早产预测研究:孕妇体重指数与自发性早产及干预性早产的关系

Objective: The purpose of this study was to evaluate the relationship between prepregnancy maternal body mass index and spontaneous preterm birth and indicated preterm birth. Study design: This was a secondary analysis of the Maternal- Fetal Medicine Units Network, Preterm Prediction study. Patients were classified into categories that were based on their body mass index. Rates of indicated and spontaneous preterm birth were compared. Results: Five hundred ninety- seven (20.5% ) of 2910 women were obese. Obese women had fewer spontaneous preterm births at < 37 weeks of gestation (6.2% vs 11.2% ; P <. 001) and at < 34 weeks of gestation (1.5% vs 3.5% ; P =. 012). Women with a body mass index of < 19 kg/m2 had 16.6% spontaneous preterm birth, with a body mass index of 19 to 24.9 kg/m2 had 11.3% spontaneous preterm birth, with a body mass index of 25 to 29.9 kg/m2 had 8.1% spontaneous preterm birth, with a body mass index of 30 to 34.9 kg/m2 had 7.1% spontaneous preterm birth, and with a body mass index of ≥ 35 kg/m2 had 5.2% spontaneous eterm birth (P <. 0001). Indicated delivery was responsible for an increasing proportion of preterm births with increasing body mass index (P =. 001). Obese women had lower rates of cervical length < 25 mm (5% vs 8% pr.; P =. 012). Multivariable regression analysis confirmed a lower rate of spontaneous preterm birth in obese gravid women (odds ratio, 0.57; 95% CI, 0.39- 0.83; P =. 003). Conclusion: Obesity before pregnancy is associated with a lower rate of spontaneous preterm birth.

两次妊娠间应用抗生素预防自发早产的一项随机临床试验

Objective: We hypothesized that upper genital tract microbial infection associated with spontaneous preterm birth may precede conception. Our objective was to estimate if antibiotic administration during the interpregnancy interval in nonpregnant women with a previous preterm birth before 34 weeks’ gestational age would reduce the rate of spontaneous preterm birth in the subsequent pregnancy. Study design: Women with a spontaneous preterm birth < 34 weeks’ gestational age were randomized at 4 months’ postpartum to receive oral azithromycin 1 g twice (4 days apart)plus sustained- release metronidazole 750 mg daily for 7 days, or identical- appearing placebos. This regimen was repeated every 4 months until the subsequent pregnancy. Results: A total of 241 women were randomized; 124 conceived a subsequent pregnancy and were available for study, including 59 in the antibiotic group and 65 in the placebo group. In the antibiotic versus placebo group, neither subsequent spontaneous preterm birth ( < 37 weeks: 52% vs 46% , P = .568; < 35 weeks: 40% vs 30% , P = .276; < 32 weeks: 31% vs 23% , P = .376) nor miscarriage ( < 15 weeks: 12% vs 14% , P = .742) was significantly different. Although not statistically significant, mean delivery gestational age in the subsequent pregnancy was 2.4 weeks earlier in the antibiotic versus placebo group (32.0 ± 7.9 vs 34.4 ± 6.3 weeks, P = .082), and mean birth weight was lower in the antibiotic group (2046 ± 1209 vs 2464 ± 1067 g, P =.060). Conclusion: Intermittent treatment with metronidazole plus azithromycin of nonpregnant women with a recent early spontaneous preterm birth does not significantly reduce subsequent preterm birth, and may be associated with a lower delivery gestational age and lower birthweight.

HPTN 024研究:应用抗生素预防绒毛膜羊膜炎和早产的作用

Objective: The use of antibiotics to prevent preterm birth has achieved mixed results. Our goal in this study was to determine if antibiotics given prenatally and during labor reduce the incidence of preterm birth and histologic chorioamnionitis. Study design: A double- blind rando-mized placebo- controlled trial of antibiotics to reduce preterm birth was conducted in 4 African sites. Both HIV- infected and uninfected pregnant women were given 2 courses of antibiotics, prenatally at 24 weeks (metronidazole 250 mg and erythromycin 250 mg tid orally for 7 days), and during labor (metronidazole 250 mg and ampicillin 500 mg q 4 hours) or identically appearing placebos. Two thousand ninety- eight HIV- infected and 335 HIV- uninfected women had evaluable end points, including gestational age determined by both obstetric and pediatric criteria and birth weight (BWT). Pre- and post- treatment rates of various sexually transmitted infections (STI) were determined and placentas were evaluated for histologic chorioamnionitis. Results: Comparing antibiotic versus placebo treated HIV- infected and uninfected women, there were few differences in mean gestational age at delivery, the percent of preterm births, the time between randomization and delivery, or BWT. Four weeks after the 24- week antibiotic/- placebo course, bacterial vaginosis, and trichomoniasis were reduced by 49% to 61% in the antibiotic groups compared with the placebo groups. However, in both the HIV- infected and uninfected groups, the placentas showed no difference in the rate of histologic chorioamnionitis. There were significant differences between HIV- infected and uninfected women, with the former having less education, a history of more stillbirths, more STIs, and in this pregnancy, a lower BWT (2949 vs 3100 g, P < .0001). Conclusion: Despite reducing the rate of vaginal infections, the antibiotic regimen used in this study did not reduce the rate of preterm birth, increase the time to delivery, or increase BWT. Failure of this regimen to reduce the rate of histologic chorioamnionitis may explain the reason the antibiotics failed to reduce preterm birth.