PubMed Health⌕ Search

Biomedical subjects

R K Tamura

Publications and source records attributed to R K Tamura.

At least 19 recordsLinked to original sources
PubMed1995

The clinical significance of a single umbilical artery as an isolated finding on prenatal ultrasound.

OBJECTIVE: To evaluate the perinatal outcome in fetuses with single umbilical artery detected on targeted prenatal ultrasound without other anomalies. METHODS: During a 3.5-year period, an isolated single umbilical artery was suspected on prenatal ultrasound examination in 57 fetuses evaluated at two referral centers. Targeted imaging to rule out concurrent fetal anomalies was normal in all cases. Pregnancy and perinatal outcome data were retrieved by review of the medical records or from conversations with referring physicians. Complete follow-up was available in 50 cases. RESULTS: A two-vessel umbilical cord was confirmed at birth in 50 neonates. The mean gestational age at delivery was 38.6 +/- 2.8 weeks; the mean birth weight was 3202.8 +/- 835.8 g. Seventeen patients (34%) underwent genetic amniocentesis, and all fetuses had a normal karyotype. The only neonate ascertained to have a congenital anomaly after birth was diagnosed with total anomalous pulmonary venous return. This neonate underwent a corrective surgical procedure and is thriving with no apparent problems at 3.5 years of age. There were no perinatal deaths. CONCLUSION: In the absence of additional sonographically detectable anomalies, an isolated single umbilical artery does not seem to affect clinical outcome and therefore should not alter routine obstetric management.

Adult↗
PubMed1994

Immunoreactive tumor necrosis factor-alpha is elevated in maternal plasma but undetected in amniotic fluid in the second trimester.

OBJECTIVE: We investigated the participation of the cellular arm of the immune system in adaptation to pregnancy by assessing plasma and amniotic fluid levels of the cytokine tumor necrosis factor-alpha. STUDY DESIGN: Fifty-five healthy pregnant women who underwent second-trimester genetic amniocentesis at a mean gestational age of 17.0 +/- 1.4 weeks composed study group A. Blood was drawn from each patient before amniocentesis, and an aliquot of amniotic fluid was obtained for this study. Twenty-one healthy patients at a mean gestational age of 35.5 +/- 4.8 weeks composed study group B, and blood was obtained from each patient at an outpatient prenatal visit. Twenty-two healthy, nonpregnant women of reproductive age composed the control group (C). All specimens were stored at -70 degrees C and collectively assayed for tumor necrosis factor-alpha by a specific enzyme-linked immunoassay. RESULTS: All patients in group A had a normal karyotype and all patients in groups A and B had uneventful pregnancies. Tumor necrosis factor-alpha was detected in the plasma of 43 of 55 (78.2%) patients in group A compared with 7 of 21 (33.3%) patients in group B (p < 0.001); tumor necrosis factor-alpha was not detected in any of the 22 women in group C. The median plasma tumor necrosis factor-alpha level for group A was 135 pg/ml (range 0 to 625 pg/ml) compared with 0 pg/ml (range 0 to 110 pg/ml) in group B (p < 0.001). Tumor necrosis factor-alpha was not detected in any of the amniotic fluid specimens studied. CONCLUSIONS: Levels of tumor necrosis factor-alpha were elevated in the plasma but not detected in the amniotic fluid of normal pregnant patients in the second trimester. These findings suggest involvement of the cellular branch of the immune system and its products, the cytokines, in the normal adaptation of the mother to the fetal allograft, with a possible role in regulating trophoblast growth and invasion.

Adult↗
PubMed1994

Isolated choroid plexus cyst(s): an indication for amniocentesis.

OBJECTIVE: Our purpose was to prospectively evaluate the risk of chromosomal abnormalities associated with isolated choroid plexus cyst(s) in gravid women undergoing second-trimester ultrasonographic examination. STUDY DESIGN: During a 24-month period 9100 pregnant women underwent midtrimester ultrasonographic evaluation. Women with a fetal diagnosis of choroid plexus cyst(s) were offered amniocentesis and a repeat examination in 4 to 6 weeks. RESULTS: A diagnosis of choroid plexus cyst(s) was made in 102 fetuses (1.1%). In four of these fetuses multiple congenital anomalies were noted. Three of the four fetuses had a chromosomal abnormality, two trisomy 18 and one unbalanced translocation, t(3;13). In the remaining 98 fetuses the choroid plexus cysts were isolated findings, that is, there were no other ultrasonographically detected anomalies. Seventy-five of these 98 fetuses underwent amniocentesis. An abnormal karyotype was identified in four fetuses: three had Down syndrome (two trisomy 21 and one unbalanced translocation, t[14;21]), and one trisomy 18. The offspring of the 23 patients in which amniocentesis was declined were phenotypically normal. CONCLUSIONS: In our prospective study the risk of chromosomal abnormality with isolated choroid plexus cyst(s) was 1:25, a risk that exceeds the 1:200 risk of pregnancy loss after amniocentesis and the 1:126 and 1:260 risk for aneuploidy and Down syndrome, respectively, in a 35-year-old pregnant women during the midtrimester. These findings indicate that amniocentesis should be offered to pregnant women in the presence of isolated fetal choroid plexus cyst(s).

Adult↗
PubMed1993

Neonatal morbidity after preterm delivery in the presence of documented lung maturity.

OBJECTIVE: Our purpose was to determine the incidence of significant neonatal morbidity in fetuses with documented pulmonary maturity delivered before 37 weeks' gestation. STUDY DESIGN: A retrospective review of 213 pregnancies with documented fetal lung maturity (lecithin/sphingomyelin ratio > or = 2.0 or phosphatidylglycerol present) and delivery before 37 weeks was performed. The incidence of neonatal respiratory distress syndrome, bronchopulmonary dysplasia, grade 3 or 4 intraventricular hemorrhage, necrotizing enterocolitis, patent ductus arteriosus, retinopathy of prematurity, infectious morbidity, hyperbilirubinemia, and admission to the special care nursery was determined for those pregnancies with intact membranes and preterm premature rupture of membranes. RESULTS: Serious neonatal morbidity declined with advancing gestational age and was less common after 32 completed weeks of pregnancy. Although the frequencies of respiratory distress syndrome, grade 3 or 4 intraventricular hemorrhage, and necrotizing enterocolitis were 19.4% (12/62), 8.1% (5/62), and 4.8% (3/62), respectively, at < or = 33 weeks' gestation, one case of respiratory distress syndrome, one case of grade 3 intraventricular hemorrhage, and one case of necrotizing enterocolitis occurred in the 151 neonates born at > or = 34 weeks' gestation. CONCLUSIONS: In spite of fetal lung maturity major neonatal morbidity was observed in our patient population. These data relating neonatal morbidity to gestational age are useful in the critical decision regarding timing of delivery.

Adult↗
PubMed1993

Placenta accreta is associated with elevated maternal serum alpha-fetoprotein.

OBJECTIVE: To determine whether placenta accreta/percreta/increta is associated with elevation of second-trimester maternal serum alpha-fetoprotein (MSAFP) levels. METHODS: We reviewed the medical records of 44 women who had emergency cesarean hysterectomy. Twenty women had placenta accreta/percreta/increta (study group) and 24 underwent cesarean hysterectomy for other indications (control group). Pertinent maternal and neonatal variables were abstracted from the prenatal records and hospital charts. Chi-square and Fisher exact tests were used to analyze categorical variables. Student t test was used to analyze continuous variables. RESULTS: Nine of 20 patients (45%) with placenta accreta/percreta/increta and none of 24 subjects in the control group had an elevated MSAFP value (P < .001). Maternal estimated blood loss was also significantly greater in the study group (4469 +/- 1851 versus 1885 +/- 1113 mL; P < .0001), as was the number of blood units transfused (7.7 +/- 4.7 versus 3.0 +/- 2.2; P < .001). None of the other examined variables were different between the groups. CONCLUSIONS: A significant association exists between placenta accreta/percreta/increta and elevated MSAFP values. Patients with an unexplained elevation of MSAFP may have an increased risk for placenta accreta and associated blood loss at cesarean hysterectomy.

Adult↗
PubMed1993

Sonographic diagnosis of congenital heart disease: comparison between the four-chamber view and multiple cardiac views.

OBJECTIVE: To report our experience in the detection of congenital heart disease using both the four-chamber view of the heart as part of the standard obstetric ultrasound examination and multiple cardiac views as part of the detailed targeted examination. METHODS: All admissions to Children's Memorial Hospital of Northwestern University Medical Center with the diagnosis of congenital heart disease between June 1988 and April 1992 were identified (N = 1947). These admissions were matched to deliveries (N = 19,321) that occurred at Prentice Women's Hospital during the same period; of these, 10,004 had at least one obstetric ultrasound examination. All fetuses were scanned either with the standard obstetric ultrasound type of examination, featuring only the four-chamber view of the heart, or by the detailed targeted imaging type of study, featuring multiple cardiac views. The type of examination performed was based on the specific request of the attending obstetrician or gynecologist. RESULTS: Thirty-three neonates who had at least one obstetric ultrasound examination were treated for congenital heart disease. An additional five pregnancies were terminated secondary to serious fetal heart defects. When only the four-chamber view was visualized, 11 of 33 fetuses (33.3%) with confirmed congenital heart disease were detected. CONCLUSIONS: Assessment of the outflow tracts is crucial for detection of many forms of congenital heart disease. However, before this is accepted as the standard of care, both the obstetric and radiologic communities should develop their skills in cardiac imaging. Only then can this sophisticated type of cardiac examination be offered to pregnant women.

Female↗
PubMed1992

Antepartum management of triplet gestations.

OBJECTIVE: We evaluated an alternative approach to the management of triplet gestations that did not include home uterine monitoring, prophylactic tocolysis, or routine antepartum hospitalization. STUDY DESIGN: Fifteen patients were managed over a 42-month period by an antepartum protocol that emphasized patient education regarding signs and symptoms of preterm labor, weekly prenatal visits after 24 weeks' gestation with cervical examination, and increased rest in an outpatient setting. Tocolytic therapy was only used for regular uterine contractions when cervical change was documented. RESULTS: Nine of 15 (60%) patients with management in this uniform manner were delivered at > or = 35 weeks' gestation, and six patients (40%) completed 37 weeks of pregnancy. Only five patients (33%) received tocolytic therapy. The mean birth weight was 1957 +/- 488 gm, and only 19 of 45 neonates (42%) were admitted to the intensive care nursery. CONCLUSION: This management scheme was effective in reducing preterm delivery and thereby optimizing perinatal outcome.

Birth Weight↗
PubMed1990

Awaiting cervical change for the diagnosis of preterm labor does not compromise the efficacy of ritodrine tocolysis.

We retrospectively studied 209 patients treated with ritodrine hydrochloride to determine whether change in cervical effacement or dilatation during a period of observation before therapy would result in decreased efficacy of ritodrine, as measured by delivery delays of 48 hours, 1 week, or until greater than or equal to 37 weeks' gestation; neonatal intensive care unit admission; and neonatal respiratory distress syndrome. Patients who were greater than or equal to 3 cm dilated on admission were at high risk of therapy failure by all outcome measures compared with patients less than 3 cm dilated. For patients less than 3 cm dilated on admission, there was no difference in outcome when patients treated for contractions only were compared with those treated after change in effacement or dilatation had been documented. We conclude that awaiting change in cervical effacement or dilatation to be more certain of the diagnosis of preterm labor will not compromise the efficacy of ritodrine tocolysis.

Adult↗
PubMed1990

Infants of diabetic mothers with accelerated fetal growth by ultrasonography: are they all alike?

We studied longitudinal ultrasonographic growth patterns (abdominal circumference, biparietal diameter) initiated early in gestation in 52 pregnancies complicated by pregestational diabetes mellitus and 19 controls. Three predominant patterns of growth were ascertained including a heretofore unrecognized pattern characterized by accelerated abdominal circumference growth (greater than 90th percentile) before 24 weeks' gestational age. Maternal and neonatal anthropometric and metabolic parameters were contrasted for the three patterns. The findings suggest that in some cases of diabetic macrosomia that can be recognized before 24 weeks' gestation, augmented growth may be influenced by factors other than fetal hyperinsulinism.

Amniotic Fluid↗
PubMed1990

The Northwestern University Twin Study. XV: Rationales for a standard of care in compromised twin pregnancies.

Current antenatal technologies have improved the obstetrician's ability to assess fetal well-being as well as to diagnose fetal compromise. These technologies have given rise to very difficult ethical issues in the management of compromised twin pregnancies: for example, a choice must be made between putting a healthy twin at risk due to preterm delivery for the sake of a compromised cotwin or of allowing the compromised twin to die in order to buy time for the healthy twin. Though each case is unique, good medical practice requires a standard of care by which consistent patient management can be proposed. In the pluralistic environment of Northwestern Memorial Hospital, our staff has favored a standard of care based on patient autonomy. This approach demands: 1) a practitioner who offers a thorough explanation of the diagnosis and possible treatment approaches; 2) time for the patient and her partner to assimilate this information and test treatment options against their personal value system; 3) a third, but disinterested, party to facilitate patient understanding and value clarification; 4) a practitioner either willing to support the patient's decisions or refer her to another practitioner who will.

Diseases in Twins↗
PubMed1989

Estimation of birth weight by use of ultrasonographic formulas targeted to large-, appropriate-, and small-for-gestational-age fetuses.

This report sought to determine whether estimates of fetal weight are enhanced by using ultrasonographic formulas targeted to the large-, appropriate-, and small-for-gestational-age fetus in both preterm and term pregnancies. Ultrasonographic fetal measurements from 575 singleton pregnancies were obtained within 7 days of delivery. The first 194 fetuses were classified into three groups on the basis of the growth percentile rank of the abdominal circumference (greater than or equal to 90%, greater than 5% and less than 90%, and less than or equal to 5%). Regression analyses were performed to generate three formulas for estimating fetal weight on the basis of the following: Gestational age (weeks) + Head circumference (cm) + 2 x Abdominal circumference (cm) + Femur length (cm). This mathematic model allowed formulation of accurate and concise tables relating the sum of these measurements to estimated birth weight. The accuracy of these formulas was then prospectively compared, first, with the formula published by Hadlock et al. (in 32 large-, 279 appropriate-, and 70 small-for-gestational-age fetuses) and second, with the formula of Weiner et al. (in 82 preterm fetuses). The difference between actual and estimated birth weights generated by the three study formulas had no systemic error (t test, p greater than 0.05). Cumulatively, there was a statistically significant reduction of random error in the birth weight estimates by use of the three study formulas versus the best single formulas of Hadlock et al. (2 SD reduced from 21.6% to 19.8% and absolute 2 SD reduced from 15.6% to 12.2%). Additionally, the three study formulas resulted in a statistically significant reduction in the absolute 2 SD error compared with the best formula by Weiner et al. in fetuses less than or equal to 34 weeks' gestation (2 SD reduced from 19.1% to 13.6%).

Birth Weight↗
PubMed1988

Apgar scores and umbilical cord arterial pH in the breech neonate.

Apgar scores and umbilical cord arterial pH measurements of 449 singleton breech deliveries are compared retrospectively to those of 1425 singleton vertex neonates. In the vaginal deliveries the Apgar scores and umbilical arterial pH were higher for the vertex neonates. There were no differences in either Apgar scores or umbilical arterial pH between the breech and vertex neonates delivered by cesarean section. Whereas Apgar scores in the less than 1000 g and greater than or equal to 2500 g weight groups were lower in the breech neonates delivered vaginally compared to cesarean section, umbilical arterial pH measurements were similar. The data suggest that liberal use of cesarean section may improve the Apgar scores but will probably not appreciably improve the acid-base status of the breech neonate.

Apgar Score↗
PubMed1988

Differing fetal growth patterns in pregnancies complicated by preterm labor.

Previous studies have demonstrated diminished ultrasonic fetal growth parameters in women delivering preterm. In this study, we tested the following hypothesis: In pregnancies complicated by spontaneous preterm labor, 1) unsuccessful tocolysis is likely to be associated with diminished fetal growth, and 2) successful tocolysis is likely to occur when fetal growth is normal. Ultrasound examinations were performed in 78 pregnancies complicated by preterm labor before 35 weeks' gestation. Tocolysis was attempted unless contraindicated or unless cervical dilatation was advanced (4 cm or greater). Pregnancies delivering before 36 weeks' gestation were compared with those delivering after this gestational age. Among the 48 pregnancies delivered before 36 weeks' gestation, a significantly greater proportion had ultrasonic growth parameters lower than normal values at corresponding gestational ages. In contrast, those pregnancies that had successful tocolysis and delivered near term demonstrated a normal distribution of ultrasound growth parameters. In pregnancies complicated by preterm labor, ultrasonic documentation of diminished fetal growth may identify the subgroup at increased risk for preterm delivery.

Adult↗
PubMed1987

Umbilical cord size and amniotic fluid volume in prolonged pregnancy.

Expectant management of prolonged pregnancy is predicated on reassuring biophysical testing. However, even the combination of a reactive nonstress test and normal amniotic fluid volume may not prevent subsequent morbidity. To test the hypothesis that diminished cord Wharton's jelly incurs risk of peripartum cord compression in addition to decreased amniotic fluid, 68 patients with confirmed gestational age greater than or equal to 41 weeks were evaluated prospectively with semiweekly nonstress tests and weekly ultrasound examinations. Amniotic fluid volume was assessed, and umbilical cord diameter was measured and then correlated with the quantity of Wharton's jelly at delivery, determined by cord circumference. A significant correlation between cord circumference and umbilical cord diameter was observed, even in those patients with decreased amniotic fluid volume. Either an amniotic fluid volume less than 3.8 cm or an umbilical cord diameter less than 1.6 cm was associated with significant cord compression patterns. Peripartum morbidity was greatest in the presence of a smaller cord and decreased fluid, suggesting a synergism between these two factors for the risk of cord compression in prolonged pregnancy.

Amniotic Fluid↗
PubMed1987

Percutaneous umbilical transfusion in severe rhesus isoimmunization: resolution of fetal hydrops.

The rhesus-sensitized fetus with the worst prognosis is one with early onset of hydropic changes. Percutaneous umbilical blood sampling now enables access to the fetal circulation and thereby allows more precise evaluation of fetal anemia and direct intravascular transfusion. A variation of this technique was used in three pregnancies complicated by fetal pericardial effusion, scalp edema, and abdominal ascites before 26 weeks' gestation. Twelve ultrasound-guided percutaneous transfusions of 30 to 85 ml packed red blood cells were administered into the umbilical cord at its placental insertion. In each fetus the hydropic changes completely resolved and pregnancy outcome was successful. Neither adjunctive therapy with digoxin or Lasix nor exchange transfusions were used. Percutaneous umbilical transfusions appear to have the potential to improve the prognosis for the severely isoimmunized fetus.

Adult↗
PubMed1987

Ultrasonic prediction of birth weight in preterm fetuses: which formula is best?

Data from previous studies have suggested that birth weight prediction was enhanced by using formulas specifically derived from preterm fetuses. However, no prospective comparison of different formulas was performed. We obtained ultrasonic data on 61 pregnancies at risk for preterm delivery with a gestational age of 29.0 +/- 3.0 weeks (mean +/- SD). In all women birth weight was predicted within 7 days of delivery. Of the 61 pregnancies, 49 (80%), 41 (67%), 30 (49%), and 17 (28%) weighed less than 1750, 1500, 1250, and 1000 gm, respectively; 14 published formulas were compared for accuracy in predicting birth weight in these four categories. The formulas with the smallest absolute mean percent errors incorporated head and abdominal circumferences and femur length. The formula of Weiner et al., derived from low birth weight infants, produced the smallest absolute mean percent error and SD, 10.9% +/- 7.9%; this error was further reduced to 7.7% +/- 6.5% in infants weighing less than 750 gm. These findings suggest that birth weight in the preterm fetus is best predicted by a formula targeted to such a population.

Birth Weight↗
PubMed1987

Underestimation of gestational age by conventional crown-rump length dating curves.

Inaccuracies in gestational age assignment based on published crown-rump length data were noted in patients with known ovulation dates. In this study, we tested the hypothesis that crown-rump length data derived from pregnancies with known ovulation dates differ from those of menstrually timed pregnancies. Seventy-two previously infertile women with known dates of ovulation had crown-rump length measurements from 35-79 days postovulation. We transformed the data to menstrual age (gestational age) by adding 14 days to the date of ovulation and compared our crown-rump length values with those of two previous reports. At corresponding crown-rump length values, the gestational ages from our data differed from those in the previous studies. We suggest using crown-rump length dating curves based on ovulation-timed pregnancies because crown-rump length data derived from menstrually dated pregnancies underestimate true gestational age.

Embryonic and Fetal Development↗