The Preterm Prediction Study: Maternal Serum Relaxin, Sonographic Cervical Length, and Spontaneous Preterm Birth in TwinsNational Institute of Child Health and Human Development Maternal Fetal Medicine Network, Bethesda, Maryland; University of Medicine and Dentistry-New Jersey Medical School, Newark, New Jersey; The Ohio State University Medical Center, 1654 Upham Drive, Columbus, OH 43210. Reprints are not available
National Institute of Child Health and Human Development Maternal Fetal Medicine Network, Bethesda, Maryland; University of Medicine and Dentistry-New Jersey Medical School, Newark, New Jersey Objective: The risk of spontaneous preterm birth has been related to decreased cervical length and to increased serum relaxin. To explore a relationship between these findings, we used data collected from two prior studies to correlate relaxin levels with cervical length and risk of spontaneous preterm birth in women with twin pregnancies. Methods: In a secondary analysis of data collected in two previous observational studies of risk factors for preterm birth, relaxin levels in maternal serum and cervical length were measured at 24 (n = 188) and 28 (n = 145) weeks in women with spontaneous twin pregnancies. Relaxin, as a continuous variable, was related by logistic regression analysis to risk of spontaneous preterm birth before 37, 35, and 32 weeks' gestation, and by Spearman correlation coefficients to cervical length at 24 and 28 weeks. Cervical length at 24 week was known to be correlated with spontaneous preterm birth before 37, 35, and 32 week (P = .03, .01, and .002, respectively) in this study population. Results: Cervical length did not correlate with relaxin levels at 24 (P = .601) or 28 (P = .304) weeks. Relationships between relaxin and spontaneous preterm birth were observed at 24 weeks for births before 37 weeks (odds ratio [OR] 1.56, 95% confidence interval [CI] 1.00, 2.44; P = 0.5), and at 28 weeks for births before 35 weeks (OR 1.97, 95% CI 1.05, 3.70; P = .034) and 32 weeks (OR 2.43, 95% CI 1.01, 5.83; P = .048). Conclusion: The absence of an association between relaxin and cervical length suggests that increased relaxin does not explain the inverse correlation between cervical length and spontaneous preterm birth in women with spontaneous twin pregnancies.
Key Words: Relaxin cervical length preterm birth
Journal of the Society for Gynecologic Investigation, Vol. 8, No. 1,
39-42 (2001) |
|
|||

