, or chorionic villus sampling—and routinely at 28 weeks and postpartum if the newborn is Rh-positive. This prevents alloimmunization and hemolytic disease in future pregnancies. Guidance is evolving: ACOG (2024) considers anti-D optional after induced or spontaneous abortion before 12 weeks.