Obstetrics and Gynecology

1046 questions

Question 1041Question →

A 29-year-old nulligravid woman comes to the office due to a 6-month history of absent menstrual periods. Menarche occurred at age 12, and her menses were previously regular, occurring every 28 to 30 days. For the past several months, she has also noticed a bilateral milky nipple discharge that stains her undergarments. The patient reports feeling unusually sluggish, experiencing generalized muscle aches, and having difficulty concentrating at her desk job. She has gained 5 kg (11 lb) over the past year despite no change in her dietary habits. She has no chronic medical conditions and takes no medications. Vital signs include a blood pressure of 110/70 mm Hg, a pulse of 58/min, and a respiratory rate of 14/min. Her body mass index (BMI) is 26 kg/m². Physical examination reveals pale, cool skin and delayed relaxation of the deep tendon reflexes. A urine pregnancy test is negative.

Laboratory results are as follows:

Laboratory TestResultReference Range
Follicle-stimulating hormone4 mIU/mL5-20 mIU/mL
Luteinizing hormone3 mIU/mL5-20 mIU/mL
Prolactin82 ng/mL<25 ng/mL
Thyroid-stimulating hormone (TSH)18.5 μ\muU/mL0.4-4.2 μ\muU/mL
Free thyroxine (T4)0.5 ng/dL0.8-2.7 ng/dL

Which of the following is the most appropriate next step in management?

Show answer & explanation

Answer: Initiation of levothyroxine

Answer

Initiation of levothyroxine
The correct answer addresses the root cause of the patient's symptoms. She has classic clinical features (fatigue, weight gain, bradycardia, delayed reflexes) and laboratory findings (elevated TSH, low free T4) of primary hypothyroidism. In primary hypothyroidism, the lack of negative feedback from thyroid hormones leads to increased secretion of thyrotropin-releasing hormone (TRH) from the hypothalamus. TRH serves as a potent stimulator of both thyrotrophs (increasing TSH) and lactotrophs (increasing prolactin) in the anterior pituitary. The resulting hyperprolactinemia suppresses the pulsatile release of gonadotropin-releasing hormone (GnRH), which subsequently decreases FSH and LH levels, leading to anovulation and secondary amenorrhea. Treating the patient with levothyroxine will restore normal thyroid hormone levels, re-establish negative feedback, decrease TRH, normalize prolactin, and ultimately restore regular menstrual cycles.

Step-by-Step Solution

1
Evaluate the clinical presentation and physical exam.
The patient presents with secondary amenorrhea, galactorrhea, weight gain, fatigue, bradycardia, and delayed deep tendon reflexes.
Identifying systemic signs points toward a broad endocrine dysfunction rather than an isolated reproductive tract issue.
2
Analyze the laboratory data provided.
Labs reveal mild hyperprolactinemia (82 ng/mL) alongside a markedly elevated TSH and low free T4, establishing a clear diagnosis of primary hypothyroidism.
Interpreting all laboratory values together prevents premature closure on a single abnormal value like prolactin.
3
Connect primary hypothyroidism to the reproductive symptoms.
Low circulating T3/T4 causes the hypothalamus to increase thyrotropin-releasing hormone (TRH) secretion. TRH directly stimulates pituitary lactotrophs to release prolactin. Elevated prolactin subsequently inhibits pulsatile GnRH release, leading to low FSH/LH and amenorrhea.
Understanding this physiological axis confirms that the hyperprolactinemia is entirely secondary to the thyroid deficiency.
4
Determine the appropriate intervention.
The primary pathology is hypothyroidism; therefore, the correct treatment is thyroid hormone replacement.
Levothyroxine will normalize free T4, turning off the excess TRH drive, which in turn normalizes prolactin levels and restores menstruation.

Key Concept

Secondary amenorrhea and galactorrhea can be caused by primary hypothyroidism due to TRH-induced stimulation of lactotrophs; the next best step is treating the underlying hypothyroidism.
Estimated Time:1m 15s
Question 1042Question →

An obstetrics triage nurse evaluates a primigravid patient at 40 weeks and 2 days gestation. The patient was admitted earlier in the day for an elective labor induction and is currently receiving an intravenous infusion of oxytocin. She reports severe, sharp pain with each contraction, and monitoring shows contractions occurring every 2.5 minutes on average. Vital signs include a blood pressure of 118/76 mm Hg, heart rate of 88/min, and respiratory rate of 18/min. To investigate a complaint of mild shortness of breath, an arterial blood gas on room air is drawn, demonstrating a pH of 7.44, PaCO₂ of 28 mm Hg, and PaO₂ of 102 mm Hg.

A continuous fetal heart rate monitor displays a baseline rate of 140/min accompanied by moderate variability. However, the tracing also reveals recurrent, symmetric decreases in the heart rate to a nadir of 120/min. The onset of each decrease is gradual, taking roughly 40 seconds to reach its lowest point. Notably, the nadir of each deceleration occurs consistently after the peak of the corresponding uterine contraction, returning to baseline only after the contraction ends. These specific decelerations are present following 60% of the recorded contractions. Pelvic examination confirms the cervix is 5 cm dilated and 90% effaced, with the fetal head at 0 station.

Based on these findings, which of the following is the most appropriate next step in management?

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Answer: Discontinue the intravenous oxytocin infusion

Answer

Discontinue the intravenous oxytocin infusion
The correct action is to discontinue the intravenous oxytocin infusion. The patient's fetal heart rate tracing is highly characteristic of recurrent late decelerations. A late deceleration is defined as a visually apparent, gradual decrease in the fetal heart rate (onset to nadir taking ≥ 30 seconds) where the nadir occurs after the peak of the uterine contraction. These decelerations occur due to uteroplacental insufficiency. When late decelerations are recurrent (occurring with ≥ 50% of uterine contractions), they signal a disruption in fetal oxygenation. The immediate first-line management is intrauterine resuscitation, which aims to optimize uteroplacental blood flow. Essential steps include maternal repositioning (e.g., left lateral decubitus), administering an intravenous fluid bolus, providing supplemental oxygen, and discontinuing uterotonic agents. Stopping oxytocin immediately reduces the frequency and intensity of contractions, relieving the stress on the uteroplacental circulation.

Step-by-Step Solution

1
Analyze the fetal heart rate tracing.
Identify recurrent late decelerations, characterized by a gradual onset and a nadir that occurs after the peak of the uterine contraction.
Accurate interpretation of decelerations is critical to determining the underlying etiology of fetal distress.
2
Determine the pathophysiology behind the tracing abnormality.
Correlate late decelerations with uteroplacental insufficiency, which causes transient fetal hypoxemia during contractions.
Understanding the mechanism dictates the appropriate physiological intervention.
3
Evaluate the maternal vital signs and laboratory findings.
Recognize that the mild respiratory alkalosis (pH 7.44, low PaCO2) is a normal physiological adaptation to pregnancy and does not require treatment.
Distinguishing physiological changes of pregnancy from pathological states prevents unnecessary and distracting interventions.
4
Select the most appropriate initial management step.
Choose to discontinue the oxytocin infusion as part of initial intrauterine resuscitation.
Stopping uterotonic agents decreases the frequency and intensity of contractions, allowing uteroplacental blood flow and fetal oxygenation to recover.

Key Concept

Recurrent late decelerations indicate uteroplacental insufficiency and must be initially managed with intrauterine resuscitation, including the discontinuation of uterotonics.
Estimated Time:1m 30s
Question 1043Question →

A couple with severe male-factor infertility due to oligozoospermia is preparing for their first treatment cycle using assisted reproductive technology. During the informed consent process, the reproductive endocrinologist details the timeline of the procedure to ensure the patients understand the clinical commitment required. Arrange the following clinical and laboratory steps of an in vitro fertilization (IVF) cycle in their correct chronological sequence, from the initiation of the treatment cycle to its completion.

Drag items to arrange them in the correct order

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Answer

The correct chronological sequence for an IVF cycle is: controlled ovarian hyperstimulation, followed by an hCG trigger shot, transvaginal oocyte retrieval, laboratory fertilization (ICSI), and finally embryo transfer.
An IVF cycle must closely follow the physiological requirements of oocyte development while optimizing for a higher yield. Multiple follicles are first stimulated with gonadotropins over several days. Final maturation is then induced by a trigger shot. The eggs must be retrieved surgically 34-36 hours later, before natural ovulation occurs. Once outside the body, they are immediately fertilized in vitro. Finally, after a short period of laboratory culture, the resulting embryo is placed back into the uterus.

Step-by-Step Solution

1
Identify the initial stimulation phase.
Exogenous gonadotropins are administered.
This grows multiple follicles to maximize the number of eggs available for the cycle.
2
Identify the final maturation phase.
An hCG or GnRH agonist trigger shot is given.
The trigger mimics the physiological LH surge, preparing the eggs for successful fertilization by resuming meiosis.
3
Identify the surgical extraction phase.
Transvaginal ultrasound-guided oocyte retrieval.
Eggs must be removed from the body after maturation but before natural ovulation releases them into the pelvic cavity.
4
Identify the laboratory phase.
Intracytoplasmic sperm injection (ICSI) or conventional insemination.
Retrieved eggs are exposed to sperm in a controlled environment to create embryos.
5
Identify the implantation phase.
Embryo transfer.
The resulting embryo is carefully placed into the uterine cavity for potential implantation.

Key Concept

Chronological Sequence of In Vitro Fertilization (IVF) Procedures
Question 1044Question →

A 2727-year-old gravida 33, para 22 at 3838 weeks and 44 days of gestation is in the labor unit undergoing induction for gestational diabetes. Uterine contractions are being augmented with a continuous infusion of a synthetic nonapeptide hormone. The continuous electronic fetal monitor demonstrates a baseline heart rate of 145145 /min with absent variability. Over the last 3030 minutes, the patient has experienced 1616 contractions. During this same timeframe, the fetal tracing displays recurrent, gradual decreases in heart rate that reach their nadir strictly after the peak of the corresponding contraction. The nursing staff immediately places the patient in the left lateral decubitus position, administers a 500500 mL intravenous bolus of lactated Ringer solution, and halts the uterotonic infusion. Ten minutes later, the patient continues to experience contractions every 9090 to 120120 seconds, and the fetal heart rate pattern remains unchanged. The patient's blood pressure is 118/76118/76 mm Hg and pulse is 8888 /min. Cervical examination reveals 55 cm dilation, 90%90\% effacement, and −1-1 station. Which of the following is the most appropriate next step in the management of this patient?

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Answer: Administer subcutaneous terbutaline

Answer

The most appropriate next step is to administer subcutaneous terbutaline to relax the uterine musculature and improve placental perfusion.
The correct answer is administering subcutaneous terbutaline. This patient is experiencing uterine tachysystole, defined as more than 55 contractions in a 1010-minute window (averaged over 3030 minutes). The excessively frequent contractions are impairing uteroplacental blood flow, leading to a Category III fetal heart rate (FHR) tracing characterized by absent variability and recurrent late decelerations. The initial management for this obstetric complication includes maternal repositioning (left lateral decubitus), an intravenous fluid bolus, and immediate cessation of any uterotonic agents. If the tachysystole and abnormal FHR pattern persist despite these initial maneuvers, the next best step is to administer a rapid-acting tocolytic medication. Subcutaneous terbutaline, a beta-2 adrenergic receptor agonist, relaxes the uterine smooth muscle, decreases contraction frequency, and allows uteroplacental perfusion to recover. If the FHR tracing does not improve following tocolysis, emergency surgical delivery would then be indicated.

Step-by-Step Solution

1
Analyze the fetal heart rate (FHR) tracing and contraction pattern.
The patient has uterine tachysystole (1616 contractions in 3030 minutes, which is >5>5 per 1010 minutes) and a Category III FHR tracing (absent variability with recurrent late decelerations).
Identifying the FHR category and contraction frequency establishes the diagnosis of tachysystole-induced fetal hypoxia.
2
Evaluate the response to initial resuscitative measures.
The patient was appropriately repositioned, given a fluid bolus, and the uterotonic agent was stopped. However, 1010 minutes later, tachysystole and the Category III tracing persist.
Standard initial intrauterine resuscitation must be attempted before advancing to pharmacological or surgical interventions.
3
Determine the next pharmacological or surgical intervention.
Because the tachysystole has not resolved with standard supportive measures and withdrawal of oxytocin, a tocolytic agent (e.g., terbutaline) is indicated to relax the uterus.
Relaxing the uterus reduces the frequency of contractions, thereby restoring uteroplacental blood flow and resolving the fetal hypoxia before resorting to operative delivery.

Key Concept

Management of uterine tachysystole with nonreassuring fetal status involves supportive measures (repositioning, fluids, stopping uterotonics) followed by tocolysis (e.g., terbutaline) if the abnormal pattern persists.
Estimated Time:1m 15s
Question 1045Question →

A reproductive endocrinology clinic is evaluating four male patients for primary infertility. Each patient has confirmed azoospermia on semen analysis but presents with a distinct endocrine laboratory profile and specific physical examination findings. Match the following clinical and laboratory profiles with their most likely underlying etiology.

Click a left item, then click its matching right item

Items

Azoospermia, decreased serum FSH and LH, decreased serum testosterone, anosmia
Azoospermia, elevated serum FSH and LH, decreased serum testosterone, small firm testes
Azoospermia, normal serum FSH and LH, normal serum testosterone, nonpalpable vas deferens
Azoospermia, decreased serum FSH and LH, elevated serum testosterone, muscular hypertrophy and testicular atrophy

Matches

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Answer

The profile with low FSH/LH, low testosterone, and anosmia matches Kallmann syndrome. The profile with high FSH/LH, low testosterone, and small testes matches Klinefelter syndrome. The profile with normal labs and nonpalpable vas deferens matches Cystic fibrosis. The profile with low FSH/LH, high testosterone, and testicular atrophy matches Exogenous anabolic steroid use.
Kallmann syndrome presents with hypogonadotropic hypogonadism and anosmia due to failed neuronal migration. Klinefelter syndrome presents with hypergonadotropic hypogonadism and small firm testes due to primary gonadal failure. CFTR mutations cause obstructive azoospermia with normal endocrine labs. Exogenous steroids suppress gonadotropins while maintaining high systemic androgens, leading to testicular atrophy.

Step-by-Step Solution

1
Analyze gonadotropin (FSH/LH) and testosterone levels to determine the level of the defect.
Low FSH/LH with low testosterone indicates central (hypogonadotropic) hypogonadism. High FSH/LH with low testosterone indicates primary (hypergonadotropic) testicular failure. Normal labs suggest an obstructive cause. Low FSH/LH with high testosterone suggests exogenous suppression.
Categorizing the endocrine axis distinguishes between hypothalamic/pituitary disorders, primary gonadal failure, obstructive pathology, and external negative feedback.
2
Correlate the endocrine categories with physical examination findings.
Central hypogonadism with anosmia points to Kallmann syndrome. Primary testicular failure with small firm testes points to Klinefelter syndrome. Obstructive azoospermia with an absent vas deferens is characteristic of Cystic fibrosis. Exogenous suppression with testicular atrophy points to anabolic steroids.
Physical findings provide the specific diagnosis within the broader endocrine category.

Key Concept

Male factor infertility workup requires distinguishing between pre-testicular (hypogonadotropic), testicular (hypergonadotropic), and post-testicular (obstructive) etiologies using FSH, LH, and testosterone levels in conjunction with physical examination.
Question 1046Question →

Match each clinical presentation or ultrasound/pathologic finding of abnormal placentation and bleeding with the corresponding obstetric diagnosis.

Click a left item, then click its matching right item

Items

Ultrasound reveals an anterior placenta with an absent retroplacental clear space, and chorionic villi attaching directly to the superficial myometrium without penetration.
Pathologic examination of a postpartum hysterectomy specimen demonstrates chorionic villi invading deep into the muscularis layer of the uterus.
Intraoperative visualization during a repeat cesarean delivery shows placental tissue penetrating completely through the uterine serosa and extending into the posterior bladder wall.
Amniotomy is immediately followed by painless, bright red vaginal bleeding and sudden, profound fetal bradycardia displaying a sinusoidal heart rate pattern.
A patient presents with sudden-onset severe, tearing abdominal pain, dark vaginal bleeding, and a rigid, hypertonic uterus on physical examination.

Matches

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Answer

Placenta accreta matches with superficial myometrial attachment; Placenta increta matches with deep myometrial invasion; Placenta percreta matches with serosal/bladder penetration; Vasa previa matches with painless bleeding after amniotomy causing fetal bradycardia; Placental abruption matches with painful bleeding and a rigid uterus.
The matching correctly identifies the spectrum of placenta accreta (accreta, increta, percreta) based on the progressive depth of villous invasion from the superficial myometrium to adjacent organs. It also correctly distinguishes the painless, fetal-origin bleeding of vasa previa from the painful, maternal-origin bleeding of placental abruption.

Step-by-Step Solution

1
Evaluate the depth of placental invasion described in the pathologic or intraoperative findings.
Identifies the specific type of morbidly adherent placenta.
Accreta involves superficial attachment, increta involves myometrial invasion, and percreta involves full-thickness serosal penetration.
2
Assess the clinical presentation of third-trimester bleeding.
Differentiates vasa previa from placental abruption.
Painless bleeding immediately after membrane rupture with a sinusoidal fetal heart tracing indicates fetal blood loss from vasa previa. Painful bleeding with a hypertonic, rigid uterus indicates maternal blood loss and uterine irritability from placental abruption.

Key Concept

Differentiating etiologies of third-trimester bleeding and morbidly adherent placentation based on the depth of chorionic villi invasion and distinct clinical presentations.
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