Browsing by Author "Diaz, S"

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    Bone turnover and density in healthy women during breastfeeding and after meaning
    (1996) Lopez, JM; Gonzalez, G; Reyes, V; Campino, C; Diaz, S
    To investigate the changes in maternal bone density and turnover associated with lactation we ran a longitudinal study in fully breastfeeding women (age 26.3+/-4.1 years, mean+/-SD) at the first (stage I, n = 30) and sixth (stage II, n = 25) months postpartum and 6 months after weaning (stage III, n = 20), and in a contemporary control group of non-nursing women. At each time point bone density, serum calcium, phosphorus, alkaline phosphatases, parathyroid hormone (PTH), osteocalcin, follicle stimulating hormone (FSH), estradiol (E(2)), prolactin (PRL) urinary hydroxyproline and creatinine (OH-P/Cr) were measured in both groups. The daily calcium intake of nursing women (1479 +/- 590 mg/day at stage I) was higher than in non-nursing women (536 +/- 231 mg/day at stage I). Biochemical markers of bone turnover were higher (p<0.05) in nursing than in non-nursing women at stages I and II, while in stage III only OH-P/Cr was elevated. The lumbar spine (L2-4) bone mineral density was similar in the two groups at the beginning of the study (1.148 +/- 0.111 g/cm(2) in nursing women vs 1.211 +/- 0.102 g/cm(2) in non-nursing women; p = 0.56), but it was lower in nursing women at stage II (1.144 +/- 0.110 g/cm(2) vs 1.216 +/- 0.095 g/cm(2) respectively; p<0.05). Right cm femoral neck bone density decreased by 3% between stages I and II in nursing women but did not differ from values in non-nursing women (0.947 +/- 0.110 vs 0.973 +/- 0.108 in stage I and 0.918 +/- 0.114 vs 0.975 +/- 0.098 in stage II respectively; p<0.05, ANOVA). After weaning, lumbar spine and femoral neck bone density increased by 6% and 8% respectively (p<0.05, ANOVA). No correlation was found between changes in bone turnover markers or bone density and parity, frequency and duration of nursing episodes, body weight, body mass index, and plasma PRL, E(2) and PTH levels. We conclude that in nursing women with a daily calcium intake at the recommended dietary allowance (>1200 mg/day), full breastfeeding extending over 6 months is characterized by increased maternal bone turnover and a transient bone loss which normalizes after weaning.
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    Post-suckling prolactin:oestradiol ratio - a potential index to predict the duration of lactational amenorrhoea in women
    (1997) Campino, C; Ampuero, S; Diaz, S; Lopez, JM; SeronFerre, M
    To assess whether the duration of lactational amenorrhoea can be predicted in individual women, we studied the pre-and post-suckling concentrations of immune prolactin (IR-PRL) and of bioactive prolactin (BIO-PRL) and basal concentrations of oestradiol in ten amenorrhoeic fully nursing women at 3 months post-partum. The women were of similar age, weight and had infants of similar growth rate, Five of these women were to experience long amenorrhoea (>180 days) and the others short amenorrhoea (<180 days), Blood samples were drawn 30 min after a suckling episode initiated at 0800 h, 1600 h and 2400 h. BIO-PRL distinguished between groups of women at 0030 h but not at other times, while there was considerable overlap between values for IR-PRL and oestradiol at all times studied, At 1630 h, the ratios post-suckling BIO-PRL: oestradiol and post-suckling IR-PRL:oestradiol were above 2000 in the women that were to experience long amenorrhoea and below this threshold in the other women, The ratio post-suckling BIO-PRL:oestradiol provided more information since the difference between the lowest ratio in the long amenorrhoea and the highest ratio in the short was 699, while it was 520 for the IR-PRL:oestradiol ratio, The determination of these ratios may help to predict the duration of lactational amenorrhoea in individual fully nursing women.