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Preterm birth prevention: evaluation of a prospective controlled randomized trial.

Over a 3-year period 5457 indigent patients were scored for risk of preterm birth and 4595 women were delivered at greater than or equal to 20 weeks' gestation. Patients at high risk (18.1%) were randomized into control and intervention groups. The latter group received weekly cervical examinations and instruction regarding subtle symptoms and signs of preterm labor. Medical providers received similar instruction. There was no difference in preterm births between control and intervention groups (20.8% vs. 22.1%). Medical providers, convinced of preterm birth prevention during year 1 of the study, defeated the study design by giving preterm birth precautions to all patients. In turn, preterm births decreased from 13.7% (year 1) to 9.3% (year 2, p less than 0.001) and remained stable in year 3 (8.7%). Preterm births during year 1 and the 8 months preceding year 1 were not different. Significant differences in preterm births between private and indigent study patients during these two periods (p less than 0.001) disappeared during years 2 and 3 of the study.

Clinical Trials as Topic↗

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.

Adult↗

Ultrasonographic examination of the uterine cervix is better than cervical digital examination as a predictor of the likelihood of premature delivery in patients with preterm labor and intact membranes.

OBJECTIVE: The purpose of this study was to compare the diagnostic performance of ultrasonographic and digital examination of the cervix in the prediction of preterm delivery in patients presenting with preterm labor and intact membranes. STUDY DESIGN: Endovaginal ultrasonography was performed in 59 patients admitted with preterm labor (20 to 35 weeks) and cervical dilatation of < 3 cm. Cervical parameters evaluated included endocervical length, the presence of funneling, funnel length, funnel width, cervical index ([Funnel length + 1]/Endocervical length), and cervical dilatation and effacement as determined by digital examination. Outcome variables were the occurrence of preterm delivery (< 36 weeks) and the admission-to-delivery interval. RESULTS: The prevalence of preterm delivery was 37.3% (22/59). Receiver-operator characteristic curve and logistic regression analyses indicated a significant relationship between the occurrence of preterm delivery and ultrasonographic cervical parameters (p < 0.005 for each) but not with the results of digital examination of the cervix. Survival analysis demonstrated a shorter admission-to-delivery interval for patients with an abnormal cervical index or endocervical length (p < 0.005 for each). CONCLUSIONS: Endovaginal ultrasonographic examination of the uterine cervix is more accurate than digital examination of the cervix in the assessment of the risk for preterm delivery in patients with preterm labor and intact membranes.

Biometry↗

Increased interleukin-6 concentrations in cervical secretions are associated with preterm delivery.

OBJECTIVE: This study sought to determine whether elevated concentrations of interleukin-6 in the cervical and vaginal secretions of patients between 24 and 36 weeks' gestation predicted subsequent preterm delivery and/or identified those preterm deliveries associated with maternal infectious morbidity. STUDY DESIGN: A cohort study was undertaken with cervical and vaginal samples collected from 161 consenting patients seen at 3- to 4-week intervals between 24 and 36 weeks. Levels of interleukin-6 were measured by immunoassay. Demographic, obstetric, neonatal, and laboratory data were analyzed by Fisher's exact test, Student t test, or Wilcoxon rank sum test, linear and multiple logistic regression, and receiver-operator characteristic curve analysis. RESULTS: There were 4.2-fold and 3.4-fold increases in maximal cervical and vaginal interleukin-6 concentrations, respectively, among patients with preterm deliveries versus term deliveries. The receiver-operator characteristics curve analysis indicated that a single cervical interleukin-6 value > 250 pg/ml of sample buffer, present between 24 and 36 weeks' gestation, optimally identified patients with subsequent preterm deliveries versus term deliveries (sensitivity 50.0%, 95% confidence interval 33.2% to 66.8%; specificity 85.0%, 95% confidence interval 78.8% to 91.2%; positive predictive value 47.2%, 95% confidence interval 30.9% to 63.5%; negative predictive value 86.4%, 95% confidence interval 80.4% to 92.4%). The optimal vaginal interleukin-6 cutoff value (> 125 pg/ml) proved less sensitive (45.5%, 95% confidence interval 28.5% to 62.4%) but equally specific (86.6%, 95% confidence interval 80.7% to 92.5%). Multiple logistic regression indicated that a cervical interleukin-6 level > 250 pg/ml was an independent predictor of preterm delivery (adjusted odds ratio 4.8, 95% confidence interval 1.7 to 14.3). Cervical interleukin-6 levels did not correlate with cervical change or gestational age at sampling. Among patients delivered preterm there were no differences in the mean white blood cell count on admission or the prevalence of vaginal pathogens, alkaline vaginal pH, chorioamnionitis, or endometritis among patients with cervical interleukin-6 values > 150 or < or = 250 pg/ml. CONCLUSIONS: Cervical interleukin-6 is a relatively insensitive, although fairly specific discriminator of patients with subsequent preterm deliveries. Among patients delivered preterm, elevated cervical interleukin-6 values are not apparently associated with maternal infectious morbidity.

Adolescent↗

Human preterm birth is associated with systemic and local changes in progesterone/17 beta-estradiol ratios.

OBJECTIVE: The purpose of this study was to determine whether human preterm birth is associated with changes in 17 beta-estradiol and progesterone concentrations in maternal plasma and amniotic fluid. STUDY DESIGN: Forty healthy women in preterm labor with singleton pregnancies and intact membranes at 32 to 36 weeks of gestation who underwent amniocentesis for evaluation of the microbiologic status of the amniotic cavity were classified into the following two groups: 20 women who were delivered within 1 week from the amniocentesis (preterm delivery group) and 20 who were delivered at term (term delivery group). Maternal plasma and amniotic fluid concentrations of progesterone and 17 beta-estradiol were measured with sensitive and specific commercially available radioimmunoassay kits. RESULTS: The median amniotic fluid concentration of 17 beta-estradiol was significantly higher in women delivered prematurely than in those who were delivered at term (1.5 ng/ml vs 0.9 ng/ml, p = 0.0001). Moreover, the median plasma 17 beta-estradiol concentration was also significantly higher in the preterm delivery group than in the term group (14.1 ng/ml vs 6.9 ng/ml, p = 0.022). In contrast, no significant difference was found in amniotic fluid and plasma concentrations of progesterone between these two groups (24.5 ng/ml vs 27.5 ng/ml and 132.0 ng/ml vs 107.5 ng/ml, respectively). The median amniotic fluid progesterone/17 beta-estradiol ratio was significantly lower in the preterm delivery group than in those delivered at term (18.4 vs 33.6, respectively, p = 0.0017). Moreover, the median plasma progesterone/17 beta-estradiol ratio was also significantly lower in the preterm delivery group than in the term group (9.8 vs 17.0, respectively, p = 0.016). CONCLUSION: Human preterm birth is associated with significantly lower progesterone/17 beta-estradiol ratios than those of women with preterm labor delivered at term.

Adult↗

Uterine artery velocimetry and spontaneous preterm delivery.

OBJECTIVE: To evaluate if idiopathic spontaneous preterm delivery is associated with abnormal uteroplacental circulation, as assessed by Doppler velocimetry. METHODS: The study was carried out on 417 women who had Doppler velocimetry performed between 25-36 weeks' gestation and were subsequently delivered vaginally. The systolic-diastolic ratio (S/D) was computed for the uterine and umbilical arteries, and the outcomes of pregnancies with spontaneous preterm and term deliveries were compared. RESULTS: Uterine artery S/D was significantly higher (P < .0001) in the 31 patients delivered preterm, whereas no significant difference was observed in the umbilical S/D. Abnormal values of uterine S/D were detected in 58.1% of the preterm group, independent of the gestational age at examination. No significant increase in S/D was observed in patients hospitalized for preterm labor who delivered subsequently at term. Spontaneous preterm delivery was associated with increased uterine S/D among both pregnancies with small for gestational age fetuses and those with appropriately grown fetuses. CONCLUSION: Preterm delivery is associated with modifications of uterine artery Doppler velocimetry, suggesting that impaired trophoblastic invasion of the placental bed may play a role in determining preterm delivery.

Adolescent↗

Maternal and perinatal outcome of patients with preterm labor and meconium-stained amniotic fluid.

OBJECTIVE: To determine the clinical significance of meconium-stained amniotic fluid (AF) observed at amniocentesis in patients with preterm labor. METHODS: A nested case-control study was constructed based on the color of AF during amniocentesis. Forty-five women admitted with preterm labor and meconium-stained AF were matched for gestational age at admission and compared with 135 women with preterm labor and clear AF. All AF samples were cultured for aerobic and anaerobic bacteria and mycoplasma. RESULTS: The rates of positive AF cultures for microorganisms, overall preterm birth (before 36 weeks), preterm birth before 32 weeks, and clinical chorioamnionitis were all significantly higher in patients with meconium-stained AF than in those with clear AF (positive AF cultures, 38 versus 11%, P < .001; preterm delivery before 36 weeks, 73 versus 41%, P < .001; preterm delivery before 32 weeks, 51 versus 17%, P < .001; and clinical chorioamnionitis, 22 versus 6%, P = .003). In contrast, no significant differences were observed between groups with respect to maternal age, gravidity, parity, abruptio placentae, placenta previa, fetal distress, cesarean rate, or puerperal morbidity. CONCLUSION: Patients with preterm labor and meconium-stained AF had higher rates of microbial invasion of the amniotic cavity, clinical chorioamnionitis, and premature deliveries than those with clear AF.

Adult↗

Follow-up of preterm children: II. Growth and development at four years of age.

In a long-term prospective study, 46 unselected infants born before 35 completed weeks of gestation were compared with 26 full-term infants. At four years of age, 44 preterms and 25 full-terms were available to follow-up. The preterms were somewhat shorter in stature and lighter in weight than the full-terms but fell well within the normal range for Swedish children. Head circumference in the preterm group was significantly correlated to neurological development. Psychometric evaluation with Griffiths' mental developmental scale showed the preterms to fall within the normal range, though their performance was inferior to that of the full-terms. The greatest differences between the groups were in scores for the subscales eye and hand coordination, performance, and practical reasoning. There was no correlation within the preterm group between the test results and birthweight, gestational age, prenatal score, perinatal score, or parental social status or education. Language development was delayed among the preterms, more of whom required speech therapy. Visual and hearing disorders were more common among preterms than expected. Although they were all in good health, more preterms than full-terms needed hospital care during the first four years of life.

Body Height↗

Neurodevelopmental profile in low-risk preterm infants at 5 years of age.

The goal of this study is to determine the neurodevelopmental profile of a group of low-risk preterm infants and to determine whether the potentially unfavourable outcome is due to a few infants with moderate to severe impairments or to a majority of infants with only slight impairments. In a prospective study 44 low-risk preterm infants, i.e. infants with a neonatal risk score indicating a favourable outcome, born between 25-34 weeks gestational age, and 18 healthy term infants were examined neurologically and tested neuropsychologically at 5 years of age. The more unfavourable outcome in the group of low-risk preterm infants compared with the term infants was largely attributable to a poorer outcome in 12 of the 44 low-risk preterm infants. The remaining low-risk preterm infants showed similar test scores compared with the term infants. From these results we conclude that the unfavourable neurodevelopmental outcome of low-risk preterm infants is due to moderate to severe impairment in a few low-risk preterm infants, rather than slight impairment in the majority. The low-risk preterm infants with an unfavourable outcome showed particular impairment on measures of visual-motor integration, concentration and auditory memory in combination with integrative functions.

Birth Weight↗

Fetal sex and indicated very preterm birth: results of the EPIPAGE study.

OBJECTIVE: This study was undertaken to explore the association between fetal sex, mode of onset of labor, and principal cause of very preterm birth. Study design The analysis uses data on 2624 very preterm singleton births less than 33 weeks' gestation from a prospective study of all very preterm births in 9 French regions in 1997. RESULTS: Fifty-seven percent of the spontaneous births were male versus 50.8% of births after medical decision (P=.005). This pattern was explained by sex differences in causes of preterm birth. Male infants had a greater incidence of very preterm birth after spontaneous labor (relative risk [RR]=1.42 [1.21-1.66]), but one third less risk of indicated preterm birth associated with hypertension both with and without growth restriction (RR=0.73 [0.55-0.97] and 0.77 [0.60-0.97]). CONCLUSION: These results support previous reports of greater male susceptibility to preterm labor. The finding that pregnancies carrying female infants have a greater predisposition to indicated very preterm birth associated with hypertension has not been reported previously and merits further study.

Confidence Intervals↗

Cerclage for prevention of preterm birth in women with a short cervix found on transvaginal ultrasound examination: a randomized trial.

OBJECTIVE: The purpose of this study was to determine the efficacy of cerclage and bed rest versus bed rest-only for the prevention of preterm birth in women with a short cervix found on transvaginal ultrasound examination. STUDY DESIGN: Women with > or =1 of high-risk factors for preterm birth (> or =1 preterm birth at < 35 weeks of gestation, > or =2 curettages, diethylstilbestrol exposure, cone biopsy, Mullerian anomaly, or twin gestation) were screened with transvaginal ultrasonography of the cervix every 2 weeks from 14 weeks of gestation to 23 weeks 6 days of gestation. Enrollment was offered to both asymptomatic women who were at high risk and who were identified to have short cervix (< 25 mm) or significant funneling (>25%) and nonscreened women who were at low risk and who were identified incidentally. The women who gave written consent were assigned randomly to receive either McDonald cerclage or bed rest-only. Both groups received similar counseling and treatment. Primary outcome was preterm birth at < 35 weeks of gestation. RESULTS: Sixty-one women were assigned randomly. Forty-seven pregnancies (77%) were high-risk singleton gestations. Thirty-one women (51%) were allocated to cerclage, and 30 women (49%) were allocated to bed rest. There were no differences between the groups in demographic characteristics, risk factors, and cervical variables. Preterm birth at < 35 weeks of gestation occurred in 14 women (45%) in the cerclage group and in 14 women (47%) in the bed rest group (relative risk, 0.94; 95% CI, 0.34-2.58). There was no difference in any obstetric or neonatal outcomes. A subanalysis of singleton pregnancies with previous preterm birth at < 35 weeks of gestation and a short cervix of < 25 mm (n = 31 women) also revealed no significant difference in recurrent preterm birth at < 35 weeks of gestation (40% vs 56%; relative risk, 0.52; 95% CI, 0.12-2.17). CONCLUSION: Cerclage did not prevent preterm birth in women with a short cervix. These results should be confirmed by larger trials.

Bed Rest↗

Combination of vaginal pH with vaginal sialidase and prolidase activities for prediction of low birth weight and preterm birth.

OBJECTIVE: The purpose of this study was to assess if easy to measure vaginal fluid biomarkers are predictive for low birth weight (LBW, <2500 g), very LBW (VLBW, <1500 g), spontaneous preterm at <37 weeks' gestation, and total preterm deliveries (at <37, <35, <32 weeks' gestation). STUDY DESIGN: Low and high cutoffs for vaginal fluid pH, sialidase, and prolidase activities were examined in a nested case-control study of 579 Danish women (from a study population of 2846 women) with samples collected at mean 17 weeks' gestation. One hundred sixteen LBW (17 VLBW), 117 preterm deliveries (85 spontaneous), and 418 normal term deliveries were analyzed. RESULTS: Vaginal pH >/=4.7 or pH >/=5 by itself was not associated with LBW or prematurity. Conversely, combination of pH >/=5 and high sialidase activity demonstrated OR 17 (CI 1.8-150) for LBW; OR 31 (CI 1.8-516) for VLBW; along with OR 18 (CI 1.6-204) for preterm at <35 weeks'; and OR 31 (CI 1.9-542) for preterm at <32 weeks' gestation. The combination of pH >/=5 and high prolidase activity demonstrated OR 13 (CI 1.3-122) for LBW; OR 33 (CI 2.0-553) for VLBW, as well as OR 9.2 (CI 0.6-150) for preterm at <35 weeks'; and OR 35 (CI 2.0-586) for preterm at <32 weeks' gestation. In this population, no woman having high sialidase and high prolidase activity had a term birth, or a baby weighting >/=2500 g at birth. CONCLUSION: In this Danish population, mid-gestation findings of vaginal fluid elevated pH with sialidase and/or prolidase were associated with LBW, VLBW, and early preterm at <35 or <32 weeks' gestation.

Adolescent↗

Tocolytic effect of a Rho-kinase inhibitor in a mouse model of lipopolysaccharide-induced preterm delivery.

OBJECTIVE: The small guanosine triphosphatase RhoA/Rho-kinase cascade has been implicated in uterine contraction. Our purpose was to evaluate the tocolytic effect of a Rho-kinase inhibitor, Y-27632, in lipopolysaccharide-induced preterm delivery in mice. STUDY DESIGN: We used an animal model of lipopolysaccharide-induced preterm delivery in C3H/HeN x B6D2F1 pregnant mice. Y-27632 was delivered continuously through an osmotic pump that was implanted into the peritoneal cavity 6 hours before lipopolysaccharide treatment. The primary outcome was the preterm delivery rate. To further study the possible involvement of this cascade in lipopolysaccharide-induced preterm delivery, we determined the effect of lipopolysaccharide and prostaglandin F2alpha on RhoA activation in mouse myometrial cells and uterine smooth muscle tissues. RESULTS: The rate of preterm delivery for lipopolysaccharide-treated animals was 94.4%. The administration of Y-27632 (1 or 10 mg/kg/d) significantly reduced the preterm delivery rate to 61.1% or 15.8%, respectively. The level of guanosine triphosphate-bound RhoA was increased after the addition of lipopolysaccharide or prostaglandin F2alpha. CONCLUSION: The RhoA/Rho-kinase cascade is involved in lipopolysaccharide-induced preterm delivery, which suggests that Rho-kinase could be used as a new therapeutic target for the prevention of preterm labor.

Amides↗

Fetal growth rates and the very preterm delivery of twins.

OBJECTIVE: Our objective was to determine whether slow fetal growth rates and twin growth patterns from 20 weeks' gestation to delivery are associated with very preterm delivery. STUDY DESIGN: Available charts were reviewed for twin pregnancies, delivered between 1979 and 2002, at 4 U.S. medical centers. The sample of 1612 pregnancies delivered at 28 week's gestation or greater and had at least 2 ultrasound evaluations of fetal size from 20 to 28 weeks or from 28 weeks to delivery for estimation of fetal growth rates (grams per week). Slow fetal growth (below the 10th percentile) was defined as less than 90 grams per week at 20-28 weeks and 168 g/week from 28 weeks to delivery. The main outcome measure was the timing of delivery. RESULTS: Of the women delivering twins, 5.3% delivered extremely preterm (28-30 weeks), 8.5% very preterm (31-32 weeks), and 40.1% preterm (33-36 weeks). Patterns of growth for the pair were highly associated with very preterm delivery. Compared with neither growing slowly (1.7%), 4.9% delivered very preterm if only 1 twin grew slowly. Very preterm was 14.6% (adjusted odds ratio 9.81; 95% confidence interval, 3.50-27.48) with both growing slowly from 28 weeks on and 20.0% (adjusted odds ratio 15.04; 95% confidence interval 5.13-44.11) with both growing slowly over both intervals. Survival analyses indicated that twins with normal growth in both intervals remained undelivered for a significantly longer number of days (P < .0001) than pairs in which one or both twins were growing slowly. CONCLUSION: Very preterm delivery of twins seems to be preceded by slowed or compromised fetal growth for the pair.

Diseases in Twins↗

Readily treatable reproductive tract infections and preterm birth among black women.

OBJECTIVE: This study sought to quantify the risks of preterm birth that are ascribable to potentially treatable reproductive tract infections among black women in Denver, Colorado. STUDY DESIGN: A secondary analysis was conducted of 4 prospective studies in Denver, Colorado, that included 1038 women who were enrolled at < 29 weeks of gestation and whose cases were followed through delivery. Rates of preterm birth, preterm labor, and preterm premature rupture of membranes were the primary outcomes that were examined. RESULTS: Bacterial vaginosis, infection with Chlamydia trachomatis, Trichomonas vaginalis, Mycoplasma hominis, Neisseria gonorrhoeae, and group B streptococcal colonization were more common among black women (P < .01) than among comparators. Preterm birth occurred more often among black women with infections that were being studied (20.4%), compared with uninfected black women (9.5%; relative risk, 2.2; 95% CI, 1.1-4.1). Up to 42% of preterm births among black women were attributable to the presence of bacterial vaginosis, T vaginalis, or C trachomatis alone or in combinations. The risk for preterm birth among infected black women who received Centers for Disease Control and Prevention recommended treatment was reduced significantly (relative risk, 0.16; 95% CI, 0.04-0.66). CONCLUSION: Black women have increased risks of prematurity that are associated with prevalent reproductive tract infections during pregnancy. Preterm birth among similar urban black women could be reduced by > 40% by the screening and treatment of common genitourinary tract infections in pregnancy.

Bacterial Infections↗

The use of progestational agents for preterm birth: lessons from a mouse model.

OBJECTIVE: On the basis of the recent Maternal Fetal Medicine Unit Networks clinical trial, the American College of Obstetricians and Gynecologists supports the administration of 17-alpha hydroxyprogesterone caproate to high-risk patients. Because inflammation/infection is believed to be a contributing factor in many cases of preterm birth, it is imperative to understand the effect of 17-alpha hydroxyprogesterone caproate treatment in this clinical situation. STUDY DESIGN: Using a mouse model of localized intrauterine inflammation, we investigated the ability of progestational agents to prevent preterm birth. On gestational day 15 (E15), dams were assigned randomly to treatment with 17-alpha hydroxyprogesterone caproate, medroxyprogesterone acetate, or vehicle before intrauterine infusion of lipopolysaccharide. All dams were monitored for morbidity and preterm birth. Three separate sets of experiments were performed to assess different outcomes at 6, 24, and 96 hours. At 6 and 24 hours, C-reactive protein, interleukin-6, and interleukin-10 levels were measured in maternal serum by enzyme-linked immunosorbent assay. RESULTS: Pretreatment with 17-alpha hydroxyprogesterone caproate or medroxyprogesterone acetate before intrauterine lipopolysaccharide treatment significantly decreased the preterm birth rate, compared with lipopolysaccharide treatment alone. Medroxyprogesterone acetate treatment was more effective than 17-alpha hydroxyprogesterone caproate treatment in the prevention of preterm birth and resulted in live pups at term. Treatment with 17-alpha hydroxyprogesterone caproate was associated with significant maternal morbidity. CONCLUSION: In the setting of intrauterine inflammation, progestational agents decrease the preterm birth rate but can result in maternal morbidity. 17-Alpha hydroxyprogesterone caproate should not be used in patients who are suspected of having subclinical infection and/or acute preterm labor. The mechanisms by which progestational agents inhibit preterm birth warrants further investigations so that the use of this drug to appropriate populations could be pursued without undue fetal or maternal harm.

17 alpha-Hydroxyprogesterone Caproate↗

Cardiovascular support in preterm infants.

BACKGROUND: Despite increasing investigation in the area of cardiovascular instability in preterm infants, huge gaps in knowledge remain. None of the current treatments for hypotension, including the use of inotropic agents, have been well studied in the preterm population, and data regarding safety and efficacy are lacking. Thus, the labeling information regarding the use of inotropes as therapeutic agents in this population is inadequate. OBJECTIVE: This article reviews the current deficiencies in knowledge with respect to measuring and achieving normal organ perfusion; summarizes the clinical, methodological, and ethical issues to consider when designing trials to evaluate medications for hemodynamic instability in the preterm neonate; and proposes 2 possible trial designs. Unanswered questions and potential obstacles for the systematic study of drugs to treat cardiovascular instability in preterm neonates are discussed. METHODS: The neonatal Cardiology Group was established in 2003 by the US Food and Drug Administration (FDA) and the National Institute of Child Health and Human Development (NICHD) as part of the Newborn Drug Development Initiative. The Cardiology Group conducted a number of teleconferences and one meeting to develop a document addressing gaps in knowledge regarding cardiovascular drugs commonly used in low-birth-weight neonates and possible approaches to investigate these drugs. This work was presented at a workshop cosponsored by the NICHD and the FDA held in March 2004 in Baltimore, Maryland. Information for this article was gathered during this initiative. RESULTS: To develop rational, evidence-based guidelines corroborated by robust scientific data for cardiovascular support in newborns, well-designed and adequately powered pharmacologic studies and clinical trials are needed to evaluate the safety and efficacy of inotropic agents and to determine the short- and long-term effects of these drugs. Trials investigating the currently available and novel therapies for cardiovascular instability in neonates will provide information that can be incorporated into product labeling and a scientific framework for cardiovascular management in critically ill neonates. The Cardiology Group identified and prioritized 2 conditions for investigation of therapeutic options for the management of neonatal cardiovascular instability: (1) cardiovascular instability in preterm neonates; and (2) cardiac dysfunction in neonates after cardiopulmonary bypass surgery. Key research questions in the area of cardiovascular instability in the preterm infant include determining optimal blood pressure (BP) in preterm infants; identifying better measures than BP to determine organ perfusion; optimizing hemodynamic treatments; and clarifying any associations between BP or therapy for low BP and mortality, intraventricular hemorrhage, periventricular leukomalacia, necrotizing enterocolitis, retinopathy of prematurity, and neurodevelopmental outcome. The Cardiology Group concluded that the study of inotropic agents in neonates using outcomes of importance to patients will require a complicated trial design to address the elements discussed. The group proposed 2 clinical trial designs: (1) a placebo-controlled trial with rescue therapy for symptomatic infants; and (2) a targeted BP trial. CONCLUSION: This summary is intended to stimulate and assist future research in the area of cardiovascular support for preterm infants.

Cardiotonic Agents↗

The accuracy of maternal anthropometry measurements as predictor for spontaneous preterm birth--a systematic review.

OBJECTIVE: To assess the accuracy with which antenatal maternal anthropometric measurements predict the risk spontaneous preterm birth. STUDY DESIGN: (1) DATA SOURCES: Studies were identified without language restrictions from MEDLINE, EMBASE, PASCAL, BIOSIS, the Cochrane Library, MEDION, National Research Register, SCISEARCH and Conference Papers, and manual searching of bibliographies of known primary and review articles, and contact with authors. (2) STUDY SELECTION AND DATA EXTRACTION: Studies were selected if they used antenatal maternal anthropometric features (pre-pregnancy weight, maternal pregnancy weight gain and maternal height) to predict spontaneous preterm birth. Two reviewers independently selected studies and extracted data on their characteristics, quality and accuracy. Accuracy data were used to form 2 x 2 contingency tables of the maternal anthropometric test results with spontaneous preterm birth as the reference standard. (3) DATA SYNTHESIS: Heterogeneity assessments were carried out to aid the decision regarding pooling of the accuracy results. Likelihood ratios for positive (LR+) and negative (LR-) test results were calculated, and summary estimates were produced in absence of heterogeneity of the accuracy results. RESULTS: There were eight primary accuracy articles that met the selection criteria, which included a total of 122,647 asymptomatic women. There were six studies on pre-pregnancy weight where five measured the body mass index (BMI) and one used an arbitrary measure. There were four studies on the adequacy of pregnancy weight gain and two studies on maternal height as a predictor for the risk of preterm birth. One article contributed three studies, while two articles provided two studies each. The commonest reference standard used was birth before 37 weeks' gestation. None of the studies fulfilled the ideal test accuracy study criteria. There was heterogeneity in the accuracy results of pre-pregnancy BMI but not in the adequacy of weight gain. All three maternal anthropometric features were poor predictors of preterm labour. Pre-pregnancy BMI is a poor predictor of preterm birth before 37 weeks' gestation (LR+ that ranged from 0.96 (95% confidence interval (CI) 0.66-1.40) to 1.75 (95% CI 1.33-2.31)) as are the adequacy of pregnancy weight gain (summary LR+ of 1.81, 95% CI 1.45-2.30) and short maternal height (LR+ of 1.79 (95% CI 1.27-2.52). CONCLUSION: Routine antenatal maternal anthropometric measurements are not useful in predicting the risk of preterm birth before 37 weeks' gestation. Further studies should address their use in combination with other test but need to use a more clinically appropriate reference standard of preterm birth, such as birth before 32-34 weeks' gestation, and improve on the quality of study design.

Anthropometry↗