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PubMed2003

[Study of the cervix of normal pregnancy and threatened preterm delivery using transvaginal sonography].

OBJECTIVE: To observe the changes of cervix in women between 16 and 35 weeks of gestation using transvaginal ultrasound and to determine the value of the cervix length in predicting preterm delivery among the women with threatened preterm labor. METHODS: Transvaginal sonography were performed in 154 normal single nulliparous pregnant women between 16 and 35 weeks of gestation and 58 women with threatened preterm labor but without premature rupture of membrane. RESULTS: (1) There is no definitely change in either cervical length or internal diameter of cervix among the pregnant women over the studied period. There was also no funneling to be observed. The mean cervical length is (36 +/- 5) mm, and the mean cervical internal diameter is (4 +/- 1) mm. (2) Eleven preterm deliveries occurred among the 58 pregnancy women with threatened preterm labor. The cervical length by sonography of 11 preterm deliveries was (18 +/- 6) mm, and was significant shorter than the women without preterm deliveries whose mean cervical length was (32 +/- 6) mm (P < 0.001). The cervical length of women who delivered pretermly was totally <or= 26 mm. (3) A cervical length of 26 mm (x-2 s) as the cutoff to predict the preterm delivery among women with the threatened preterm labor has a 100% of sensitivity, 81% of specificity, 55% positive predictive value and a 100% of negative predictive value. CONCLUSIONS: Cervical length by transvaginal sonography can be used to predict preterm delivery among the women with threatened preterm labor. Among women treated for preterm delivery, a cervical length of less than 26 mm indicated a high risk of preterm delivery, and intensive management is required.

Adult↗

PubMed1995

Implications of idiopathic preterm delivery for previous and subsequent pregnancies.

OBJECTIVE: To describe the relationship between pregnancy complications and fetal outcome in first and second pregnancies, focusing on idiopathic and indicated preterm birth of singleton infants in either pregnancy. METHODS: Included in the study were 13,967 women in Denmark who gave birth to their first singleton infant in 1982 and a second infant in 1982-1987. Information on pregnancy and birth was obtained by linking the National Medical Birth Register and the National Register of Hospital Discharges, based on personal identification numbers. RESULTS: The risk of a preterm second birth in women with idiopathic and indicated preterm first birth did not differ significantly (15.2 and 12.8%, respectively). However, women with idiopathic preterm birth in the first pregnancy tended to repeat idiopathic preterm birth twice as often as women with indicated preterm birth repeated indicated preterm birth (11.3 versus 6.4%). Adjustment by logistic regression analysis for other risk factors for preterm birth did not influence the relative risk (6.0 before 32 weeks and 4.8 for 32-36 weeks) of a second preterm birth after a first preterm birth. Women with idiopathic preterm delivery in their first and second pregnancies gave birth to infants with lower birth weight than in previous or subsequent pregnancies. Emergency cesarean delivery in a first term pregnancy was a risk factor for subsequent idiopathic preterm birth. CONCLUSION: Idiopathic preterm birth is associated with emergency cesarean delivery at term in previous pregnancies and infants with lower birth weight in previous and subsequent pregnancies.

Birth Weight↗

PubMed2006

The Maternal-Fetal Medicine Units Cesarean Registry: safety and efficacy of a trial of labor in preterm pregnancy after a prior cesarean delivery.

OBJECTIVE: This study was undertaken to compare success rates of vaginal birth after cesarean (VBAC) delivery, and uterine rupture as well as maternal/perinatal outcomes between women with preterm and term pregnancies undergoing trial of labor (TOL), and to compare maternal and neonatal morbidities in those women with preterm pregnancies undergoing a TOL versus repeat cesarean delivery without labor (RCD). STUDY DESIGN: Prospective 4-year observational study of women with a singleton gestation and a prior cesarean delivery at 19 academic centers. Clinical characteristics, maternal complications and VBAC delivery success for those with a preterm (24(0)-36(6) weeks) TOL, preterm RCD and term TOL (> or = 37 weeks) were analyzed. RESULTS: Among 3119 preterm pregnancies with prior cesarean delivery, 2338 (75%) underwent a TOL. 15,331 women undergoing TOL at term were also analyzed as a control group. TOL success rates for preterm and term pregnancies were similar (72.8% vs 73.3%, P = .64). Rates of uterine rupture (0.34% vs 0.74%, P = .03) and dehiscence (0.26% vs 0.67%, P = .02) were lower in preterm compared with term TOL. Thromboembolic disease, coagulopathy and transfusion were more common in women undergoing a preterm TOL than those at term. Among women undergoing a preterm TOL, rates of uterine dehiscence, coagulopathy, transfusion, and endometritis were similar to those having a preterm RCD. After controlling for gestational age at delivery and race, neonatal outcomes such as Neonatal Intensive Care Unit (NICU) admission, intraventricular hemorrhage, sepsis, and ventilatory support were similar in both groups except for a higher rate of respiratory distress syndrome in those delivered after a TOL. CONCLUSION: The likelihood of VBAC success after TOL in preterm pregnancies is comparable to term gestations, with a lower risk of uterine rupture. Perinatal outcomes are similar with preterm TOL and RCD. TOL should be considered as an option for women undergoing preterm delivery with a history of prior cesarean delivery.

Adult↗

PubMed1988

A prospective random trial of home uterine activity monitoring in pregnancies at increased risk of preterm labor. Part II.

Daily uterine activity monitoring has been reported to be helpful in improving the percentage of women with preterm labor eligible for tocolysis, with a corresponding decline in preterm delivery. The first year of our trial of ambulatory tocodynamometry in 157 women at risk of preterm labor did not reveal significant differences in rates of preterm labor and preterm delivery between two groups of women randomly assigned to receive preterm labor education, frequent (5 days/week) telephone contact, and self-palpation of uterine activity (group EP), or to preterm labor education, daily telephone contact, and the Term Guard ambulatory uterine activity monitor (group EM). We report results from the second year (n = 152), yielding a total study population of 309. Forty-three subjects were later excluded, producing 266 subjects who completed the study. Comparison of preterm labor and preterm delivery rates, mean birth weight, and gestational age at delivery revealed no significant differences between the groups for the second year or for the combined data from both years of the study. Interestingly, comparison of all subjects enrolled in year 1 with all those enrolled in year 2 reveals significant decreases in the rates of both preterm labor and preterm delivery. Frequent attention to symptoms and signs of preterm labor, and improved patient and physician education and awareness, may be responsible for this decline in preterm labor and delivery in high-risk pregnancies.

Female↗

PubMed1996

The preterm prediction study: a clinical risk assessment system.

OBJECTIVE: Our aims were to develop a risk assessment system for the prediction of spontaneous preterm delivery using clinical information available at 23 to 24 weeks' gestation and to determine the predictive value of such a system. STUDY DESIGN: A total of 2929 women were evaluated between 23 and 24 weeks' gestation at 10 centers. Demographic factors, socioeconomic status, home and work environment, drug and alcohol use, and medical history were evaluated. Information regarding symptoms, cultures, and treatments in the current pregnancy were ascertained. Anthropomorphic and cervical examinations were performed. Univariate analysis and multivariate logistic regression were performed in a random selection, constituting 85% of the study population. The derived risk assessment system was applied to the remaining 15% of the population to evaluate its validity. RESULTS: A total of 10.4% of women were delivered of preterm infants. The multivariate models for spontaneous preterm delivery were highly associated with spontaneous preterm delivery (p < 0.0001). A low body mass index (<19.8) and increasing Bishop scores were significantly associated with spontaneous preterm delivery in nulliparous and multiparous women. Black race, poor social environment, and work during pregnancy were associated with increased risk for nulliparous women. Prior obstetric outcome overshadowed socioeconomic risk factors in multiparous women with a twofold increase in the odds of spontaneous preterm delivery for each prior spontaneous preterm delivery. Current pregnancy symptoms, including vaginal bleeding, symptomatic contractions within 2 weeks, and acute or chronic lung disease were variably associated with spontaneous preterm delivery in nulliparous and multiparous women. When the system was applied to the remainder of the population, women defined to be at high risk for spontaneous preterm delivery (> or = 20% risk) carried a 3.8-fold (nulliparous women) and 3.3-fold (multiparous women) higher risk of spontaneous preterm delivery than those predicted to be at low risk. However, the risk assessment system identified a minority of women who had spontaneous preterm deliveries. The sensitivities were 24.2% and 18.2% and positive predictive values were 28.6% and 33.3%, respectively, for nulliparous and multiparous women. CONCLUSIONS: Although it is possible to develop a graded risk assessment system that includes factors that are highly associated with spontaneous preterm delivery in nulliparous and multiparous women, such a system does not identify most women who subsequently have a spontaneous preterm delivery. This system has investigational value as the basis for evaluating new technologies designed to identify at-risk subpopulations.

Black People↗

PubMed2000

Economic burden of hospitalizations for preterm labor in the United States.

OBJECTIVE: To determine patient factors associated with hospital care costs for preterm labor and to develop a clinically applicable cost model for evaluating economic consequences of interventions to reduce preterm-labor hospitalizations. METHODS: Maryland state hospital discharge data from 1993-1996 were used to identify hospitalizations for preterm labor without delivery and preterm labor with early delivery. Median regression was used to determine the association between patient factors and hospital care costs in Maryland and to develop a model to estimate hospital care costs nationally. National estimates of hospitalizations for preterm labor were from the 1994 National Hospital Discharge Survey. RESULTS: During the 4-year study period, there were 25,104 hospitalizations for preterm labor, undelivered, and preterm labor with early delivery in Maryland. Maternal comorbidity, antenatal procedures, types of insurance, and lengths of stay associated significantly with hospital costs for preterm labor. National costs for preterm labor, undelivered, were more than $360 million. Incremental costs for preterm labor with early delivery, compared with term delivery, ranged from $21 million to $191 million. Total expenditures for preterm-labor hospitalization for the United States were estimated in excess of $820 million. CONCLUSION: Hospitalizations for preterm labor comprise a substantial portion of maternal cost of perinatal care in the United States. Maternal comorbidity and procedures account for major differences in costs per admission. Strategies to reduce hospitalizations for preterm labor should focus on economic and clinical outcomes in evaluating their overall values.

Adult↗

PubMed1993

The epidemiology of preterm birth.

Secular trends in the prevalence of preterm birth and international comparisons of the rates of preterm birth are difficult to interpret because of differences, both formal and informal, in the registration of extremely preterm births. Accurate estimation of gestational age is another problem in the measurement of preterm birth. Preterm birth is heterogeneous in several ways. It is heterogeneous in terms of the extent to which the birth is preterm (20-27 weeks, 28-31 weeks or 32-36 weeks of gestation); in whether the birth was elective or spontaneous; and among spontaneous idiopathic preterm births, in whether there was preterm labour or premature rupture of the membranes. Case-control study designs taking account of these subgroups have been a recent feature of epidemiologic approaches. The classic social associations of preterm birth--low socioeconomic status, extremes of maternal age, primiparity, being unmarried--apply to extremely preterm and moderately preterm births as well as to the mildly preterm group. The strength of these associations is small compared with factors in the prior reproductive history and with medical and obstetric complications of the current pregnancy. Recent epidemiological research activities have focused on the ways in which risk factors such as physical workload, drugs and alcohol, lack of social support and infection might be mediating factors between sociodemographic status and preterm birth. As Eastman (1947) pointed out almost 50 years ago, 'only when the factors causing prematurity are clearly understood can any intelligent attempt at prevention be made'.

Adult↗

PubMed2003

Delivery of singleton preterm infants in New South Wales, 1990-1997.

OBJECTIVE: To examine trends in the maternal characteristics and delivery of singleton preterm infants in an Australian population. DESIGN: Population-based descriptive study. SETTING: New South Wales (NSW), Australia. POPULATION: The population included 37 500 singleton preterm births from 1 January 1990 to 31 December 1997. METHODS: Data were obtained from the NSW Midwives' Data Collection (MDC) and rates over time were calculated. Preterm birth by Caesarean section before the onset of labour or where labour was induced were considered to be medically indicated. MAIN OUTCOME MEASURES: Preterm rates, medically indicated preterm birth rates, mode of delivery andneonatal outcomes, and trends over time. RESULTS: Among singleton infants, there was no significant change over time in the rate of preterm birth (annual average 5.5%), preterm births that were medically indicated (annual average 29.3%) or neonatal outcomes of preterm births. The rate of indicated preterm birth varied by gestational age and was highest (39.7%) at 29-32 weeks' gestation. Instrumental preterm births declined over time from 9.5 to 7.8% with a shift from forceps to vacuum use and episiotomy rates declined from 19.7 to 14.8%. CONCLUSIONS: Increases in the reported overall preterm rate (singletons and multiples) were not due to increased delivery of singleton infants. Changes in the management of singleton preterm births were similar to changes observed in term births such as decreasing forceps and episiotomy usage. It may be to time to reassess whether Australian clinicians would be willing to randomise patients to clinical trials of the best method of delivery for preterm infants.

Adult↗

PubMed2000

Evidence for the participation of interstitial collagenase (matrix metalloproteinase 1) in preterm premature rupture of membranes.

OBJECTIVE: Rupture of membranes is thought to result from the effects of physical forces in localized areas of the membranes weakened by the degradation of structural collagens. Matrix metalloproteinases are enzymes that degrade extracellular matrix components and have been implicated in membrane rupture. The objective of this study was to determine whether spontaneous rupture of membranes is associated with a change in the amniotic fluid concentration of interstitial collagenase (matrix metalloproteinase 1 [MMP-1]), a major collagenase. STUDY DESIGN: A cross-sectional study was conducted to determine MMP-1 concentrations in amniotic fluid from 353 women in the following categories: (1) term with intact membranes not in labor and in labor, (2) preterm labor who delivered at term, (3) preterm labor who delivered preterm without microbial invasion of the amniotic cavity, (4) preterm labor who delivered preterm with microbial invasion of the amniotic cavity, (5) preterm premature rupture of membranes with and without microbial invasion of the amniotic cavity, (6) term premature rupture of membranes not in labor and in labor, and (7) mid trimester of pregnancy. Microbial invasion of the amniotic cavity was determined by an amniotic fluid culture positive for microorganisms. MMP-1 concentrations in amniotic fluid were determined by means of sensitive and specific immunoassays. RESULTS: (1) MMP-1 was detectable in 81.3% of amniotic fluid samples (287/353), and its concentrations increased with advancing gestational age (r = 0.4; P <.001). (2) Preterm premature rupture of membranes was associated with a significant increase in the median amniotic fluid concentration of MMP-1 (P =.02). (3) Women with term premature rupture of membranes had a significantly lower amniotic fluid MMP-1 concentration than those with intact membranes at term not in labor (P <.001). (4) Microbial invasion of the amniotic cavity in patients in preterm labor with intact membranes and in patients with preterm premature rupture of membranes was also associated with significant increases in the median amniotic fluid MMP-1 concentrations (P <.05 and P <.01, respectively). (5) Patients with preterm premature rupture of membranes and microbial invasion of the amniotic cavity had a significantly higher median amniotic fluid MMP-1 concentration than those with intact membranes and microbial invasion of the amniotic cavity (P =.01). (6) Neither term nor preterm parturition was associated with changes in amniotic fluid MMP-1 concentrations (P =.6 and P =.3, respectively). CONCLUSION: (1) Collagenase 1 (MMP-1) is a physiologic constituent of amniotic fluid. (2) Preterm premature rupture of membranes (in both the presence and absence of infection) was associated with an increase in the amniotic fluid MMP-1 concentrations. (3) Neither term nor preterm parturition was associated with a significant increase in the amniotic fluid concentration of MMP-1.

Amnion↗

PubMed2001

Occupational fatigue and preterm premature rupture of membranes. National Institute of Child Health and Human Development Maternal-Fetal Medicine, Units Network.

OBJECTIVE: The aim of this study was to prospectively determine the relationship between occupational fatigue and spontaneous preterm delivery segregated into the etiologically distinct categories of spontaneous preterm labor, preterm premature rupture of membranes, and indicated preterm delivery. STUDY DESIGN: A total of 2929 women with singleton pregnancies at 22 to 24 weeks' gestation were enrolled in a multicenter (10 sites) Preterm Prediction Study. Patients reported the number of hours worked per week and answered specific questions designed to determine the following 5 sources of occupational fatigue described by Mamelle et al: posture, work with industrial machines, physical exertion, mental stress, and environmental stress. Fatigue was quantified (0-5 index) according to the number of these sources positively reported. Simple and Mantel-Haenszel chi2 tests were used to test the univariate association and hypothesis of a linear trend between sources of occupational fatigue and spontaneous preterm delivery. Covariables were considered by multivariate logistic regression analysis. Women who did not work outside the home were considered separately from those who worked but did not report any sources of occupational fatigue. RESULTS: Each source of occupational fatigue was independently associated with a significantly increased risk of preterm premature rupture of membranes among nulliparous women but not among multiparous women. The risk of preterm premature rupture of membranes increased (P = .002) with an increasing number of sources of occupational fatigue-not working outside the home, 2.1%; working but not reporting fatigue, 3.7%; working with 1 source of fatigue, 3.2%; working with 2 sources of fatigue, 5.2%; working with 3 sources of fatigue, 5.1%; and working with 4 or 5 sources of fatigue, 7.4%. There was also a significant relationship (P = .01) between preterm premature rupture of membranes and an increasing number of hours worked per week among nulliparous women. Neither spontaneous preterm labor nor indicated preterm delivery was significantly associated with occupational fatigue among either nulliparous or multiparous women. CONCLUSION: The occupational fatigue index of Mamelle et al discriminated a group of nulliparous women at increased risk for preterm premature rupture of membranes. The relationship between preterm premature rupture of membranes and occupational fatigue or hours worked may provide guidelines according to which nulliparous women and their employers can be advised.

Adolescent↗

PubMed2002

Fetal plasma MMP-9 concentrations are elevated in preterm premature rupture of the membranes.

OBJECTIVE: The objective of this study was to determine whether the concentrations of matrix metalloproteinase-9 (MMP-9) in the fetal (fetal plasma and amniotic fluid) and maternal compartments (plasma) are different in patients presenting with preterm premature rupture of membranes (PROM) than in those with preterm labor and intact membranes. STUDY DESIGN: Fetal plasma MMP-9, interleukin-1beta (IL-1beta), IL-6, soluble tumor necrosis factor receptors 1 (sTNF-R1) and 2 (sTNF-R2) were measured in fetuses with preterm labor and intact membranes (n = 96) and preterm PROM (n = 43). The concentrations of analytes were determined with sensitive and specific immunoassays. A P value <.05 was considered significant. RESULTS: (1) The median fetal plasma MMP-9 concentration was significantly higher in fetuses with preterm PROM than in those with preterm labor (P =.035). (2) In contrast, fetal plasma IL-1beta, sTNF-R1, and sTNF-R2 were significantly higher in patients with preterm labor than in those with preterm PROM (IL-1beta, P =.01; sTNF-R1, P =.003; and sTNF-R2, P =.02). (3) The median amniotic fluid concentration of MMP-9 was higher in patients with preterm PROM than in those with preterm labor (P <.001). CONCLUSION: Fetuses with preterm PROM have increased concentrations of an enzyme (MMP-9) implicated in the mechanism of membrane rupture but lower concentrations of IL-1beta, sTNF-R1, and sTNF-R2 than fetuses with preterm labor and intact membranes. A role for the fetus in the genesis of preterm PROM deserves consideration.

Adolescent↗

PubMed2004

Fetal cardiac dysfunction in preterm premature rupture of membranes.

BACKGROUND: Preterm premature rupture of membranes (PROM) is associated with one-third of preterm births. In about 50% of preterm PROM cases, the fetuses will elicit a fetal inflammatory response syndrome (FIRS). FIRS is associated with the impending onset of preterm labor, periventricular leukomalacia, neonatal sepsis, and long-term handicap, including the development of bronchopulmonary dysplasia and cerebral palsy. The fetal myocardium is a potential target organ of proinflammatory cytokines released during FIRS. The objective of this study was to determine whether preterm PROM is associated with functional changes in the fetal heart, as determined by fetal echocardiography. METHODS: A retrospective study was conducted to assess the diastolic function of fetuses with preterm PROM with documented microbial invasion of the amniotic cavity (n = 25), preterm PROM without microbial invasion of the amniotic cavity (n = 42), and fetuses from normal pregnancies (control group = 150). Pregnancies with multiple gestation, fetal distress, fetuses that were small for gestational age, and major congenital anomalies were excluded. Fetal echocardiography studies were performed with two-dimensional ultrasound, color Doppler imaging and pulsed Doppler ultrasound. Non-parametric statistics were used for comparisons. A p value of < 0.05 was considered significant. RESULTS: The prevalence of positive amniotic fluid cultures for micro-organisms in patients with preterm PROM was 35.8% (24/67). Ureaplasma urealyticum was the most frequent isolate, either alone (41.7%; 10/24) or with other micro-organisms (29.2%; 7/24). Fetuses with preterm PROM had a higher delta early diastolic filling/atrial contraction (E/A) peak velocity ratio, a higher delta E/A velocity-time integral (VTI) ratio, a lower delta A peak velocity, a lower delta A VTI, and a lower A VTI/total VTI ratio in the mitral valve compared to those with uncomplicated pregnancies. The delta E/A peak velocity ratio was significantly higher and the delta A VTI significantly lower in fetuses with preterm PROM and microbial invasion of the amniotic cavity than in those with preterm PROM without microbial invasion of the amniotic cavity. CONCLUSIONS: Preterm PROM is associated with changes in fetal cardiac function consistent with increased left ventricular compliance. These observations were also noted in fetuses with microbial invasion of the amniotic cavity. Our findings suggest that fetal cardiac function is altered in preterm PROM and, in particular, in cases with intra-amniotic infection.

Echocardiography↗

PubMed2003

Antimicrobial peptides in amniotic fluid: defensins, calprotectin and bacterial/permeability-increasing protein in patients with microbial invasion of the amniotic cavity, intra-amniotic inflammation, preterm labor and premature rupture of membranes.

OBJECTIVE: Neutrophil defensins (HNP 1-3), bactericidal/permeability-increasing protein (BPI) and calprotectin (MRP8/14) are antimicrobial peptides stored in leukocytes that act as effector molecules of the innate immune response. The purpose of this study was to determine whether parturition, premature rupture of the membranes (PROM) and microbial invasion of the amniotic cavity (MIAC) are associated with changes in amniotic fluid concentrations of these antimicrobial peptides. STUDY DESIGN: Amniotic fluid was retrieved by amniocentesis from 333 patients in the following groups: group 1, mid-trimester with a subsequent normal pregnancy outcome (n = 84); group 2, preterm labor and intact membranes without MIAC who delivered at term (n = 36), or prematurely (n = 52) and preterm labor with MIAC (n = 26); group 3, preterm PROM with (n = 26) and without (n = 26) MIAC; and group 4, term with intact membranes in the absence of MIAC, in labor (n = 52) and not in labor (n = 31). The concentrations of HNP 1-3, BPI and calprotectin in amniotic fluid were determined by specific and sensitive immunoassays. Placentae of patients in both preterm labor with intact membranes and preterm PROM groups who delivered within 72 h of amniocentesis were examined. Non-parametric statistics, receiver-operating characteristic (ROC) curves and Cox regression models were used for analysis. A p value of < 0.05 was considered statistically significant. RESULTS: Intra-amniotic infection was associated with a significant increase in amniotic fluid concentrations of immunoreactive HNP 1-3, BPI and calprotectin in both women with preterm labor and intact membranes, and women with preterm PROM. Preterm PROM was associated with a significant increase in amniotic fluid concentrations of immunoreactive HNP 1-3, BPI and calprotectin. Preterm parturition was associated with a significant increase in amniotic fluid concentrations of immunoreactive HNP 1-3, BPI and calprotectin, while parturition at term was associated with a significant increase in amniotic fluid concentrations of immunoreactive HNP 1-3. Among patients with preterm labor and intact membranes, elevation of amniotic fluid HNP 1-3, BPI and calprotectin concentrations was associated with intra-amniotic inflammation, histological chorioamnionitis and a shorter interval to delivery. CONCLUSION: MIAC, preterm parturition and preterm PROM are associated with increased amniotic fluid concentrations of immunoreactive HNP 1-3, BPI and calprotectin. Moreover, elevated amniotic fluid concentrations of BPI, immunoreactive HNP 1-3 and calprotectin are associated with intra-amniotic inflammation, histological chorioamnionitis and shorter amniocentesis-to-delivery interval in patients presenting with preterm labor with intact membranes.

Amnion↗

PubMed1992

Cigarettes, coffee, and preterm premature rupture of the membranes.

Premature (prior to 37 completed weeks of gestation) rupture of the membranes (preterm PROM) is one of the most common underlying causes of preterm delivery. However, there have been few epidemiologic studies of this obstetric complication. The authors studied the relation of maternal cigarette smoking and coffee consumption to both preterm PROM and spontaneous preterm labor not complicated by premature rupture of the membranes (preterm NONPROM) in a large cross-sectional data base. The 307 preterm PROM and 488 preterm NONPROM cases who delivered during 1977-1980 at the Boston Hospital for Women were compared with 2,252 randomly selected women who delivered at term at that institution. Multiple logistic regression techniques were used to derive maximum likelihood estimates of adjusted odds ratios (OR) and 95% confidence intervals (CI). After confounders had been adjusted for, the relative risk of preterm PROM for women who reported ever having smoked during pregnancy, as compared with nonsmokers, was 1.6 (95% CI 1.1-2.4). However, no gradient between the number of cigarettes smoked per day and the risk of preterm PROM was observed. Similar results were observed for preterm NONPROM. Women who consumed three or more cups of coffee daily during the first trimester had a 2.2-fold greater risk of preterm PROM than did women who drank two or fewer cups (95% CI 1.5-3.3). Among coffee drinkers, there was some evidence of a linear trend in the risk of preterm PROM as coffee consumption increased. Consumption of three or more cups of coffee per day was less strongly associated with the occurrence of preterm NONPROM (adjusted OR = 1.4, 95% CI 1.0-1.9).

Adolescent↗

PubMed2005

Estimated effect of 17 alpha-hydroxyprogesterone caproate on preterm birth in the United States.

OBJECTIVE: A multicenter, randomized placebo-controlled trial among women with singleton pregnancies and a history of spontaneous preterm birth found that weekly injections of 17 alpha-hydroxyprogesterone caproate (17P), initiated between 16 and 20 weeks of gestation, reduced preterm birth by 33%. The current study estimated both preterm birth recurrence and the potential reduction in the national preterm birth rate. METHODS: Using 2002 national birth certificate data, augmented by vital statistics from 2 states, we estimated the number of singleton births delivered to women eligible for 17P through both a history of spontaneous preterm birth and prenatal care onset within the first 4 months of pregnancy. The number and rate of recurrent spontaneous preterm births were estimated. To predict effect, the reported 33% reduction in spontaneous preterm birth attributed to 17P therapy was applied to these estimates. RESULTS: In 2002, approximately 30,000 recurrent preterm births occurred to women eligible for 17P, having had a recurrent preterm birth rate of 22.5%. If 17P therapy were delivered to these women, nearly 10,000 spontaneous preterm births would have been prevented, thereby reducing the overall United States preterm birth rate by approximately 2%, from 12.1% to 11.8% (P < .001), with higher reductions in targeted groups of eligible pregnant women. CONCLUSION: Use of 17P could reduce preterm birth among eligible women, but would likely have a modest effect on the national preterm birth rate. Additional research is urgently needed to identify other populations who might benefit from 17P, evaluate new methods for early detection of women at risk, and develop additional prevention strategies. LEVEL OF EVIDENCE: III.

17 alpha-Hydroxyprogesterone Caproate↗

PubMed2006

Bacterial vaginosis in a cohort of Danish pregnant women: prevalence and relationship with preterm delivery, low birthweight and perinatal infections.

OBJECTIVE: To determine the prevalence of bacterial vaginosis (BV) in the second trimester of pregnancy in a Danish population using the Schmidt criteria and to examine whether BV was associated with subsequent preterm delivery, low birthweight or perinatal infections. DESIGN: Prospective cohort study. SETTING: Department of Obstetrics and Gynaecology at a University Hospital, Denmark. POPULATION: Three thousand five hundred and forty pregnant women aged 18 years or more. METHODS: A smear from the vagina was obtained from all women, air-dried and stored for subsequent diagnosis of BV. After rehydration with isotonic saline, the smear was examined in a phase-contrast microscope at 400x, and the numbers of lactobacilli morphotypes and small bacterial morphotypes were counted. A score for BV was calculated according to the method described by Schmidt. The outcome of pregnancy from 20 weeks of gestation was examined in the 3262 singleton pregnant women who were included in this study before 20 weeks of gestation. The relationship between BV and adverse outcome of pregnancy was examined by univariate and multivariate analyses. MAIN OUTCOME MEASURES: Prevalence of BV, preterm delivery (<37 weeks), low birthweight (<2500 g), preterm delivery of a low-birthweight infant and clinical chorioamnionitis. RESULTS: The prevalence of BV was 16%, and the rate of preterm delivery was 5.2% in the study population of 3262 singleton pregnant women who were included before 20 weeks of gestation. Mean birthweight was significantly lower in infants of women with BV than in infants of women without BV (3408 versus 3511 g, P < 0.01). Univariate analyses showed that BV was marginally associated with preterm delivery but significantly associated with low birthweight, preterm delivery of a low birthweight infant, indicated preterm delivery and clinical chorioamnionitis. Multivariate analyses, which adjusted for previous miscarriage, previous preterm delivery, previous conisation, smoking, gestational diabetes, fetal death and preterm premature rupture of membranes, showed that BV was significantly associated with low birthweight (OR 1.95, 95% CI 1.3-2.9), preterm delivery of a low-birthweight infant (OR 2.5, 95% CI 1.6-3.9), indicated preterm delivery (OR 2.4, 95% CI 1.4-4.1) and clinical chorioamnionitis (OR 2.7, 95% CI 1.4-5.1). CONCLUSIONS: The prevalence of BV determined using the Schmidt criteria in the early second trimester of pregnancy was similar to that found in similar studies. The presence of BV before 20 weeks of gestation was an independent risk factor for delivery of an infant with low birthweight, preterm delivery of a low-birthweight infant, indicated preterm delivery and clinical chorioamnionitis.

Cohort Studies↗

PubMed2006

Maternal birthplace and breastfeeding initiation among term and preterm infants: a statewide assessment for Massachusetts.

OBJECTIVES: Among premature infants, formula feeding increases the risk for necrotizing enterocolitis, delayed brainstem maturation, decreased scoring on cognitive and developmental tests, and delayed visual development. With this in mind, many interventions are designed to increase breast milk consumption in preterm infants. Breastfeeding initiation rates among US premature infants are not collected nationally, however, and published data on breastfeeding rates in this population are limited. In addition, national surveys calculate breastfeeding rates among term infants according to maternal race/ethnicity, but maternal birthplace is not recorded. This is likely to be important, because breastfeeding is the cultural norm in the countries of origin for many non-US-born US residents. Massachusetts has a diverse racial/ethnic population, including many non-US-born women. The goals of this study were to compare breastfeeding initiation rates among preterm and term infants in Massachusetts in 2002 and to determine the effect of maternal race/ethnicity and birthplace on breastfeeding initiation rates among term and preterm infants. METHODS: Massachusetts Community Health Information Profile, an online public health database that was created by the Massachusetts Department of Public Health, includes breastfeeding initiation data that are obtained from the electronic birth certificate, which we used to compare breastfeeding rates among preterm and term infants. Birth-linked demographics and data that also were accessed were maternal age, race/ethnicity, birthplace, and health insurance (public or private) as an indicator of socioeconomic status and infant's gestational age. We assessed the association between breastfeeding initiation and maternal birthplace, as well as race/ethnicity and the other potential confounders, using logistic regression. RESULTS: There were 80,624 births in Massachusetts in 2002, and 8.2% (6611) of newborns had a gestational age <37 weeks. The state's overall breastfeeding initiation rate was 74.6%. We excluded records of mothers who were younger than 15 years and older than 39 years, nonsingleton births, infants with a gestational age <24 weeks and >42 weeks, and records with missing data. Of the total births in Massachusetts, 67,884 (84%) met inclusion criteria for this study. Breastfeeding initiation rates were lowest among preterm infants of the youngest gestational ages. Breastfeeding initiation was 76.8% among term infants born at 37 to 42 weeks, 70.1% among infants born at 32 to 36 weeks, and 62.9% among infants born at 24 to 31 weeks. In univariate analysis, among preterm infants, a lower proportion of US-born black, Asian, and Hispanic mothers initiated breastfeeding than US-born white mothers; non-US-born black and non-US-born Hispanic mothers had the highest breastfeeding initiation rates. Among term infants, US-born black mothers had the lowest initiation rates, and non-US-born black and non-US-born Hispanic mothers had the highest. In multivariate logistic regression, however, after controlling for mother's age, race, birthplace, and insurance, US-born white mothers were least likely to breastfeed either term or preterm infants when compared with any other racial/ethnic group, including US-born black mothers. The likelihood that non-US-born Hispanic mothers would breastfeed was almost 8 times greater than that for US-born white mothers for a preterm infant and almost 10 times greater for a term infant. In multivariate logistic regression analysis stratified by gestational age for both preterm and term infants, older mothers and mothers with private health insurance were most likely to breastfeed. CONCLUSIONS: In Massachusetts, preterm infants were less likely to receive breast milk than term infants, and the likelihood of receiving breast milk was lowest among the youngest preterm infants. In multivariate logistic regression, mothers who were born outside the United States were more likely than US-born mothers to breastfeed either term or preterm infants in all racial and ethnic groups. In an unexpected finding, US-born white mothers were less likely to breastfeed term or preterm infants than US-born black mothers or mothers of any other racial or ethnic group.

Adolescent↗

PubMed1993

A review of risk scoring for preterm birth.

Risk scoring is a quantitative method used to screen populations to identify persons at increased risk of developing a specific adverse health outcome. Risk scoring for preterm birth has taken the form of a simple additive score with risk factors based on clinical experience to sophisticated multivariable risk models using a large number of factors from several domains. It appears that our attempts at defining an effective risk scoring method for preterm birth have been unsuccessful. The positive predictive values (the percent of women defined as high risk that actually go on to have a preterm birth) have been relatively low (20% to 30%) and vary depending on the population studied. Several difficulties with risk scoring for preterm birth are identified. The biggest limitation of current efforts at screening for preterm birth is our ignorance of the causes of preterm birth. The role of recently defined risk factors, of the potential for synergistic relationship between risk factors, and of physician or hospital factors needs to be evaluated. Epidemiologic evidence is suggestive that preterm birth can be subclassified into preterm labor, preterm rupture of the membranes, and medically induced preterm births; however, substantial problems with misclassification, detection bias, and questionable biologic feasibility argue that these subgroups need to be validated before they can be used with confidence. Careful attention should also be paid to the statistical and methodologic limitations of risk scoring. Unless a single risk factor for a disease outcome has a relative risk over 5 and is very prevalent in the population (more than 25%), most of the disease cases will not have the risk factor. It may be unrealistic, however, to think that a single risk factor will adequately define women at high risk for preterm birth. Therefore in the future, if several lesser risk factors can be identified, multivariate modeling may prove useful in defining a valid high-risk group. In addition, attention should be paid to ensure that the risk factor assessment tools obtain accurate information and are easily reproducible among different health care providers. The reduction of preterm birth in France that occurred over a decade was accompanied by radical social changes in the ways in which the population and government perceived pregnancy and childbirth. In addition to universal access to prenatal care, population-based social changes to liberalize pregnancy leave policies and a commitment to supporting women during pregnancy were the focus of the government's commitment to reducing preterm birth.(ABSTRACT TRUNCATED AT 400 WORDS)

Discriminant Analysis↗