A 29-year-old woman, gravida 1, para 0, at 36 weeks' gestation is brought to the emergency department after an episode of dizziness and vomiting followed by loss of consciousness lasting 1 minute. She reports that her symptoms started after lying down on her back to rest, as she felt tired during yoga class. Her pregnancy has been uncomplicated. On arrival, she is diaphoretic and pale. Her pulse is 115/min and blood pressure is 90/58 mm Hg. On examination, the patient is lying in the supine position with a fundal height of 36 cm. There is a prolonged fetal heart rate deceleration to 80/min. Which of the following is the most appropriate action to reverse this patient's symptoms in the future?

Lying in the left lateral decubitus position

Gentle compression with an abdominal binder

Lying in the supine position and elevating legs

Performing the Valsava maneuver

A 27-year old primigravid woman at 37 weeks' gestation comes to the emergency department because of frequent contractions for 4 hours. Her pregnancy has been complicated by hyperemesis gravidarum which subsided in the second trimester. The contractions occur every 10–15 minutes and have been increasing in intensity and duration since onset. Her temperature is 37.1°C (98.8°F), pulse is 110/min, and blood pressure is 140/85 mm Hg. Uterine contractions are felt on palpation. Pelvic examination shows clear fluid in the vagina. The cervix is 50% effaced and 3 cm dilated. After 4 hours the cervix is 80% effaced and 6 cm dilated. Pelvic examination is inconclusive for the position of the fetal head. The fetal heart rate is reassuring. Which of the following is the most appropriate next step?

Perform external cephalic version

Perform Mauriceau-Smellie-Veit maneuver

A 29-year-old G1P0 female at 32 weeks gestation presents to the emergency department with vaginal bleeding. She has had minimal prenatal care to-date with only an initial visit with an obstetrician after a positive home pregnancy test. She describes minimal spotting that she noticed earlier today that has progressed to larger amounts of blood; she estimates 30 mL of blood loss. She denies any cramping, pain, or contractions, and she reports feeling continued movements of the baby. Ultrasound and fetal heart rate monitoring confirm the presence of a healthy fetus without any evidence of current or impending complications. The consulted obstetrician orders blood testing for Rh-status of both the mother as well as the father, who brought the patient to the hospital. Which of the following represents the best management strategy for this situation?

If mother is Rh-negative and father is Rh-positive then administer RhoGAM

After 28 weeks gestation, administration of RhoGAM will have no benefit

If mother is Rh-positive and father is Rh-negative then administer RhoGAM

If mother is Rh-negative and father is Rh-negative then administer RhoGAM

If mother is Rh-negative and father is Rh-positive, RhoGAM administration is not needed

A 24-year-old primigravida at 28 weeks gestation presents to the office stating that she “can’t feel her baby kicking anymore.” She also noticed mild-to-moderate vaginal bleeding. A prenatal visit a few days ago confirmed the fetal cardiac activity by Doppler. The medical history is significant for GERD, hypertension, and SLE. The temperature is 36.78°C (98.2°F), the blood pressure is 125/80 mm Hg, the pulse is 70/min, and the respiratory rate is 14/min. Which of the following is the next best step in evaluation?

Confirmation of cardiac activity by Doppler

Order platelet count, fibrinogen, PT and PTT levels

A 30-year-old woman, gravida 2, para 1, at 38 weeks' gestation comes to the hospital for regular, painful contractions that have been increasing in frequency. Her pregnancy has been complicated by gestational diabetes treated with insulin. Pelvic examination shows the cervix is 50% effaced and 4 cm dilated; the vertex is at -1 station. Ultrasonography shows no abnormalities. A tocometer and Doppler fetal heart monitor are placed on the patient's abdomen. The fetal heart rate monitoring strip shows a baseline heart rate of 145/min with a variability of ≥ 15/min. Within a 20-minute recording, there are 7 uterine contractions, 4 accelerations, and 3 decelerations that have a nadir occurring within half a minute. The decelerations occur at differing intervals relative to the contractions. Which of the following is the most appropriate next step in the management of this patient?

Placement of fetal scalp electrode

A 15-year-old girl is brought to the physician by her mother because of lower abdominal pain for the past 5 days. The pain is constant and she describes it as 7 out of 10 in intensity. Over the past 7 months, she has had multiple similar episodes of abdominal pain, each lasting for 4–5 days. She has not yet attained menarche. Examination shows suprapubic tenderness to palpation. Pubic hair and breast development are Tanner stage 4. Examination of the external genitalia shows no abnormalities. Pelvic examination shows bulging, bluish vaginal tissue. Rectal examination shows an anterior tender mass. Which of the following is the most effective intervention for this patient's condition?

Administer gonadotropin-releasing hormone agonist therapy

Administer oral contraceptives pills

A 37-year-old woman, gravida 2, para 1, at 35 weeks' gestation is brought to the emergency department for the evaluation of continuous, dark, vaginal bleeding and abdominal pain for one hour. Her first child was delivered by lower segment transverse cesarean section because of a nonreassuring fetal heart rate. The patient has a history of hypertension and has been noncompliant with her hypertensive regimen. Her medications include methyldopa, folic acid, and a multivitamin. Her pulse is 90/min, respirations are 16/min, and blood pressure is 145/90 mm Hg. The abdomen is tender, and hypertonic contractions can be felt. There is blood on the vulva, the introitus, and on the medial aspect of both thighs. The fetus is in a breech presentation. The fetal heart rate is 180/min with recurrent decelerations. Which of the following is the cause of fetal compromise?

Placental tissue covering the cervical os

Rupture of aberrant fetal vessels

A 26-year-old pregnant woman (gravida 2, para 1) presents on her 25th week of pregnancy. Currently, she has no complaints. Her previous pregnancy was unremarkable. No abnormalities were detected on the previous ultrasound (US) examination at week 13 of pregnancy. She had normal results on the triple test. She is human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV)-negative. Her blood type is III(B) Rh+, and her partner has blood type I(0) Rh-. She and her husband are both of Sardinian descent, do not consume alcohol, and do not smoke. Her cousin had a child who died soon after the birth, but she doesn't know the reason. She does not report a history of any genetic conditions in her family, although notes that her grandfather “was always yellowish-pale, fatigued easily, and had problems with his gallbladder”. Below are her and her partner’s complete blood count and electrophoresis results. Complete blood count Patient Her husband Erythrocytes 3.3 million/mm3 4.2 million/mm3 Hb 11.9 g/dL 13.3 g/dL MCV 71 fL 77 fL Reticulocyte count 0.005 0.008 Leukocyte count 7,500/mm3 6,300/mm3 Platelet count 190,000/mm3 256,000/mm3 Electrophoresis HbA1 95% 98% HbA2 3% 2% HbS 0% 0% HbH 2% 0% The patient undergoes ultrasound examination which reveals ascites, liver enlargement, and pleural effusion in the fetus. Further evaluation with Doppler ultrasound shows elevated peak systolic velocity of the fetal middle cerebral artery. Which of the following procedures can be performed for both diagnostic and therapeutic purposes in this case?

Percutaneous fetal thoracentesis

Fetal heart rate abnormalities for USMLE Step 1: High-Yield OB/GYN Lessons

FHR Basics - The Heart of the Matter

Baseline Rate: Average FHR over 10 mins. Normal: 110-160 bpm.
- Tachycardia: >160 bpm (maternal fever, infection, drugs).
- Bradycardia: <110 bpm (fetal hypoxia, maternal hypotension).
Variability: Fluctuations in baseline FHR. The single most important predictor of fetal oxygenation.
- Moderate (6-25 bpm amplitude) is reassuring.
- Absent/Minimal (<5 bpm) is non-reassuring.
Accelerations: Abrupt ↑ in FHR. Reassuring sign of fetal well-being.

Fetal Heart Rate Tracing Categories (I, II, III)

⭐ Loss of variability is the most significant sign of fetal compromise.

Decelerations (📌 VEAL CHOP):
- Variable → Cord Compression
- Early → Head Compression
- Acceleration → Okay!
- Late → Placental Insufficiency (most worrisome)

Periodic Changes - VEAL CHOP Soup

📌 VEAL CHOP Mnemonic:

Variable Decels → Cord Compression
Early Decels → Head Compression
Accelerations → Okay / Oxygenated
Late Decels → Placental Insufficiency

VEAL CHOP Mnemonic for Fetal Heart Rate Patterns

Early Decelerations: Mirror contractions; nadir matches contraction peak. Benign.
Late Decelerations: Delayed onset after contraction starts; nadir after peak. Ominous.
- Management (SOUP): Stop Pitocin, Oxygen, Uterine tocolysis, Position change.
Variable Decelerations: Abrupt (onset to nadir <30s), sharp drop. Most common.
Accelerations: ↑ >15 bpm for >15 sec. Reassuring.

⭐ Late decelerations are the most worrisome pattern, reflecting uteroplacental insufficiency and fetal hypoxemia, requiring immediate intrauterine resuscitation.

3-Tier System - Sorting the Signals

A standardized framework for interpreting fetal heart rate (FHR) patterns to predict fetal acid-base status.

⭐ Absent baseline variability combined with recurrent late decelerations is highly specific for fetal acidemia and requires prompt action.

High-Yield Points - ⚡ Biggest Takeaways

Remember the VEAL CHOP mnemonic for FHR patterns and their causes.

Late decelerations are the most ominous sign, indicating uteroplacental insufficiency.

Variable decelerations are caused by cord compression; manage by repositioning the mother.

Loss of variability is the single most important predictor of fetal compromise.

A sinusoidal pattern is rare but severe, suggesting fetal anemia (e.g., Rh isoimmunization, vasa previa).

Accelerations are reassuring signs of a healthy, non-acidotic fetus.

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