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The authors investigated the role of stress and cortisol with patients having preterm labor (PTL) and preterm birth (PTB). The relationships of maternal cortisol, perceived stress, fetal fibronectin (fFN), and genitourinary infections to PTL and PTB were studied. A prospective, longitudinal, observational study (n = 78) was conducted in a private practice in central Texas. Subjects had 4 blood draws for cortisol measurements grouped by 15-19, 20-22, 23-26, 27-30, and 31-35 weeks of gestation. Subjects had 2 vaginal swabs forfFN, chlamydia, and bacterial vaginosis screens at 23-26 and 27-30 weeks with assessment of psychosocial stress at 23-26 and 31-35 weeks. Statistical analysis was by analysis of variance, Pearson correlations, Fisher exact test, and logistic regression. There were no significant differences between the PTB, PTL, and term groups on cortisol levels at any of the gestational periods. Cortisol concentrations at any gestational stage did not correlate with gestational age at birth. A relationship of cortisol to race was observed when comparing Caucasians to other ethnic groups. A correlation (r = 0.42, P < 0.001) between the change in Perceived Stress Scale (PSS) score and gestational age was observed. The greater the decrease in PSS scores, the longer was the gestational age. A significant increase in cortisol at 19-21 weeks (P < 0.04), 23-26 weeks (P < 0.05), and 31-35 weeks (P < 0.01) was observed in patients having genitourinary infection. PTL was also significantly increased in subjects having positive genitourinary infections at either 23-26 weeks or 27-30 weeks (P < 0.01). The sensitivity of fFN to predict PTL collected at 27-30 weeks was 40%, specificity 86%, positive predictive value 55%, and negative predictive value 83%. These results indicate that cortisol is a poor predictor of either PTL or PTB. A decrease in perceived stress during the 2nd trimester was associated with an increase in length of gestation, suggesting the possibility of stress reduction as an appropriate intervention for lengthening gestational age.

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The prevalence of lumbosacral intervertebral disk bulge and herniation on sagittal magnetic resonance (MR) images was determined in 45 pregnant subjects and 41 asymptomatic nonpregnant women of childbearing age. MR technique differed for the pregnant and nonpregnant groups. Fifty-three percent of pregnant and 54% of nonpregnant women had an abnormal disk (bulge or herniation) at one or more levels (L3-4, L4-5, or L5-S1). The difference was not statistically significant. There was also no significant difference in the distribution of outcomes among the 45 pregnant subjects, 17 parous nonpregnant women, and 24 nulliparous women. The results suggest that lumbosacral disk bulges or herniations are common in women of childbearing age, whether pregnant or not, and that, contrary to an earlier report, pregnant women do not have an increased prevalence of disk abnormalities.

The relationships and predictive abilities of perceived stress, selected clinical risk factors, and corticotropin-releasing hormone (CRH) levels in maternal plasma were investigated for their association with preterm labor (PTL), preterm birth, and gestational age at delivery. An exploratory, prospective, longitudinal research design was used to measure CRH 4 times over pregnancy, perceived stress at 24 and 32 weeks of pregnancy, clinical risk factors, and genitourinary infections in low-income women. Multiple regression analyses revealed that a model of measurement ofperceived stress at 24 or 32 weeks, CRH at 24 or 32 weeks, and PTL (indicated by a diagnosis by the physicians on the medical record and greater than 5 contractions per hour on the fetal monitor) was predictive of as much as 0.23 to 0.27 of the variance in gestational age at birth. Entering ethnicity as a variable into a model did not improve the predictive value. An analysis of variance between Caucasian and Hispanic ethnic groups revealed differences in CRH levels. However, simple regression analysis of ethnicity as a predictor showed a weak r2 with no significance for prediction. There was some evidence of an association of smoking with stress and both PTL and preterm birth. The measurement of stress combined with the measurement of CRHfrom maternal plasma may improve the prediction of which pregnant women are at riskfor pretern birth. The measurement of CRH has potential as an early biological marker of preterm birth.

The 13C NMR spectra of the dipeptides carnosine, anserine, homocarnosine, and glycyl-L-histidine and component amino acids in solid powders are compared. The observed chemical shifts are the same as would be expected from high-resolution NMR spectroscopy, but the observed sensitivity is very dependent on the identity of the N-terminal amino acid residue. Signal intensities from carnosine are greatly enhanced by addition of CoCl2. The sensitivity of 13C NMR spectra recorded with cross polarization and magic angle sample spinning may be improved without seriously affecting resolution by introduction of paramagnetic metal ions or free radicals.Comparison of 13C NMR spectra of benzenoid and heterocyclic analogues of poly(p-phenylene) and lower oligomers that are recorded with cross polarization and magic angle sample spinning (CP/MAS) indicates that chemical structure greatly affects the intensity of NMR spectra of solids.1,2 The intensities of CP/MAS 13C NMR spectra of poly(p-phenylene) and its lower oligomers were found to increase as the free-radical contents of these oligomers increase, but the resolution appeared not to be seriously affected.1,2 This observation suggests that the sensitivity of 13C NMR spectroscopy to solid samples might also be increased by the introduction of paramagnetic metal ions.Carnosine (/3-alanyl-L-histidine) provides a well-characterized sample for determining the effect of paramagnetic metal ions on CP/MAS 13C NMR spectra. The structure of carnosine in the Acknowledgment. This investigation was supported by a Cottrell Research Grant from the Research Corporation and a Biomedical Research Support Grant from the Medical College of Wisconsin.