High relaxin levels during the 18th gestational week were associated with an increased risk of very preterm delivery (odds ratio, 11.3; 95% confidence interval, 2.14-59.1) and spontaneous very preterm delivery (odds ratio, 5.5; 95% confidence interval, 1.3-23).
In addition, they had significantly higher rates of both indicated preterm delivery (odds ratio, 4.8; 95% confidence interval, 3.0-7.5) and spontaneous preterm delivery (odds ratio, 2.1; 95% confidence interval, 1.4-3.0) at <35 weeks' gestation than did control women.
Uterine rupture occurred more frequently among women undergoing a trial of labor than among those undergoing elective repeat cesarean delivery (odds ratio, 2.10; 95% confidence interval, 1.45-3.05).
They also had higher risks of having preeclampsia (odds ratio, 6.7), small-for-gestational age (odds ratio, 9.7), preterm delivery (odds ratio, 5.9), miscarriage, and intrauterine fetal death (odds ratio, 11.8).
In patients without preterm labor, antibiotic treatment did not significantly decrease preterm delivery at <37 weeks of gestation, in all patients combined (odds ratio, 0.83; 95% CI, 0.57-1.21) nor in high-risk patients with a previous preterm delivery (odds ratio, 0.50; 95% CI, 0.22-1.12).
Logistic regression analysis controlling for duration of labor, induction, birth weight, maternal age, year of birth, epidural analgesia, and oxytocin augmentation indicated that, among women with a single scar, those with a prior vaginal delivery had a risk of uterine rupture that was one fifth that of women without a previous vaginal delivery (odds ratio, 0.2; 95% confidence interval, 0.04-0.8).
In one study antibiotic treatment in patients with preterm labor led to a nonsignificant decrease in the rate of preterm deliveries (odds ratio, 0.31; 95% CI, 0.03-3.24).
Units with guidelines for intrapartum foetal heart monitoring had higher rate of normal vaginal deliveries (odds ratio (OR): 1.34; 99% confidence interval (CI): 1.05 1.70) and lower rate of Caesarean section for foetal distress (OR: 0.57; 99% CI: 0.34 0.96).
Multivariate analysis of the number of sessions attended revealed that trainees working in a unit with less than 3999 deliveries attended significantly more theatre sessions compared to trainees in units with 4000-5999 and over 6000 deliveries, odds ratio (OR) 2.99 p = 0.007 955% CI 1.34-6.67).
Main outcomes: Odds of Caesarean section (CS) compared to other deliveries, and odds of forceps or ventouse delivery, compared to normal delivery, by assigned 'ethnic' group.
Maternal B-Pb ≥ 5.00 μg/dl increased the risk of preterm delivery (adjusted odds ratio 2.00, 95% confidence interval 1.35 3.00) but not of having an LBW infant (adjusted odds ratio 1.37, 95% confidence interval 0.86 2.18) in multivariable logistic multiple regression analysis (Table 3).
