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PubMed2005

Decreased serum level of macrophage inflammatory chemokine-3beta/CCL19 in preterm labor and delivery.

OBJECTIVE: Chemokines are small soluble molecules which mediate leukocyte migration and may be involved in the pathophysiology of preterm labor. We aimed to determine if serum concentrations of selected chemokines are changed in preterm labor and delivery. STUDY DESIGN: A novel array-based enzyme-linked immunosorbent assay was used to quantitate serum levels of nine chemokines from a single sample: MDC/CCL22, TARC/CCL17, ITAC/CXCL11, I-309/CCL1, IP-10/CXCL10, MIP-1alpha/CCL3, -1beta/CCL4, -3alpha/CCL20 and -3beta/CCL19. Women in preterm labor who delivered (n = 17), women at preterm pregnancy not in labor (n = 13) and women in labor at term (n = 8) participated. RESULTS: In the preterm delivery group of patients, the MIP-3beta/CCL19 concentration was in mean (+/-S.D.) 70.4+/-31.7 pg/mL, which was significantly lower than that in preterm gravidas not in labor of 123+/-34 pg/mL (p < 0.001) and those in labor at term of 118+/-25.6 pg/mL (p < 0.01). The other measured chemokines did not differ significantly. CONCLUSIONS: Of a small number of examined chemokines, we were able to show that one of them, MIP-3beta/CCL19 was significantly lower in women with preterm labor and delivery. Whether or not this chemokine has a potential as biochemical marker of preterm delivery remains to be determined.

Adult↗

PubMed2006

Are early grammatical and phonological working memory abilities affected by preterm birth?

UNLABELLED: There have been few investigations of the effects of very immature preterm birth on specific linguistic competencies and phonological working memory at preschool age. Study 1 aimed to investigate early grammatical abilities in very immature healthy preterms, taking into account their cognitive development and biological and social factors. The linguistic and cognitive differences found between preterms and fullterms led to investigate in Study 2 the role of phonological working memory on preterms' grammatical development. Very immature preterm birth resulted to affect grammatical, cognitive and phonological working memory abilities until 3.5 years leading to persisting difficulties in comparison with fullterms, albeit not severe deficits. Tight relations between phonological working memory and grammar were found both in preterms and fullterms, that highlights the reciprocal support of these abilities in development. A partial compensatory effect by the maternal level of education on preterms' grammatical and cognitive abilities was also found. LEARNING OUTCOMES: The reader will become familiar with the relations between grammatical and phonological working memory abilities in typical and preterm 3.5-year-old children.

Articulation Disorders↗

PubMed2006

Is contralateral exploration necessary in preterm infants with unilateral inguinal hernia?

PURPOSE: Contralateral inguinal exploration has been the preferred approach to preterm infants with unilateral inguinal hernia. There is no literature evidence to justify this. The aim of this prospective study is to analyze the incidence and to determine any risk factors for the development of contralateral metachronous hernia (MH) in the preterm when compared with term infants. METHODS: Preterm and term infants with unilateral inguinal hernia younger than 6 months who underwent surgery were included. Those infants who subsequently developed MH were analyzed. RESULTS: Two hundred sixty-six patients met the inclusion criteria. One hundred five were preterm and 161 were term. Ten preterm (10.31%) and 9 term infants (5.92%) presented subsequently with MH (P =.18). All but 1 were male. There was no relation between the side of hernia, presentation with incarceration, age at surgery, sex of the patient, and the development of MH. However, a trend toward a higher incidence of MH in very low birth weight and early gestational age preterms was noted. CONCLUSION: There is no significant difference between the occurrence of MH in preterm when compared with term infants. Routine contralateral exploration in preterm infants with its associated risks is therefore not justified in unilateral hernia.

Female↗

PubMed2006

The effect of preterm birth on neonatal cerebral vasculature studied with magnetic resonance angiography at 3 Tesla.

Preterm birth is associated with a high incidence of neurodevelopmental deficits. Magnetic resonance imaging (MRI) has proved to be a valuable tool for monitoring development in the preterm brain. We used a dedicated time-of-flight (TOF) magnetic resonance angiography (MRA) protocol at 3 Tesla (3T) optimized to assess morphological characteristics of the neonatal cerebral vessels associated with preterm birth in a sample of 37 infants. We found statistically significant decreased tortuosity in all proximal segments of the cerebral vasculature (anterior, middle and posterior cerebral arteries) in the preterm infants imaged at term equivalent age compared to the term born infants, with no differences in vessel diameter between the two groups. This distinct phenotype of decreased tortuosity was shown to persist until 18 months of age in longitudinal MRA studies in infants born preterm, suggesting that this is not a delay in maturation. Biparietal head diameter measurements were significantly smaller in the preterm at term infants and were inversely correlated with middle cerebral artery tortuosity measurements in both the term born and the preterm at term infants. To our knowledge, this is the first systematic MRA study on the effect of preterm delivery on neonatal cerebral vasculature. Our intention is to build on the findings of this study by combining the data with other measurements of brain growth and vascular haemodynamics to understand more about the interdependence of vessel and brain development and their relationship to prematurity.

Adult↗

PubMed1991

Epidemiologic characteristics of preterm delivery: etiologic heterogeneity.

Preterm delivery (less than 37 weeks completed gestation) is known to result from diverse etiologic pathways, which can be grouped into idiopathic preterm labor, preterm premature rupture of the membranes, and medical complications. Data from publications providing sufficient detail to subdivide preterm delivery cases into these groups were tabulated. In spite of inconsistent terminology and incomplete reporting, patterns were identified. Black women have a markedly higher risk of preterm delivery, which is especially pronounced for preterm premature rupture of the membranes. Idiopathic preterm labor is predominant in lower-risk, white populations. These observations encourage consideration of subcategories of preterm delivery in studies of etiology and prevention.

Abortion, Induced↗

PubMed1994

Effect of metronidazole in patients with preterm birth in preceding pregnancy and bacterial vaginosis: a placebo-controlled, double-blind study.

OBJECTIVE: Our purpose was to determine whether treatment of bacterial vaginosis with metronidazole in patients with preterm delivery in the penultimate pregnancy from preterm labor or premature rupture of membranes reduces the risk of subsequent preterm birth. STUDY DESIGN: From January 1989 to June 1992 patients with a singleton gestation between 13 and 20 weeks and a history of preterm birth in the preceding pregnancy from either idiopathic preterm labor or premature rupture of membranes were screened for bacterial vaginosis. Those with a positive screen were randomized to receive 250 mg of metronidazole three times a day for 7 days or placebo in a double-blind design. Data were analyzed with Student t and chi 2 tests, and differences considered significant at p < 0.05. RESULTS: Of 94 eligible patients, 80 were enrolled and completed the study, of which 44 received metronidazole. Both groups were comparable in number of entry variables. Compared with the placebo group, patients in the metronidazole group had significantly fewer hospital admissions for preterm labor, 12 (27%) versus 28 (78%); preterm births, eight (18%) versus 16 (39%); births of infants weighing < 2500 gm, six (14%) versus 12 (33%); and premature rupture of membranes, two (5%) versus 12 (33%). CONCLUSION: Treatment of bacterial vaginosis with metronidazole was effective in reducing preterm births in patients with a history of prematurity in the preceding pregnancy.

Adult↗

PubMed1996

The value of fetal fibronectin in cervical and vaginal secretions and of ultrasonographic examination of the uterine cervix in predicting premature delivery for patients with preterm labor and intact membranes.

OBJECTIVE: We compared the diagnostic performances of fetal fibronectin assay of cervical and vaginal secretions and of transvaginal ultrasonographic evaluation of the uterine cervix in the prediction of preterm delivery of patients presenting with preterm labor and intact membranes. STUDY DESIGN: One hundred eight patients admitted to the hospital for preterm labor and with intact membranes underwent assay of fibronectin in the cervical and vaginal secretions and transvaginal ultrasonographic evaluation of the uterine cervix. The ultrasonographic parameters evaluated were cervical length, presence of funneling, and cervical index ([Funnel length + 1]/Cervical length). Outcome measures were occurrence of preterm delivery, defined as birth before the thirty-seventh week of gestation, and the admission-to-delivery interval. RESULTS: Forty-seven patients (43.5%) were delivered preterm. Receiver characteristic curve analysis showed that a level of fetal fibronectin in cervical secretions > or = 60 ng/ml had the highest diagnostic performance in predicting preterm delivery (sensitivity 80.9%, specificity 83.6%). Multiple stepwise logistic regression analysis indicated that the cervical index significantly improved the prediction of preterm delivery achieved by the fetal fibronectin assay. In patients with cervical secretion fibronectin levels > or = 60 ng/ml, survival analysis showed a shorter admission-to-delivery interval in the presence of an abnormal cervical index (p < or = 0.001). CONCLUSIONS: The assay of fetal fibronectin in cervical secretions is more accurate than ultrasonographic evaluation of the uterine cervix in the prediction of preterm delivery. Combined use of the fetal fibronectin assay and the cervical index improves the diagnostic efficiency and allows prediction of the admission-to-delivery interval, identifying a subgroup of patients who may require aggressive treatment.

Adult↗

PubMed1996

Can a "snapshot" sagittal view of the cervix by transvaginal ultrasonography predict active preterm labor?

OBJECTIVE: Our purpose was to test the hypothesis that wedging of the cervical internal os determined by transvaginal ultrasonography is associated with premature labor and delivery. STUDY DESIGN: Seventy patients admitted to the hospital for threatened preterm labor were evaluated by transvaginal ultrasonography before institution of therapy. Bivariate and logistic regression analyses were performed to determine the variables that made a significant contribution to the prediction of preterm delivery. RESULTS: Preterm delivery was significantly associated with the presence of cervical wedging, as noted on cervical scan, and with short cervical length. A history of previous preterm delivery was of marginal significance as a predictor of preterm delivery (p=0.09). Preterm delivery was not significantly correlated with age, previous voluntary termination of pregnancy, gestational age at the time of study, previous normal spontaneous vaginal delivery, or tocolytic therapy. Use of wedging as a diagnostic test for the prediction of preterm delivery yielded a sensitivity of 100% a specificity of 74.5%, a positive predictive value of 59.4%, and a negative predictive value of 100%. CONCLUSION: The presence of wedging and shorter cervical length was suggestive of true preterm labor requiring aggressive management. A transvaginal ultrasonographic "snapshot" view of the cervix seems to be a more reliable method to evaluate the cervix in patients with threatened premature labor than are uterine contractions alone.

Adult↗

PubMed1996

Group B Streptococcus and preterm premature rupture of membranes: a randomized, double-blind clinical trial of antepartum ampicillin.

OBJECTIVE: Our purpose was to determine whether ampicillin prolongs the latency period after preterm premature rupture of membranes in patients colonized with group B Streptococcus. STUDY DESIGN: Sixty patients presenting at < or = 35 weeks' gestation with preterm premature rupture of membranes were included in the study. Cervical, vaginal, and perianal cultures for group B premature rupture were obtained. The participants then were randomized to receive either ampicillin or placebo intravenously for 24 hours and then orally until hospital discharge or delivery. All patients were treated without the use of tocolytic drugs. The chi(2) test, Fisher exact test, Student t test, and Wilcoxon signed-rank test were used for statistical analysis when appropriate. RESULTS: Fifteen patients had cultures positive for group B Streptococcus. Patients with cultures positive for group B Streptococcus who received ampicillin (n = 8) were more likely not to have been delivered of their infants 48 hours after preterm premature rupture of membranes than patients who received placebo (n = 7), a statistically significant difference (100% vs 43%; p = 0.01; relative risk 2.3; 95% confidence interval 1.2 to 4.5). Seven days after preterm premature rupture of membranes, however, there was no significant difference in percentage of patients with cultures positive for group B Streptococcus who remained undelivered (63% vs 29%; p = 0.19; relative risk, 2.2; 95% confidence interval 0.7 to 7.1). Among patients with cultures negative for group B Streptococcus, there was a trend for patients who received ampicillin to remain undelivered 48 hours after preterm premature rupture of membranes compared with those who received placebo, but the difference was not statistically significant (87% vs 64%; p = 0.07; relative risk, 1.4; 95% confidence interval 1.0 to 1.9). There also was no difference in percentage of patients with cultures negative for group B Streptococcus who remained undelivered 7 days after preterm premature rupture of membranes 39% vs 27%; p = 0.40; relative risk, 1.4; 95% confidence interval 0.61 to 3.3). There were no differences between the treatment and placebo arms of the group B Streptococcus positive and negative cohorts in incidence of cesarean section, chorioamnionitis, postpartum endometritis, or neonatal infectious morbidity. CONCLUSION: Use of antibiotics increases the percentage of patients with cultures positive for group B Streptococcus who remain undelivered 48 hours after preterm premature rupture of membranes. Antibiotic therapy may provide a window of opportunity for maternal treatment with corticosteroids to decrease the risk for neonatal morbidity among these preterm gestations.

Adult↗

PubMed1999

Impact of the fetal fibronectin assay on admissions for preterm labor.

OBJECTIVE: The aim of the study was to determine whether use of the fetal fibronectin assay would decrease the number of admissions to labor and delivery for diagnosis and treatment of preterm labor. STUDY DESIGN: A prospective cohort design was used to compare preterm labor admissions during a 12-month period of fetal fibronectin assay use (study) against a baseline period before fetal fibronectin assay was implemented as standard protocol. Patients coming to the physician's office or hospital with signs and symptoms of preterm labor had a sample obtained for fetal fibronectin assay per labeling criteria. Comparisons were made with the Mann-Whitney U test, independent Student t test, chi2 test, and Fisher exact test. P <.05 was considered significant. RESULTS: There was no difference noted in the number of deliveries between the baseline and study years. During the study year 251 of 330 patients evaluated for preterm labor met study criteria and had the fetal fibronectin assay completed. Eight patients did not have fetal fibronectin assay results available because of specimen handling errors, leaving 243 subjects available for study. Compared with the baseline year, the study year had significantly fewer admissions for preterm labor, preterm labor admissions per patient, and prescriptions written for tocolytic agents. In addition, the length of stay per admitted patient was significantly reduced. The study population had no differences in neonatal outcomes from the baseline population in terms of deliveries at <35.0 weeks' gestation, number of admissions to the neonatal intensive care unit, neonatal intensive care unit length of stay, or days of ventilatory support per patient admitted to the neonatal intensive care unit. CONCLUSIONS: Use of the fetal fibronectin assay resulted in significantly reduced preterm labor admissions, length of stay, and prescriptions for tocolytic agents. No negative impact on neonatal outcomes was observed. Reductions in admissions for preterm labor and in charges per admission resulted in approximately $486,000 saved during the study period. A trend toward increased corticosteroid administration (for neonates ultimately admitted to the neonatal intensive care unit) was noted.

Adolescent↗

PubMed1999

Role of oxytocin in the initiation of term and preterm labor in rats: changes in oxytocin receptor density and plasma oxytocin concentration and the effect of an oxytocin antagonist, L-366,509.

OBJECTIVE: Our purpose was to compare the functional roles of oxytocin in term and preterm labor in rats by both biochemical and pharmacologic means. STUDY DESIGN: We determined the myometrial oxytocin receptor density and the maternal plasma concentrations of oxytocin and progesterone on gestational days 18, 20, and 22 (morning) and at the onset of delivery (day 22 afternoon) in rats with labor at term and at the onset of delivery (day 20 afternoon) in rats in preterm labor induced by the combined use of bilateral ovariectomy and estradiol injection. We also evaluated the effects of an oxytocin antagonist, L-366,509, on the initiation of both term and preterm labor. RESULTS: The number of tritiated oxytocin binding sites in myometrial membranes rapidly increased on gestational day 22 (morning) in rats with term labor. Plasma progesterone level decreased in an inverse fashion. A rapid increase in circulating oxytocin concentration was observed at the onset of delivery in rats in labor at term. Both the plasma oxytocin concentration and the receptor density had the same values in rats with preterm labor as in rats with term labor. L-366,509 delayed the initiation of labor in rats with term and preterm labor in a dose-dependent manner. CONCLUSION: It is confirmed biochemically and pharmacologically that oxytocin plays an important role in the initiation of both term and preterm labor in rats. The oxytocin antagonist examined was able to delay term and preterm labor, so it might prove useful in clinical practice for the treatment of preterm labor.

Animals↗

PubMed1999

Predicting risk of preterm delivery by second-trimester measurement of maternal plasma corticotropin-releasing hormone and alpha-fetoprotein concentrations.

OBJECTIVE: Many women who have preterm labor have abnormally high plasma concentrations of the placental peptide corticotropin-releasing hormone and the fetal product alpha-fetoprotein in early pregnancy. This study was designed to evaluate the ability of these biochemical tests and a clinical risk factor score to prospectively discriminate pregnancies at high risk for preterm delivery. STUDY DESIGN: Eight hundred sixty women were studied prospectively from the early second trimester until delivery. A risk factor score for preterm delivery was calculated from the clinical history and maternal plasma corticotropin-releasing hormone and alpha-fetoprotein concentrations were measured by radioimmunoassay between 17 and 30 weeks' gestation. The risk factor score, corticotropin-releasing hormone concentration, and alpha-fetoprotein concentration for each woman were expressed as individual odds or likelihood ratios for preterm delivery and as a combined risk estimate derived from the 3 tests. RESULTS: Sixty women had preterm deliveries (n = 37 spontaneous labor, n = 23 planned deliveries), and these women had significantly higher concentrations of corticotropin-releasing hormone (median 1.92 multiples of the median) and alpha-fetoprotein (median 1.32 multiples of the median) than did women with term deliveries (median 1.00 multiples of the median, P <.001 for both tests), with these abnormalities being evident from early in the second trimester. The risk factor score was >/=10 in 28% of women with preterm delivery and 7% of women with term delivery. The combination of all 3 markers resulted in a higher detection rate and a higher positive predictive value than the risk factor score, corticotropin-releasing hormone concentration, or alpha-fetoprotein concentration alone, correctly discriminating 37% of women who would have preterm deliveries with a false-positive rate of 5%. The positive predictive value was also 37% (odds of being affected given a positive result were 1:1.7). CONCLUSIONS: The combination of measurement of maternal plasma corticotropin-releasing hormone and alpha-fetoprotein concentrations in the second trimester with risk factor scoring provides a more accurate indicator of the risk of preterm delivery than does risk factor scoring alone. This method of risk assessment may therefore be of use in targeting prevention strategies.

Adolescent↗

PubMed2003

ACOG practice bulletin. Management of preterm labor. Number 43, May 2003.

Preterm birth is the leading cause of neonatal mortality in the United States, and preterm labor precedes 40-50% of preterm births. Preterm birth accounts for 35% of all U.S. health care spending for infants and 10% of all such spending for children. Approximately 467,000 live births annually (11.5% of all live births) occur before term in the United States, and preterm births are responsible for three quarters of neonatal mortality and one half of long-term neurologic impairments in children. The purpose of this document is to present the various methods proposed to manage preterm labor and the evidence for their roles in clinical practice. Despite the numerous management methods proposed the incidence of preterm birth has changed little over the past 40 years (Fig. 1). Uncertainty persists about the best strategies for managing preterm labor.

Female↗

PubMed1997

Cervicovaginal washing prolactin assay in prediction of preterm delivery.

OBJECTIVE: Our purpose was to determine the utility of cervicovaginal washing prolactin assay in prediction of preterm birth in women without rupture of membranes. METHODS: Sixty-six women with normal singleton pregnancy were submitted to cervicovaginal washing and serum prolactin assays. The latency period to delivery and gestational age at admission and at delivery were also recorded. According to uterine contractions and obstetrical history regarding the previous preterm delivery, the pregnant women were divided into 4 groups: 18 symptomatic (group 1) and 15 asymptomatic (group 2) pregnancies who had previously had preterm delivery, and 18 symptomatic (group 3) and 15 asymptomatic (group 4) pregnancies without a history of prior preterm delivery were enrolled in the study. RESULTS: The cervicovaginal washing prolactin concentrations were significantly higher in groups 1 and 3 than in group 4 (P < 0.0083). With respect to the latency period to delivery and the birth weeks, groups 2 and 4 were significantly higher than groups 1 and 3 (F < 0.0001). In the evaluation of the whole group, a significant negative correlation was observed both between cervicovaginal washing prolactin concentrations and the lapsed times to delivery, and the gestational ages at delivery. The finding of a cervicovaginal washing prolactin value exceeding 50 ng/ml in the 12 days preceding preterm delivery had sensitivity, specificity, positive and negative predictive values of 65%, 95%, 86%, and 81%, respectively. CONCLUSIONS: A cervicovaginal washing prolactin value more than 50 ng/ml precedes preterm delivery within 12 days at > 29 weeks. The easy application, the good feasibility, the success in identifying pregnancies at risk for preterm labor, and the cost effectiveness suggests cervicovaginal washing prolactin assay as a biochemical marker for preterm delivery.

Adult↗

PubMed2000

Frequency and significance of preterm delivery in twin pregnancies.

OBJECTIVE: We investigated the frequency of preterm delivery and its influence on the neonatal outcome in twin pregnancies at a perinatal center. Are there differences in the course of twin pregnancies with preterm or term delivery? METHOD: A retrospective investigation was carried out at the Department of Obstetrics on 502 twin pregnancies and deliveries between 1978 and 1993. Pregnancy history and clinical parameters were compared among preterm (<37+0 weeks) and term deliveries. RESULT: Median duration of all twin pregnancies was 36+3 weeks of gestation. In the preterm group, preterm labor was more frequent, both, the first and the second neonate had lower birth weight and were more often admitted to the neonatal intensive care unit (NICU) where they stayed longer than full-term neonates needing intensive care. Perinatal deaths occurred only in the preterm group. CONCLUSIONS: The incidence of preterm delivery is significantly elevated in twin pregnancies and consequently the incidence of low- and very-low-birth-weight-infants and perinatal mortality. Preterm delivery is the main reason why twin pregnancies are at a higher risk for an adverse neonatal outcome and thereby cause considerable costs.

Adolescent↗

PubMed2002

A longitudinal study of the development of shifts of gaze to a peripheral stimulus in preterm infants with transient periventricular echogenicity.

Shifts of gaze to peripheral targets were studied longitudinally, between 6 and 26 weeks corrected age, in full-term and very preterm infants with transient periventricular echogenicity (PVE). Before 10 weeks, simple shifts of gaze were faster and more frequent in preterms with PVE<14 days than in full-terms, suggesting these preterms profited from additional early visual experience. After 16 weeks, there were subtle differences between full- and preterm infants in the development of shifts of gaze requiring disengagement. The differences suggest that, after disengagement had become established, its fine-tuning occurred more slowly in the preterms. Slower fine-tuning of disengagement was not associated with duration of PVE, since it was more marked in preterms with PVE<14 days than in preterms with PVE> or =14 days. The differences in performance between full- and preterm infants were small. However, even small differences may affect the efficiency of visually guided behaviors.

Age Factors↗

PubMed1998

Effect of preterm birth on pulmonary function at school age: a prospective controlled study.

OBJECTIVE: To assess long-term pulmonary outcome of a regional cohort of children born at < 32 weeks' gestation compared with a matched term control group. STUDY DESIGN: All 125 surviving children born at 24 to 31 weeks' gestation during a 1-year period and a sociodemographically matched term control group were evaluated at age 7 years. RESULTS: Preterm children with previous bronchopulmonary dysplasia (BPD) were twice as likely to require rehospitalization during the first 2 years of life than were preterm children without BPD (53% vs 26%, P < .01). At 7 years of age the BPD group had more airway obstruction than did both preterm children without BPD and the term control group (significantly reduced mean forced vital capacity, forced expiratory volume in 1 second, and forced expiratory flow, 25% to 75% vital capacity, all, P < .001). Lung function among preterm children without previous BPD was similar to that of the term control group. Bronchodilator responsiveness was observed twice as often in preterm children with previous BPD (20 of 43, 47%) compared with preterm children without BPD (13 of 53, 25%) or the term control group (23 of 108, 21%, P < .001). These differences remained significant after adjustment was done for birth weight and gestational age. CONCLUSION: Preterm children without BPD demonstrate pulmonary function at school age similar to that of children in a healthy term control group, whereas preterm children with previous BPD demonstrate abnormal pulmonary function.

Birth Weight↗

PubMed2001

Vaginal fetal fibronectin levels and spontaneous preterm birth in symptomatic women.

OBJECTIVE: To relate vaginal fetal fibronectin levels in women with symptoms of preterm labor to subsequent spontaneous preterm birth. METHODS: Quantitative fetal fibronectin values were calculated from women who participated in two prospective multicenter trials relating fetal fibronectin to subsequent spontaneous preterm birth. The study populations consisted of women who presented with symptoms of preterm labor between 24(0)/(7) and 34(6)/(7) weeks, a singleton pregnancy, intact membranes, no prior tocolysis, and cervical dilation less than 3 cm. RESULTS: The characteristics of the two study populations were similar. In both populations, the rates of delivery within 7, 14, and 21 days after sampling were clustered into three distinct fetal fibronectin groups (less than 40, 40-100, and 100 ng/mL or more). As fetal fibronectin values increased, the risk of subsequent spontaneous preterm birth also increased. Delivery within 7 days of sampling was 0.4%, 3.3%, and 18.2% (trial A) and 1.4%, 8.0%, 30.0% (trial B) as the fetal fibronectin levels increased from less than 40 ng/mL, to 40-100 ng/mL, and to at least 100 ng/mL, respectively. CONCLUSION: In women with symptoms of preterm labor, an increase in fetal fibronectin from under 40 ng/mL, to 40-100 ng/mL, to at least 100 ng/mL was associated with a progressive increase in the risk of subsequent spontaneous preterm birth. The use of a single fetal fibronectin cutoff of 50 ng/mL for defining a positive test in women with symptoms of preterm labor should be reevaluated.

Adult↗