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Biomedical subjects

W H Clewell

Publications and source records attributed to W H Clewell.

At least 19 recordsLinked to original sources

Intracervical prostaglandin E2 gel. Safety for outpatient cervical ripening before induction of labor.

Cervical ripening prior to induction of labor is often necessary for medical complications of pregnancy. We proposed to prospectively determine the safety of administering prostaglandin E2 (PGE2) gel intracervically in an outpatient setting. Four hundred forty-six patients underwent 515 gel procedures as outpatients. Trained perinatal nurses placed 0.5 mg of PGE2, prepared in a standard methylcellulose base, in the intracervical canal. The PGE2 dose was administered every two hours for a total of three doses if labor did not start. The patient was sent home two hours after the last dose if she was not in active labor. Labor started in 90 patients (20%) during the gel procedure; they were admitted to the labor-and-delivery unit. The remaining patients were discharged. Eighty-eight patients (20%) were later admitted in active labor prior to scheduled induction. One patient (0.02%) was found to have occasional prolonged decelerations on admission and underwent a cesarean section two hours after admission; the Apgar scores were 8 and 9 and the arterial pH, 7.21. Hyperstimulation with excessive intrauterine activity caused significant deceleration of the fetal heart rate in four patients (0.8%), two of whom required transfer to the labor-and-delivery unit but none of whom needed a cesarean section for fetal distress. PGE2 gel can be administered safely intracervically as an outpatient procedure by trained perinatal nurses.

Ambulatory Care

Aggressive therapeutic amniocentesis for treatment of twin-twin transfusion syndrome.

Acute severe twin-twin transfusion syndrome occurs in about 1% of monochorionic twin gestations. In the most severe form, acute hydramnios develops in the recipient twin's sac and fetal hydrops may be present. The donor twin is anemic and oligohydramnios is present, so that the donor appears "stuck" in a cocoon made by its adherent amnion. In this report, aggressive therapeutic amniocentesis restored amniotic fluid volume to normal in both sacs in all pregnancies. Fetal hydrops resolved in three of five (60%) of the fetuses affected. Pregnancy was extended a mean 80 +/- 33 days (+/- 2 SD) and perinatal survival was 79%. These findings contrast dramatically with the virtual 100% mortality reported in the literature with no therapy. Repeated aggressive amniocentesis effectively reversed the physiology of twin-twin transfusion syndrome and should be the treatment of choice for acute hydramnios, which previously had no recommended therapy.

Acute Disease

Twin-twin transfusion syndrome.

Twin-twin transfusion syndrome associated with acute polyhydramnios in one sac and severe oligohydramnios in the other, which characteristically is diagnosed between 18 and 28 weeks, is associated with a high mortality rate for the involved twins. Patients who are managed without intervention have essentially 100% perinatal mortality. Nineteen patients with this diagnosis were treated at Good Samaritan Medical Center over a 5-year period. Because of the known perinatal mortality and because of early experiences with the twin-twin transfusion syndrome, we began to actively intervene in such patients with various modes of therapy. As experience was gained, it was found that repeated therapeutic amniocenteses, if performed before severe maternal abdominal distention or labor, appears to be beneficial.

Amniocentesis

Intrauterine diagnosis and treatment of fetal goitrous hypothyroidism.

Newborn screening programs for the detection of congenital hypothyroidism have dramatically shortened the time before treatment is begun. However, concern still exists about central nervous system sequelae which may persist due to a period of untreated intrauterine hypothyroidism. Presence of polyhydramnios led to the ultrasound diagnosis of a fetal goiter. Hypothyroidism was confirmed at 34 weeks gestation by percutaneous fetal blood sampling, which revealed an elevated TSH (186 mU/L) and a low T4 (19.3 nmol/L). Intraamniotic fluid injections of 500 micrograms levothyroxine sodium (T4) every 10-14 days increased fetal serum T4 (59.2 nmol/L), decreased fetal serum TSH (14 mU/L), decreased amniotic fluid TSH, and decreased the size of the fetal goiter. The infant was born at term without perinatal complications. Thyroid function studies on cord blood were normal (T4, 109.4 nmol/L; TSH, 1.3 mU/L), and the infant was discharged on oral T4. Follow-up examination at age 6 weeks revealed that the infant was developmentally normal and clinically and chemically euthyroid. Intrauterine T4 therapy can suppress fetal TSH and treat fetal hypothyroidism despite hypothyroid levels of serum T3. Highly sensitive TSH assays may allow the use of amniotic fluid TSH as a marker for fetal hypothyroidism.

Adult

Fetal goitrous hypothyroidism. A new diagnostic and therapeutic approach.

We present a first case in whom fetal hypothyroidism with goiter was both successfully diagnosed and treated in utero. An obstetrical sonogram at 33 weeks revealed a bilobed fetal neck mass, compatible with enlarged thyroid gland, associated with neck hyperextension, reduced gastric fluid, and polyhydramnios. Umbilical blood sampling after volume reduction amniocentesis confirmed fetal hypothyroidism with a euthyroid mother. Fetal T4 measured 1.3 micrograms/dl, free T4 0.3 ng/dl, and thyroid-stimulating hormone 186 microU. Intraamniotic levothyroxine, 500 micrograms, was given twice with a 14-day interval. The head flexed, gastric fluid increased, and amniotic fluid levels returned to normal. Prenatal (36 weeks) and neonatal blood sampling demonstrated return to euthyroid indices. Ultrasonic estimates of thyroid volume decreased by over 50%. Vaginal delivery at 39 weeks was uncomplicated. The newborn appeared normal and is being maintained on thyroid replacement therapy.

Adult

Fetal haemoglobin measurement in the assessment of red cell isoimmunisation.

A reference range of fetal haemoglobin concentration (g/dl) was established from umbilical cord blood samples obtained by cordocentesis (n = 200) or at delivery (n = 10). In normal pregnancy the mean fetal haemoglobin increases linearly from 11 g/dl at 17 weeks' gestation to 15 g/dl at 40 weeks' gestation and one standard deviation is approximately 1 g/dl. The haemoglobin was also measured in fetal blood from 154 red cell isoimmunised pregnancies from 17 to 36 weeks' gestation. In 48 fetuses with ultrasound features of hydrops the haemoglobin was 7-10 g/dl below the normal mean for gestation. It is proposed that in pregnancies complicated by red cell isoimmunisation the severity of the disease should be assessed and treated on the basis of the deviation of the fetal haemoglobin from the normal mean for gestation into mild (haemoglobin deficit less than 2 g/dl), moderate (deficit 2-7 g/dl), and severe (deficit greater than 7 g/dl).

Blood Transfusion, Intrauterine

Accuracy of ultrasound diagnoses in pregnancies complicated by suspected fetal anomalies.

Referral of pregnancies complicated by suspected fetal anomalies to level III perinatal centres for further evaluation and management is increasing as use of real-time ultrasound spreads, but the sensitivity and specificity of the prenatal diagnoses made in this population are unknown. We undertook a prospective study that followed pregnancies referred to a designated programme dealing with suspected fetal abnormalities. Follow-up of 257 pregnancies revealed that 282 separate anomalies were accurately diagnosed in 212 cases. Normal anatomy was correctly predicted in 42 cases, 16 per cent of the referred population. False-positive and false-negative rates were 1.5 per cent (4/257) and 2 per cent (1/46), respectively. However, 37 per cent of those infants born with anomalies had additional problems not prenatally detected by ultrasound. These results indicate that prenatal ultrasound diagnoses are remarkably accurate overall but that they may be insensitive to associated anomalies in individual cases.

Congenital Abnormalities

Congenital hydrocephalus: treatment in utero.

Congenital hydrocephalus occurs in about 1 in every 1,000 live births. Is is rarely lethal but frequently severely handicapping. It can be diagnosed by ultrasound as early as 20 weeks of gestation. When not accompanied by other serious malformations, it may be amenable to treatment in utero. Experimental treatment by shunting the lateral ventricle to the amnion has been shown to control ventricular enlargement during fetal life. The mental development of treated babies has, however, been disappointing. At this time no in utero treatment of fetal hydrocephalus is being done.

Amniotic Fluid

Twin-twin transfusion syndrome: the surgical removal of one twin as a treatment option.

The twin-twin transfusion syndrome, associated with acute polyhydramnios in the 18th to 28th week of gestation, has a high perinatal mortality rate. Patients managed without intervention have essentially a 100% mortality rate for the involved twins. Different methods of intervention have been described, including therapeutic amniocentesis, selective feticide, and placental vessel puncture. In this case report we describe selective removal of one twin at 21 weeks of gestation by hysterotomy in a patient with the twin-twin transfusion syndrome.

Abortion, Eugenic

Posterior urethral obstruction. Prenatal sonographic findings and clinical outcome in fourteen cases.

Fourteen cases of fetal urethral obstruction were reviewed retrospectively. The purpose of this study was to emphasize the following: 1) prenatal sonographic findings: 2) clinical outcome: and 3) associated congenital anomalies. Decreased amniotic fluid volume complicated 12 pregnancies (86%). A dilated posterior urethra was identified in nine fetuses (64%) and an enlarged bladder in 13 (93%). Evaluation of the fetal kidneys revealed hydronephrosis in 81%, increased parenchymal echogenicity in 73% and macroscopic renal cysts in 15%. There were seven live births, but only two neonates survived beyond 5 weeks. Pulmonary hypoplasia contributed to the five postnatal deaths. Associated congenital anomalies were noted at autopsy in six cases.

Amniotic Fluid

Measurement of human fetoplacental blood volume in erythroblastosis fetalis.

The fetoplacental blood volume of the human fetus was measured with the change in hematocrit at the time of intravascular transfusion for severe erythroblastosis. A total of 121 measurements were made between 18 and 31 weeks' gestation. The volume ranged from 117 ml/kg at 18 weeks to 93.1 ml/kg at 31 weeks. These values compare closely with those reported for the sheep fetus and, when they are extrapolated to term, are similar to the blood volume of human newborns plus the residual placental blood volume.

Blood Transfusion, Intrauterine

Relationship of fetal hemoglobin and oxygen content to lactate concentration in Rh isoimmunized pregnancies.

Fetal blood samples were obtained fetoscopically from 32 Rh isoimmunized pregnancies at 18-32 weeks' gestation, and the hemoglobin concentration, plasma lactate concentration, and oxygen content were measured. When the hemoglobin concentration was more than 8 g/dL, the umbilical arterial and venous lactate concentrations were equal. Abnormal elevations of lactate were found in the umbilical artery at hemoglobin concentrations below 8 g/dL (oxygen content 2 mmol/L) and in the umbilical vein at hemoglobin concentrations below 4 g/dL (oxygen content 2 mmol/L); the arterial lactate values were higher than the venous. These results show that lactate is produced by the human fetus stressed by anemic hypoxia and suggest that compensatory cardiovascular mechanisms are unable to maintain adequate oxygenation to all tissues when the umbilical venous oxygen content falls below 2 mmol/L.

Anemia

Prematurity.

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Birth Weight

Changes in cervical compliance at parturition independent of uterine activity.

A new animal model has been developed to measure intrinsic changes of cerivcal compliance during spontaneous parturition or exposure to hormonal manipulation. Intermittent measurements of cervical compliance and continous measurements of uterine and cervical pressure were made during the last month of gestation of nine pregnant ewes. Cervical compliance increased abruptly and dramatically during spontanous and dexamethasone-induced parturition. Maternal progesterone supplementation at parturition inhibited uterine contractions but not the increase in cervical compliance, demonstrating the independence of the two events. The cervix was found to contract rhythmically and vigorously with a gradual decrease in activity as parturition approached.

Animals

Comparison of uterotrophic and vascular effects of estradiol-17beta and estriol in the mature organism.

Estradiol-17beta (E2) has been considered the most potent of the natural estrogens in terms of uterine growth and vasodilatation. As a result of studies of uterine growth in rodents, estriol (E3) has been considered an "impeded" estrogen. In this study, direct comparisons of the actions of E2 and E3 on the sheep uterus were made in nonpregnant, oophorectomized ewes by using bilateral uterine artery catheters and electromagnetic flow transducers. Intra-arterial injections of E2 or E3 had equal growth-promoting and vascular effects. There were slight but statistically significant differences in the time course of vasodilatation. Estriol induced a more prolonged dilatation than did estradiol.

Animals