USMLE Step 2 Quiz
Practice Prenatal Care And Antenatal Screening in USMLE Step 2 with focused quiz questions that help you check what you know, review explanations, and build confidence with test-style prompts.
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A 28-year-old primigravid woman at 10 weeks gestation presents for her first prenatal visit. Her medical history is unremarkable, and she has had no complications with the pregnancy to date. She asks about the expected schedule for her future appointments.
Assuming an uncomplicated pregnancy, what is the recommended frequency of prenatal visits for this patient from now until 28 weeks gestation?
This quiz focuses on Prenatal Care And Antenatal Screening, giving you a quick way to practice the rules, question types, and explanations that matter most for USMLE Step 2.
Try each quiz question before looking at the correct answer. Use the explanations to review missed ideas, then come back to similar questions until the pattern feels familiar.
A 28-year-old primigravid woman at 10 weeks gestation presents for her first prenatal visit. Her medical history is unremarkable, and she has had no complications with the pregnancy to date. She asks about the expected schedule for her future appointments.
Assuming an uncomplicated pregnancy, what is the recommended frequency of prenatal visits for this patient from now until 28 weeks gestation?
Explanation: For a standard, uncomplicated pregnancy, the recommended schedule for prenatal visits is every 4 weeks until 28 weeks gestation, every 2 weeks from 28 to 36 weeks, and then weekly from 36 weeks until delivery. This schedule allows for routine monitoring of maternal and fetal well-being.
A 30-year-old woman is attending a preconception counseling visit. Her obstetric history is significant for a previous pregnancy that was affected by an anencephalic fetus. She is otherwise healthy and takes no medications.
What is the most appropriate daily dose of folic acid to recommend for this patient, starting at least one month prior to attempting conception?
Explanation: Women with a history of a prior pregnancy affected by a neural tube defect (NTD) are at high risk for recurrence. The standard recommendation for these women is high-dose folic acid supplementation of 4 mg (4000 mcg) daily, starting at least one month before conception and continuing through the first trimester. The 0.4 mg (400 mcg) dose is recommended for average-risk women.
A 29-year-old G2P1 woman at 7 weeks gestation presents for her first prenatal visit. Her medical history is significant for hypertension, for which she has been taking lisinopril for the past two years. Her blood pressure in the office is 148/92 mmHg.
Which of the following is the most appropriate next step in managing her hypertension?
Explanation: Angiotensin-converting enzyme (ACE) inhibitors like lisinopril are contraindicated in pregnancy due to their association with fetal renal dysplasia, oligohydramnios, and skull defects. They should be discontinued immediately. Given her elevated blood pressure, antihypertensive therapy is still required. Labetalol, methyldopa, and nifedipine are considered first-line agents for managing hypertension during pregnancy. Losartan is an angiotensin II receptor blocker (ARB) and carries similar teratogenic risks as ACE inhibitors.
A 26-year-old primigravida at 9 weeks gestation tells you she typically has a glass of wine with dinner two to three times per week. She has heard conflicting information and asks if this amount is safe for her baby.
What is the most appropriate counseling for this patient regarding alcohol consumption?
Explanation: No safe level of alcohol consumption during pregnancy has been established. All major medical organizations, including the American College of Obstetricians and Gynecologists (ACOG), recommend complete abstinence from alcohol throughout pregnancy due to the risk of fetal alcohol spectrum disorders. Recommending a 'safe' limit is inappropriate. A detailed ultrasound at this early gestation would not be able to identify features of fetal alcohol syndrome.
A 32-year-old G1P0 woman undergoes first-trimester combined screening at 12 weeks gestation. Her results show an increased nuchal translucency of 3.5 mm, a low maternal serum pregnancy-associated plasma protein-A (PAPP-A) level, and a high maternal serum beta-hCG level.
These findings are most suggestive of an increased risk for which of the following fetal conditions?
Explanation: The classic first-trimester screening pattern for Trisomy 21 includes an increased nuchal translucency, high beta-hCG, and low PAPP-A. Trisomy 18 and Trisomy 13 are typically associated with low levels of both beta-hCG and PAPP-A. Open neural tube defects are screened for in the second trimester with maternal serum alpha-fetoprotein (MSAFP), which would be elevated.
A 27-year-old G2P1 woman at 16 weeks gestation undergoes a second-trimester quadruple screen. The results are returned with a significantly elevated maternal serum alpha-fetoprotein (MSAFP) level. The other markers (hCG, estriol, inhibin A) are normal, and the calculated risk for aneuploidy is low.
Which of the following is the most appropriate next step in the evaluation of this finding?
Explanation: An elevated MSAFP can be caused by several factors, including incorrect gestational dating, multiple gestation, fetal demise, or fetal anomalies such as neural tube defects or abdominal wall defects. The first step is to perform a detailed ultrasound to confirm the gestational age, assess for multiples, and carefully evaluate fetal anatomy. If the ultrasound is unrevealing, amniocentesis may be offered. CVS is not indicated as it is a first-trimester procedure and does not assess amniotic fluid AFP. Cell-free DNA testing screens for aneuploidy, not neural tube defects.
A 36-year-old G2P1 woman at 11 weeks gestation received a high-risk result on her cell-free DNA screen for Trisomy 21. After counseling, she decides she wants a definitive diagnosis and wishes to proceed with testing as soon as possible.
Which diagnostic procedure is most appropriate to offer this patient at her current gestational age?
Explanation: For definitive genetic diagnosis in the first trimester, chorionic villus sampling (CVS) is the procedure of choice. It is typically performed between 10 and 13 weeks gestation. Amniocentesis is performed later, usually after 15 weeks gestation. PUBS is a late-trimester procedure used for specific indications like rapid karyotyping or fetal blood transfusion. Ultrasonography can identify markers suggestive of aneuploidy but is not a diagnostic genetic test.
A 29-year-old G1P0 woman with a pre-pregnancy BMI of 27 kg/m² presents for a routine prenatal visit at 18 weeks gestation. She has no personal or family history of diabetes.
When is the most appropriate time to perform routine screening for gestational diabetes mellitus in this patient?
Explanation: Universal screening for gestational diabetes mellitus (GDM) is recommended for all pregnant women between 24 and 28 weeks gestation, typically with a 1-hour 50-g glucose challenge test. Early screening in the first trimester is reserved for women with high-risk factors (e.g., severe obesity, history of GDM). Screening later than 28 weeks is not standard practice.
A 33-year-old G2P1 woman presents for her routine prenatal visit at 36 weeks and 2 days gestation. Her pregnancy has been uncomplicated. She reports feeling well and notes good fetal movement.
Which of the following is the most appropriate screening to perform at this visit as part of routine antenatal care?
Explanation: Universal screening for Group B Streptococcus (GBS) colonization is recommended for all pregnant women between 36 0/7 and 37 6/7 weeks gestation. This is done via a rectovaginal culture. The results guide the use of intrapartum antibiotic prophylaxis to prevent neonatal GBS disease. A 3-hour GTT is a diagnostic test for GDM, performed earlier in pregnancy. Biophysical profiles and nonstress tests are methods of fetal surveillance reserved for high-risk pregnancies or specific indications, not routine screening at this stage.
A 28-year-old woman with a seizure disorder that is well-controlled with valproic acid comes to your office for preconception counseling. She has been seizure-free for three years and is planning to conceive within the next year.
Which of the following is the most appropriate counseling regarding her antiepileptic medication?
Explanation: Valproic acid has the highest risk of major congenital malformations (especially neural tube defects) among commonly used antiepileptic drugs and should be avoided in women of childbearing potential if possible. Preconception counseling is the ideal time to transition to a safer alternative with a lower teratogenic risk, such as lamotrigine or levetiracetam, while ensuring continued seizure control. Discontinuing medication entirely is dangerous, and phenobarbital also carries significant teratogenic risks.
A 22-year-old G1P0 woman at 17 weeks gestation is informed that her quadruple screen results indicate a 1 in 50 risk for Trisomy 21. She is very anxious and states she 'needs to know for sure' if the baby has Down syndrome.
Which of the following is the most appropriate next step to offer this patient?
Explanation: When a patient has a high-risk aneuploidy screen and desires a definitive diagnosis, the appropriate next step is to offer invasive diagnostic testing. At 17 weeks gestation, this is an amniocentesis. Repeating the screen is not useful. Cell-free DNA is another, more accurate, screening test, but it is not diagnostic. While it is true that many positive screens are false positives, this response dismisses the patient's stated desire for certainty.
A 30-year-old G1P0 woman presents for her routine prenatal visit at 28 weeks gestation. Her medical history and pregnancy course have been uncomplicated. Her immunization record is reviewed.
Which of the following vaccinations is most appropriate to administer to the patient at this visit?
Explanation: The Tdap vaccine is recommended during each pregnancy, ideally between 27 and 36 weeks gestation. This timing maximizes the maternal antibody response and passive antibody transfer to the fetus, providing protection against pertussis (whooping cough) in early infancy. MMR and Varicella are live-attenuated vaccines and are contraindicated during pregnancy. The HPV vaccine is not recommended during pregnancy.
A 32-year-old G1P0 woman at 10 weeks gestation is an experienced marathon runner. Her pregnancy has been uncomplicated. She asks for advice on whether she can continue her high-intensity training.
What is the most appropriate advice regarding exercise for this patient?
Explanation: For pregnant women with no contraindications, regular exercise is encouraged. Women who were highly active before pregnancy, like this patient, can safely continue their activities, provided they stay hydrated, avoid overheating, and modify their routine as their body changes. There are no data to support discontinuing high-intensity exercise in an uncomplicated pregnancy. Strict heart rate limits are an outdated concept; perceived exertion is now the recommended guide.
A 26-year-old G1P0 woman at 12 weeks gestation undergoes routine initial prenatal labs. Her urinalysis is normal, but the reflex urine culture grows >100,000 colony-forming units/mL of Escherichia coli. The patient denies any dysuria, frequency, or urgency.
What is the most appropriate next step in management?
Explanation: This patient has asymptomatic bacteriuria, which must be treated during pregnancy to reduce the risk of complications such as pyelonephritis, preterm birth, and low birth weight. Nitrofurantoin is a safe and effective first-line antibiotic for this condition in the first and second trimesters. A test of cure should be performed after treatment. Reassurance is inappropriate as treatment is indicated. Doxycycline is a tetracycline and is contraindicated in pregnancy.
A 25-year-old G1P0 woman is found to be blood type O-negative at her initial prenatal visit. Her antibody screen is negative. Her partner's blood type is A-positive.
In addition to receiving Rho(D) immune globulin for any episode of vaginal bleeding, when should this patient be scheduled to routinely receive prophylactic Rho(D) immune globulin?
Explanation: For all Rh(D)-negative pregnant women with a negative antibody screen, routine antepartum prophylaxis with Rho(D) immune globulin is recommended at 28 weeks gestation. This significantly reduces the risk of third-trimester alloimmunization. A second dose is given postpartum if the infant is confirmed to be Rh(D)-positive. Waiting until delivery misses the opportunity to prevent sensitization during pregnancy.
A 24-year-old G1P0 woman presents for her first prenatal visit at 8 weeks gestation. She feels well and has no significant medical history. Routine initial prenatal laboratory studies are ordered.
In addition to a complete blood count, blood type with Rh status, and urinalysis, which of the following is an essential component of the initial prenatal laboratory screening panel?
Explanation: Universal screening for syphilis is a standard and essential part of initial prenatal care in the United States. Early detection and treatment of maternal syphilis can prevent congenital syphilis, a devastating condition. Serum progesterone is not routinely checked. MSAFP is part of the second-trimester screen (15-20 weeks). The 1-hour glucose challenge test for gestational diabetes is typically performed at 24-28 weeks unless the patient has high-risk factors.
A 31-year-old G3P2 woman who is A-positive presents at 10 weeks gestation. Her initial antibody screen is positive. Further testing identifies the antibody as anti-Kell (anti-K). Her previous two children are healthy. The patient's partner is available for testing.
Which of the following is the most appropriate initial step in managing this finding?
Explanation: Anti-Kell is a clinically significant antibody that can cause severe fetal anemia. The first step in management is to assess the risk to the fetus by determining the paternal Kell antigen genotype. If the father is Kell-negative, the fetus cannot be Kell-positive, and no further surveillance is needed. If the father is Kell-positive (especially if heterozygous), the fetus is at risk, and further management with serial fetal middle cerebral artery Doppler studies would be warranted to monitor for anemia. Rho(D) immune globulin is for preventing Rh(D) alloimmunization, which is irrelevant here.
A 40-year-old G1P0 woman at 11 weeks gestation is discussing her options for aneuploidy screening. Due to her age, she is at increased risk. She expresses a desire for the most accurate non-invasive screening test available.
Which of the following is the most appropriate test to offer this patient?
Explanation: Cell-free DNA (cfDNA) screening is a non-invasive blood test that analyzes fetal DNA fragments in the maternal circulation. It has the highest detection rate and lowest false-positive rate for common trisomies (21, 18, 13) compared to other screening methods like the combined screen or quad screen. Given the patient's advanced maternal age and her desire for the most accurate screening test, cfDNA is the most appropriate option. Amniocentesis is a diagnostic test, not a screening test, and it is invasive.
A 31-year-old G2P1 with a known history of Hashimoto's thyroiditis presents at 6 weeks gestation. She takes levothyroxine 100 mcg daily. A TSH level drawn today is 3.5 mU/L. The target TSH in the first trimester is <2.5 mU/L.
Which of the following is the most appropriate next step in her management?
Explanation: Pregnancy increases thyroid hormone requirements, often by 25-30%, due to increased thyroid-binding globulin and placental deiodinase activity. In a patient with hypothyroidism, the levothyroxine dose must be increased to maintain a euthyroid state, which is crucial for fetal neurodevelopment. Her TSH is already above the first-trimester goal of <2.5 mU/L, indicating her current dose is insufficient. Therefore, the dose should be increased immediately. Propylthiouracil is used to treat hyperthyroidism.
A 34-year-old woman with a history of chronic hypertension well-controlled on hydrochlorothiazide presents for her first prenatal visit at 8 weeks gestation. Her blood pressure in the office is 145/95 mmHg.
Which of the following is the most appropriate change to her medication regimen?
Explanation: First-line antihypertensive agents in pregnancy include methyldopa, labetalol, and nifedipine. While thiazide diuretics may be continued if already established and effective, methyldopa is preferred as first-line therapy and for medication switches. ACE inhibitors like lisinopril are contraindicated in pregnancy due to teratogenic effects. Discontinuing medication would be unsafe given her elevated blood pressure and would increase risk for complications like preeclampsia.