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were determined simultaneously in mothers and their children from delivery to several months of age. Maternal blood samples, drawn approximately 6 wk before the expected date of delivery, were also analyzed. At delivery, total vitamin D metabolites in maternal and fetal plasma were closely correlated, maternal levels being higher. Unbound (free) vitamin D metabolite concentrations were higher in fetal than in maternal plasma, with the exception of free 1,25(OH)zD levels, which were equal. This suggests a rapid placental transfer of 1,25(OH)zD. 24,25(OH)2D and 25,26(OH)2D levels both in mothers and children were closely correlated with the precursor sterol 250HD. For 1,25(OH)zD, no correlation could be demonstrated with any of the other vitamin D metabolites. DBP concentrations in maternal plasma at the time of delivery were about twice the mean adult reference value. In cord blood, DBP levels were in the lower part of the adult reference range. Maternal total 1,25(OH)2D levels, which were twice the reference mean during pregnancy, fell sharply after delivery but free 1,25(OH)2D levels much less. Analogous to the biochemical changes in the mother, the infants' DBP levels fell after birth, as a result of the sudden disappearance of the estrogen stimulus. At the same time, the mineral supply via the placenta was cut off. These two factors are probably responsible for a stimulus to 1,25(OH)2D synthesis (and/ or inhibition of 1,25(OH)zD degradation), resulting in a sharp increase of 1,25(OH)zD and an even stronger increase of free 1,25(OH)2D. Concentrations of 250HD and 1,25(OH)zD in breast milk were low. Such water-soluble metabolites as 250HD-glucuronides were not detected. Judged by plasma 250HD levels, the vitamin D stores of most children born to mothers with normal vitamin D status are depleted approximately 8 wk after delivery. Therefore, supplementation with an appropriate dose of vitamin D shortly after birth seems advisable, especially in winter. (Pediatv Res 25: 623-628, 1989) Received July 5, 1988; accepted February 9, 1989 Calcium metabolism in the pregnant woman and the fetus differs extensively from the usual adult pattern. Calcification of the fetal skeleton begins at the 8th wk. At birth, the neonate has accumulated about 30 g of calcium and 17 g of phosphorus (1). The maternal skeleton is protected against excessive bone resorption by high calcitonin levels (2). During pregnancy, the fetus builds up vitamin D stores. This is only possible if vitamin D and/or its metabolites are able to cross the placenta. As newborn infants are usually not exposed to direct sunlight, they have to rely on these stores.The aims of this study were I) to obtain information about placental transfer of vitamin D metabolites by measuring them in maternal and cord plasma at birth; 2) to estimate vitamin D stores in the newborn (indirectly) by longitudinal measurements of the four common vitamin D metabolites in plasma of exclusively breastfed babies; 3) to investigate, by milk analyses, if human milk supplements these st...

We studied pituitary-gonadal function during the first year of life in 48 boys born with 56 undescended testes in order to test the hypotheses that functional insufficiency of the hypothalamo-pituitary-gonadal axis and disorders of testosterone (T) biosynthesis occur in such boys. Cryptorchidism persisted for longer than 1 yr in 29 boys (30 testes; group I), whereas spontaneous descent occurred in 19 boys (20 testes; group II), in 6 after the sixth month. A control group (group III) included 160 boys. Basal and peak LHRH-stimulated serum LH and FSH and basal serum T values were determined at 3, 6, and 12 months. Serum T, dihydrotestosterone (DHT), progesterone (P), 17-hydroxypregnenolone, 17-hydroxyprogesterone, dehydroepiandrosterone sulfate, and androstenedione before and after hCG administration were determined at age 1 yr. Comparing the 3 groups, cross-sectional evaluation revealed no significant differences in basal or peak LHRH-stimulated serum LH and FSH levels, except that basal serum LH levels were slightly higher in group II than in group III. Comparing groups I and II, longitudinal evaluation revealed similar basal and peak LHRH-stimulated serum LH and FSH values, with comparable changes with time. Basal serum T, DHT, and T precursor levels were similar in all three groups, with similar rises of T and DHT and variable minimal increases in androstenedione and dehydroepiandrosterone sulfate after hCG stimulation. We conclude that during the first year of life, boys with cryptorchidism have no functional insufficiency of the hypothalamo-pituitary-gonadal axis or disorders in T biosynthesis.

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