Vaginal delivery after cesarean section: a five-year study.

All pregnancies that were complicated by a previous cesarean section were reviewed for a five-year period from 1978 to 1982. Of 799 such pregnancies, 216 underwent a trial of labor, and 66% experienced successful vaginal delivery. When the primary cesarean section was for cephalopelvic disproportion, 54% delivered vaginally, 75% breech, and 70% for fetal distress or other nonrepeating indications. There was no evidence of uterine scar disruption in the vaginally delivered group. Vaginal delivery after previous cesarean section can be a safe alternative for carefully selected patients cared for in the proper environment.

Duplex Doppler ultrasound in the evaluation of growth in twin pregnancies.

Fifty-six multiple pregnancies were evaluated for evidence of discordant growth using traditional ultrasonic methods and duplex Doppler ultrasound. The pregnancies consisted of 52 sets of twins and four sets of triplets. Duplex Doppler ultrasound predicted normal growth in 44 of 45 normal sets of fetuses, and correctly predicted discordant growth in nine of 11 discordant sets of twins. Among those nine abnormal sets, Doppler ultrasound predicted that six would become discordant before this was recognized by traditional ultrasonic measurements. Duplex Doppler ultrasound is useful in predicting and confirming concordant and discordant growth, and defining the cause of fetal discordancy.

Smoking and pregnancy.

This paper reviews the effects of tobacco and cigarette smoking on general health and pregnancy and gives general evidence-based guidelines regarding tobacco cessation. The paper outlines a simple proven health-care plan that providers can use for their pregnant patients who smoke and discusses future advances in smoking cessation.

Fetal blood flow measurements in severe rhesus isoimmunization. A case report.

Maternal isoimmunization can result in fetal anemia. Current management of isoimmunized pregnancies involves amniocentesis and spectrophotometry. Pulsed Doppler ultrasound can provide fetal blood flow determinations from the fetal umbilical vein. A pregnancy complicated by severe rhesus isoimmunization was studied with Doppler ultrasound. Increased fetal umbilical blood flow was associated with increased fetal hemolysis. Umbilical vein blood flow decreased after intrauterine transfusion. Doppler ultrasound assessment of fetal blood flow is a useful noninvasive adjunct in isoimmunized pregnancies.

Percutaneous umbilical blood sampling. A new technique for prenatal diagnosis.

Direct access to fetal blood during the second and third trimesters of pregnancy opens new fields of prenatal diagnosis and in utero fetal treatment. Percutaneous umbilical blood sampling, a method that involves ultrasonographically guided needle insertion into the umbilical vein, appears to have an acceptable complication rate. This technique has tremendous potential for use in evaluating fetal status.

A pocket computer program for obstetric ultrasound calculations.

A pocket computer program is currently being used to perform complicated obstetric ultrasound calculations at the Medical Center Hospital of Vermont. The program calculates decimal weeks between dates, gestational age from biparietal diameter, crown-rump length or femur length, total intrauterine volume, head-abdominal circumference ratios, projected gestational age from previous measurements, and estimated fetal weight. Calculations can be printed for a permanent record. The pocket computer program provides a convenient, accurate, and affordable method of obstetric ultrasound analysis.

Gastroschisis: prenatal CT diagnosis.

The prenatal sonographic findings of gastroschisis are well defined. This report describes the CT appearance of fetal gastroschisis discovered as an incidental finding when a 25-year-old pregnant woman underwent CT for blunt abdominal trauma.

Percutaneous fetal umbilical blood sampling: procedure safety and normal fetal hematologic indices.

Percutaneous umbilical blood sampling allows direct access to the fetal circulation. We describe our experience with the procedure in the first 100 patients whose fetuses were at risk for hemolytic anemia, chromosomal abnormalities, coagulopathy, or intrauterine infection. Hematologic indices, including hemoglobin, hematocrit, red blood cell count, white blood cell count, and platelet count, were analyzed from 50 of the fetuses who were normal at delivery. Normal values and gestational age regression curves (from 17 to 37 weeks' gestation) are presented. The technique and complications of the procedure are described. Percutaneous umbilical blood sampling affords useful information in prenatal diagnosis and entails a low rate of complications.

Detection of fetal blood contamination by amniotic fluid obtained during cordocentesis.

When a fetal blood sample is obtained by cordocentesis it is important to know whether the sample is diluted with amniotic fluid. This study was designed to assess whether contaminated fetal blood samples could be discriminated from noncontaminated ones by the ferning test, and if so what is the minimum dilution ratio of amniotic fluid/fetal blood that is detectable. Fetal blood samples were diluted with amniotic fluid and were tested for ferning under the microscope after the plasma was separated from the cells. At a dilution ratio of 0.2 ml of amniotic fluid to 1 ml of fetal blood, 30% of the samples tested positive for ferning. A rate of 100% detection of ferning was achieved at a dilution ratio of 0.6:1. In conclusion, screening fetal blood samples for ferning can detect amniotic fluid contamination. The sensitivity of the test for ferning depends on the dilution ratio. The test cannot assess how much amniotic fluid was added to the blood sample.

Maternal-fetal substrate relationships in the third trimester in human pregnancy.

The maternal-fetal relationship of metabolic substrates was examined in 12 mothers undergoing cordocentesis for clinical reasons between 23 and 36 weeks' gestation. Twenty cordocentesis procedures were performed. Blood glucose, insulin, beta-hydroxybutyrate, glycerol and lactate were measured in simultaneously obtained maternal and fetal samples. There was a linear correlation between fetal and maternal concentration of glucose (y = 0.687x + 0.756, R2 = 0.65 and p = 0.001), and beta-hydroxybutyrate (y = 0.443x + 0.16, R2 = 0.938 and p = 0.0001). No relation between fetal insulin and glucose concentration was observed. No correlation was seen between maternal and fetal lactate concentration. The data on glycerol could be divided into two groups. When the fetal glycerol levels were below 100 mumol/l, the fetal glycerol concentration was always less than the simultaneously obtained maternal level. However, when the fetal glycerol levels were greater than 100 mumol/l, the corresponding maternal levels were lower than that in the fetus. The exact mechanism or significance of higher fetal glycerol levels remains unknown. These data demonstrate the usefulness of cordocentesis in the understanding of fetal metabolism. In correlation with isotopic tracer, cordocentesis could provide detailed insight into human fetus in the future.

Normal blood gases in fetuses with absence of end-diastolic umbilical artery velocity.

Five fetuses with absent end-diastolic umbilical artery velocity had normal fetal acid-base status assessed by cordocentesis. Each fetus, despite widely differing pathologic conditions, deteriorated over the next several days. These cases confirm an earlier report of normal gases with absent umbilical artery end-diastolic velocity. Normal blood gases on cordocentesis cannot provide extended reassurance in fetuses with absent end-diastolic velocity.

Changes in sodium transport during the human menstrual cycle and pregnancy.

1. We have studied the transport of Na+ and K+ by erythrocytes during the follicular and luteal phases of the human menstrual cycle, and in pregnant compared with non-pregnant women. Venous blood was drawn from 10 healthy young women (not taking any medication or hormones) 1-2 days after menstruation and from the same women 7-9 days after ovulation. For the pregnancy part of the study, blood was drawn from eight other normotensive non-pregnant women and from eight age-matched normotensive pregnant women (36-43 weeks gestation). 2. Intracellular erythrocyte and plasma Na+ and K+ concentrations were measured by flame photometry. The increase in the intracellular Na+ concentration during a 1 h 37 degrees C incubation of fresh whole blood with 0.2 mmol/l ouabain (compared with no ouabain) was measured to determine the rate of active Na+ efflux. The Na(+)-K+ pump rate constant was calculated by dividing the active Na+ efflux rate by the intracellular Na+ concentration. 3. In fresh blood, the intracellular erythrocyte Na+ concentration (P < 0.002) and the plasma K+ concentration (P < 0.01) were both lower in pregnant than in non-pregnant women. The Na(+)-K+ pump rate constant was higher (P < 0.02) during the luteal phase than during the follicular phase, and in pregnant compared with non-pregnant women. 4. We conclude that short-acting hormones in the plasma most probably account for the changes in the Na(+)-K+ pump rate constant during the menstrual cycle.

Trends in an obstetric patient population: an eighteen-year study.

OBJECTIVE: Our goal was to evaluate various trends including gestational age, birth weight, and mode of delivery in an inner-city obstetric patient population delivered at a tertiary medical center. STUDY DESIGN: We used an 18-year computerized perinatal database collected prospectively since 1975 in an inner-city tertiary medical center. More than 63,500 deliveries from 1975 through 1992 were evaluated. Trends in gestational age, birth weight, and mode of delivery were investigated with Cox-Stuart, regression, and other trend analysis methods. RESULTS: The number of deliveries increased from 2682 in 1975 to 4740 in 1991, an increase of 77%. The median maternal age has increased from 20 years in 1975 to 23 years in 1992 (p < 0.001). Overall, the mean gestational age has declined monotonically from 39.2 +/- 2.84 weeks in 1975 to 38.3 +/- 3.17 weeks in 1992 (p = 0.057). While the median and lower percentiles of birth weight for singleton births have declined, the 75th and higher percentiles of birth weight have increased during 18 years. Overall, the proportion of preterm births (< 37 completed weeks gestational age) has increased from 3.3% in 1975 to 7.8% in 1991 (p < 0.001). During this period the proportion of low-birth-weight infants (< 2,500 gm) increased significantly from 12.7% to 17.3% (p < 0.001). The proportion of cesarean section deliveries for private patients has declined from 37% in 1975 to 25% in 1992 (p = 0.025), while this proportion has increased monotonically for staff patients from 10% to 17% during this period (p < 0.001). CONCLUSIONS: Considering the large size of the database and diverse background of the study population, we believe that these trends can provide a realistic characterization of an obstetric patient population for a large inner-city urban population.

Improvement in CT pelvimetry.

When computed tomographic (CT) digital radiography is used for pelvimetry, measurement error may occur. Geometric distortion in the lateral direction of the CT digital radiograph can lead to an error in any measurement of the transverse pelvic inlet. The authors measured the magnitude of this error on two scanners and present a general method for correction of this potential error. The authors also showed that an additional dose reduction is possible if the patient is imaged in the posteroanterior rather than anteroposterior projection.