ABPS Family Medicine Obstetrics common mistakes
ABPS Family Medicine Obstetrics · Understand the traps and how to avoid them.
When a question describes a patient with a chronic condition (e.g., epilepsy, thyroid disease, prior VTE) who is planning pregnancy, the candidate jumps to managing the condition in pregnancy rather than first addressing preconception optimization and contraception until the condition is controlled.
Candidates pattern-match to the 'pregnant patient' script and skip the stem's timing cues ('planning pregnancy', 'considering conception'), so they select an intrapartum or antenatal intervention instead of the preconception step the question is testing.
What to do instead
Before answering, underline the timing word in the stem (preconception vs. currently pregnant vs. postpartum) and ask what the next step is at that time point; if conception is not yet achieved, the answer usually involves contraception, medication adjustment to a pregnancy-compatible regimen, or folic acid/immunization optimization.
The candidate cannot distinguish which antihypertensive agents are safe in pregnancy and selects an ACE inhibitor, ARB, or atenolol for a pregnant patient, or avoids all treatment of severe hypertension out of fear of harming the fetus.
Chronic hypertension management outside pregnancy centers on ACEi/ARB, and candidates carry that habit into obstetric questions; conversely, some overcorrect and under-treat severe hypertension, missing the maternal stroke risk.
What to do instead
Memorize a short safe-list (labetalol, nifedipine, methyldopa) and a short avoid-list (ACEi, ARB, direct renin inhibitors, atenolol) and rehearse that acute severe hypertension in pregnancy is treated promptly with IV labetalol/hydralazine or oral nifedipine; treatment protects the mother and is not withheld.
When presented with a preeclampsia-spectrum stem, the candidate orders or interprets the wrong confirmatory tests (e.g., relying on uric acid or a single blood pressure, or missing that proteinuria is no longer required when other severe features are present) and misclassifies severity.
Older teaching emphasized proteinuria and 24-hour urine collection, and candidates conflate chronic hypertension, gestational hypertension, and preeclampsia without a structured framework, so they miss severe features (thrombocytopenia, transaminitis, renal insufficiency, pulmonary edema, visual/cerebral symptoms).
What to do instead
Use a fixed checklist for every hypertensive stem: gestational age >20 weeks, new-onset hypertension, then scan for severe features (BP ≥160/110, platelets <100k, AST/ALT >2x, creatinine >1.1 or doubling, pulmonary edema, new cerebral/visual symptoms). Classify by checklist, not by proteinuria alone.
The candidate mismanages shoulder dystocia by applying fundal pressure, pulling on the head, or cutting an episiotomy as the first maneuver, instead of proceeding through a recognized sequence (McRoberts, suprapubic pressure, then internal maneuvers).
Under time pressure the instinct is to 'pull harder' or to do the most familiar procedure; candidates also confuse the order of maneuvers and forget to call for help and document.
What to do instead
Drill the sequence as a fixed algorithm: call for help, McRoberts, suprapubic pressure, then rotational/manual maneuvers (Rubin, Woods screw, delivery of posterior arm), episiotomy only if needed for access, never fundal pressure. Rehearse the sequence aloud until it is automatic.
The candidate misreads fetal heart rate tracings described in text (e.g., calls a category II tracing category I, or fails to identify recurrent late decelerations as a sign of uteroplacental insufficiency requiring intrauterine resuscitation and possible delivery).
Tracings are described verbally rather than shown, so candidates skim the description and anchor on a single feature (baseline rate) rather than integrating variability, accelerations, and decelerations; they also confuse variable with late decelerations.
What to do instead
For every tracing stem, extract four data points explicitly (baseline, variability, accelerations, decelerations) and assign a category before choosing management; link recurrent late decelerations to uteroplacental insufficiency and recurrent variable decelerations to cord compression, and pair each with the correct resuscitation step.
The candidate selects the wrong antibiotic or prophylaxis regimen for group B Streptococcus (GBS), or omits intrapartum prophylaxis when indicated, or treats a colonized patient who does not meet criteria.
GBS guidance is detailed (screening timing, indications for prophylaxis, penicillin as first-line, clindamycin susceptibility testing for penicillin allergy) and candidates rely on vague memory of 'give antibiotics in labor' without the specific criteria.
What to do instead
Build a one-page GBS card: screen at 36 0/7–37 6/7 weeks; prophylaxis for prior GBS-affected infant, GBS bacteriuria this pregnancy, or positive screen; penicillin G first-line, cefazolin for non-anaphylactic allergy, clindamycin only with susceptibility testing, vancomycin for anaphylaxis with resistant organism. Test yourself on the exceptions.
The candidate fails to recognize an obstetric emergency pattern (postpartum hemorrhage from uterine atony, or a postpartum patient with headache and hypertension concerning for postpartum preeclampsia) and chooses a routine next step instead of the time-critical action.
Emergency stems bury the key finding among normal vitals or a reassuring narrative, and candidates default to the routine postpartum order set rather than escalating; they also underweight delayed postpartum preeclampsia presenting after discharge.
What to do instead
For any stem with bleeding, hypotension, or a postpartum headache with elevated BP, run a 'red-flag screen' first: quantify blood loss, check uterine tone, start uterotonics and hemorrhage protocol for atony; for postpartum hypertension with headache, check BP and labs and treat as preeclampsia until proven otherwise. Practice recognizing the pattern before reading the answer choices.
The candidate gives unsafe or contraindicated medication advice in pregnancy or lactation (e.g., recommends a live vaccine, prescribes a teratogen without noting contraception, or tells a breastfeeding mother to stop a compatible medication unnecessarily).
Candidates memorize a few classic teratogens but lack a structured approach to risk assessment and default to 'stop the drug' or 'don't vaccinate', which is often the wrong answer when benefit outweighs risk.
What to do instead
Separate the question into three buckets: known teratogens (avoid or substitute), drugs with reassuring data (continue), and live vaccines (avoid in pregnancy, generally safe in lactation). For lactation, check compatibility before recommending cessation; for teratogens, always pair the prescription with contraception counseling.
The candidate answers an ethics or professionalism stem by choosing the option that satisfies the patient's or family's request rather than the option that reflects informed consent, confidentiality, or the physician's fiduciary duty (e.g., disclosing to a partner without consent, or acceding to a demand for a non-indicated cesarean).
Candidates conflate 'patient satisfaction' with the ethically correct answer and are uncomfortable with conflict, so they pick the accommodating option instead of the one honoring autonomy, beneficence, and professional standards.
What to do instead
For ethics stems, identify the principle at stake (autonomy, confidentiality, nonmaleficence, justice) and choose the option that respects informed consent and the patient's decision-making capacity; when a patient requests a non-indicated procedure, the correct answer is usually shared decision-making and documentation, not automatic acquiescence or refusal.
The candidate misapplies prenatal screening and diagnostic testing logic (e.g., treats a screening test as diagnostic, orders the wrong test for gestational age, or fails to offer diagnostic testing after a high-risk screen) and mishandles aneuploidy screening options.
Screening algorithms (cell-free DNA, combined first-trimester screen, quad screen, integrated screen) have different windows and detection rates, and candidates blur screening with diagnosis, so they skip the confirmatory step or choose a test outside its valid gestational window.
What to do instead
Map each test to its gestational window and purpose: screening tests estimate risk and require diagnostic confirmation (CVS 10–13 weeks, amniocentesis ≥15 weeks); cell-free DNA is a screening test with high detection but is not diagnostic. For any abnormal screen, the next step is counseling about diagnostic testing, not immediate treatment.