Biomedical subjects

B M Mercer

Publications and source records attributed to B M Mercer.

At least 19 recordsLinked to original sources

PubMed2006

The physiology of fetal membrane rupture: insight gained from the determination of physical properties.

Premature rupture of the fetal membranes is a major cause of preterm birth and its associated infant morbidity and mortality. Recently, it has become clear that rupture of the fetal membranes, term or preterm, is not merely the result of the stretch and shear forces of uterine contractions, but is, in significant part, the consequence of a programmed weakening process. Work in the rat model has demonstrated that collagen remodeling, with activation of matrix metalloproteinases (MMPs), and apoptosis increase markedly in the amnion at end-gestation, suggesting that these processes are involved in fetal membrane weakening. We have developed fetal membrane strength testing equipment and a systematic tissue sampling methodology that has allowed us to demonstrate that term, non-labored, fetal membranes have a zone of weakness overlying the cervix, which contains biochemical markers of both collagen remodeling and apoptosis. These findings provide strong support for the concept of programmed fetal membrane weakening prior to labor. Our model has also been used to establish the physical properties of individual fetal membrane components (amnion, chorion), determine the sequence of events during the fetal membrane rupture process, and demonstrate that treatment of fetal membranes with TNF or IL-1beta, in vitro, induces weakness and the identical biochemical markers of collagen remodeling and apoptosis seen in the physiological weak zone. The ability to simultaneously correlate macroscopic physical properties with histological and biochemical fetal membrane characteristics, presents a unique perspective on the physiology of fetal membrane rupture.

Amnion↗

PubMed2004

The impact of chorionicity on umbilical cord acid-base values in twin gestations.

OBJECTIVE: To evaluate the impact of chorionicity on inter-twin differences in acid-base status at birth. METHODS: Records for twin pregnancies delivered at > or = 24 weeks' gestation from 1 January 1990 to 31 June 2000 were reviewed. Collected data included maternal demographics, gestational age, fetal presentation, anesthesia, delivery mode, inter-twin interval, umbilical artery (UA) and venous (UV) acid-base values, Apgar scores and birth weights. The influence of chorionicity on umbilical cord biochemistry was evaluated. (p < 0.05 was considered significant.) RESULTS: Analysis was carried out in 87 twin pairs (29 monochorionic, MC; and 58 dichorionic, DC). MC and DC twins were similar in maternal age (25.5 vs. 28.2 years), estimated gestational age (33.7 vs. 33.6 weeks), Cesarean delivery (55.2 vs. 52.6%), delivery interval (10 vs. 5 min) and respective birth weights (twin A, 1882 vs. 1981; and twin B, 1828 vs. 1872 g). MC first twins had a higher UA pH (7.31 +/- 0.05 vs. 7.26 +/- 0.08; p = 0.0005) than DC first twins. MC first and second twins had higher UA and UV bicarbonate levels than their DC counterparts (DeltapH = 21.7 +/- 5.1 vs. 18.5 +/- 3.1 mmol/l and 22.0 +/- 3.5 vs. 19.6 +/- 2.5 mmol/l, respectively; p = 0.003). MC twins were more discordant in UA pH than DC twins (DeltapH = 0.043 +/- 0.09 vs. 0.003 +/- 0.07; p = 0.009). MC and DC twins had a similar venous pH (DeltapH = 0.01 +/- 0.06 vs. 0.02 +/- 0.06; p = 0.5). CONCLUSIONS: There is a significant association between placental chorionicity and umbilical cord biochemistry in twins. Although it is possible that the mechanism of this finding is related to placental angioarchitecture, it is unlikely to be a result of simple mixing of blood volumes between twins. The physiology of underlying processes requires further study.

Adult↗

PubMed2001

Obstetric antecedents to apparent stillbirth (Apgar score zero at 1 minute only).

OBJECTIVE: To identify antecedent risk factors for the delivery of an infant with an Apgar score of 0 at 1 minute who is subsequently successfully resuscitated. METHODS: Infants born between January 1986 and February 1999 with 1-minute Apgar score of 0 followed by 5-minute Apgar score above 0 were studied. Each eligible infant was randomly matched with two control infants, born in the same year, with 1-minute Apgar score greater than 0. Hospital records of their mothers were reviewed. The variables were compared between the groups by univariate analysis. Those factors demonstrating significant differences were then analyzed by logistic regression. P <.05 was considered statistically significant. RESULTS: Seventy-four of 81,603 infants (0.9:1000 births) born with an Apgar score of 0 at 1 minute only were compared with 148 control babies. Univariate analysis revealed significant differences between study and control group regarding: gestational age, abruptio placentae, preterm premature rupture of membranes, chorioamnionitis, preeclampsia, small-for-gestational age, male gender, bradycardia, and abnormal fetal heart rate (FHR) other than bradycardia, respectively. Logistic regression of these factors found gestational age, bradycardia, and abnormal FHR to be independent risk factors for the delivery of an apparent stillborn infant. After exclusion of FHR criteria, logistic regression found gestational age (odds ratio [OR] 0.8 per week), male gender (OR 2.5), preeclampsia (OR 3.9), and abruptio placentae (OR 13.6) to be independent risk factors for the delivery of an apparent stillborn infant. CONCLUSION: Preterm birth, male gender, preeclampsia, and abruptio placentae are independently associated with an increased risk of apparent stillbirth.

Abruptio Placentae↗

PubMed2001

Antibiotics and the management of preterm premature rupture of the fetal membranes.

Preterm premature rupture of membranes remains an important cause of preterm birth and neonatal morbidity and mortality. Although the underlying pathophysiology remains largely undefined, subclinical infection has been implicated both in the mechanism of membrane rupture and the resultant neonatal morbidity. The use of maternal systemic antibiotics reduces both neonatal and maternal morbidity in the expectant management of PPROM. Although concern persists over the development of resistant strains of organisms involved with neonatal sepsis, current data support the use of antibiotics in this setting. Further study is needed regarding the risks and benefits of additional tocolytic therapy or antenatal corticosteroids in the management of PPROM, and the predictors of successful and unsuccessful conservative management, and subclinical intrauterine infection. This will be helpful in the ultimate delineation of the optimal management scheme for PPROM.

Anti-Bacterial Agents↗

PubMed2001

The preterm prediction study: can low-risk women destined for spontaneous preterm birth be identified?

OBJECTIVE: Half of all preterm births occur in women without clinical risk factors. Our goal was to assess fetal fibronectin assay, Bishop score, and cervical ultrasonography as screening tests to predict which low-risk pregnancies will end in preterm birth. STUDY DESIGN: We performed a secondary analysis of data collected at 22 to 24 weeks' gestation from low-risk subjects enrolled in the Preterm Prediction Study, an observational study of risk factors for preterm birth conducted by the National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network. Analysis was limited to primigravid women and to women who did not have a history of preterm birth or spontaneous pregnancy loss at <20 weeks' gestation. Bishop score (> or =4), fetal fibronectin level (> or =50 ng/mL), and cervical length (< or =25 mm) at 24 weeks' gestation were evaluated alone and in sequence as tests to predict spontaneous delivery before 35 weeks' gestation. RESULTS: Of the 2929 subjects enrolled in the original study, 2197 (1207 primigravid women and 900 low-risk multiparous women) met criteria for this analysis. There were 64 spontaneous births before 35 weeks' gestation (3.04%). All three tests were significantly related to birth before 35 weeks' gestation (high Bishop score: relative risk, 3.6; 95% confidence interval, 2.1-6.3; fetal fibronectin detection: relative risk, 8.2; 95% confidence interval, 4.8-13.9; short cervical length: relative risk, 6.9; 95% confidence interval, 4.3-11.1). However, the sensitivities of the tests alone were low (23.4% for high Bishop score, 23.4% for fetal fibronectin detection, and 39.1% for short cervix), as were the sensitivities for Bishop score followed by cervical ultrasonography (14.1%) and fetal fibronectin assay followed by cervical scan (15.6%). CONCLUSION: In the setting of low-risk pregnancy, fetal fibronectin assay and cervical ultrasonography have low sensitivity for preterm birth before 35 weeks' gestation. Sequential screening with Bishop score or fetal fibronectin assay followed by cervical ultrasonography further decreased sensitivity to only 15% among low-risk women.

Cervix Uteri↗

PubMed2001

The Preterm Prediction Study: toward a multiple-marker test for spontaneous preterm birth.

OBJECTIVE: The Preterm Prediction Study evaluated 28 potential biologic markers for spontaneous preterm birth in asymptomatic women at 23 to 24 weeks gestational age. This analysis compares those markers individually and in combination for an association with spontaneous preterm birth at <32 and <35 weeks gestational age. STUDY DESIGN: With the use of a nested case-control design from an original cohort study of 2929 women, results of tests from 50 women with a spontaneous preterm birth at <32 weeks and 127 women with a spontaneous preterm birth at <35 weeks were compared with results from matched-term control subjects. RESULTS: In the univariate analysis, the most potent markers that are associated with spontaneous preterm birth at <32 weeks by odds ratio were a positive cervical-vaginal fetal fibronectin test (odds ratio, 32.7) and <10th percentile cervical length (odds ratio, 5.8), and in serum, >90th percentiles of alpha-fetoprotein (odds ratio, 8.3) and alkaline phosphatase (odds ratio, 6.8), and >75th percentile of granulocyte colony-stimulating factor (odds ratio, 5.5). Results for spontaneous preterm birth at <35 weeks were generally similar but not as strong. Univariate and multivariate logistic regression analyses demonstrated little interaction among the tests in their association with spontaneous preterm birth. Combinations of the 5 markers were evaluated for their association with <32 weeks spontaneous preterm birth. Ninety-three percent of case patients had at least 1 positive test result versus 34% of control subjects (odds ratio, 24.0; 95% CI, 6.4-93.4). Among the case patients, 59% had >or=2 positive test results versus 2.4% of control subjects (odds ratio, 56.5; 95% CI, 7.1-451.7). If a cutoff of 3 positive test results was used, 20% of case patients and none of the control subjects had positive test results (P < .002). With the use of only the 3 serum tests (alkaline phosphatase, alpha-fetoprotein, and granulocyte colony-stimulating factor), any positive test identified 81% of cases versus 22% of control subjects (odds ratio, 14.7; 95% CI, 5.0-42.7). For spontaneous preterm birth at <35 weeks gestation, any 2 positive tests identified 43% of cases and 6% of control subjects (odds ratio, 11.2; 95% CI, 4.8-26.2). CONCLUSION: Overlap among the strongest biologic markers for spontaneous preterm birth is small. This suggests that the use of tests such as maternal serum alpha-fetoprotein, alkaline phosphatase, and granulocyte colony-stimulating factor as a group or adding their results to fetal fibronectin test and cervical length test results may enhance our ability to predict spontaneous preterm birth and that the development of a multiple-marker test for spontaneous preterm birth is feasible.

Alkaline Phosphatase↗

PubMed2001

An in vitro model and case report that used gelatin sponge to restore amniotic fluid volume after spontaneous premature rupture of the membranes.

OBJECTIVE: The purpose of this project was to study an in vitro model for plugging membrane defects with gelatin sponge and to develop a method with which to use this material to treat premature rupture of the membranes. STUDY DESIGN: Fetal membranes were fixed over the opening of a flask that was filled with saline solution and gelatin sponge. Defects of various sizes were created, and the usefulness of differing sizes of gelatin sponge to obstruct the defects was observed. This technique was then applied to a case of previable, spontaneous premature rupture of the membranes. RESULTS: Fifteen amniotomies were performed in the in vitro model. The gelatin sponge obstructed all defects less than 7 mm in length, when pieces up to 1 x 1 cm in dimension (n = 8 amniotomies) were used. For larger defects or those defects with a complex shape (such as cruciate), gelatin sponge was not effective at arresting fluid loss (n = 4 amniotomies). An inspection of larger gelatin sponge pieces, after instillation through a 12-gauge angiocatheter, revealed 36% (15 of 42 pieces) of 1 x 1 - cm pieces remained intact. A case of spontaneous, previable premature rupture of the membranes was treated with this material. A favorable outcome was observed. CONCLUSION: Gelatin sponge is successful at arresting the egress of fluid through membrane defects when smaller defects are present. Complex or larger linear defects may not be treated by this method alone and necessitate adjuvant therapies. This therapeutic strategy can be applied to cases of previable, spontaneous premature rupture of the membranes.

Adult↗

PubMed2000

Preterm prediction study: is socioeconomic status a risk factor for bacterial vaginosis in Black or in White women?

Bacterial vaginosis (BV), an important risk factor for preterm birth, is a more common infection in Black compared with White pregnant women. Because Black women in the United States are more likely to have lower measures of socioeconomic status (SES), this study examined the hypothesis that BV is associated with low SES. The project evaluated data from the Preterm Prediction Study of 2,929 women prospectively followed during their pregnancies. The women, who were screened for BV at 24 and 28 weeks of gestation, underwent a structured interview to evaluate demographic factors, SES, home and work environment, drug or alcohol use, and prior medical history. Black women in the study had many measures of lower SES compared with the White women, and reported less use of tobacco, alcohol and drugs. In neither the Black nor White women was an association found between BV and measures of SES (with the sole exception of "absence of a home telephone"). Most measures of SES do not explain the difference in rates of BV in Black and in White pregnant women.

Black or African American↗

PubMed2000

The preterm prediction study: granulocyte colony-stimulating factor and spontaneous preterm birth. National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network.

OBJECTIVE: Granulocyte colony-stimulating factor is elevated in the amniotic fluid and plasma of women with chorioamnionitis and active preterm labor. We investigated the relationship between plasma granulocyte colony-stimulating factor and subsequent spontaneous preterm birth in pregnant women without symptoms. STUDY DESIGN: We performed a nested case-control study involving 194 women who had a singleton spontaneous preterm birth and 194 matched term control subjects from the patient pool (n = 2929) enrolled in the Preterm Prediction Study. Plasma collected at 24 and 28 weeks' gestation was analyzed for granulocyte colony-stimulating factor, and the results were compared with subsequent spontaneous preterm birth. RESULTS: Compared with term control subjects, women who were delivered of their infants spontaneously at <28 weeks' gestation had increased mean granulocyte colony-stimulating factor values at 24 weeks' gestation (84.7 +/- 38.4 vs 67.7 +/- 28.6 pg/mL; P =.049), and women who were delivered of their infants at <32 weeks' gestation had increased mean plasma granulocyte colony-stimulating factor values at 28 weeks' gestation (80.4 +/- 24.1 vs 55.9 +/- 16.5 pg/mL; P =. 001). At 24 weeks' gestation a granulocyte colony-stimulating factor value >75th percentile in control subjects (approximately 80 pg/mL) was found in 48.9% (23/47) of all women delivered of their infants at <32 weeks' gestation versus 14.9% (7/47) of the term control subjects (adjusted odds ratio, 6.2; 95% confidence interval, 1.8-20. 8). At 28 weeks' gestation a granulocyte colony-stimulating factor value >75th percentile was found in 36.8% (7/19) of women delivered of their infants at <32 weeks' gestation versus 5.3% (1/19) of term control subjects (adjusted odds ratio, 25.7; 95% confidence interval, 1.5-470.4). When measured at 24 or 28 weeks' gestation, granulocyte colony-stimulating factor did not predict spontaneous preterm birth at 32 to 34 weeks' gestation or at 35 to 36 weeks' gestation. CONCLUSION: In pregnant women without symptoms at 24 and 28 weeks' gestation, elevated plasma granulocyte colony-stimulating factor levels are associated with subsequent early (<32 weeks' gestation) spontaneous preterm birth, especially within the next 4 weeks, but not with late spontaneous preterm birth. These data provide further evidence that early spontaneous preterm birth is associated with an inflammatory process that is identifiable by the presence of a cytokine in maternal plasma several weeks before the early spontaneous preterm birth; however, later spontaneous preterm birth is not associated with this process.

Adolescent↗

PubMed2000

The Preterm Prediction Study: sequential cervical length and fetal fibronectin testing for the prediction of spontaneous preterm birth. National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network.

OBJECTIVES: This study was undertaken to further elucidate the pathogenesis of preterm birth by means of traditional risk factors and new markers for preterm birth derived from the Preterm Prediction Study. STUDY DESIGN: A total of 3076 women (2929 with singleton gestations and 147 with twin pregnancies) were categorized according to the presence of risk factors including black race, low body mass index, the presence of bacterial vaginosis, and previous preterm birth. At 24 and 28 weeks' gestation cervical length was measured and categorized as short (</=25 mm) or normal (>25 mm). Vaginal and cervical fetal fibronectin concentrations were measured at 24, 26, 28, and 30 weeks' gestation and results were categorized as positive (>/=50 ng/mL) or negative (<50 ng/mL). RESULTS: At 24 to 26 weeks' gestation women with each of the risk factors were more likely to have positive fibronectin test results or to have a short cervix. Among women with negative fetal fibronectin results at 24 to 26 weeks' gestation those with a short cervix were more likely to have positive fetal fibronectin results at 28 to 30 weeks' gestation, and among those with normal cervical length those women who had positive fetal fibronectin results were more likely to have a short cervix at later evaluation. Most women who had positive fetal fibronectin results at 24 to 26 weeks' gestation had negative results at 28 to 30 weeks' gestation, whereas most but not all women who had a short cervix at 24 to 26 weeks' gestation still had a short cervix at 28 to 30 weeks' gestation. In each period women with both a positive fetal fibronectin result and a short cervix were at substantially increased risk of spontaneous preterm birth; women with either marker alone had intermediate and approximately equal risks of spontaneous preterm birth, and women without either marker had a low risk of spontaneous preterm birth. CONCLUSION: Regardless of other risk factors, a short cervix predicts a subsequent positive fetal fibronectin result, and a positive fetal fibronectin result predicts subsequent cervical shortening. These data do not support a single sequence of events leading to spontaneous preterm birth.

Biomarkers↗

PubMed2000

Outcome after successful resuscitation of babies born with apgar scores of 0 at both 1 and 5 minutes.

OBJECTIVE: Our purpose was to evaluate the outcome of infants who underwent successful resuscitation after initial Apgar scores of 0 at both 1 and 5 minutes. STUDY DESIGN: Eligible infants were identified through the perinatal database at the University of Tennessee, Memphis. Hospital records and long-term outcomes, where available, of babies who met the above criteria occurring between January 1986 and February 1999 were reviewed. RESULTS: Thirty-three of 81,603 infants (0.4/1000 births) met our study criteria. Twenty-two (67%) babies died during hospitalization. Mortality decreased significantly from 100% for babies with a birth weight of <750 g to 38% for those weighing > or =2500 g at birth (P =.03). All 6 babies delivered before 26 weeks' gestation died. The incidence of 10-minute Apgar scores >0 was significantly higher among survivors than among those who subsequently died (82% vs 33%, P <.05). Nine survivors had hypoxic-ischemic encephalopathy diagnosed before discharge. Of the 7 infants with available follow-up, 4 had significant persisting morbidity. Two infants had normal neurologic examinations at follow-up. CONCLUSION: Survival in babies born with 1- and 5-minute Apgar scores of 0 is predicted by birth weight, gestational age, and 10-minute Apgar score. Long-term sequelae are common but not ensured.

Adult↗

PubMed2000

The impact of digital cervical examination on expectantly managed preterm rupture of membranes.

OBJECTIVE: The purpose of this study was to examine the effects of digital cervical examination on maternal and neonatal outcomes among women with preterm rupture of membranes. STUDY DESIGN: This analysis includes data from a previously reported trial of antibiotic treatment during expectant management of rupture of membranes at 24 to 32 weeks' gestation in singleton and twin gestations. Patients from both the randomized trial (n = 299 in the antibiotic group and n = 312 in the placebo group) and the observational component (n = 183) are included in this analysis. The groups were divided into those with one (n = 161) or two digital cervical examinations (n = 27) and those with no digital cervical examinations (n = 606). RESULTS: The gestational ages at enrollment were similar in the two groups (29 +/- 2 weeks' gestation for one or two examinations vs 29 +/- 2 weeks' gestation for no examinations; P =.85). There were no differences in chorioamnionitis (27% vs 29%; P =.69), endometritis (13% vs 11%; P =.5), or wound infection (0.5% vs 1%; P >.999) between the group with one or two examinations and the no-examination group. Infant outcomes were also similar in the two groups, including early sepsis (6% vs 5%; P =.68), respiratory distress syndrome (51% vs 45%; P =.18), intraventricular hemorrhage (7% vs 7%; P =.67), necrotizing enterocolitis (5% vs 3%; P =.19), and perinatal death (7% vs 5%; P =.45). A composite outcome made up of these neonatal outcomes was not different (56% vs 48%; P =.10) between the group with one or two examinations and the no-examination group. The time from rupture to delivery was shorter in the digital examination group (median value, 3 vs 5 days; P <. 009). Multivariable analysis to adjust for antibiotic study group, group B streptococcal culture status, race, and maternal transfer did not modify these results. CONCLUSION: Performance of one or two digital cervical examinations during the course of expectant management of rupture of membranes between 24 and 32 weeks' gestation was associated with shorter latency but did not appear to worsen either maternal or neonatal outcome.

Adult↗

PubMed2000

The Preterm Prediction Study: prediction of preterm premature rupture of membranes through clinical findings and ancillary testing. The National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network.

OBJECTIVE: Our objective was to determine the relative importance of demographic characteristics, clinical risk factors, and ancillary screening tests in the prediction of preterm birth as a result of premature rupture of membranes. STUDY DESIGN: A total of 2929 women were evaluated in 10 centers at 23 to 24 weeks' gestation. Demographic and clinical characteristics were ascertained. Cervicovaginal fetal fibronectin and bacterial vaginosis were evaluated. Cervical length was measured by vaginal ultrasonography. Patients were evaluated for spontaneous preterm birth caused by preterm premature rupture of membranes at <37 and <35 weeks' gestation. Multivariate analyses were performed separately for nulliparous women and multiparous women. RESULTS: Premature rupture of membranes at <37 weeks' gestation complicated 4.5% of pregnancies, accounting for 32.6% of preterm births. Univariate analysis revealed low body mass index, pulmonary disease, contractions within 2 weeks, short cervix (</=25 mm), positive results of fetal fibronectin screening, bacterial vaginosis, and a previous preterm birth caused by premature rupture of membranes (in multiparous women) to be significantly associated with preterm birth caused by premature rupture of membranes in the current gestation. Short cervix, previous preterm birth caused by premature rupture of membranes in multiparous women, and presence of fetal fibronectin were the strongest predictors for both preterm birth caused by premature rupture of membranes at <37 and <35 weeks' gestation. Women with positive fetal fibronectin screening results and a short cervix had greater risks both of preterm birth caused by premature rupture of membranes at <37 weeks' gestation (relative risk, 4.9) and of preterm birth caused by premature rupture of membranes at <35 weeks' gestation (relative risk, 13.5) than did those without these risk factors. Multiparous women with all three risk factors had a 31. 3-fold increased risk of preterm birth caused by premature rupture of membranes at <35 weeks' gestation. CONCLUSION: The combination of short cervical length, previous preterm birth caused by preterm premature rupture of membranes, and positive fetal fibronectin screening results was highly associated with preterm delivery caused by preterm premature rupture of membranes in the current gestation.

Cervix Uteri↗

PubMed2000

Antibiotics and preterm labor.

In summary, a definite association has been demonstrated between preterm labor and genital tract infection. Conclusions regarding the true benefits of antibiotics as adjunctive therapy in treatment of preterm labor are inconsistent. Whereas some of the studies were able to demonstrate significant prolongation of pregnancy, no consistent reduction in either maternal or neonatal morbidity has been demonstrated. However, because the actual incidental morbidity rate is low in the populations studied, the power of this finding is also low. The potential risks for using antimicrobials has yet to be adequately addressed. It has been shown that bacterial resistance can develop when antibiotics are used without specific aim or when a specific bacteria is undertreated. It has been recently shown that prenatal and intrapartum antibiotic use is associated with an increased risk for antibiotic resistant neonatal sepsis if infection occurs. Because of these reasons, we discourage the administration of antibiotic treatment to women in preterm labor for the purpose of pregnancy prolongations. Treatment should be directed towards those with specific indications for treatment (e.g., intrapartum, group B streptococci prophylaxis, urinary tract infection, etc). The primary flaw in these many evaluations of preterm labor is the true incidence of preterm birth. The clinical diagnosis of preterm labor is a difficult one. Approximately one-half of those individuals with preterm contractions will not deliver until term. So, the use of antibiotics for all women in idiopathic preterm labor is destined to treat many women who are unlikely to benefit. If we were able to truly identify those who were in "true" labor, perhaps we could be more selective in determining who may benefit from antibiotics. Biochemical markers such as onco-fetal fibronectin could well-be a helpful marker. Goldberg et al evaluated FFN in vaginal and cervical secretions while attempting to better-predict who would have upper genital tract infection. In this large, multicenter trial, patients were tested for FFN every 2 weeks from 23 to 30 weeks gestation. In those patients who proceeded to deliver before 32 weeks gestation, increased levels of cervical FFN (> 50 ng/ml) were identified in approximately one-quarter. Fetal fibronectin was positive in 4% of their samples and was found to be twice as likely in one with bacterial vaginosis. They showed that the presence of increased FFN was associated with upper genital tract infection (clinical and histologic chorioamnionitis) as a main reason for preterm labor and delivery (increased risk 16-20-fold). Those with increased FFN levels were also shown to have an increased incidence of neonatal sepsis as well. Peaceman et al used FFN to attempt to identify those at risk for preterm delivery among women with contractions between 24 and 34 6/7 weeks gestation. Those with negative FFN were less likely to deliver within 7 days of the test. The negative predictive value was 99.7%, suggesting that this test may be helpful in identifying women who would not benefit from antibiotic treatment. However, if in the absence of prospective clinical trials demonstrating the efficacy of this approach, we discourage the use of FFN screening for this indication.

Anti-Bacterial Agents↗

PubMed1999

A randomized comparison of oral misoprostol versus Foley catheter and oxytocin for induction of labor at term.

OBJECTIVE: We sought to compare the efficacy and safety of oral misoprostol administered to patients with the efficacy and safety in a control group treated with a Foley catheter and oxytocin for induction of labor. STUDY DESIGN: Two hundred patients requiring induction of labor at term with a Bishop score of </=5 were randomized to receive oral misoprostol or a cervical Foley catheter plus oxytocin. Patients in the misoprostol group received 50 microg at 4-hour intervals for a maximum of 6 doses or until an adequate contraction pattern developed. Those in the control group had a Foley catheter inserted in the cervix, whereas oxytocin was administered intravenously by a standard incremental infusion protocol to a maximum dose of 36 mU/min. RESULTS: In multiparous patients the percentage delivered of their neonates within 24 hours and the median induction-to-delivery times were similar in the 2 groups. In nulliparous patients, however, delivery within 24 hours was significantly less likely in the misoprostol group (53.4% vs 82. 5%; P <.001), and the median induction-to-delivery time was longer (23.3 hours vs 17.2 hours; P <.01). There were no differences in the incidence of meconium, chorioamnionitis, low Apgar scores, or cesarean delivery. The incidence of hyperstimulation was higher in the oxytocin-Foley group (4.1% vs 13.1%; P =.02). CONCLUSION: Oral misoprostol is as effective as oxytocin-Foley catheter for inducing labor in multiparous women. Misoprostol appears less efficacious in nulliparous patients.

Administration, Oral↗

PubMed1999

The preterm prediction study: effect of gestational age and cause of preterm birth on subsequent obstetric outcome. National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network.

OBJECTIVE: We sought to evaluate the association between prior spontaneous preterm delivery and subsequent pregnancy outcome. STUDY DESIGN: A total of 1711 multiparous women with singleton gestations were prospectively evaluated at 23 to 24 weeks' gestation. Prior pregnancies were coded for the presence or absence of a prior spontaneous preterm delivery. If a prior spontaneous preterm delivery had occurred, the gestation of the earliest prior delivery (13-22, 23-27, 28-34, and 35-36 weeks' gestation) was recorded. Current gestations were categorized as spontaneous preterm delivery at <28, <30, <32, <35, or <37 weeks' gestation. The risk of spontaneous preterm delivery in the current gestation was determined on the basis of the occurrence, gestational age, and cause of the earliest prior spontaneous preterm delivery. RESULTS: The incidences of spontaneous preterm delivery before 28, 30, 32, 35, and 37 weeks' gestation were 0.8%, 1.1%, 1.9%, 5.1%, and 11.9%, respectively. Those with a prior spontaneous preterm delivery carried a 2.5-fold increase in the risk of spontaneous preterm delivery in the current gestation over those with no prior spontaneous preterm delivery (21. 7% vs 8.8%; P </=.001). Gravid women with an early prior spontaneous preterm delivery (23-27 weeks' gestation) had a higher risk of recurrent spontaneous preterm delivery (27.1% vs 8.8%; P </=.001). Prior spontaneous preterm delivery was more closely associated with subsequent early spontaneous preterm delivery at <28 weeks' gestation (relative risk, 10.6) than for spontaneous preterm delivery overall (relative risk, 2.5). An early prior spontaneous preterm delivery (23-27 weeks' gestation) was most highly associated with early spontaneous preterm delivery (<28 weeks' gestation) in the current gestation (relative risk, 22.1). The relationship between prior spontaneous preterm delivery and current outcome was not as strong for those with a very early spontaneous preterm delivery (13-22 weeks' gestation). Prior spontaneous preterm delivery caused by preterm premature rupture of the membranes and preterm labor was significantly associated with similar outcomes in the current gestation (P <.001). CONCLUSION: Prior spontaneous preterm delivery is highly associated with recurrence in the current gestation. An early prior spontaneous preterm delivery is more predictive of recurrence and is most highly associated with subsequent early spontaneous preterm delivery.

Adult↗

PubMed1999

Neonatal outcome in severe preeclampsia at 24 to 36 weeks' gestation: does the HELLP (hemolysis, elevated liver enzymes, and low platelet count) syndrome matter?

OBJECTIVE: Our purpose was to compare neonatal outcome after preterm delivery of infants whose gestation was complicated by the HELLP (hemolysis, elevated liver enzymes, and low platelet count) syndrome, partial HELLP syndrome, or severe preeclampsia. STUDY DESIGN: We reviewed the maternal and neonatal charts from 269 consecutive pregnancies complicated by the HELLP syndrome or severe preeclampsia managed at our perinatal center. The HELLP syndrome was defined by previously published laboratory criteria. Viable pregnancies were divided into 3 groups: HELLP syndrome, partial HELLP syndrome (at least 1, but not all 3, features of the HELLP syndrome), and severe preeclampsia (no features of the HELLP syndrome). Results were compared by means of chi2 analysis and Student t test where appropriate. Logistic regression was used to evaluate outcome variables at different gestational ages. RESULTS: There were no significant differences in complications among the 3 groups at each gestational age. There was, as expected, a significant decrease in morbidity and mortality rates with advanced gestational age. CONCLUSIONS: In severe preeclampsia, neonatal morbidity and death are related to gestational age rather than to the presence or absence of the HELLP syndrome. Whether expectant management is safe for women with the HELLP syndrome requires further study.

Adult↗

PubMed1999

Obstetric determinants of neonatal survival: antenatal predictors of neonatal survival and morbidity in extremely low birth weight infants.

OBJECTIVE: The aim of the study was to compare clinical and ultrasonographic variables obtained before delivery as predictors of neonatal survival and morbidity in infants weighing </=1000 g at birth. STUDY DESIGN: Maternal data available before the birth of singleton infants with birth weights </=1000 g who were delivered at the 11 tertiary perinatal centers of the National Institute of Child Health and Human Development Network of Maternal-Fetal Medicine Research Units were studied. Births that followed extramural delivery, antepartum stillbirths, multiple gestations, induced abortions, infants with major malformations, and fetuses delivered at <20 weeks' gestation were excluded. Ultrasonographic variables, including estimated fetal weight, obstetrically estimated gestational age, femur length, and biparietal diameter, and clinical variables, such as maternal race, antenatal care, substance abuse, medical treatment, reason for delivery, fetal gender, and presentation, were studied with logistic regression as predictors of neonatal outcome, including intrapartum stillbirth, neonatal death, and survival to 120 days after birth or to discharge from the hospital with or without the presence of markers of major morbidity. RESULTS: Eight hundred eight infants met enrollment criteria; 63 were excluded because of incomplete data and 32 were excluded because of malformations, leaving 713 for analysis, 386 of whom had an ultrasonographic examination within 3 days of delivery that recorded femur length, biparietal diameter, and estimated fetal weight. Forty-two percent of births were the result of preterm labor, 22% were the result of preterm ruptured membranes, 12% were the result of preeclampsia or eclampsia, 9% were the result of fetal distress, 4% were the result of placenta previa or abruptio placentae, and 2% were the result of intrauterine growth restriction. Perinatal mortality before 24 weeks' gestation exceeded 81% (19% stillbirths and 62% neonatal deaths) but declined sharply thereafter. Most survivors born before 26 weeks' gestation had serious morbidity. Fetal femur length and estimated gestational age predicted survival better than did biparietal diameter or estimated fetal weight. Infants who survived with markers of serious long-term morbidity could not be distinguished from those who survived without morbidity markers before delivery by ultrasonography or clinical data. Threshold values for ultrasonographic measurements of biparietal diameter and femur length were developed to distinguish fetuses with no chance of survival. CONCLUSION: Ultrasonographic assessment of either fetal femur length or gestational age predicts neonatal mortality better than do other antenatal tests. No tests accurately predicted neonatal morbidity in infants weighing </=1000 g at birth.

Female↗