A prospective study of circulating prolactin during primigravid pregnancy

Relationship between serum prolactin concentration, vascular angiotensin sensitivity and arterial blood pressure during third trimester pregnancy

Prolactin may play an important role in the pathogenesis of pregnancy-induced hypertension (PIH) and preeclampsia. In 105 normotensive nulliparous women at 28 to 32 weeks of gestation, the relationship between serum prolactin concentration (PRL) and blood pressure behaviour was examined under standardized conditions. Neither postural change from left lateral to supine recumbency nor the infusion of low doses of angiotensin-II-amide had an effect on PRL levels. Similar mean PRL levels were found in pregnant women with a low angiotensin pressor dose (ADP less than 10 ng x kg-1 x min-1) or "angiotensin sensitivity", a positive supine pressor response (delta pd greater than or equal to 20 mmHg) or an increased serum uric acid concentration (greater than 3.6 mg/dl), which are criteria for an increased risk of developing hypertensive complications. However, in the group of subjects with angiotensin sensitivity, a significant correlation was found (a) between PRL levels and the APD and (b) between PRL levels and diastolic blood pressure increase after 5 min of supine recumbency. These results may reflect diminished dopaminergic activity in the central nervous system, which could influence both blood pressure and prolactin secretion.

Prolactin in severe toxemia of pregnancy

Plasma PRL levels were measured in 111 normal pregnant women and in 21 patients with severe toxemia of pregnancy. Twelve of 21 patients with severe toxemia of pregnancy showed high PRL levels in zone A (greater than mean value + 1 S.D. of PRL values in normal pregnancy). These 12 were significantly lower (P less than 0.02) in the Ccre rate, at 70.2 +/- 19.2 ml/min, than 5 toxemia patients (101.4 +/- 26.7 ml/min) in zone B (mean + 1 S.D. approximately mean) and 4 toxemia patients (110.0 +/- 35.3 ml/ml) in zone C (mean approximately mean -1 S.D.). Also, BUN, proteinuria and uric acid levels in zone A patients were higher than in those in zone B and C. However, no correlation was found between PRL levels and mean diastolic and systolic blood pressure. These results suggest that high PRL concentrations in toxemia of pregnancy may be associated with renal dysfunction.