Nitric oxide metabolites in preterm and induced labor.

BACKGROUND: Nitric oxide has potent relaxant effects on the pregnant uterus and has been associated with a quiescent uterus in animal and human studies. Nitric oxide donors have been used to arrest preterm labor and a reduction in nitric oxide production has been reported before the onset of labor. OBJECTIVE: The aim of the study was to estimate the serum levels of nitrate and nitrite in women undergoing spontaneous preterm labor and induced labor. MATERIALS AND METHOD: Venous blood was drawn from 39 patients before the onset of labor (control) and also from 17 patients undergoing induction of labor who were in active labor (study group A), and 24 patients in spontaneous preterm labor (study group B). Serum concentrations of nitrate and nitrite were estimated in the samples using the HPLC method. RESULTS: The maternal age of the patients was similar in all the groups. There was no significant difference in the mean gestational age at delivery between the control and group-A patients (38.86 vs. 38.29 weeks); however, there was a significant difference between the control and group-B patients (38.86 vs. 30.92; p < 0.0001), and between study groups A and B (38.29 vs. 30.92 weeks; p < 0.0001). The mean serum levels of nitrite in groups A and B (0.563 +/- 0.15 and 0.512 +/- 0.13, respectively) were significantly lower than the level in the control group (0.915 +/- 0.13; p < 0.0001). Although the serum nitrate levels in study groups A and B were lower than in the control group, this difference was not significant. The maternal outcome was satisfactory but, as expected, the mean birth weight of the babies in group B (1,665.73 +/- 863.84 g) was significantly lower than the birth weights in the control and group-A patients (p < 0.0001). CONCLUSION: There is a drop in nitric oxide production in active preterm labor and induced labor. These findings need to be confirmed in larger studies to establish the role of nitric oxide in the initiation of labor.

Differential expression of T-helper cytokines in the peritoneal fluid of women with normal ovarian cycle compared with women with chronic anovulation.

BACKGROUND: Estrogen and progesterone immunoregulate the genital environment by expression of cytokines and growth factors. OBJECTIVE: To investigate the pattern of expression of T-helper cytokines during the ovarian cycle compared with women with chronic anovulation resistant to clomiphene citrate. HYPOTHESIS: Expression of T-helper cytokines in women with chronic anovulation may be different from the pattern in women with a normal ovarian cycle. METHODS: We evaluated 31 infertile women having laparoscopy for evaluation of tubal patency and evidence of ovulation in two groups during (a) the luteal phase (17 women) and (b) the follicular phase (14 women). A third group was composed of 14 women with polycystic ovarian syndrome, but they were resistant to clomiphene citrate for induction of ovulation and had laparoscopic ovarian cautery. Peritoneal fluid was collected during laparoscopy. Estimation of T-helper cytokine interleukin (IL)-2, tumor necrosis factor (TNF)-alpha, IL-4 and IL-6 in serum, peritoneal fluid and culture of the peritoneal mononuclear cells was performed by ELISA. Serum luteinizing hormone (LH), follicle stimulating hormone (FSH), prolactin, estradiol and progesterone were evaluated by the Vidas Parametric System. RESULTS: The LH : FSH ratio was significantly higher in the women with polycystic ovaries than in the ovulatory groups. IL-2 and IFN-gamma were more highly expressed in the follicular phase but the T-helper 2 cytokines IL-4 and IL-6 predominated in the luteal phase, serum, peritoneal fluid and culture of the peritoneal mononuclear cells. From the follicular to the mid-luteal phase, IL-6 increased three to fivefold in the serum and peritoneal fluid, but there was low expression with anovulation. CONCLUSIONS: The peritoneal fluid levels of IL-4 and IL-6 are higher in the luteal phase. Low IL-6 levels in chronic anovulation may be a marker of resistance to clomiphene citrate.