A nurse is caring for a pregnant client who is experiencing leg cramps.

These cramps are primarily caused by:.

Serum creatinine and urea are waste products of protein metabolism that are normally filtered by the kidneys and excreted in urine.

In pregnancy, the glomerular filtration rate (GFR) increases by about 50%, which means more creatinine and urea are cleared from the blood.Therefore, serum creatinine and urea levels decrease in pregnancy compared to nonpregnant women.

A. Increased serum creatinine and urea levels are wrong because they indicate impaired kidney function or dehydration, which are not normal in pregnancy.

C. Unchanged serum creatinine and urea levels are wrong because they do not reflect the increased GFR in pregnancy.

D. Increased glomerular filtration rate is correct but it is not a finding regarding serum creatinine and urea levels, which are the focus of the question.

Normal ranges for serum creatinine and urea vary depending on the laboratory and the units used, but based on a nonpregnant reference interval of 45-90 μmol/l (0.51-1.02 mg/dl) for creatinine and 2.5-6.4 mmol/l (7-18 mg/dl) for urea, a serum creatinine of >77 μmol/l (0.87 mg/dl) and a blood urea of >8.5 mmol/l (24 mg/dl) should be considered outside the normal range for pregnancy.

Leg cramps are painful muscle contractions that typically affect the calf, foot or both.

They are common during pregnancy, often happening at night during the second and third trimesters.

While the exact cause of leg cramps during pregnancy isn’t clear, various theories point to the following causes of leg cramps during pregnancy: 2

Pregnancy fatigue from carrying the extra baby weight

Compression of the blood vessels in the legs

Diet (an excess of phosphorus and a shortage of calcium or magnesium)

Pregnancy hormones since they seem to cause so many pregnancy aches and pains

Choice A is wrong because increased joint laxity is not a cause of leg cramps, but rather a result of hormonal changes that relax the ligaments and joints in preparation for childbirth.

Choice B is wrong because increased spinal curvature is not a cause of leg cramps, but rather a result of the changing center of gravity and posture during pregnancy.

Choice D is wrong because decreased muscle strength is not a cause of leg cramps, but rather a consequence of muscle fatigue and weight gain during pregnancy.

Normal ranges for calcium are 8.5 to 10.2 mg/dL, for magnesium are 1.7 to 2.2 mg/dL, and for phosphorus are 2.5 to 4.5 mg/dL.