Fetal heart rate monitoring category 3 during the 2nd stage of labor is an independent predictor of fetal acidosis.

OBJECTIVE: To determine whether fetal heart rate (FHR) monitoring categories during the 1st and 2nd stage of labor can predict arterial cord pH <7.2. MATERIALS AND METHODS: A case control study was conducted including 653 consecutive term deliveries (37 weeks gestation and above) that were divided according to fetal pH ≤ 7.2 (n = 315) and fetal pH > 7.2 (n = 338). Deliveries occurred during the year 2013 in tertiary medical center, where arterial cord pH is routinely taken after birth. Intrapartum FHR monitoring categorization was defined according to the ACOG committee guidelines by two obstetricians. Multivariable models were constructed to control for confounders. RESULTS: Variable decelerations, late decelerations and bradycardia during the 1st and 2nd stages of labor were significantly higher in group of deliveries ended in cord pH < 7.2 compared with group of deliveries ended in cord pH > 7.2. A significant association was observed between category 2 and 3 during the 1st stage of labor and pH ≤ 7.2. However, while controlling for FHR category 3 at the 2nd stage of labor, 1st stage categorization lost its association with pH <7.2, and only category 3 during the 2nd stage were noted as an independent risk factor for acidosis. CONCLUSION: FHR monitoring category 3 during the 2nd stage of labor is an independent predictor of fetal acidosis as expressed by arterial cord pH < 7.2.

Differences in membrane fluidity and fatty acid composition between phenotypic variants of Streptococcus pneumoniae.

Phase variation in the colonial opacity of Streptococcus pneumoniae has been implicated as a factor in the pathogenesis of pneumococcal disease. This study examined the relationship between membrane characteristics and colony morphology in a few selected opaque-transparent couples of S. pneumoniae strains carrying different capsular types. Membrane fluidity was determined on the basis of intermolecular excimerization of pyrene and fluorescence polarization of 1,6-diphenyl 1,3,5-hexatriene (DPH). A significant decrease, 16 to 26% (P < or = 0.05), in the excimerization rate constant of the opaque variants compared with that of the transparent variants was observed, indicating higher microviscosity of the membrane of bacterial cells in the opaque variants. Liposomes prepared from phospholipids of the opaque phenotype showed an even greater decrease, 27 to 38% (P < or = 0.05), in the pyrene excimerization rate constant compared with that of liposomes prepared from phospholipids of bacteria with the transparent phenotype. These findings agree with the results obtained with DPH fluorescence anisotropy, which showed a 9 to 21% increase (P < or = 0.001) in the opaque variants compared with the transparent variants. Membrane fatty acid composition, determined by gas chromatography, revealed that the two variants carry the same types of fatty acids but in different proportions. The trend of modification points to the presence of a lower degree of unsaturated fatty acids in the opaque variants compared with their transparent counterparts. The data presented here show a distinct correlation between phase variation and membrane fluidity in S. pneumoniae. The changes in membrane fluidity most probably stem from the observed differences in fatty acid composition.