Suzanne P. Cliver

Multicenter randomized trial of cerclage for preterm birth prevention in high-risk women with shortened midtrimester cervical length

OBJECTIVE The objective of the study was to assess cerclage to prevent recurrent preterm birth in women with short cervix. STUDY DESIGN Women with prior spontaneous preterm birth less than 34 weeks were screened for short cervix and randomly assigned to cerclage if cervical length was less than 25 mm. RESULTS Of 1014 women screened, 302 were randomized; 42% of women not assigned and 32% of those assigned to cerclage delivered less than 35 weeks (P = .09). In planned analyses, birth less than 24 weeks (P = .03) and perinatal mortality (P = .046) were less frequent in the cerclage group. There was a significant interaction between cervical length and cerclage. Birth less than 35 weeks (P = .006) was reduced in the less than 15 mm stratum with a null effect in the 15-24 mm stratum. CONCLUSION In women with a prior spontaneous preterm birth less than 34 weeks and cervical length less than 25 mm, cerclage reduced previable birth and perinatal mortality but did not prevent birth less than 35 weeks, unless cervical length was less than 15 mm.

A multicenter study of preterm birth weight and gestational age-specific neonatal mortality

OBJECTIVE This analysis was performed to present updated neonatal mortality data by age and birth weight for preterm newborns and to demonstrate the influence of plurality, ethnicity, and infant sex on mortality. STUDY DESIGN Preterm birth weight and gestational age-specific mortality rates were compiled from the five centers that participated in the March of Dimes Multicenter Preterm Birth Prevention Project. In each center gestational age was assessed by standardized methods. A birth weight and gestational age-specific mortality chart for preterm births was created with live-birth data. RESULTS In each birth weight group mortality decreased as the gestational age advanced; for each gestational age group heavier infants had less mortality. Female infants < 29 weeks survived better than male infants, and singletons < 29 weeks survived better than twins. Survival for black preterm newborns was better than that of whites but differences were not significant. Mortality for black term infants was significantly higher. The largest improvement in survival occurred between 25 and 26 weeks. At 30 weeks survival was > 90% and improved < 1% per week thereafter. CONCLUSIONS When compared with rates in previous reports, mortality rates appear to have improved, especially at gestational ages < 29 weeks. These data may be useful in decision-making and in counseling patients at risk for preterm delivery.

Medical, psychosocial, and behavioral risk factors do not explain the increased risk for low birth weight among black women☆☆☆★★★

OBJECTIVE Our purpose was to determine whether various demographic, behavioral, housing, psychosocial, or medical characteristics explain the difference in pregnancy outcome between black and white women. STUDY DESIGN A sample of 1491 multiparous women with singleton pregnancies, 69% of whom were black and 31% of whom were white and who enrolled for care between Oct. 1, 1985, and March 30, 1988, participated in the study. The frequencies of various demographic, medical environmental, and psychosocial risk factors among black and white women were determined. The outcome measures were birth weight, gestational age, fetal growth restriction, preterm delivery and low birth weight. RESULTS White infants were heavier and born later than black infants. The white women in this sample smoked more cigarettes, moved more frequently, and had worse psychosocial scores. The black women had lower incomes, were less likely to be married, and had more hypertension, anemia, and diabetes. Besides race, only maternal height, weight, blood pressure, diabetes, and smoking had a consistent impact on outcome and did not explain the difference in outcome between the two groups. CONCLUSION In this low-income population, many of the risk factors for low birth weight were more common among white women than black women. Nevertheless, black women had more infants born preterm, with growth restriction, and with low birth weight than did white women. The various maternal characteristics studied did not explain these differences.

Intrauterine growth retardation and preterm delivery: prenatal risk factors in an indigent population

Prenatally ascertained risk factors for low birth weight were evaluated in a population of 17,000 indigent women for their specific effect on intrauterine growth retardation and on the rate of preterm delivery. In a univariate analysis, intrauterine growth retardation occurred more frequently in women who were black, single, primiparous, less than 17 or greater than 30 years old, short, thin, had a previous preterm delivery, consumed alcohol, took drugs, or gained limited weight. Preterm delivery occurred significantly more frequently in women who were black, single, thin, less than 17 or greater than 30 years old, had less than a twelfth grade education, or gained limited weight. In logistic regression analyses, race, parity, maternal age, a history of preterm delivery, smoking, short stature, low weight, and low weight gain remained significant risk factors of intrauterine growth retardation. Of these factors, smoking, short stature, low weight, and low weight gain showed the greatest correlation. Factors significantly related to preterm delivery included black race, single marital status, younger or older ages, previous preterm delivery, smoking, low weight, and very low or high weight gain. A previous preterm delivery and very low maternal weight had the greatest correlation. Identification of specific risk factors of both intrauterine growth retardation and preterm delivery should aid in the development of strategies to reduce the prevalence of these conditions.

Strategies for the Prevention of Early-onset Neonatal Group B Streptococcal Sepsis: A Decision Analysis

Objective: To perform a decision analysis to understand better the implications of 19 potential group B streptococcus screening and treatment strategies. Methods: We searched the literature to locate appropriate articles from which to derive probability estimates. Using decision analysis, we determined the likely outcomes of 19 group B streptococcus screening and treatment strategies and focused on three main outcomes: 1) number of expected cases of early‐onset neonatal group B streptococcal sepsis, 2) percentage of gravidas treated with intrapartum antibiotics, and 3) total costs. Results: The strategy recently recommended by two committees of the American Academy of Pediatrics (universal 28‐week maternal rectovaginal group B streptococcal culture and treatment of culture‐positive, high‐risk patients in labor) is among the least effective at reducing neonatal sepsis and the most costly. Strategies based on the currently available rapid streptococcus identification tests are ineffective at reducing neonatal sepsis and are costly. Three strategies outperform the rest: 1) Universal intrapartum maternal antibiotic treatment is the most effective strategy in reducing early‐onset neonatal group B streptococcal sepsis (6% of expected) and is also the least costly; 2) intrapartum treatment based solely on risk factors (recently endorsed by ACOG) lowers the rate of neonatal sepsis to 31% of expected with an 18% maternal treatment rate and low total costs; and 3) universal 36‐week maternal culture, and treatment of all patients experiencing preterm birth and all culture‐positive patients results in 14% of expected neonatal sepsis, with a 27% maternal treatment rate and low total costs. Conclusion: Given the present state of knowledge, three strategies emerge from this decision analysis as most optimal for the prevention of early‐onset neonatal group B streptococcal sepsis: universal treatment, treatment based on risk factors, and treatment based on preterm delivery and 36‐week culture status. (Obstet Gynecol 1994;83:483‐94)

Periodontal disease and upper genital tract inflammation in early spontaneous preterm birth.

OBJECTIVE: To estimate the relationship between maternal periodontal disease and both early spontaneous preterm birth and selected markers of upper genital tract inflammation. METHODS: In this case-control study, periodontal assessment was performed in 59 women who experienced an early spontaneous preterm birth at less than 32 weeks of gestation, in a control population of 36 women who experienced an early indicated preterm birth at less than 32 weeks of gestation, and in 44 women with an uncomplicated birth at term (≥ 37 weeks). Periodontal disease was defined by the degree of attachment loss. Cultures of the placenta and umbilical cord blood, cord interleukin-6 levels, and histopathologic examination of the placenta were performed for all women. RESULTS: Severe periodontal disease was more common in the spontaneous preterm birth group (49%) than in the indicated preterm (25%, P = .02) and term control groups (30%, P = .045). Multivariable analyses, controlling for possible confounders, supported the association between severe periodontal disease and spontaneous preterm birth (odds ratio 3.4, 95% confidence interval 1.5–7.7). Neither histologic chorioamnionitis, a positive placental culture, nor an elevated cord plasma interleukin-6 level was significantly associated with periodontal disease (80% power to detect a 50% difference in rate of histological chorioamnionitis, α = 0.05). CONCLUSION: Women with early spontaneous preterm birth were more likely to have severe periodontal disease than women with indicated preterm birth or term birth. Periodontal disease was not associated with selected markers of upper genital tract inflammation. LEVEL OF EVIDENCE: II-2

Smoking, maternal age, fetal growth, and gestational age at delivery

The relationship between smoking and maternal age and their combined effects on birth weight, intrauterine growth retardation, and preterm delivery were studied. Smoking lowers birth weight both by decreasing fetal growth and by lowering gestational age at delivery. However, the effect of smoking on both fetal growth and gestational age is significantly greater as maternal age advances. In a multiple logistic regression model adjusting for race, parity, marital status, maternal weight, weight gain, and alcohol use, smoking was associated with a fivefold increased risk of growth retardation in women older than 35 but less than a twofold increased risk in women younger than 17. Smoking reduced birth weight by 134 gm in young women but 301 gm in women older than 35. Smoking in older women also was associated with more instances of preterm delivery and a lower mean gestational age when compared to women 25 or younger.

The Effect of Cigarette Smoking on Neonatal Anthropometric Measurements

Objective To estimate the effect of maternal cigarette smoking on birth weight, crown-heel length, and ten other neonatal anthropometric measurements. Methods Data are from a cohort study on risk factors for fetal growth retardation (FGR) in multiparous women conducted from December 1985 through October 1988. Information on smoking status was collected four times during pregnancy. Data analysis included 1205 singleton infants of women delivering at term. Neonatal anthropometric measurements were obtained within 48 hours of birth, including birth weight, crown-heel length, ponderal index, head and abdominal circumferences, arm length and circumference, femur length and thigh circumference, and triceps, thigh, and subscapular skinfold measurements. Analysis of covariance models were used to assess the independent effect of smoking on each neonatal measurement. Results Neonates born to women who reported smoking during the first trimester had a 0.6–1.9% reduction in most neonatal anthropometric measurements, resulting in an overall reduction of birth weight of 130 g (4%). Neonates born to women who continued to smoke throughout pregnancy had an average adjusted reduction in birth weight of 189 g (5.9%), compared with a 55 g (1.7%) reduction for neonates born to women who stopped smoking after the first trimester. For women who continued to smoke throughout pregnancy, an increased number of cigarettes smoked was associated with increased reductions in birth weight and neonatal chest and abdominal circumferences. For women who stopped smoking after the first trimester, stopping was a better predictor of neonatal anthropometric measurements than the number of cigarettes smoked early in pregnancy. Conclusions Except for the ponderal index, all neonatal anthropometric measurements studied showed some negative effect of maternal cigarette smoking. Head circumference is the measurement least reduced. Smoking cessation is a better predictor of infant size than the number of cigarettes smoked in the first trimester.

The relationship between psychosocial profile, health practices, and pregnancy outcomes

Background. The influence of psychosocial factors such as stress, anxiety, depression, and self‐esteem on birth weight is controversial. A prospective study was conducted to evaluate the relationship between pregnancy outcomes, psychosocial profile, and maternal health practices. Methods. 3,149 low‐income, predominantly African‐American pregnant women participated in this study. A 28‐item psychosocial scale measured the constructs of negative and positive affect, self esteem, mastery, worry, and stress. Maternal health practices were assessed with 11 questions dealing with diet, exercise, and the use of preventive medical and dental services. Results. A low score on either scale indicated “poor” psychosocial or health practices status. Low birth weight, preterm delivery, and intrauterine growth retardation occurred in 10.9, 10.1 and 7.3% of the pregnant women respectively. In women with low psychosocial scores, the risk of both low birth weight and preterm delivery was 40% higher and the mean birth weight of infants was 51 g (p=0.02) lower as compared to women with high scores. Negative affect (a measure of depression) was the only factor significantly associated with both infant birth weight (β= − 71.2, p=0.001) and low birth weight (AOR = 1.4, 95% CI = 1.1–1.7). When data were stratified by body mass index, the adverse effect of negative affect scores on birth weight and low birth weight was present only in thin women. Health practice scores were not associated with any of the pregnancy outcomes. Conclusion. Thin women with a poor psychosocial profile and who are depressed during pregnancy are at increased risk of giving birth to low birth weight and preterm infants.

Effects of domestic violence on preterm birth and low birth weight

Background.  Domestic violence is increasingly recognized as a potentially modifiable risk factor for adverse pregnancy outcomes. This study was conducted to evaluate the relationship between abuse during pregnancy or within the last year and low birth weight and preterm birth.