Preterm Birth · Prediction
Porter TF et al., 1997 · Obstet Gynecol
To examine the risk of preterm birth for mothers who themselves were born before term. Data were taken from a linked data base of birth certificates composed of two cohorts: 1) a parental cohort of women born between 1947 and 1957 and 2) their offspring born between 1970 and 1992. "Preterm mothers" were women in the parental cohort who were born at less than 37 weeks' gestation. "Term mothers" were women in the parental cohort born at or after 38 weeks' gestation. Preterm mothers and term mothers were matched for birth year, county of birth, marital status, parity, and age. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for the risk of preterm delivery in preterm mothers. Multiple logistic regression was used to assess the interaction of concomitant variables with the risk of premature delivery. The risk of preterm birth was significantly higher in preterm mothers than in term mothers (OR 1.18; 95% CI 1.02, 1.37). The risk increased as the gestational age at the mothers' birth decreased (less than 30 weeks'; OR 2.38; 95% CI 1.37, 4.16). The interaction between maternal age and parity increased the risk of preterm delivery at less than 34 weeks in some age and parity strata. An increased risk of preterm delivery exists for women who themselves were born before 37 weeks' gestation. The risk is inversely correlated with the maternal gestational age at birth and is influenced by maternal age and parity.
Preterm Birth · Prediction
Henriksen TB et al., 1997 · Obstet Gynecol
To test whether subfertile women may be at higher risk of preterm delivery. We used data from two population-based cohort studies on risk factors and pregnancy outcome for approximately 20,000 deliveries in three major Danish obstetric departments. The Aalborg-Odense study comprised all pregnant women attending routine antenatal care at two obstetric departments from 1984 to 1987. In all, 11,850 women (86%) filled in a questionnaire at about 36 weeks' gestation. The Aarhus study addressed women at the routine visit near 16 weeks' gestation from 1989 to 1991; a study questionnaire was returned by 6857 (80%). Both studies excluded women with chronic illnesses, multiple fetuses, and inability to speak Danish. Only women with planned pregnancies were included in the analysis. In all, 8855 and 3985 women from Aalborg-Odense and Aarhus, respectively, were eligible for the analyses. In both cohorts, women were categorized according to their waiting time to pregnancy (0-6 months, 7-12 months, and greater than 1 year) and according to examination or treatment for infertility (yes, no). Preterm delivery was defined as birth before 37 completed weeks. Compared with women who tried for 6 months or less before they conceived, women who tried for 7-12 months had 1.3 times (95% confidence interval [CI] 0.8, 2.1) the adjusted risk of preterm delivery in both cohorts, and women with a time to pregnancy of greater than 12 months had adjusted relative risks for preterm delivery of 1.6 (95% CI 1.1, 2.2) for Aalborg-Odense and 1.7 (95% CI 1.1, 2.6) for Aarhus. The results remained similar after excluding women with infertility treatment. Pregnant women with subfertility and clinically defined infertility are more prone to preterm delivery, even in the absence of infertility treatment.
Preterm Birth · Prediction
Goldenberg RL et al., 1998 · Am J Public Health
This study was undertaken to determine the relationship between fetal fibronectin, short cervix, bacterial vaginosis, other traditional risk factors, and spontaneous preterm birth. From 1992 through 1994, 2929 women were screened at the gestational age 22 to 24 weeks. The odds ratios for spontaneous preterm birth were highest for fetal fibronectin, followed by a short cervix and history of preterm birth. These factors, as well as bacterial vaginosis, were more strongly associated with early than with late spontaneous preterm birth. Bacterial vaginosis was more common--and a stronger predictor of spontaneous preterm birth--in Black women, while body mass index less than 19.8 was a stronger predictor in non-Black women. This analysis suggests a pathway leading from Black race through bacterial vaginosis and fetal fibronectin to spontaneous preterm birth. Prior preterm birth is associated with spontaneous preterm birth through a short cervix. Fetal fibronectin and a short cervix are stronger predictors of spontaneous preterm birth than traditional risk factors. Bacterial vaginosis was found more often in Black than in non-Black women and accounted for 40% of the attributable risk for spontaneous preterm birth at less than 32 weeks.
Preterm Birth · Prediction
Topp M et al., 1997 · Acta Obstet Gynecol Scand
Preterm infants are at 8 times higher risk than term infants for pre- and perinatal brain damage, resulting in cerebral palsy. In this paper we have analysed the influence of prenatal and birth-related risk factors on cerebral palsy in preterm infants. In a register-based study, 175 preterm singleton infants with cerebral palsy, born in 1982-86, were compared with 687 controls matched by gestational age and year of birth. Statistically significant higher rates in cases were found in parity > or = 3 (22% vs. 16%, p < 0.05), Cesarean section (67% vs. 56%, p < 0.01), and low Apgar scores at 1 minute (45% vs. 36%, p < 0.05). By multivariate analyses, two variables remained statistically significant: parity > or = 3 (adjusted OR = 1.53 (95% CI 1.00-2.34), p < 0.05) and Cesarean section (adjusted OR = 1.57 (95% CI 1.07-2.32), p < 0.05). Pregnancy complications preceding preterm birth did not imply a higher risk of cerebral palsy. Delivery by Cesarean section was a prognostic factor for developing cerebral palsy, and the predictive value of Apgar scores was highly limited.
