Congenital malformations are common in monozygotic twinning. Dichorionicity occurs only in dizygotic twinning.

Correct Answer: B

Rationale: Monozygotic twins typically have a single chorion, not two.

Correct Answer: C

Rationale: A major degree of placenta praevia is a definitive indication for elective cesarean section.

Correct Answer: D

Rationale: Upper urinary imaging is the appropriate next step in the workup for Melanie based on the presentation of microscopic hematuria with no other identifiable explanation. Upper urinary imaging, such as an ultrasound or CT scan, can help evaluate the upper urinary tract, including the kidneys and ureters, to investigate potential causes of hematuria. This step is commonly recommended before proceeding to invasive procedures like cystoscopy or consultation with a urologist. It allows for a non-invasive assessment of the upper urinary system to identify any potential abnormalities that may be causing the hematuria in the patient.

Correct Answer: B

Rationale: The best approach to managing the patient with ascites who has responded to spironolactone with weight loss is to add a loop diuretic to the current regimen. Spironolactone is an aldosterone antagonist that primarily works on the distal convoluted tubule, while loop diuretics, such as furosemide, act on the thick ascending limb of the loop of Henle. Combining these two diuretics can result in a synergistic effect, increasing diuresis and reducing fluid retention in patients with ascites. This combination therapy is often used in patients who do not respond adequately to spironolactone alone, and it is considered a common strategy in the management of ascites due to cirrhosis. Therefore, adding a loop diuretic to the spironolactone regimen is the most appropriate next step to optimize diuresis and fluid management in this patient.

Correct Answer: D

Rationale: A hot, dry vagina and lack of descent suggest abnormal labor patterns.