Hydroxyproline and creatinine levels in normal amniotic fluid

Total hydroxyproline and creatinine concentrations as well as their ratios were determined in 29 amniotic fluid samples from normal pregnancies between the 16th and 20th week of gestation. Total hydroxyproline and creatinine levels, and their ratios, were not statistically different considering either the values at each week or those of the whole 5-week period. Our results, compared with the few others reported in the literature, can provide indications useful for defining the normal range in amniotic fluid, in relation to the weeks of gestation.