Maternal-Fetal Medicine and High-Risk Obstetrics
Core concepts
High-risk obstetrics is about risk stratification and surveillance intensity. Master the medical complications of pregnancy (pregestational and gestational diabetes, chronic and gestational hypertension, thyroid disease, cardiac disease, epilepsy, thrombophilia, autoimmune disease) and their fetal/neonatal effects. Understand fetal growth restriction versus small-for-gestational-age, placental insufficiency, and the role of Doppler surveillance. Know preterm labor management (tocolysis indications, antenatal corticosteroids, magnesium for neuroprotection), preterm premature rupture of membranes, multiple gestation complications, and isoimmunization. Genetic counseling and prenatal diagnosis (screening vs. diagnostic testing, cell-free DNA limitations) are heavily tested.
Traps
- Pregestational vs. gestational diabetes: congenital anomaly risk is tied to periconceptional glycemic control in pregestational disease; gestational diabetes mainly drives macrosomia and metabolic complications.
- Corticosteroids: benefit is greatest before 34 weeks; do not withhold when delivery is imminent if time permits, but avoid unnecessary repeat courses.
- Magnesium sulfate: used for seizure prophylaxis in preeclampsia and fetal neuroprotection before early preterm delivery-know dosing and toxicity monitoring (reflexes, respiratory rate, urine output).
- Fetal growth restriction: distinguish constitutionally small from pathologically growth-restricted; abnormal umbilical artery Doppler changes management.
- Isoimmunization: titers and middle cerebral artery Doppler guide surveillance; intrauterine transfusion is the treatment for severe fetal anemia.
Worked example / rule of thumb
A patient at 32 weeks with severe-range blood pressure and new thrombocytopenia. Rule of thumb: severe features define severe preeclampsia regardless of proteinuria, and delivery is the definitive treatment; magnesium and antihypertensives stabilize the patient until delivery is arranged.
Study strategy
Create a table of medical conditions × pregnancy effect × fetal effect × surveillance; this structures most MFM questions.