Biomedical subjects

William F Rayburn

Publications and source records attributed to William F Rayburn.

At least 19 recordsLinked to original sources

PubMed2006

Pharmacokinetics of a controlled-release misoprostol vaginal insert at term.

OBJECTIVE: The objective of this investigation was to report the pharmacokinetic properties of misoprostol administered intravaginally to women at term via a controlled-release hydrogel polymer insert. METHODS: This open-label, dose escalation trial consisted of 31 nulliparous women at term who were treated intravaginally in cohorts of six with inserts containing reservoirs from 25 through 300 microg (7 at 200 microg) of misoprostol. Inserts remained intravaginally until the patient went into labor, developed adverse events, or completed 24 hours of treatment. Complete data about residual drug in the inserts and plasma concentrations of misoprostol acid were gathered for 27 and 25 patients, respectively. RESULTS: Misoprostol was released at a constant rate (5.1% total dose per hour) with the amount absorbed being directly proportional to the dose reservoir. For the 25-, 50-, 100-, 200-, and 300-microg reservoir doses, the maximum median plasma concentrations were 6.4, 11.3, 21.7, 40.8, and 74.2 pg/mL, respectively, and the area under the curve until drug removal was 39, 117, 223, 269, and 477 pg x h/mL. Regardless of dose, the peak plasma concentration occurred at approximately 7 hours after insertion and the elimination half-life of the misoprostol acid was 0.55 hours (95% confidence interval, 0.36 to 1.32 hours). CONCLUSIONS: Misoprostol is released from the vaginal insert in a controlled manner and is eliminated rapidly after removal. Pharmacokinetic parameters are proportional to the reservoir dose.

Administration, Intravaginal↗

PubMed2006

Effect of chronic maternal methadone therapy on intrapartum fetal heart rate patterns.

OBJECTIVE: Treatment of maternal opioid dependence with methadone is associated with a delay in fetal heart rate (FHR) accelerations in nonstress tests. The objective of this investigation was to determine the effect of methadone maintenance therapy on intrapartum FHR patterns. METHODS: This retrospective cohort study compared intrapartum FHR tracings from 56 methadone-treated patients > or =36 weeks gestation with a control group of nonsubstance using patients matched for maternal age, parity, gestational age, and ethnicity. Blinded FHR interpretation included the recording of baseline, variability, accelerations, and late or severe variable decelerations. The 8-point FHR scoring system was based on the National Institute of Child Health and Human Development Research Planning Workshop guidelines. We considered a 25% reduction in the score during the latent phase to be significant. RESULTS: The median maintenance dose of methadone was 70 mg daily, with a range between 20 mg and 130 mg. Each patient tested negative for other substances on urine screening before admission. The significantly lower FHR score in the methadone group (mean difference, 1.4; 95% confidence interval, 1.1 to 1.7) was attributed to a lower baseline (P <.05), less moderate or marked variability (P <.01), and a lower proportion of accelerations during the first stage of labor (P <.01). A higher proportion of methadone-exposed fetuses had late or severe variable decelerations in the second stage (44.2% vs 22.9%; P <.03). Analgesic needs, operative vaginal or cesarean delivery rates, and Apgar scores less than 7 at 1 and 5 minutes were not significantly different between the two groups. CONCLUSIONS: Chronic maternal methadone treatment affects intrapartum FHR patterns by reducing the variability, baseline, and proportion of accelerations during the first stage. These subtle drug-induced effects do not compromise intrapartum decision-making or immediate newborn adjustments.

Adult↗

PubMed2006

Cross-over trial of fetal heart rate response to halogen light and vibroacoustic stimulation.

OBJECTIVE: The purpose of this study was to compare the effect of halogen light and vibroacoustic stimulation on fetal heart rate (FHR) responsiveness and on nonstress test (NST) results. METHODS: Sixty consecutively-chosen patients between 33 and 39 weeks of gestation underwent an NST on at least three weekly occasions. Each received halogen light (Vector Compact Sport Spot, Ft Lauderdale, FL, USA), vibroacoustic (SolaTone Artificial Larynx, Temecula, CA, USA), and no stimulation in a randomized order. The transabdominal light or vibroacoustic stimulation lasted for 10 seconds. If no initial FHR acceleration occurred, then the stimulus was repeated 10 minutes later up to a maximum of three times. The investigators who interpreted the FHR patterns were blinded as to the type of stimulus used. RESULTS: Reactive results were present in 171 tests (vibroacoustic: 98.3%; light: 96.6%; none: 93.3%). Compared with no stimulation, the mean difference in time from the onset of recorded "stimulation" to the first FHR acceleration was shorter (p < 0.01) with either light (2.7 minutes, 95% confidence interval (CI) 0.9-4.5 minutes) or vibroacoustic stimulation (2.6 minutes, 95% CI 0.8-4.4 minutes). The mean time difference until a reactive result was also shorter (p < 0.05) with either light (2.7 minutes, 95% CI 0.1-4.9 minutes) or vibroacoustic stimulation (2.4 minutes, 95% CI 0.1-4.7 minutes) than with no stimulation. The need for repeated stimulation during each test was infrequent (light: 5.0%; vibroacoustic: 3.3%). No adverse effect from external stimulation was noted on the FHR tracing. CONCLUSION: Halogen light stimulation is an acceptable alternative to vibroacoustic stimulation in provoking a more rapid fetal heart rate response and in shortening the time before a reactive nonstress test result.

Acoustic Stimulation↗

PubMed2006

Elective induction of labor.

Induction of labor rates have more than doubled nationwide in the past 15 years. The increase in medically induced inductions was slower than the overall increase, suggesting that inductions for marginal or elective reasons rose more rapidly. Elective inductions seem to account for at least half of all inductions and 10% of all deliveries. Whether the experience of an elective induction is satisfactory to the patient, obstetrician, and intrapartum crew warrants more widespread attention. Cesarean rates are high for nulliparas undergoing an induction with an unfavorable cervix. Prospective studies are limited or nonexistent to recommend induction of labor for elective or marginal indications. Until more prospective work is performed, it will be difficult to evaluate the true impact of the elective induction of labor on population-wide cesarean delivery rates. Strategies for increased obstetrician awareness are proposed through practice guidelines and through clinical research trials.

Attitude to Health↗

PubMed2006

Beer consumption among hazardous drinkers during pregnancy.

OBJECTIVE: The objective of this study was to examine the prevalence of beer consumption among hazardous drinkers in our pregnant patient population. METHODS: This prospective clinic-based cohort study involved women who were surveyed during their first prenatal visit. Hazardous drinking was identified on alcohol surveys as frequent or binge drinking habits with related consequences. Participants completed initial and postpartum interviews about the quantity, frequency, and type (beer, wine, liquor, and/or combinations) of alcoholic beverages consumed before and after pregnancy recognition. RESULTS: Of the total 4,494 patients who completed the survey, 203 (4.52%) met criteria for hazardous drinking, met study eligibility criteria, and completed the interviews. Beer was consumed most often (n = 151, 74.4%) and in greater quantities than wine (P < .05) or liquor (P < .01). Beer continued to be consumed by 52.3% women after pregnancy recognition. Although abstinence for prolonged periods was common during pregnancy, beer was consumed more than wine and liquor per drinking episode (2.7 versus 0.9 drinking units per drinking day; P = .002) indicating a binging pattern. Very few switched to drinking either a light beer (n = 6) or a nonalcoholic beer (n = 1). CONCLUSION: Beer is the most consumed among women with hazardous drinking habits before and after pregnancy awareness. Focusing on binge beer drinking is worthwhile during routine prenatal questioning. LEVEL OF EVIDENCE: II-2.

Adult↗

PubMed2006

Tenure of academic chairs in obstetrics and gynecology: a 25-year perspective.

OBJECTIVE: To assist in predicting future leadership needs, this longitudinal study examines turnover and net retention rates among chairs at university obstetrics and gynecology departments between 1981 and 2005. METHODS: A database of appointment dates and tenure of chairs at each of 125 Association of American Medical Colleges-approved United States medical schools was collated using membership listings from the Association of Professors of Gynecology and Obstetrics and from the Council of University Chairs in Obstetrics and Gynecology. Complete data from 118 departments were confirmed by selective correspondence at individual departments and further review by the investigators. RESULTS: A total of 260 individuals (232 men, 28 women) became new chairs between 1981 and 2005. The annual turnover rate increased gradually from 6.0% to 12.7%. Five-year net retention rates remained steady between 1982 and 1997 but dropped after 1997 (85.6% compared with 63.2%; P=.03). A chair's tenure ranged widely (1 to 23 years; median 8 years), regardless of gender or school type, size, or location. Approximately one half of interim chairs became permanent chairs, usually at their own institution. The number of new women chairs increased from none in 1981 to 17 (15.2% of total chairs) in 2005. CONCLUSION: Academic chair positions in obstetrics and gynecology experienced a doubling in annual turnover rates, while retention rates declined. The proportion of chairs occupied by women increased progressively. LEVEL OF EVIDENCE: II-2.

Administrative Personnel↗

PubMed2006

Impact of alcohol exposure after pregnancy recognition on ultrasonographic fetal growth measures.

BACKGROUND: More than 3 decades after Jones and Smith (1973) reported on the devastation caused by alcohol exposure on fetal development, the rates of heavy drinking during pregnancy remain relatively unchanged. Early identification of fetal alcohol exposure and maternal abstinence led to better infant outcomes. This study examined the utility of biometry for detecting alcohol-related fetal growth impairment. METHODS: We obtained fetal ultrasound measures from routine ultrasound examinations for 167 pregnant hazardous drinkers who were enrolled in a brief alcohol intervention study. The fetal measures for women who quit after learning of their pregnancies were compared with measures for women who continued some drinking throughout the course of their pregnancies. Because intensity of alcohol consumption is associated with poorer fetal outcomes, separate analyses were conducted for the heavy (average of >or=5 drinks per drinking day) alcohol consumers. Fetal measures from the heavy-exposed fetuses were also compared with measures from a nondrinking group that was representative of normal, uncomplicated pregnancies from our clinics. Analyses of covariance were used to determine whether there were differences between groups after controlling for influences of gestational age and drug abuse. RESULTS: Nearly half of the pregnant drinkers abstained after learning of their pregnancies. When women reportedly quit drinking early in their pregnancies, fetal growth measures were not significantly different from a non-alcohol-exposed group, regardless of prior drinking patterns. Any alcohol consumption postpregnancy recognition among the heavy drinkers resulted in reduced cerebellar growth as well as decreased cranial to body growth in comparison with women who either quit drinking or who were nondrinkers. Amphetamine abuse was predictive of larger cranial to body growth ratios. CONCLUSIONS: Alterations in fetal biometric measurements were observed among the heavy drinkers only when they continued drinking after becoming aware of their pregnancies. Although the reliance on self-reported drinking is a limitation in this study, these findings support the benefits of early abstinence and the potential for ultrasound examinations in the detection of fetal alcohol effects.

Alcohol Drinking↗

PubMed2005

Required research by medical students and their choice of a women's health care residency.

OBJECTIVE: This study searches for association between the subject of medical students' required research projects and subsequent choices of residency, focusing specifically on women's health fields. STUDY DESIGN: Students at our school graduating between 1997 and 2004 (n = 535) were required to undertake a research project beginning in the preclinical years. The subject of their required research project was related to their subsequent choice of residency. RESULTS: Ninety-nine of the 535 projects (18.5%) were women's health related. Although overall there was no significant relationship between the research project and residency choice, students who completed a women's health care project were nearly twice (1.8, 95% CI, 1.4-2.3) as likely to enter a women's health (obstetrics and gynecology or family medicine) residency than those who did not. CONCLUSION: An association exists between student participation in women's health research beginning during preclinical years and the subsequent choice of a women's health residency.

Choice Behavior↗

PubMed2005

Misoprostol dose selection in a controlled-release vaginal insert for induction of labor in nulliparous women.

OBJECTIVE: The purpose of this study was to identify the maximum tolerable dose and to determine the efficacy of different misoprostol dose reservoirs in an intravaginal controlled-release hydrogel polymer. STUDY DESIGN: Nulliparous women at > or = 37 weeks' gestation requiring cervical ripening and induction of labor were treated with misoprostol in a controlled-release, retrievable hydrogel polymer vaginal insert. Sequential cohorts of 6 patients were to be treated with escalating dose reservoirs of 25, 50, 100, 200, and 300 mug. The insert was to be removed upon onset of active labor, at 24 hours, or earlier if treatment-related adverse events occurred. The safety end point was determination of the maximum tolerable dose (MTD) based on occurrence of hyperstimulation syndrome. Our primary efficacy end point was time to vaginal delivery. RESULTS: Increasing reservoir doses of misoprostol up to 100 microg produced more rapid increases in modified Bishop scores, less need for oxytocin, and a shorter time to vaginal delivery. Doses above 100 microg did not further enhance cervical ripening or shorten time to vaginal delivery. The median time to vaginal delivery was 14.2 hours using the 100 microg dose. Uterine hyperstimulation and adverse fetal heart rate effects occurred with the 200 and 300 microg inserts. CONCLUSION: The 100 microg vaginal insert resulted in successful cervical ripening and rapid vaginal delivery with an acceptable safety profile for future randomized clinical trials.

Administration, Intravaginal↗

PubMed2005

Obstetrics and gynecology residents as teachers of medical students: predictors of excellence.

OBJECTIVE: The purpose of this study was to assess variables that might predict which intern candidates will become excellent teachers of medical students. STUDY DESIGN: This retrospective cohort study compared demographic characteristics, previous work experience, United States Medical Licensing Examinations scores, honors on core clerkships, membership in Alpha Omega Alpha, and match list ranking of 43 residents to identify predictors of excellent teaching evaluations during residency. RESULTS: Fifteen residents (35%) were identified as excellent teachers. They were more likely to have had previous work experience, to be older, or to be male. They were not more likely to have higher United States Medical Licensing Examinations test scores, more honors grades, Alpha Omega Alpha membership, or a higher rank list position. CONCLUSION: Work experience, age, and male gender are associated with increased likelihood of being identified as an excellent teacher by medical students. Programs in which residents have a significant role as teachers of students may consider these factors in the residency selection process.

Adult↗

PubMed2005

Chemotherapeutic drugs in pregnancy.

Chemotherapy may be indicated for the treatment of cancer during pregnancy. The decision to use chemotherapy significantly impacts the pregnancy, and in turn the pregnancy may affect the treatment options available to patients with cancer. This review provides information about the effects of chemotherapeutic agents in pregnancy, taking into account both the mother and the fetus. For convenience, the agents are divided into categories based upon class and mechanism of action. These include alkylating agents, antimetabolites, nucleoside analogs, topoisomerase I inhibitors, topisomerase II inhibitors, vinca alkaloids, taxanes, and biologics such as signaling and growth factor blocking agents.

Antineoplastic Agents↗

PubMed2005

Consequences of routine delivery at 38 weeks for A-2 gestational diabetes.

OBJECTIVE: To report our intrapartum experience with routine delivery at 38 weeks of gestation of A-2 diabetic pregnancies requiring primarily oral hypoglycemic therapy. METHODS: This retrospective study consisted of 143 consecutive women with gestational diabetes not controlled with diet alone (A-2). Each underwent a routine trial of labor at 38 weeks of gestation. The preinduction condition of the cervix, need for oxytocin, and primary cesarean rates were primary endpoints. For comparison, a control group during that same period consisted of 137 consecutive diet-controlled diabetic (A-1) pregnancies with the same eligibility criteria who underwent expectant management at 38 weeks. RESULTS: The study group was more likely to have an unfavorable cervix (75% versus 45%; p < 0.001) and to require oxytocin (76% versus 56%; p < 0.001). Early onset meconium was less common in the study group (3.5% versus 13.1%; p < 0.01). Primary cesarean rates were low and not different between the study and control groups (12.7% versus 11.7%; p < 0.8). The only stillbirth was in the control group and was associated with a tight double nuchal cord encirclement. Mean birth weights and the frequency of birth weights > 4000 g were not different between groups. Shoulder dystocia, low Apgar scores, and admissions to the special care nursery were infrequent in either group. No respiratory difficulties requiring resuscitation or prolonged nursery care were encountered. CONCLUSION: Routine delivery at 38 weeks in an A-2 diabetic population is not associated with additional intrapartum morbidity or a greater need for cesarean delivery.

Administration, Oral↗

PubMed2005

Vaginal misoprostol for cervical ripening at term: comparison of outpatient vs. inpatient administration.

OBJECTIVE: To compare outpatient with inpatient misoprostol for preinduction cervical ripening at term. STUDY DESIGN: This concurrent cohort study was conducted between August 1999 and July 2002 at a rural community hospital. Pregnancies > or =38 weeks with an unfavorable cervix were eligible if there was a reactive nonstress test with no regular contractions or active medical/obstetric complications. Outpatients were given a single dose of misoprostol (50 microg intravaginally). A cohort group consisted of similar patients undergoing misoprostol therapy in the hospital. RESULTS: No differences were found between the outpatient (n=177) and inpatient (n=96) misoprostol groups for maternal age, parity, gestational age, and initial cervical dilation and station. No home deliveries occurred with outpatient therapy. Advanced cervical dilation at hospital admission the next morning was more common with outpatient misoprostol (10.2% vs. 2.1%; RR 5.0, 95% CI 1.2, 21.5). Differences in mean times from admission to vaginal delivery were significantly shorter with outpatient than inpatient misoprostol (nulliparas, 3.1 hours, 95% CI 1.5, 4.7; multiparas, 5.3 hours; 95% CI 3.8, 6.8). The very low proportions of fetal intolerance to labor, low Apgar scores and newborn complications were not different between the 2 groups. CONCLUSION: Outpatient vaginal misoprostol in a selected population led to more advanced cervical dilation at hospital admission the next morning and explained the shorter time until vaginal delivery.

Administration, Intravaginal↗

PubMed2004

Accuracy of home pregnancy tests at the time of missed menses.

OBJECTIVE: The purpose of this study was to investigate the validity of home pregnancy tests (HPTs) around the time of the missed menses. STUDY DESIGN: Levels of human chorionic gonadotropin (hCG) were determined in urine around the time of the missed menses, and 5th and 95th centiles were calculated. In a blind study evaluating 18 brands of HPTs, each was tested six times with five concentrations of hCG, 0 to 100 mIU/mL. Sensitivity was defined as the concentration at which six of six brands gave positive results, at the suggested reading time or at an extended time. RESULTS: It was estimated that a sensitivity of 12.5 mIU/mL was needed to detect 95% of pregnancies at the time of missing menses. Only 1 of 18 HPTs had this sensitivity. If faintly discernible results considered, 2 of 18 brands gave false-positive or invalid results. Clear positive results were given by only 44% of the brands at 100 mIU/mL hCG. If one accepted faintly discernible and extended reading times, all brands responded at 100 mIU/mL. A test with 100 mIU/mL sensitivity would detect approximately 16% of pregnancies at the time of missed menses. CONCLUSION: The utility of HPTs is questioned. Clinicians need to be aware of the limitations of current HPT brands.

Chorionic Gonadotropin↗

PubMed2004

Chronic prenatal exposure to carbamazepine and behavior effects on mice offspring.

OBJECTIVE: The purpose of this study was to assess the impact of chronic prenatal exposure to a therapeutic dose of carbamazepine on the behavior of mice offspring in a randomized, placebo-controlled manner. STUDY DESIGN: Twenty-eight C3H/He mice were assigned randomly to treatment groups that were given food that contained either carbamazepine (25 mg in 10 g food) or a placebo for 1 week before mating and throughout gestation. Adult offspring from eight litters of each group were evaluated for standard tasks for motor, arousal/motivation, anxiety, and cognition. Statistical comparisons included analysis of variance and the Fisher exact test. RESULTS: Compared with the placebo group, there were no significant differences among the carbamazepine offspring in the duration of gestation, litter size, and birth weights. Fewer locomotor chamber movements were recorded in the carbamazepine group than in the placebo-exposed group at postnatal day 21 (469 vs 555 counts for 60 minutes, P<.03) and as adults (510 vs 688 counts for 60 minutes, P<.03) Coordination, balance, and exploratory behavior did not differ between exposure groups. A startle response from auditory arousal was decreased in carbamazepine-exposed adults (1.4% vs 21.9%, P<.03). Performances on anxiety/motivation tasks and on learning/memory tasks revealed no significant differences between exposure groups. CONCLUSION: Although prenatal exposure induced subtle arousal effects and slower locomotor activity, carbamazepine did not have an impact on coordination, cognition, or responses to anxiety-provoking conditions. Correlation in humans is recommended.

Animals↗

PubMed2004

Effect of halogen light stimulation on nonstress testing.

OBJECTIVE: This study was undertaken to determine whether external stimulation using a halogen light source influences fetal heart rate (FHR) responsiveness and nonstress test results. STUDY DESIGN: A total of 107 patients at 32 to 42 weeks' gestation undergoing a nonstress test were randomly assigned to have either transabdominal light stimulation or no light stimulation. The light (Vector Compact Sport Spot, Ft Lauderdale, Fla) was turned on for 10 seconds. If no qualifying FHR acceleration was observed, then the stimulus was repeated at 10-minute intervals for a maximum of 3 times. The investigators were blinded as to light stimulation for FHR interpretation. RESULTS: Reactive results were present in 52 cases in each group. Light stimulation led to a significantly shorter time (P <.02) until the first FHR acceleration (difference: 2.1 minutes; 95% CI 0.4-3.8 minutes). The height and width of the first acceleration were indistinguishable between groups. The time until a reactive result was significantly shorter after light stimulation (difference: 4.2 minutes; 95% CI 2.0-6.4 minutes). CONCLUSION: The earlier onset of FHR accelerations after halogen light stimulation prompted a more rapid reactive nonstress test result.

Confidence Intervals↗

PubMed2004

Pharmacotherapy for pregnant women with addictions.

OBJECTIVE: Dependence on alcohol, nicotine, or illicit drugs during pregnancy continues to be a problem of major medical, social, and fetal consequences. The purpose of this systematic review was to summarize current experience that pertains to pharmacotherapy for pregnant women with specific chemical addictions. STUDY DESIGN: Studies were identified through Medline and HealthSTAR (1979-2003) that linked specific pharmacotherapy with pregnancy. This article reviews the English language literature for clinical studies that link the 2 conditions. In addition, reference lists of all articles that were obtained were evaluated for other potential citations. RESULTS: Pregnant women are excluded systematically from almost all drug trials. Most knowledge about the fetal effects from maternal substance and medication use comes from animal data and from case reports and small clinical series. With the exception of methadone and nicotine replacement, clinical experience with antiaddictive medications in pregnant women is either very limited (alcohol, stimulants) or nonexistent (cannabis, hallucinogens). CONCLUSION: Antiaddiction medications are important in the treatment of pregnant women with opioid and nicotine dependence and are of growing importance in the treatment of alcohol and stimulant dependence. Future directions will be toward increasing knowledge about current drug therapy and in developing new antiaddiction medications.

Adolescent↗

PubMed2004

Chronic prenatal exposure to carbamazepine and perinatal outcomes of C3H/He mice.

OBJECTIVES: This study was undertaken to determine a daily therapeutic dose of carbamazepine and to measure its effect on reproductive performance and perinatal outcomes of mice. STUDY DESIGN: Adult C3H/He mice were given carbamazepine in rodent chow in either a 0.25% or a 1.0% mixture. Comparisons between doses included nongravid weight change, plasma drug steady-state concentrations, and response to a maximal electroshock seizure test. The strain was then fed either the preferred dose of carbamazepine or a placebo 1 week before starting to mate and throughout gestation to compare reproductive performance and offspring early development. RESULTS: Mice who ate the 0.25% carbamazepine mixture displayed no evoked seizure activity and, in contrast to the 1.0% mixture, did not lose weight. This daily dose of 542+/-35 mg/kg produced a trough steady-state plasma concentration that was consistent with a protective threshold in humans. Differences from placebo controls were not statistically significant for the number of cycles necessary to conceive or for the duration of gestation. The litter size, survival rates, birth weights, weight gain, and onset of eye openings and teeth eruptions of the pups were not statistically significant between the two groups. CONCLUSION: Long-term prenatal exposure to a subtoxic yet therapeutic dose of carbamazepine did not impair reproductive performance or early growth and development of exposed mice offspring.

Animals↗