Michael C. Gordon

Late-Preterm Birth : Does the Changing Obstetric Paradigm Alter the Epidemiology of Respiratory Complications?

OBJECTIVE: To analyze the effect of gestational age, delivery mode, and maternal–fetal risk factors on rates of respiratory problems among infants born 34 or more weeks of gestation over a 9-year period. METHODS: Retrospective analysis of prospectively collected maternal and neonatal data on all inborn births at 34 or more weeks of gestation at a single tertiary care center for the years 1990–1998. Specific diagnostic criteria were concurrently applied by a single investigator. RESULTS: Over the 9-year period, late-preterm births increased by 37%, whereas births at more than 40 weeks decreased by 39%, resulting in a decrease in median age at delivery from 40 weeks to 39 weeks (P<.001). Respiratory problems occurred in 705 term or late-preterm infants (4.9%), with clinically significant morbidity (respiratory distress syndrome, meconium aspiration syndrome, or pneumonia) least common at 39–40 weeks of gestation. Respiratory morbidity was greater among infants born by cesarean delivery or complicated vaginal delivery compared with uncomplicated cephalic vaginal delivery. The rate of respiratory morbidity did not change over time (1990–1992 1.3%, 1993–1995 1.5%, 1996–1998 1.4%, P=.746). The etiologic fraction for respiratory morbidity did not change over time for infants 34–36 weeks but decreased twofold for infants born after 40 weeks. CONCLUSION: Over the 9-year study period, reduced respiratory morbidity associated with decreased births after 40 weeks were offset by the adverse respiratory effect of increased cesarean delivery rates and increased late-preterm birth rates. LEVEL OF EVIDENCE: III

The assessment of impulsivity and mediating behaviors in hyperactive and nonhyperactive boys.

Twenty boys (6–8 years) rated by their teachers as hyperactive and a matched sample of nonhyperactive boys performed a task that required them to withhold responding for a set time interval in order to be rewarded (DRL 6-second schedule). Half of each group worked on a one-button console while the other half was provided with additional collateral buttons. Results indicated that hyperactive children were relatively unable to perform efficiently on the task, and that this deficit endured regardless of age, IQ, or experimental condition. DRL was thus found to discriminate accurately between teacher-rated and parent-rated hyperactive and nonhyperactive children. Furthermore, a wide variety of self-generated mediating behaviors was observed, and it was determined that a childs DRL performance was related to the kind of mediating behaviors he displayed. Results are discussed in terms of the clinical assessment of hyperactivity and the training of impulsive children.

Perinatal outcome and long-term follow-up associated with modern management of diabetic nephropathy

Objective To determine outcomes in pregnancies complicated by class F diabetes mellitus cared for at a single center, and to assess renal function in these women. Methods A retrospective review (1988–1994) of all pregnant women with class F diabetes was performed, as well as an evaluation of current renal function. Results Forty-six pregnancies in 45 women reached a mean (± standard deviation) gestational age of 35.8 ± 2.3 weeks, with a mean birth weight of 2623 ± 818 g. No deliveries occurred before 30 weeks and 39 (84%) were at least 34 weeks. Perinatal survival was 100%. Women with initial serum creatinine exceeding 1.5 mg/dL or more than 3 g/24 hours proteinuria had an increased risk of early delivery, lower birth weight, preeclampsia, and cesarean delivery. Twenty-four individuals (53%) developed preeclampsia and seven met criteria for severe preeclampsia. By the third trimester, 26 women (58%) had greater than a 1 g/24 hour increase in proteinuria and 16 (36%) demonstrated more than a 15% fall in creatinine clearance. Follow-up was obtained in 34 subjects with a mean duration of 2.8 years. Individuals with initial creatinine clearance greater than 90 mL/minute and less than 1 g of protein per 24 hours had less loss of renal function at follow-up, as measured by creatinine clearance. At follow-up, mean protein excretion had decreased 1.9 g/24 hours from third-trimester values, but eight women (24%) maintained protein excretion exceeding 3 g/24 hours. Conclusion Modern management of class F patients can result in good perinatal outcomes. Renal function studies early in pregnancy can be used to define the risk of perinatal morbidity and long-term progression of renal disease.

Insulin and glucose modulate glucose transporter messenger ribonucleic acid expression and glucose uptake in trophoblasts isolated from first-trimester chorionic villi

OBJECTIVE Our purpose was to determine the effects of insulin and glucose on glucose transport and expression of GLUT1 glucose transporter messenger ribonucleic acid in first-trimester human trophoblast-like cells. STUDY DESIGN First-trimester human trophoblast-like cells were maintained as a continuous cell line. For 2[3H]deoxy-D-glucose uptake and messenger ribonucleic acid studies the cells were incubated in the presence or absence of insulin (10(-7) to 10(-11) mol/L) or D-glucose (0 to 50 mmol/L) for 0 to 24 hours. Glucose transport was measured by incubating cells with 0.1 mmol/L 2[3H]deoxy-D-glucose for 5 minutes. Specific uptake was determined by incubating companion cultures with 10 mumol/L cytochalasin B. The cells were then solubilized with sodium hydroxide and the radioactivity counted. Data were expressed as nanomoles of 2[3H]deoxy-D-glucose transported per milligram of protein per 5 minutes and analyzed by one-way analysis of variance with post hoc testing by the method of Tukey. GLUT1 messenger ribonucleic acid was measured by Northern blotting of total ribonucleic acid samples hybridized to a phosphorus 32-labeled complementary deoxyribonucleic encoding the rat GLUT1 glucose transporter. As a control for loading efficiency, blots were stripped and rehybridized to a 40-mer phosphorus 32-labeled beta-actin oligonucleotide probe. RESULTS Insulin treatment resulted in a dose-dependent increase in the transport of 2[3H]deoxy-D-glucose at 24 hours (p < 0.001 at 10(-7) mol/L). This change was first detected at 12 hours of incubation. These data closely paralleled the insulin-induced increase in GLUT1 messenger ribonucleic acid seen in Northern blots. In contrast to insulin, increasing concentrations of D-glucose did not change the transport of 2[3H]deoxy-D-glucose. However, when cells were incubated in low concentrations of D-glucose (0 or 1 mmol/L), an enhancement in the uptake of 2[3H]deoxy-D-glucose (p < 0.001) was observed. Kinetic studies indicated that D-glucose augmentation of 2[3H]eoxy-D-glucose uptake was significant at 9 hours (p < 0.05). The effects of D-glucose on GLUT1 messenger ribonucleic acid expression paralleled the uptake of 2[3H]deoxy-D-glucose, although the modulation of GLUT1 messenger ribonucleic acid levels by glucose was much less pronounced than in insulin-treated cells. CONCLUSION Although it has been assumed that the placenta has a limited role in influencing glucose transport to the fetus, our in vitro data demonstrate that both insulin and glucose can modulate glucose transport at the cellular level of the placental trophoblast. Thus maternal insulin and glycemic status may influence the expression of GLUT1, the major trophoblast glucose transporter protein, therefore directly affecting first-trimester placental glucose transport. These in vitro data may help explain the association between maternal glucose abnormalities and impaired fetal development during the first trimester when placental GLUT1 messenger ribonucleic acid expression is at its peak.

CORONARY ARTERY DISEASE IN INSULIN-DEPENDENT DIABETES MELLITUS OF PREGNANCY (CLASS H) : A REVIEW OF THE LITERATURE

Coronary heart disease and myocardial infarction are uncommon complications during pregnancy. Women with insulin-dependent diabetes mellitus (IDDM) have a much greater risk of serious coronary heart disease, but few cases of myocardial infarctions occurring during pregnancy have been reported. Significant maternal morbidity has been reported in half of these cases. This is a case of a myocardial infarction occurring at 21 weeks of gestation in a patient with class R/F IDDM and the subsequent pregnancy management as well as a review of the literature concerning Class H IDDM in pregnancy.

Transvaginal cervical length scans to prevent prematurity in twins: a randomized controlled trial

BACKGROUND Twin pregnancies are associated with an increased risk of perinatal morbidity and mortality primarily due to spontaneous preterm deliveries. The mean gestational age for delivery is 35.3 weeks and twins account for 23% of preterm births <32 weeks. A number of strategies have been proposed to prevent preterm deliveries: tocolytics, bed rest, hospitalization, home uterine activity monitoring, cerclage, and most recently, progesterone. Unfortunately, none have proven effective. Recent metaanalyses and reviews suggest that transvaginal cervical length (TVCL) ultrasound in the second trimester is a powerful predictor of preterm birth among asymptomatic women. Indeed, TVCL has the highest positive and negative predictive values for determining the risk of spontaneous preterm delivery in twin pregnancies. It follows that TVCL assessment may allow identification of a subset of twin pregnancies that re better candidates for interventions intended to prevent prematurity. OBJECTIVE We sought to determine whether use of TVCL prolongs gestation in twin pregnancies. STUDY DESIGN This is a multicenter, randomized, controlled trial of 125 dichorionic or monochorionic/diamniotic twin pregnancies without prior preterm birth <28 weeks. The study group (n = 63) had TVCL and digital exams monthly from 16-28 weeks and were managed with a standard algorithm for activity restriction and cerclage. The control group (n = 62) had monthly digital cervical examinations but no routine TVCL ultrasound examinations. The primary outcome was gestational age at delivery. Secondary outcomes included percentage of deliveries <35 weeks, and maternal and neonatal outcomes. RESULTS The mean gestational age at delivery was 35.7 weeks (95% confidence interval [CI], 35.2-36.2) among those managed with TVCL and 35.5 weeks (95% CI, 34.7-36.4) among the control patients. The Kaplan-Meier estimates of deliveries <38 weeks were not significantly different between groups. This was true whether we compared curves with a log-rank test (P = .67), Breslow test (P = .67), or Tarone-Ware test (P = .64). The percentage of deliveries <35 0/7 weeks did not differ: 27.4% for subjects managed with routine TVCL and 28.6% for control subjects (relative risk, 0.96; 95% CI, 0.60-1.54). Our study had an 80% power to detect a 12-day difference in the gestational age at delivery with 95% confidence. CONCLUSION The overall mean length of gestation and the percentage of women delivering <35 weeks did not differ between twin gestations managed with TVCL and digital exams monthly from 16-28 weeks with a standard algorithm for activity restriction and cerclage and controls who had monthly digital cervical examinations but no routine TVCL. Routine second-trimester transvaginal ultrasound assessment of cervical length is not associated with improved outcomes when incorporated into the standard management of otherwise low-risk twin pregnancies.