Resumption of ovarian function during lactational amenorrhoea in breastfeeding women with polycystic ovarian syndrome: metabolic aspects.
BACKGROUND
Polycystic ovarian syndrome (PCOS) is a common endocrine-metabolic disorder in women, a high percentage of whom exhibit peripheral insulin resistance. After delivery, in normal women, lactation imposes a metabolic adaptation, the impact of which on the insulin resistance of PCOS patients is not known. The aim of this study was to evaluate the effect of lactation on insulin resistance, glucose and insulin metabolism, and sex hormone-binding globulin (SHBG) and insulin-like growth factor binding protein-1 (IGFBP)-1 concentrations in fully breast-feeding normal and PCOS women during the postpartum period (lactational amenorrhoea) and also after weaning.


METHODS
Twelve lactating PCOS (LPCOS) women and six normal lactating (NL) women of similar age and body mass index (BMI) were selected for the study. At the 4th and the 8th week postpartum (pp), and 8 weeks after weaning, a 2 h, 75 g oral glucose tolerance test (oGGT) was performed, followed by an insulin tolerance test 2 days later. For the oGGT, glucose and insulin were measured in each sample and SHBG and IGFBP-1 were determined in the fasting sample.


RESULTS
During lactation, fasting insulin levels were similar in both groups. In LPCOS women 2 h insulin concentrations were significantly higher, and SHBG and IGFBP-1 concentrations were significantly lower, than those observed in NL women. In both groups, insulin sensitivity evaluated by the insulin tolerance test was not modified. After weaning, in LPCOS women, SHBG and IGFBP-1 concentrations remained lower and insulin concentrations remained higher than those observed in NL women ( P < 0.05 ).


CONCLUSIONS
In PCOS women, insulin resistance is not modified during lactation. Lactation has a transitory beneficial effect on insulin levels and biological markers of insulin resistance.
Maliqueo
M
M
Division of Endocrinology, Department of Internal Medicine, San Juan de Dios Hospital, School of Medicine, University of Chile, Santiago, Chile.
Sir-Petermann
T
T
Salazar
G
G
Pérez-Bravo
F
F
Recabarren
S E
SE
Wildt
L
L
D000328:Adult; D000568:Amenorrhea / Q000503:physiopathology*; D001786:Blood Glucose / Q000378:metabolism; D015992:Body Mass Index; D005215:Fasting; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000097:blood; D007774:Lactation; D010053:Ovary / Q000503:physiopathology*; D011085:Polycystic Ovary Syndrome / Q000503:physiopathology*; D049590:Postpartum Period; D012738:Sex Hormone-Binding Globulin / Q000032:analysis; D014886:Weaning
D001786:Blood Glucose; D007328:Insulin; D018970:Insulin-Like Growth Factor Binding Protein 1; D012738:Sex Hormone-Binding Globulin