A male newborn delivered at 32 weeks' gestation to a 41-year-old woman dies shortly after birth. The mother did not receive prenatal care and consistently consumed alcohol during her pregnancy. At autopsy, examination shows microcephaly, an eye in the midline, a cleft lip, and a single basal ganglion. Failure of which of the following processes is the most likely cause of this condition?

Formation of the 1st branchial arch

Closure of the rostral neuropore

Development of the metencephalon

A 30-year-old woman, gravida 2, para 1, at 40 weeks' gestation is admitted to the hospital in active labor. Her first pregnancy and delivery were complicated by iron deficiency anemia and pregnancy-induced hypertension. She has had no routine prenatal care during this pregnancy but was diagnosed with oligohydramnios 4 weeks ago. The remainder of her medical history is not immediately available. A 2400-g (5.4-lb) female newborn is delivered vaginally. Examination of the newborn shows a short, mildly webbed neck and low-set ears. Ocular hypertelorism along with slanted palpebral fissures are noted. A cleft palate and hypoplasia of the nails and distal phalanges are present. There is increased coarse hair on the body and face. Which of the following best explains the clinical findings found in this newborn?

Fetal posterior urethral valves

A 31-year-old G3P0 is admitted to the hospital with profuse vaginal bleeding and abdominal pain at 34 weeks gestation. She reports passing bright blood with clots and no water in the discharge. She denies recent trauma or medical illnesses. She had no prenatal care. Her previous pregnancies culminated in spontaneous abortions in the second trimester. She has a 6-year history of drug abuse and cocaine smoking 2 hours prior to the onset of her symptoms. Her blood pressure is 160/90 mm Hg, the heart rate is 93/min, the respiratory rate is 19/min, and the temperature is 36.9℃ (98.4℉). The fetal heart rate is 110/min. On examination, the patient is lethargic. Her pupils are constricted, but reactive to light bilaterally. There are no signs of trauma. Abdominal palpation identifies lower abdominal tenderness and strong uterine contractions. The fundus of the uterus is between the xiphoid process and umbilicus. The patient’s perineum is grossly bloody. On pelvic examination, the vaginal canal is without lesions. The cervix is almost completely effaced and 2 cm dilated. Which of the following options is the most likely cause of the patient’s pregnancy-related condition?

Abrupt constriction of maternal and placental vessels

Thrombosis of the placental vessels

Dramatic decrease in thrombocytes

Premature rupture of the membranes

Rupture of the placental vessels

A 35-year-old woman gravida 2, para 1, comes to the physician for her first prenatal visit. Pregnancy and delivery of her first child were uncomplicated. She is not sure about the date of her last menstrual period. Pelvic examination shows a uterus consistent in size with a 10-week gestation. An ultrasound examination confirms the gestational age and shows one fetus with no indication of multiple gestations. During counseling on pregnancy risks and possible screening and diagnostic tests, the patient states she would like to undergo screening for Down syndrome. She would prefer immediate and secure screening with a low risk to herself and the fetus. Which of the following is the most appropriate next step in management at this time?

Nuchal translucency, pregnancy-associated plasma protein-A, human chorionic gonadotropin

Maternal serum α-fetoprotein, human chorionic gonadotropin, unconjugated estriol, and inhibin A

A 67-year-old man comes to the clinic for establishment of care. He recently retired and moved to Florida with his wife. His past medical history includes hypertension, diabetes, chronic back pain, and hyperlipidemia. According to the patient, he takes lisinopril, metformin, atorvastatin, acetaminophen, and methadone. His previous doctor prescribed methadone for breakthrough pain as he has been having more severe pain episodes due to the recent move. He is currently out of his methadone and asks for a refill on the prescription. A physical examination is unremarkable except for mild lower extremity edema bilaterally and diffuse lower back pain upon palpation. What is the best initial step in the management of this patient?

Assess the patient's pain medication history

Refer the patient to a pain management clinic

Inform the patient that methadone is not the best option and do not prescribe

Encourage the patient to switch to duloxetine

Prescribe a limited dose of methadone for breakthrough back pain

A 23-year-old primigravida presents to her physician’s office at 12 weeks gestation complaining of increased sweating and palpitations for the last week. She does not have edema or dyspnea, and had no pre-existing illnesses. The patient says that the symptoms started a few days after several episodes of vomiting. She managed the vomiting at home and yesterday the vomiting stopped, but the symptoms she presents with are persistent. The pre-pregnancy weight was 54 kg (119 lb). The current weight is 55 kg (121 lb). The vital signs are as follows: blood pressure 130/85 mm Hg, heart rate 113/min, respiratory rate 15/min, and temperature 37.0℃ (98.6℉). The physical examination is significant for diaphoresis, an irregular heartbeat, and a fine resting tremor of the hands. The neck is not enlarged and the thyroid gland is not palpable. The ECG shows sinus tachyarrhythmia. The thyroid panel is as follows: Thyroid stimulating hormone (TSH) < 0.1 mU/L Total T4 178 nmol/L Free T4 31 pmol/L Which of the following is indicated?

Ensure proper hydration and prescribe a beta-blocker

Schedule a subtotal thyroidectomy

Substance use in pregnancy for USMLE Step 2 CK: High-Yield OB/GYN Lessons

Alcohol Use - The Teratogen Tipple

A leading preventable cause of birth defects and intellectual disability. No amount of alcohol is safe during pregnancy.
Fetal Alcohol Syndrome (FAS) triad:
- Facial anomalies: Smooth philtrum, thin vermilion border, small palpebral fissures.
- Growth restriction: Pre- and/or postnatal (≤10th percentile).
- CNS abnormalities: Microcephaly, functional deficits (e.g., ADHD).

⭐ Alcohol is most teratogenic in the first trimester; it induces widespread apoptosis and failed neural crest cell migration.

Tobacco & Nicotine - Up in Smoke

Pathophysiology: Nicotine (vasoconstrictor) & Carbon Monoxide (↓ $O_2$ delivery) → uteroplacental insufficiency & fetal hypoxia.
Fetal Risks:
- Symmetrical fetal growth restriction (FGR) / low birth weight (LBW).
- ↑ risk of preterm labor, placental abruption, spontaneous abortion.
- Postnatal: ↑ risk of Sudden Infant Death Syndrome (SIDS), asthma, colic.
Management: Cessation counseling is first-line. Nicotine replacement therapy (NRT) is a second-line option.

⭐ Exam Favorite: Tobacco is the leading preventable cause of Fetal Growth Restriction (FGR).

Opioids - Narcotic Neonates

Maternal Management: Opioid use disorder (OUD) managed with methadone or buprenorphine. Avoids withdrawal cycles harmful to the fetus.
Neonatal Abstinence Syndrome (NAS): Onset typically 24-72 hours post-birth.
- CNS: Irritability, high-pitched cry, tremors, seizures.
- GI: Poor feeding, vomiting, diarrhea.
- Autonomic: Sweating, fever, tachypnea.
Management:
- Finnegan scoring to assess severity.
- Supportive: Swaddling, low stimulation, caloric support.
- Pharmacologic: Morphine is first-line.

⭐ High-Yield Fact: Buprenorphine is associated with a shorter duration of treatment and hospital stay for the neonate compared to methadone.

Clinical Features of Neonatal Abstinence Syndrome

Cocaine & Stimulants - Vasoconstriction Vexation

Mechanism: Intense sympathomimetic action → potent vasoconstriction → ↓ uteroplacental blood flow & placental ischemia.
Maternal Risks: Placental abruption, hypertensive crisis, preterm labor, uterine tachysystole, myocardial infarction.
Fetal & Neonatal Risks: Asymmetric IUGR, low birth weight, neurobehavioral deficits (irritability, hypertonia).
⚠️ Management: Avoid β-blockers (e.g., labetalol) due to risk of unopposed α-stimulation. Prefer benzodiazepines for seizures/agitation & hydralazine for hypertension.

⭐ Cocaine is a primary cause of painful third-trimester bleeding from placental abruption.

Screening & Management - Universal Precautions

Universal Screening: Screen ALL pregnant patients for substance use at the first prenatal visit.
- Use validated questionnaires (e.g., 4P's, NIDA Quick Screen).
Urine Drug Screen (UDS):
- Not routine; perform based on risk factors identified during screening.
- Requires informed consent; be aware of state-specific reporting laws.
Management:
- A non-judgmental, supportive approach is crucial.
- Coordinate with a multidisciplinary team (social work, addiction specialists).

⭐ Universal screening is vital as many women with substance use disorder do not fit typical stereotypes.

SBIRT Implementation Process in Maternity Care

High-Yield Points - ⚡ Biggest Takeaways

Alcohol is the leading preventable cause of intellectual disability; look for classic FAS facies (smooth philtrum, thin upper lip).

Cocaine use is strongly linked to placental abruption and fetal hypoxia due to potent vasoconstriction.

Opioids (e.g., heroin) classically cause Neonatal Abstinence Syndrome (NAS); manage maternal use with methadone or buprenorphine.

Tobacco is the most common cause of intrauterine growth restriction (IUGR) and low birth weight.

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