The sperm chromatin structure assay (SCSA) was used to measure over 500 human semen samples from two independent studies: Study I, 402 samples from 165 presumably fertile couples wishing to achieve pregnancy over 12 menstrual cycles; Study II, samples from 115 patients seeking fertility counselling. The SCSA measures susceptibility to DNA denaturation in situ in spermatozoa exposed to acid for 30 s, followed by acridine orange staining. SCSA data from the male partners of 73 couples (group 1) achieving pregnancy during months 1-3 of Study I were used as the standard of 'sperm chromatin compatible with high fertility' and were significantly different from those of 40 couples (group 3) achieving pregnancy in months 4-12 (P < 0.01) and those of male partners of 31 couples (group 4) not achieving pregnancy (P < 0.001). Group 2 contained couples who had a miscarriage. SCSA values for Study II were almost twice that of the Study I fertility standards. Within-couple repeatability tended to be less for group 3 than for groups 1, 2 or 4. Based on logistic regression, spermatozoa with denatured DNA (cells outside the main population, COMP alpha t) were the best predictor for whether a couple would not achieve pregnancy. Some 84% of males in group 1 had COMP alpha t < 15%, while no couples achieved pregnancy in group 1 with > or = 30% COMP alpha t, a threshold level considered not compatible with good fertility. Using selected cut-off values for chromatin integrity, the SCSA data predicted seven of 18 miscarriages (39%).

This study reports the temporal pattern of milk output in 2 groups of lactating mothers during the first 6 weeks postpartum. A study aim was to examine if the average milk output for postpartum days 6 and 7 (baseline) predicts milk adequacy at week 6 postpartum. Mothers of preterm (< or = 31 weeks) infants (n = 95) used mechanical expression to initiate and maintain their milk supply; mothers of a singleton healthy term infant (n = 98) fed their infant at the breast. Baseline milk output was predictive of milk adequacy, defined as > or = 500 mL/d at week 6 (P = .000). Preterm mothers were 2.81 times more at risk of not producing adequately than term mothers were. Study findings suggest that interventions that promote the initiation and maintenance of an adequate milk supply during the first week postbirth are critical.

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