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A SERIAL STUDY IN PREGNANCY OF THE PLASMA CONCENTRATIONS OF RENIN, CORTICOSTEROIDS, ELECTROLYTES AND PROTEINS AND OF HAEMATOCRIT AND PLASMA VOLUME
Author(s) -
Weir R. J.,
Paintin D. B.,
Brown J. J.,
Fraser R.,
Lever A. F.,
Robertson J. I. S.,
Young J.
Publication year - 1971
Publication title -
bjog: an international journal of obstetrics and gynaecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.157
H-Index - 164
eISSN - 1471-0528
pISSN - 1470-0328
DOI - 10.1111/j.1471-0528.1971.tb00321.x
Subject(s) - plasma renin activity , endocrinology , medicine , aldosterone , chemistry , blood proteins , oncotic pressure , gestation , blood pressure , pregnancy , blood volume , plasma osmolality , hematocrit , blood plasma , renin–angiotensin system , biology , vasopressin , albumin , genetics
Summary Fifteen pregnant women (including one with a twin conception) were studied at the 16th, 28th, 34th and 38th weeks of gestation. Blood pressure increased slightly in late pregnancy in 3 women, including the one with twins; the remainder had normal pregnancies throughout. Plasma concentrations of renin, electrolytes, haemoglobin and proteins, together with plasma volume, osmolality, colloid osmotic pressure and packed cell volume, were measured in all the women; plasma concentrations of aldosterone in 7; and plasma corticosterone and cortisol in 6. Between the 16th and the 38th weeks of gestation there was no significant change in the mean plasma electrolyte concentrations, osmolality, colloid osmotic pressure or haematocrit. Plasma volume increased markedly between the 16th and 34th weeks. The mean plasma protein concentration showed a significant rise between the 28th and 38th weeks. Plasma renin concentration was increased above the non‐pregnant range in most, but not all, of the women. Plasma aldosterone concentration was markedly increased in all measurements in each of the 7 women studied, the highest mean value being found at 16 weeks. With the exception of 3 of a total of 24 estimations, plasma corticosterone remained within the normal non‐pregnant range. Plasma cortisol was increased above the non‐pregnant range at 38 weeks in all the women studied; less consistent increases were found in earlier weeks. Multiple regression analysis revealed no significant correlation between any of the factors measured in the 12 women whose blood pressures remained normal throughout.