Maternal inflammatory markers and term labor performance




Materials and Methods


A nested cohort study was performed. The initial cohort consisted of 607 nulliparous women who were candidates for a trial of labor from Feb. 5, 2006, through March 12, 2009. Subjects were enrolled prospectively prior to labor onset at ≥37 0/7 weeks’ gestation. Women with active infections, autoimmune conditions, or those taking antiinflammatory agents were excluded. Labor progress is modeled in reverse time with the time of full dilation anchoring at time 0; only parturients who reached full dilation were considered. Subjects were excluded if they failed to achieve complete dilation, yielding a total of 334 subjects. Maternal blood was collected on our labor and delivery unit at the onset of regular, painful contractions in patients undergoing labor induction or at admission in patients with spontaneous labor. Maternal serum samples were stored at –80° C until batch multiplex analysis. Levels of cytokines IL-1, IL-6, and TNF-α were quantified using custom kits (BioRad, Hercules, CA) and standard protocols on the Luminex 200 platform (Luminex Corp, Austin, TX). Maternal data on gestational age at enrollment, height, weight, race, ethnicity, and other demographic variables were collected prospectively. Intrapartum data including hourly maternal temperature and duration of epidural analgesia were collected prospectively on specific study forms. Detailed chart review was performed to abstract data on every cervical examination over the course of labor. For each cervical examination, the associated self-reported maternal pain score, oxytocin dose, and membrane status was recorded. Cervical examinations were performed at the discretion of the physician, and were not proscribed at a set interval.


Statistical analysis on demographic variables was performed with SAS software (version 9.2; SAS Institute, Cary, NC) and SPSS software (version 12.0, IBM Corp, Armonk, NY). Maternal and neonatal characteristics were compared by the Mann-Whitney U test for continuous variables and χ 2 or Fisher exact test for categorical variables. Patients were categorized by cytokine quartiles for each cytokine for further analysis as the distribution was not normally distributed. Where there was a positive association with both first and fourth quartile, the strongest association was considered for inclusion in the final model.


Labor progress model


Labor progress was analyzed using the biexponential model for labor progress previously derived and validated by Debiec et al. This model requires estimation of 3 variables: a rate constant for latent labor, a rate constant for active labor, and the number of centimeters of cervical dilation associated with the active phases. The relationship is described by the equation:


<SPAN role=presentation tabIndex=0 id=MathJax-Element-1-Frame class=MathJax style="POSITION: relative" data-mathml='CD=Ce−λ1×time+(10−C)e−λ2×time’>CD=Ceλ1×time+(10C)eλ2×timeCD=Ce−λ1×time+(10−C)e−λ2×time
C D = C e − λ 1 × t i m e + ( 10 − C ) e − λ 2 × t i m e

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May 11, 2017 | Posted by in GYNECOLOGY | Comments Off on Maternal inflammatory markers and term labor performance

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