Which finding is considered a probable sign of pregnancy?

A. Hemoglobin A1c: Hemoglobin A1c reflects average blood glucose over the past 2–3 months and is useful for diagnosing preexisting diabetes, but it is not the standard screening test for gestational diabetes.

B. Urine glucose: Urine glucose testing is unreliable for diagnosing gestational diabetes because glucose may not appear in the urine until blood glucose levels are significantly elevated.

C. Glucose Tolerance Test: The glucose tolerance test, typically a 1-hour screening followed by a 3-hour diagnostic test if indicated, is the standard method for detecting gestational diabetes during pregnancy.

D. Random blood glucose level: Random glucose measurements provide a snapshot of glucose at a single moment and do not reliably screen for gestational diabetes, as blood sugar fluctuates throughout the day.

A. It is a type IV hypersensitivity reaction: Urticaria is typically a type I hypersensitivity reaction mediated by IgE, not a delayed type IV reaction. Type IV reactions involve T-cell–mediated responses, such as contact dermatitis, rather than immediate histamine-mediated reactions.

B. Histamine release leads to vasodilation: Urticaria results from mast cell degranulation and histamine release, which increase vascular permeability and cause local vasodilation. This leads to the characteristic erythema, swelling, and itching associated with hives.

C. Wheals appear first followed by erythema: In urticaria, erythema and wheals usually appear simultaneously as a result of histamine-induced vasodilation and plasma leakage into the dermis. There is no distinct sequence of wheals followed by erythema.

D. The nonpruritic rash blanches with pressure: Urticarial lesions are typically pruritic (itchy), not nonpruritic, and may blanch under pressure due to transient vasodilation. Pruritus is a hallmark symptom distinguishing urticaria from other rashes.