Urinary calcium as an early marker for preeclampsia

Area of Science:

• Obstetrics and Gynecology
• Nephrology
• Nutritional Science

Background:

• Preeclampsia is a serious pregnancy complication characterized by hypertension and organ damage.
• Reduced urinary calcium excretion has been observed in preeclampsia, but its temporal relationship with hypertension is unclear.

Purpose of the Study:

• To prospectively investigate whether reduced urinary calcium excretion precedes the development of hypertension in at-risk pregnant women.
• To determine if urinary calcium levels can serve as an early predictor for preeclampsia.

Main Methods:

• Prospective study of 103 nulliparous women at risk for preeclampsia.
• Serial 24-hour urine collections for calcium excretion measurement at multiple gestational points (10-24, 25-32, and 33 weeks to term).
• Post-delivery chart review to diagnose preeclampsia and gestational hypertension.

Main Results:

• Women who developed preeclampsia excreted significantly less urinary calcium (169 mg/24 hours) compared to normotensive women (298 mg/24 hours) at the first collection (before 24 weeks' gestation).
• This reduced calcium excretion persisted throughout pregnancy.
• A urinary calcium threshold of 195 mg/24 hours predicted preeclampsia with high significance (87% incidence below threshold vs. 2% above).

Conclusions:

• Altered urinary calcium excretion appears to be an early pathophysiological event in preeclampsia, preceding hypertension.
• Urinary calcium levels measured early in pregnancy may aid in identifying women at high risk for developing preeclampsia.
• This finding opens avenues for early intervention strategies in high-risk pregnancies.