A longitudinal study of urinary calcium, magnesium, and zinc excretion in lactating and nonlactating postpartum women.
Postpartum lactating (n = 12) and nonlactating (n = 11) women and never pregnant women (n = 14) collected urine samples and diet records 2 d each month for 6 mo to determine whether postpartum women conserved urinary calcium, magnesium, or zinc. Mean daily excretions were analyzed by repeated-measures analysis of variance and covariance to assess group and time effects. Lactating women excreted less urinary calcium (1-6 mo) than never pregnant (n = 8) and nonlactating (n = 4) women who did not use oral contraceptives (P < 0.01); however, excretion rose (P < 0.05) by 3 mo postpartum. In the nonlactating and never pregnant groups, women using oral contraceptives excreted less urinary calcium than the other women (P < 0.01). Lactating women excreted less urinary zinc (1-6 mo) than did control and non-lactating women (P < 0.01). Mechanisms may possibly be operating during lactation that depress urinary calcium for > or = 2 mo and urinary zinc < or = 6 mo postpartum.
Klein
C J
CJ
Department of Nutrition and Food Science, University of Maryland, College Park 20742.
Moser-Veillon
P B
PB
Douglass
L W
LW
Ruben
K A
KA
Trocki
O
O
D000328:Adult; D000704:Analysis of Variance; D002118:Calcium / Q000652:urine*; D003276:Contraceptives, Oral / Q000494:pharmacology; D004435:Eating / Q000502:physiology; D005260:Female; D006801:Humans; D007774:Lactation / Q000502:physiology / Q000652:urine*; D008137:Longitudinal Studies; D008274:Magnesium / Q000652:urine*; D049590:Postpartum Period / Q000502:physiology / Q000652:urine*; D015032:Zinc / Q000652:urine*
D003276:Contraceptives, Oral; D008274:Magnesium; D015032:Zinc; D002118:Calcium