Neuraxial analgesia effects on labour progression: facts, fallacies, uncertainties and the future.

Approximately 60% of women who labour in the USA receive some form of neuraxial analgesia, but concerns have been raised regarding whether it negatively impacts the labour and delivery process. In this review, we attempt to clarify what has been established as truths, falsities and uncertainties regarding the effects of this form of pain relief on labour progression, negative and/or positive. Additionally, although the term 'epidural' has become synonymous with neuraxial analgesia, we discuss two other techniques, combined spinal-epidural and continuous spinal analgesia, that are gaining popularity, as well as their effects on labour progression.

Allele-specific loss in chromosome 9p loci in preneoplastic lesions accompanying non-small-cell lung cancers.

BACKGROUND: Carcinogenesis is a multistep process, which may begin as a consequence of chromosomal changes. Deletions in the short arm of chromosome 9 (9p) have been observed in lung carcinomas. In addition, morphologically recognizable preneoplastic lesions, frequently multiple in number, precede onset of invasive carcinomas. PURPOSE: We tested for deletions and loss of heterozygosity (LOH) at 9p loci in preneoplastic and neoplastic foci in lungs of patients with non-small-cell lung carcinomas (NSCLCs). METHODS: Seven archival, paraffin-embedded, surgically resected NSCLC specimens were selected. They were predominantly from patients with adenocarcinomas and contained multiple preneoplastic lesions, including hyperplasia, metaplasia, dysplasia, and carcinoma in situ (CIS). Fifty-three histologically identified preneoplastic and malignant lesions present in bronchi, bronchioles, and alveoli were precisely microdissected from stained tissue sections with a micromanipulator. Stromal lymphocytes were used to determine constitutional heterozygosity. The specimens were analyzed for LOH using polymerase chain reaction-based assays for polymorphism in dinucleotide repeats (microsatellite markers) in interferon alfa (IFNA) and D9S171 loci on 9p. RESULTS: All seven cases were constitutionally heterozygous for one or both microsatellite markers. Five of seven cases had LOH at one or both 9p loci in the invasive primary cancers (doubly informative cases). Four of these five cases also revealed LOH in preneoplastic foci. In the doubly informative cases, LOH was detected in five (38%) of 13 foci of hyperplasia, four (80%) of five foci of dysplasia, and three (100%) of three CIS lesions. LOH was detected in preneoplastic lesions from all regions of the respiratory tract, including bronchi, bronchioles, and alveoli, and involved five different cell types. The identical allele was lost from both the preneoplastic lesions and the corresponding tumors (12 of 12 lesions, 17 of 17 comparisons), a phenomenon we have referred to as "allele-specific mutation." Statistical analyses employing a cumulative binomial test demonstrated that the probabilities of such findings occurring by chance are 2.4 x 10(-4) and 7.6 x 10(-6), respectively. From comparisons with the previously published data on other chromosomal abnormalities in the same tissue specimens, it appears that LOH at 3p and 9p loci occurred early in the hyperplasia stage, but the ras gene point mutations were relatively late, at the CIS stage. CONCLUSIONS: LOH at 9p loci occurs at the earliest stage in the pathogenesis of lung cancer and involves all regions of the respiratory tract. LOH in NSCLC is not random but targets a specific allele in individuals. Studying preneoplastic lesions may help identify intermediate markers for risk assessment and chemoprevention.

Antibodies against autologous tumor cell proteins in patients with small-cell lung cancer: association with improved survival.

BACKGROUND: The frequency and clinical relevance of human antitumor immune responses is not well known, and few target antigens have been identified. PURPOSE: This study was designed to determine the frequency of antibodies reactive against extracts of autologous tumor cell lines and to correlate these data with survival. METHODS: Serum samples were obtained from 40 lung cancer patients treated on National Cancer Institute protocols. These sera were used as probes in immunoblots against protein extracts from tumor cell lines derived from each of these patients. RESULTS: We detected serum antibodies against autologous tumor cell proteins in 21 (58%) of the 36 patients with small-cell lung cancer (SCLC) and three (75%) of the four with non-small-cell lung cancer (NSCLC). Two patients' sera detected the p53 tumor suppressor gene product and two detected the product of the HuD gene (associated with paraneoplastic neurological syndromes) in their autologous tumor cell lysates. SCLC patients with antibodies against autologous tumor cell proteins had improved survivals compared with those in the antibody-negative group (P = .059). All patients who lived longer than 36 weeks were antitumor antibody positive. Sera from six (86%) of seven patients with limited disease were positive for antibodies that reacted against autologous tumor cells, compared with 15 of 29 (52%) of sera from patients with extensive disease. CONCLUSIONS: Our results suggest that the sera from patients with SCLC frequently contain antibodies against tumor cell proteins and that these antibodies are associated with improved survival. IMPLICATIONS: These data suggest that an antitumor immune response may affect tumor growth, and that the anonymous proteins detected by antitumor antibodies in lung cancer patient sera may represent proteins involved in the development of lung cancer or in its clinical manifestations.

Treatment of atypical depression with cognitive therapy or phenelzine: a double-blind, placebo-controlled trial.

BACKGROUND: Patients with atypical depression are more likely to respond to monoamine oxidase inhibitors than to tricyclic antidepressants. They are frequently offered psychotherapy in the absence of controlled tests. There are no prospective, randomized, controlled trials, to our knowledge, of psychotherapy for atypical depression or of cognitive therapy compared with a monoamine oxidase inhibitor. Since there is only 1 placebo-controlled trial of cognitive therapy, this trial fills a gap in the literature on psychotherapy for depression. METHODS: Outpatients with DSM-III-R major depressive disorder and atypical features (N = 108) were treated in a 10-week, double-blind, randomized, controlled trial comparing acute-phase cognitive therapy or clinical management plus either phenelzine sulfate or placebo. Atypical features were defined as reactive mood plus at least 2 additional symptoms: hypersomnia, hyperphagia, leaden paralysis, or lifetime sensitivity to rejection. RESULTS: With the use of an intention-to-treat strategy, the response rates (21-item Hamilton Rating Scale for Depression score, < or =9) were significantly greater after cognitive therapy (58%) and phenelzine (58%) than after pill placebo (28%). Phenelzine and cognitive therapy also reduced symptoms significantly more than placebo according to contrasts after a repeated-measures analysis of covariance and random regression with the use of the blind evaluator's final Hamilton Rating Scale for Depression score. The scores between cognitive therapy and phenelzine did not differ significantly. Supplemental analyses of other symptom severity measures confirm the finding. CONCLUSIONS: Cognitive therapy may offer an effective alternative to standard acute-phase treatment with a monoamine oxidase inhibitor for outpatients with major depressive disorder and atypical features.

Effect of body mass index on maternal morbidity following peripartum hysterectomy.

The objective of this study was to estimate the impact of maternal body mass index (BMI) on maternal morbidity following unscheduled peripartum hysterectomy. A retrospective cohort study of consecutive peripartum hysterectomies at our institution from 1988 through 2012; scheduled hysterectomies were excluded. Medical records were reviewed and maternal, foetal and surgical data collected for each subject. Maternal BMI was categorized by the National Institute of Health classifications for overweight and obese. Statistical analyses included evaluation for trend. A total of 360,774 women delivered at Parkland Hospital during the study period with 665 (1.8 per 1000 deliveries) unscheduled peripartum hysterectomies performed. BMI was available for 635 women. Gestational diabetes, chronic hypertension and pregnancy-related hypertension were significantly higher in all three obesity categories, P = < 0.01. Post-partum complications, such as venous thrombosis and composite surgical morbidity did not differ among BMI groups. Estimated blood loss and units transfused did not differ across the BMI categories, P = 0.42 and P = 0.38, respectively. Increasing BMI was associated with longer surgical times and more wound infections, P = 0.01. These complications should be considered when approaching a peripartum hysterectomy in patients with obesity.

Locus coeruleus cell loss in the aging human brain: a non-random process.

Quantitative neuroanatomical techniques were used to determine whether with aging there is random or systematic loss of locus coeruleus (LC) neurons in the human brain. The cells were identified by immunohistochemical staining for the catecholaminergic enzyme tyrosine hydroxylase and/or by neuromelanin pigment content. Cell locations were mapped, using computer imaging procedures, in horizontal sections spaced 0.5 to 0.8 mm throughout the rostrocaudal extent of the nucleus in 17 cases, from 1 to 104 years of age. Neuromelanin pigment accumulated within the neurons with aging. In brains less than 25 years of age there were many fewer pigment-containing neurons than tyrosine hydroxylase-containing neurons; however, by the fifth decade the number of cells identified by the two markers was comparable. From the first to the tenth decade of life there is over a 50% loss of LC neurons: in four cases from "young" individuals (1-28 years of age) there were 21,084 +/- 653 tyrosine hydroxylase immunostained cells (mean +/- standard error of the mean) on one side of the brain; in seven cases from "old" individuals (60-82 years of age) there were 16,502 +/- 921 pigment-containing cells; and in the three cases from the "oldest" individuals (103-104 years of age) there were 9,493 +/- 1,236 pigment-containing neurons. In both the "old" and "oldest" groups, compared to the "young," there was significantly greater loss of rostral cells than caudal cells. These data indicate a systematic loss of cells such that the rostral, forebrain-projecting neurons decrease in number with aging to a greater extent than do the caudal, spinal cord-projecting neurons.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of in vivo cocaine administration on human platelet aggregation.

To evaluate whether cocaine administration to human volunteers in vivo increases platelet aggregation, 12 healthy male volunteers were studied twice in a prospective, double-blinded fashion. There was a decrease in aggregation following cocaine exposure compared to placebo, which was most prominent at high doses of adenosine diphosphate.

Loss of heterozygosity and microsatellite alterations in p53 and RB genes in adenoid cystic carcinoma of the salivary glands.

Adenoid cystic carcinomas (ACC) constitute approximately 20% of malignant salivary gland tumors. Several histological types of ACC are recognized and may coexist in a single tumor. The authors divided ACC into lower grade (tubular and cribriform subtypes) and higher grade (trabecular and solid) subtypes. A preliminary analysis of 10 ACCs showed a relatively high incidence of loss of heterozygosity (LOH) at the p53 and RB genes and low or absent K-ras mutations and LOH at chromosomal loci 3p, 5q, 8p, and 9p. From 21 tumors, the authors carefully microdissected and analyzed 36 subtype foci. Three interrelated pieces of evidence indicate that the relatively poor prognosis higher grade subtype arises from one or more of the lower grade subtypes via progression events associated with mutations in the p53 or RB genes. First, the number of mutations (both LOH and microsatellite alterations) at either gene is greater in higher grade foci than in lower grade foci; second, multiple mutations (two and occasionally three) are present in only higher grade foci; and third, when lower and higher grade foci are present in the same tumors, identical mutations plus other mutations are present in the corresponding higher grade foci. These findings suggest that molecular analyses of ACCs may provide information of prognostic importance.

p53 immunostaining positivity is associated with reduced survival and is imperfectly correlated with gene mutations in resected non-small cell lung cancer. A preliminary report of LCSG 871.

We investigated the correlation of p53 abnormalities with survival in 85 patients with non-small cell lung cancer (NSCLC) who had undergone resection with curative intent as part of Lung Cancer Study Group (LCSG) 871. Our previous studies showed that only a subset of p53 mutations in lung cancers result in overexpression. In addition, protein overexpression has been described in the absence of mutation. Therefore, we determined both p53 protein overexpression (by immunostaining) and p53 and ras gene mutations (by single-strand conformation polymorphism and DNA sequencing) in this set of resected tumor specimens. Clinical follow-up data were available for 75 cases. Of the studied patients, 64% showed p53 overexpression and 51% had mutant p53 sequences; however, the concordance rate was only 67%. There was a negative survival correlation with positive p53 immunostaining (p = 0.05), but not with the presence of gene mutations (p = 0.62) in this group of patients. Overexpression of p53 protein determined by immunostaining may contribute to adverse outcome due to the ability of p53 to act as a dominant oncogene, or alternatively, overexpression may reflect ongoing DNA damage in the tumor as a marker for a more aggressive behavior. When adjusted for stage, age, and gender by multivariate analysis, however, there was no independent impact of p53 overexpression on survival.

Frequent loss of the short arm of chromosome 9 in resected non-small-cell lung cancers from Japanese patients and its association with squamous cell carcinoma.

We analyzed 87 Japanese non-small-cell lung carcinomas (NSCLC) including 30 squamous cell, 51 adenocarcinomas and 6 large-cell carcinomas for loss of heterozygosity (LOH) on the short arm of chromosome 9, and we correlated our findings with clinicopathological features. We used four polymorphic microsatellite markers on 9p (interferon A gene, D9S171, D9S126, and D9S169), which flank the critical region (9p21-22) involved in lung cancer. We observed alterations of DNA sequences at 9p in NSCLC (27 of 82 informative cases or 33%). Concordance among the four markers was high (87%), indicating that the deletions often were relatively large. The 27 genetic alterations observed on 9p include 26 examples of LOH, 1 homozygous deletion, and 1 case with LOH and evidence of microsatellite alteration characterized by shift in band mobility. We noted a high frequency of LOH at 9p especially in squamous cell carcinoma (17 of 29 informative cases or 59%), and in poorly differentiated NSCLC (12 of 23 informative cases or 52%). There was no correlation between LOH at 9p and the other clinical parameters, including survival, gender, tumor size and the presence of regional or distant metastases. In contrast to other reports, we found only rare instances of homozygous deletions (1%) and microsatellite alteration showed as a mobility shift (1%). Our findings demonstrate that LOH at the short arm of chromosome 9 is correlated with squamous cell and poorly differentiated carcinomas in Japanese patients with NSCLC.

Interphase cytogenetic (in situ hybridization) analysis of astrocytomas using archival, formalin-fixed, paraffin-embedded tissue and nonfluorescent light microscopy.

Astrocytomas contain nonrandom chromosomal abnormalities that recently have been correlated with shortened patient survival. Two frequently reported aberrations are trisomy 7 and monosomy 10. We assessed the numerical complement of chromosomes 7 and 10 in formalin-fixed, paraffin-embedded brain biopsy tissue from 28 diffuse astrocytomas by in situ hybridization using a nonfluorescent enzymatic detection system. Clinical follow-up of at least 5 years was available in 26 cases (93%). Monosomy 10 was identified in 7 cases (25%): astrocytoma, 1 case; anaplastic astrocytoma, 1 case; and glioblastoma, 5 cases. Trisomy 7 was identified in 11 cases (39%): astrocytoma, 5 cases; glioblastoma, 6 cases. Multivariate analysis revealed that monosomy 10 was the most statistically significant negative predictor of patient survival. Numerical chromosomal abnormalities are detectable in astrocytomas in archival tissue using interphase cytogenetics and nonfluorescent light microscopy. Although larger studies are required, our data suggest that potentially useful prognostic information may be obtained with this approach.

Use of universal precautions in interventional radiology: results of a national survey.

OBJECTIVE: To determine current use of universal precautions by practicing interventional radiologists in the United States. METHODS: National survey mailed to interventional radiologists, conducted anonymously in November 1991. Of 1530 survey forms mailed to practicing interventional radiologists, 817 (53%) were returned and 804 (52%) were completed and evaluable. Both academic and private practice settings were represented. RESULTS: Eighty-five percent of respondents had changed their use of infection control measures in the previous 10 years. Of these, 96% cited personal concerns about AIDS as a reason for making changes. Sixty-two percent made changes in response to Centers for Disease Control and Prevention and Occupational Safety and Health Administration recommendations as well. Use of barrier precautions was quite variable. Although 86% of respondents always wore a sterile gown during procedures, only 32% routinely wore a face mask or shield and only 29% of those who did not wear corrective glasses routinely wore protective eye gear during procedures. Seven percent of respondents routinely double gloved for procedures. Twenty percent of reported percutaneous injuries occurred during recapping of used sharps; an additional 6% were related to improper disposal of used sharps. CONCLUSIONS: We conclude that use of universal precautions by interventional radiologists in the United States is variable. Some practices that may lead to preventable injury to health care workers remain common.

Age-related differences in the distribution of peripheral atherosclerosis: when is atherosclerosis truly premature?

BACKGROUND: The natural history of peripheral atherosclerosis in young adults appears to be unfavorable compared with that in older patients. No universally accepted definition of "premature" atherosclerosis exists, however, making comparison of clinical studies difficult. This study examined age-related differences in distribution of atherosclerotic lesions and determined an age threshold at which such differences became apparent. Such a threshold may provide a definition of premature atherosclerosis. METHODS: Arteriograms of all patients 49 years of age and younger undergoing evaluation of lower extremity ischemia during the past 5 years were reviewed and the findings were tabulated. Medical records were reviewed to obtain demographic data, assess risk factors, and confirm disease etiology. Exclusion criteria included normal arteriograms (three patients), history of acute or remote trauma (six patients), unclear cause of ischemic symptoms (three patients), arteritis (four patients), aneurysmal disease (one patient), and acute ischemia without prior chronic symptoms (12 patients). For comparison we also reviewed arteriograms performed during the same period in 140 patients older than 50 years of age who had chronic lower extremity ischemia caused by atherosclerosis. RESULTS: The mean age of the 59 study patients was 43.4 +/- 5.8 years (median age, 46 years; range, 25 to 49 years). Arteriograms were available in all cases; medical records were available in 54 (92%). Atherosclerosis involved only the aortoiliac segment in 25 patients (42%), the femoropopliteal-tibial arteries alone in 21 (36%), and both levels in 13 (22%). Patients with distal atherosclerosis had a higher prevalence of diabetes than those with proximal atherosclerosis (p = 0.004). Ninety-two (66%) of the 140 patients older than 50 years of age had atherosclerosis confined to a single arterial segment, which was not significantly different from the prevalence of single-level disease in the study group. However, 25 (54%) of the 46 study patients with single-level atherosclerosis had aortoiliac disease compared with only 15 (16%) of 92 patients older than 50 years of age with single-level disease (p < 0.001). CONCLUSIONS: In contrast to the pattern of disease in older adults, atherosclerosis in young, nondiabetic patients most commonly involves the aortoiliac segment. Differences in lesion distribution become increasingly apparent with age but are most striking between those 49 years of age and younger and those 50 years of age and older. Accordingly, we propose that premature peripheral atherosclerosis be defined as beginning at or before the age of 49 years.

Abdominal aortic aneurysms and malignant neoplasia: double jeopardy.

BACKGROUND: This study was performed to determine whether there is a significant association between abdominal aortic aneurysms (AAAs) and malignancy and to determine the impact of malignancy on late survival in patients with AAA. METHODS: We studied 126 men undergoing AAA repair and compared them with 99 men undergoing aortofemoral bypass (AFB) for occlusive disease and with 100 men undergoing herniorrhaphy during the same period. RESULTS: Fifty-one (40%) patients with AAA, 23 (23%) patients undergoing AFB, and 21 (21%) patients undergoing herniorrhaphy were diagnosed with cancer (p = 0.002). By life table analysis the proportion of subjects remaining cancer free at 5 years was 0.60 +/- 0.05 for AAA, 0.83 +/- 0.04 for AFB, and 0.81 +/- 0.04 for herniorrhaphy (p = 0.004). Multivariate analysis selected four independent risk factors for cancer: presence of AAA (p = 0.003, odds ratio 1.4, confidence interval [CI] 1.2 to 1.7), age (p = 0.001, odds ratio per year 1.1, CI 1.0 to 1.1), smoking (p = 0.04, odds ratio 1.5, CI 1.0 to 2.2), and hypertension (p = 0.04, odds ratio 0.73, CI 0.5 to 1.0). Cancer deaths accounted for 32% of late deaths in patients with AAA, which was not different compared with 26% of late deaths in patients undergoing AFB and 36% of late deaths in patients undergoing herniorrhaphy. Five-year cancer-free survival was 0.44 +/- 0.05 for patients with AAA, 0.64 +/- 0.05 for patients undergoing AFB, and 0.70 +/- 0.05 for patients undergoing herniorrhaphy (p < 0.001, AAA versus herniorrhaphy only). CONCLUSIONS: Cancer is more prevalent in men with AAA than in men undergoing AFB or herniorrhaphy. The presence of AAA appears to be an independent risk factor for cancer. Despite the higher cancer prevalence in patients with AAA, cardiovascular disease accounted for the largest number of late deaths in this series, minimizing differences in cancer-free survival between patients with AAA and patients undergoing AFB.

High-dose oxytocin: 20- versus 40-minute dosage interval.

OBJECTIVE: To determine whether an increase in the oxytocin dosing interval would decrease the incidence of uterine hyperstimulation. METHODS: This study included 1801 consecutive pregnancies receiving high-dose oxytocin. Oxytocin was used for labor augmentation in 1167 and induction in 634 women. Twenty- and 40-minute dosage intervals were compared. The study period was based on an 80% likelihood of detecting 5 and 10% differences in the cesarean and hyperstimulation rates, respectively. Statistics were analyzed with chi 2, Fisher, and Wilcoxon rank-sum tests where appropriate. Multivariate logistic regression and analysis of covariance were used to control for confounding demographic variables. RESULTS: Comparison of the 20- and 40-minute regimens for labor induction yielded no differences in the rates of cesarean delivery for dystocia (16 versus 19%) or fetal distress (5 versus 6%). The 20-minute regimen for augmentation was associated with a significant reduction in cesarean for dystocia (8 versus 12%; P = .05). The incidence of uterine hyperstimulation was greater with the 20-minute than the 40-minute regimen for induction (40 versus 31%; P = .02), but not for augmentation (31 versus 28%). Neonatal outcomes were unaffected by the dosage interval for both augmentation and induction. CONCLUSION: A 40-minute dosing interval for high-dose oxytocin offers no clear advantage over a 20-minute interval. Both regimens were safe and efficient, with no differences in perinatal outcome. The 20-minute interval was associated with fewer cesareans for dystocia when used for labor augmentation, whereas the 40-minute interval resulted in less hyperstimulation when used for labor induction.

Prolonged pregnancy: induction of labor and cesarean births.

OBJECTIVE: To determine the effects of labor induction on cesarean delivery in post-date pregnancies. MATERIALS AND METHODS: A total of 1325 women who reached 41 weeks' gestation between December 1, 1997, and April 4, 2000, and who were scheduled for induction of labor at 42 weeks were included in this prospective observational study. Cesarean delivery rates were compared between those women who entered spontaneous labor and those who underwent induction. Women with any medical or obstetric risk factors were excluded. A power analysis was performed to determine how many patients would be required to show no effect of labor induction on cesarean delivery with a beta of.8 and an alpha of.05. Approximately 5200 patients would be required, taking an estimated 28 years to accrue at our institution. RESULTS: Admission to delivery was longer (5.7 compared with 11.1 hours, P =.001) and more likely to extend beyond 10 hours (55 compared with 24%, P =.001) in the induction group. Cesarean deliveries were increased in the induced group (19 compared with 14%, P <.001) due to cesarean for failure to progress (14 compared with 8%, P <.001). Independent risk factors for cesarean delivery included nulliparity, undilated cervix prior to labor, and epidural analgesia. Correction for these risk factors using logistic regression analysis revealed that it was the risk factors, and not induction of labor per se, that increased cesarean delivery. CONCLUSION: Risk factors intrinsic to the patient, rather than labor induction itself, are the cause of excess cesarean deliveries in women with prolonged pregnancies.

Class A1 gestational diabetes: a meaningful diagnosis?

OBJECTIVE: To compare pregnancy outcomes in women diagnosed as having class A1 gestational diabetes with those of a group with a normal 3-hour glucose tolerance test (GTT) to assess morbidities attributable to glucose intolerance. METHODS: Selective 50-g GTT identified pregnant women who received a 3-hour GTT. Over a 16-month period, 159 women were diagnosed as having class A1 gestational diabetes according to the National Diabetes Data Group criteria. During the latter 12 months of this time period, 151 women who had a normal GTT result were identified for comparison. RESULTS: There were statistically significant differences in age and the development of peripartum hypertension in women with class A1 gestational diabetes compared with the normal 3-hour GTT group. There were no significant differences in any neonatal outcome variable, including percent delivering large for gestational age (LGA) neonates in women with A1 diabetes compared to controls. Overall, 111 (36%) of the 310 neonates were classified as LGA, a rate more than double that in the singleton population in our hospital. Maternal weight, parity, and a history of a previous macrosomic infant were significantly associated with LGA outcome. Mean maternal weight was the same in the two GTT groups, implying an independent effect on fetal size. Obstetric interventions were not significantly different between the groups, so differences in intervention could not account for the lack of difference in outcome variables. The impact of dietary counseling in the class A1 diabetic women is also an unlikely explanation for the lack of differences in outcome. Within the normal-GTT group, women with one abnormal 3-hour value had a frequency of LGA infants similar to that of women with all normal 3-hour GTT values. These results suggest that there is a selection effect of screening for glucose intolerance that may relate more to other risk factors for LGA outcome than to glucose intolerance. Maternal obesity is an independent and more potent risk factor for large infants than is glucose intolerance. CONCLUSION: The diagnosis of class A1 gestational diabetes is not significantly associated with obstetric and perinatal morbidities. A nondiscriminating diagnostic test undermines the validity of population screening for glucose intolerance.

Forty weeks and beyond: pregnancy outcomes by week of gestation.

OBJECTIVE: To assess pregnancy outcomes at 40, 41, and 42 weeks' gestation when labor induction is done routinely at 42 but not 41 weeks. METHODS: We reviewed all singleton pregnancies delivered at 40 or more weeks' gestation between 1988 and 1998 at Parkland Memorial Hospital, Dallas, Texas. We excluded women with hypertension, prior cesarean, diabetes, malformations, breech presentation, and placenta previa. Labor characteristics and neonatal outcomes of pregnancies at 41 and 42 weeks' gestation were compared with pregnancies that ended at 40 weeks. Women with certain dating criteria had induction of labor at 42 weeks. Gestational age was calculated from the last menstrual period (LMP), sonography when available, and clinical examination. If the fundal height between 18 and 30 weeks was within 2 cm of gestational age, the reported LMP was accepted as correct. Sonogram was used to calculate gestational age if a discrepancy was identified. Statistical analysis consisted of chi(2) and analysis of variance. RESULTS: We studied 56,317 pregnancies: 29,136 at 40 weeks, 16,386 at 41 weeks, and 10,795 at 42 weeks. Labor complications increased from 40 to 42 weeks, including oxytocin induction (2% versus 35%, P <.001), length of labor (5.5 +/- 4.9 versus 8.8 +/- 6. 5 hours, P <.001), prolonged second stage of labor (2% versus 4%, P <.001), forceps use (6% versus 9%, P <.001), and cesarean delivery (7% versus 14%, P <.001). Neonatal outcomes were similar in the three groups, including 5-minute Apgar score less than 4, admission to the neonatal intensive care unit (NICU), umbilical artery pH less than 7, seizures, and perinatal mortality. Sepsis was more frequent in the 42-week group than the other groups (0.1 versus 0.3%, P =. 001), as was admission to the NICU (0.4 versus 0.6%, P =.008). CONCLUSION: Routine labor induction at 41 weeks likely increases labor complications and operative delivery without significantly improving neonatal outcomes.

Chorioamnionitis and the prognosis for term infants.

OBJECTIVE: To assess the effects of clinical chorioamnionitis and labor complications on short-term neonatal morbidity, including seizures. METHODS: This was a retrospective cohort study of all live-born term infants who weighed more than 2500 g delivered between 1988 and 1997 at Parkland Memorial Hospital, Dallas, Texas. Infant outcomes were compared between women with and without clinical diagnoses of chorioamnionitis. Chorioamnionitis was based on maternal fever of 38C or greater with supporting clinical evidence including fetal tachycardia, uterine tenderness, and malodorous infant. RESULTS: A total of 101,170 term infants were analyzed, 5144 (5%) of whom were born to women with chorioamnionitis. Apgar scores of 3 or less at 5 minutes, umbilical artery pH of 7.0 or less, delivery-room intubation, sepsis, pneumonia, seizures in the first 24 hours, and meconium aspiration syndrome were all increased in infants exposed to chorioamnionitis. After adjustment for confounding factors, including route of delivery and length of labor, chorioamnionitis remained significantly associated with intubation in the delivery room (odds ratio [OR] 2.0; 95% confidence interval [CI] 1.5, 2.6), pneumonia (OR 2.2; 95% CI 1.7, 2.8), and sepsis (OR 2.9; 95% CI 2.1, 4.1). Short-term neurologic morbidity, manifest as seizures, was not related to maternal infection during labor, but was significantly related to other labor complications. CONCLUSION: The main short-term neonatal consequence of chorioamnionitis is infection. Short-term neurologic morbidity in infants is related to labor complications and not chorioamnionitis per se.

Outcome of twin pregnancies according to intrapair birth weight differences.

OBJECTIVE: To assess the clinical significance of twin intrapair birth weight differences. METHODS: This was a retrospective study of twin pregnancy outcomes. Intrapair birth weight differences were stratified into the following six groups: 14% or less, 15-20%, 21-25%, 26-30%, 31-40%, and 41% or more using the larger infant as the growth standard. Statistical analysis was done using the Mantel-Haenzel chi2 test. RESULTS: We studied 1370 consecutive women who delivered at Parkland Hospital, Dallas, Texas, between January 1, 1988, and December 31, 1996, and had twin gestations and live births or fetal deaths within 7 days of delivery. Greater birth weight discordance was significantly associated with preterm delivery due to intervention (P<.001). Noncephalic-cephalic presentations and cesarean delivery were also associated with greater discordance (P = .001 and .02, respectively). Neonatal morbidities, including low birth weight, intensive care admission, and respiratory distress, were all associated with higher birth weight discordance. Fetal abnormalities were more common with increased discordance (P<.001). Greater birth weight discordance was also associated with intrauterine fetal death. There were no differences in outcome for the smaller compared with the larger twin of the twin pair. CONCLUSION: Twin birth weight discordance is problematic because severe divergent fetal growth increases the risk of fetal death and leads to obstetric intervention and consequent neonatal morbidity due to prematurity.