Apart from their key role in immunologic signaling, cytokines are thought to play a part in ovulation, implantation, placentation, and parturition. There is mounting evidence that cytokines can contribute to preterm births associated with intrauterine infection. This study measured levels of cytokines produced by maternal peripheral blood mononuclear cells after stimulation by mitogen, autologous placental cells, and an extract of trophoblast antigen. Cytokine levels were compared in 30 women admitted in active preterm labor with intact membranes who had preterm delivery (PTD) and 54 control women who had had at least 3 normal pregnancies. Mean gestational ages were 26.8 weeks in the PTD group and 39.4 weeks in the control women. Without stimulation, serum levels of interleukin-6 (IL-6) were significantly higher in the PTD group from the second trimester onward. Levels of interferon-␥ (IFN-␥) also were higher in PTD, whereas levels of tumor necrosis factor-␣ were significantly higher in normal women. Analysis of stimulated cultures confirmed significantly higher levels of the type 1 cytokines IFN-␥ and IL-2 in the PTD group. Women with normal pregnancies exhibited significantly greater production of the type 2 cytokines IL-4, IL-5, and IL-10. The ratios of type 2 to type 1 cytokines suggested a bias to type 1 cytokines in women with PTD. This study indicated a bias toward increased production, by maternal lymphocytes of women with PTD, of type 1 cytokines that are known to induce numerous cytotoxic and inflammatory actions. Production of type 2 cytokines, which augment humoral immunity, is less evident in these women. Reportedly normal pregnancy is associated with a predisposition to type 2 immunity, whereas predominantly type 1 reactivity can lead to failed pregnancy.
ABSTRACTApproximately 1% of pregnant women are asthmatic and the prevalence could be increasing, like it is in the general population. The authors used data from a nested case-control study to learn whether maternal asthma is associated with a greater risk of preterm labor and delivery. The study group included 312 women who delivered before 37 completed weeks gestation and, as a control group, 424 women who delivered a singleton infant at term. Women with a history of asthma were approximately twice as likely as others to have preterm delivery (odds ratio [OR], 2.03; 95% confidence interval [CI], 1.01-4.09). A slightly stronger association (OR, 2.37; 95% CI, 1.15-4.88) was evident after adjusting for maternal age, race/ethnicity, parity, Medicaid payment status, and smoking during pregnancy. Asthma correlated with a greater than 2-fold increase in risk of both spontaneous and medically induced preterm delivery, but the association was statistically significant only for the latter. Maternal asthma was associated with both moderate (34-36 weeks) and very (before 34 weeks) preterm deliveries. These findings point to an increased risk of preterm delivery in asthmatic women.
ABSTRACTPreterm delivery before 37 completed weeks gestation remains the major...
