Peripartum colloid osmotic pressures: correlation with serum proteins.

Colloid osmotic pressure is a principal regulator of capillary fluid exchange. Alterations in colloid osmotic pressure in preeclamptic patients, as well as significant peripartum changes in colloid osmotic pressure in normotensive patients, are reported. In a study of 72 normotensive and preeclamptic patients, peripartum colloid osmotic pressure, serum albumin, and total serum protein were compared. Both groups exhibited significantly lower colloid osmotic pressure in the postpartum period than that measured antepartum. The mean antepartum colloid osmotic pressure in preeclamptic patients was significantly lower than in normotensive subjects. Regression equations were calculated [colloid osmotic pressure = 5.21 (total serum protein) -11.4 (r2 = 0.851)] and [colloid osmotic pressure = 8.1 (serum albumin) -8.2 (r2 = 0.891)]. Within the physiologic ranges most commonly reported for normotensive and preeclamptic patients, the use of these equations allowed calculation of colloid osmotic pressure to within 10% of measured values in 75 and 80% of the cases, respectively. Where direct measurement of colloid osmotic pressure is not readily available, calculated values may be helpful in patient management.

Blood mononuclear cell magnesium in normal pregnancy and preeclampsia.

Magnesium (Mg) is effective in the treatment of pregnancy-induced hypertension (PIH). In order to determine if patients with PIH are Mg deficient, we assessed mononuclear cell magnesium content (mMg) and serum Mg concentrations (sMg) in 23 normal pregnant women and in 12 women with PIH admitted in active labor. The sMg concentration in women with PIH was 1.74 +/- 0.1 mg/dl (mean +/- SD) and was not significantly different from normal pregnant women at 1.69 +/- 0.2 mg/dl. Both groups had sMg concentrations lower than in normal, non-pregnant controls (sMg = 1.96 +/- 0.1 mg/dl, p less than 0.001). The mMg content in normal pregnant women did not differ significantly from that in women with PIH (1.54 +/- 0.26 micrograms Mg/mg protein and 1.50 +/- 0.26 micrograms Mg/mg protein respectively). The normal control mean mMg was 1.36 +/- 0.17 micrograms Mg/mg protein, slightly lower than in normal pregnancy (p less than 0.005) and PIH (p less than 0.02). Mononuclear Mg content did not correlate with sMg concentration. These data suggest that PIH is not associated with an intracellular Mg deficit. Further studies utilizing other measures of intracellular Mg are indicated to assess the presence or absence of Mg deficiency in patients with both normal pregnancy and pregnancy complicated by PIH.