Two days ago, a woman gave birth to a full-term infant.

Last night, she awakened several times to urinate and noted that her gown and bedding were wet from profuse diaphoresis.

One mechanism for the diaphoresis and diuresis that this woman is experiencing during the early postpartum period is:

Choice A rationale

A distended bladder displaces the uterus superiorly and laterally, most commonly to the right, as described. This displacement physically impedes the uterus from contracting effectively (uterine atony), preventing the compression of blood vessels at the placental site. The most serious consequence of this inability to contract is excessive uterine bleeding or postpartum hemorrhage.

Choice B rationale

A ruptured bladder is extremely rare in the immediate postpartum period solely due to simple distention. While prolonged, severe distention can lead to complications, the immediate and most common danger is compromised uterine contractility, not a structural rupture of the bladder wall.

Choice C rationale

A urinary tract infection (UTI) is a potential consequence of bladder distention because urinary stasis promotes bacterial growth. However, a UTI develops over time and is not the immediate or most serious risk compared to acute postpartum hemorrhage from uterine atony.

Choice D rationale

Bladder wall atony (loss of muscle tone) can result from overdistention and may hinder the bladder from emptying properly. While true, this is a cause or complication of the distention itself, but the resulting uterine atony and subsequent hemorrhage pose a more immediate and serious threat to maternal stability. —.

Choice A rationale

The basal metabolic rate (BMR) typically returns to normal non-pregnant levels within 1 to 2 weeks postpartum, and an increased BMR is not the primary physiological mechanism for the massive fluid loss observed as diaphoresis and diuresis during the initial 2-5 days postpartum. The body is focused on excreting excess extracellular fluid.

Choice B rationale

Elevated temperature caused by infection would be accompanied by other signs such as foul-smelling lochia or uterine tenderness, which are pathological, not a normal mechanism for fluid loss. Normal postpartum temperature may be slightly elevated due to exertion or dehydration, but not for profuse fluid elimination.

Choice C rationale

Pregnancy is associated with an approximate 30-45.

Choice D rationale

While increased venous pressure in the lower extremities is a common issue during pregnancy due to the gravid uterus compressing the inferior vena cava, it leads to edema, not diuresis and diaphoresis as the primary mechanism for eliminating the excess blood volume; this pressure normally decreases postpartum.