PubMed Health⌕ Search

Biomedical subjects

L A Bracero

Publications and source records attributed to L A Bracero.

At least 19 recordsLinked to original sources
PubMed2002

Maternal glycemic control and umbilical artery Doppler velocimetry.

OBJECTIVE: To determine whether information from umbilical artery Doppler flow velocity waveforms significantly improves the prediction of adverse perinatal outcome, independently of maternal glycemic control, in pregnancies complicated by diabetes. STUDY DESIGN: The medical records of 277 pregnant women with diabetes were reviewed. Glycemic control was determined by glycosylated hemoglobin concentration and umbilical artery Doppler velocimetry by using systolic/diastolic ratios (S:D), both obtained during the third trimester. Pregnancies with adverse perinatal outcome were compared to those with good outcome. Logistic regression analysis was used to adjust for glycemic control, and to test whether an elevated umbilical artery Doppler S:D ratio was independently associated with pregnancy outcome. RESULTS: Adverse pregnancy outcome occurred in 51.6% of these pregnancies (143/277). The mean third-trimester glycosylated hemoglobin (7.7 +/- 1.9% vs. 6.7 +/- 1.3%, p < 0.001) and the umbilical artery S:D ratio were significantly higher (2.6 +/- 0.6 vs. 2.4 +/- 0.3, p < 0.001) in the pregnancies with adverse outcome. Logistic regression analysis showed that umbilical artery S:D ratio was an independent predictor of adverse perinatal outcome after adjusting for the third-trimester glycosylated hemoglobin level. Forty per cent of patients with normal Doppler findings (S:D ratio of < 3.0) and normal glycemic control values (glycosylated hemoglobin level of < 7.5%) had an adverse pregnancy outcome. Sixty-three per cent of patients with an abnormal result for one of these tests had an adverse pregnancy outcome. Ninety-six per cent of patients with both abnormal Doppler findings and abnormal glycemic control had an adverse pregnancy outcome. CONCLUSION: Umbilical artery Doppler velocimetry improves the predictive value for adverse perinatal outcome, independently of glycemic control, in pregnancies complicated by diabetes. The combination of an abnormal umbilical artery S:D ratio and abnormal glycosylated hemoglobin was strongly associated with adverse pregnancy outcome.

Adult↗
PubMed2001

Sonographically estimated fetal weight percentile as a predictor of preterm delivery.

OBJECTIVE: To evaluate the association between relative growth restriction and preterm birth. STUDY METHODS: Pregnant women referred for sonographic fetal weight assessments between 24 and 34 weeks of gestation were studied for gestational age at delivery. If a patient underwent more than one study, only the last one was considered. Patients with delivery induced iatrogenically or with abnormal growth patterns due to known pathology, such as maternal diabetes or fetal congenital anomaly, were excluded. A gestational age of 37 weeks or less was considered preterm and a gestational age of more than 37 weeks at delivery was considered term. Fetal weight estimation was obtained by Hadlock's formula based on biparietal diameter, femur length, and head and abdominal circumferences. The estimated fetal weight percentile was computed according to William's tables. Mean gestational age and incidence of preterm delivery for each fetal weight percentile between 1 and 100, at increments of 10, were calculated. The mean estimated fetal weight percentile, biparietal diameter, femur length, head circumferences and abdominal circumferences of preterm and term patients were compared. RESULTS: Among the 419 patients who met the inclusion criteria, duration of gestation was significantly shorter in fetuses with low estimated fetal weight percentile. The risk of preterm birth was 49% in fetuses of less than the 40th birth-weight percentile compared with a risk of 20% in fetuses of more than the 40th birth-weight percentile, representing a relative risk of 2.3. Individual fetal measurements indicate a head-sparing effect in the preterm group. CONCLUSION: Sonographically estimated fetal weight percentile measured between 24 and 34 weeks' gestation may be used as an additional and individually pertinent predictor of preterm birth.

Cohort Studies↗
PubMed1999

Comparison of visual and computerized interpretation of nonstress test results in a randomized controlled trial.

OBJECTIVE: This study tested the null hypothesis that the number of fetal surveillance tests and perinatal outcomes would not differ statistically between pregnancies randomized to visual or computerized interpretation of antepartum nonstress test results. STUDY DESIGN: A prospective, randomized controlled trial was conducted, which required a sample size of 404 patients. By using a random-number table with assignment codes concealed in opaque envelopes, half of the patients were randomized to computerized interpretation of nonstress test results and half to standard visual interpretation of nonstress test results. The amount of antepartum testing and the perinatal outcome were measured and compared between the groups. Logistic regression analysis was used to control for maternal risk factors while morbidity differences between the 2 groups were assessed. RESULTS: The 2 randomized groups were similar at baseline, but the computerized interpretation group had significantly fewer biophysical profiles compared with the visual interpretation group (1.3 +/- 1.8 vs 1.9 +/- 2.1; P =.002). The patients in the computerized interpretation group spent less time per test than patients in the visual interpretation group (12 vs 20 minutes; P =.038). After the 5 pregnancies with congenital anomalies were excluded, the overall perinatal outcome was similar in the 2 groups. The computerized interpretation group, however, had a slightly lower proportion of infants who required >/=2 days of neonatal intensive care (7.4% vs 12.4%; P =.086; odds ratio, 0.56; 95% confidence interval, 0.29-1.09). The average number of neonatal intensive care days was also slightly lower in the computerized interpretation group (0.4 vs 0.9; P =.105). Neither of these variables was statistically significant. CONCLUSIONS: Computerized interpretation of nonstress test results is associated with fewer additional fetal surveillance examinations, less time spent in testing, and a similar length of stay in the neonatal intensive care unit compared with standard visual interpretation.

Adult↗
PubMed1998

Umbilical artery catheters and blood flow velocities in the superior mesenteric artery: effect of insertion, removal, aspiration, and bolus infusion.

PURPOSE: We studied whether umbilical artery catheters (UACs) affect blood flow in the superior mesenteric artery (SMA) of neonates. METHODS: Noninvasive duplex pulsed Doppler sonography was used to measure peak systolic velocity, end-diastolic velocity, and mean flow velocity in the SMA. The resistance index and pulsatility index were calculated from these data. Thirty-two infants weighing 450-2,520 g at birth were enrolled in the study. Gestational age at birth was 24-37 weeks. Eighteen infants were studied before and after UAC insertion. Twenty infants were studied before and after UAC removal. Eleven infants with UACs were studied before and during aspiration of blood from the UAC and during bolus infusion of 5% dextrose solution into the UAC. Data were compared before and after UAC insertion; before and after UAC removal; and before and during aspiration and during bolus infusion. RESULTS: Blood flow velocities and vascular resistance were similar in all comparisons except for increases in end-diastolic and mean velocities after UAC insertion. CONCLUSIONS: Insertion and removal of UACs, aspiration of blood from UACs, and bolus infusion of fluids into UACs do not diminish blood flow velocity or increase vascular resistance in the SMA.

Blood Flow Velocity↗
PubMed1998

Glucose ingestion and whole blood ionized calcium and magnesium in the third trimester of pregnancy.

OBJECTIVE: To test the hypothesis that glucose ingestion leads to a decrease in plasma ionized calcium (iCa) and ionized magnesium (iMg) during the third trimester of pregnancy. METHODS: We studied 54 women who underwent a 50 g glucose challenge test (GCT) and 27 women who underwent a 3-hour 100 g glucose tolerance test (GTT) because of an abnormal GCT. Plasma glucose was measured with an automated chemistry analyzer, while whole blood iCa and iMg were measured using an ion-selective electrode. RESULTS: The 1-hour plasma glucose post-GCT correlated inversely with whole blood iCa (r = -0.322, p = 0.027). The 3-hour plasma glucose GTT revealed a similar, but not statistically significant, decrease in blood iCa (r = -0.378, p = 0.356). The combined 1-hour peak plasma glucose during GTT and GCT correlated inversely with iCa (r = -0.376, p = 0.001), but not with iMg (r = 0.050, p = 0.737). Using multiple regression with iCa as the dependent variable and plasma glucose and glucose dose (50 or 100 g) as independent variables, both plasma glucose and glucose dose were inversely correlated with iCa (R2 = 0.45, p < 0.001). CONCLUSION: We conclude that in pregnancy, induced hyperglycemia correlates with a drop in blood iCa concentrations; however a 100 g glucose load leads to a lesser iCa decrease than a 50 g load.

Adult↗
PubMed1998

Optimal maternal weight gain during singleton pregnancy.

The aim of this study was to determine optimal maternal weight gain in a singleton pregnancy and evaluate the current recommendations. We used a historical prospective design to evaluate the association between pregnancy weight gain and perinatal outcome. All singleton pregnancies without congenital anomalies delivered between 1987 and 1993 at a single institution in New York City were analyzed. After adjusting for the prepregnancy body mass index, we determined the weight gain associated with optimal perinatal outcome. During this 6-year study period, 20,971 pregnant women met the inclusion criteria. Among them, 1,975 (9.4%) had adverse perinatal outcome. Prepregnancy weight and weight gain during pregnancy were strongly associated with adverse outcome. For women of average size, optimal outcome was found in those who gained between 31 and 40 pounds. For women underweight prior to pregnancy, optimal outcome occurred in those who gained 36-40 pounds. For women who were overweight or obese, a gain of 26-30 pounds was associated with optimal outcome. Weight gain during pregnancy is strongly associated with perinatal outcome, independent of important confounding factors, and should be carefully monitored during pregnancy. A randomized controlled trial is required to determine if perinatal and maternal outcome can be improved by advising pregnant women to gain weight using these new ranges rather than the Institute of Medicine's recommendations.

Adolescent↗
PubMed1997

Ampicillin/sulbactam versus cefotetan for the prevention of infection following cesarean delivery in high-risk patients: a randomized double-blind trial.

The objective of this study was to compare the efficacy and safety of a single intravenous dose of 1 g ampicillin plus 0.5 g sulbactam to a single intravenous dose of 1 g cefotetan in the prevention of postoperative infection following cesarean delivery in high-risk patients. In this single-center comparative study, women who were to undergo cesarean delivery and who were at high risk of developing postoperative infection were randomized into two treatment groups. At the time the umbilical cord was clamped, one group was treated intravenously with 1 g ampicillin plus 0.5 g sulbactam, and the other was treated intravenously with 1 g cefotetan. The two groups were evaluated for evidence of postoperative infections and adverse experiences. A total of 170 women who were at high risk of developing postoperative infection following cesarean delivery (87 in the ampicillin/sulbactam group and 83 in the cefotetan group) were analyzed. Successful prophylaxis, absence of any infection including absence of febrile morbidity with no other symptoms, was reported in 69 of 87 (79%) patients receiving ampicillin/sulbactam and in 60 of 83 (72%) patients receiving cefotetan. One patient in each group had an infection at the incision site. There were no statistically significant differences in the rates of endometritis or urinary tract infections. The mean duration of hospitalization was 5.5 days for patients receiving ampicillin/sulbactam and 5.7 days for patients receiving cefotetan. A single intravenous dose of the combination of ampicillin/sulbactam was as safe and effective as a single intravenous dose of cefotetan when administered for the prevention of infections following cesarean delivery in patients at high risk of developing postoperative morbidity. Both antibiotics were safe and well tolerated with no unusual or unexpected events.

Adult↗
PubMed1997

Doppler velocimetry discordancy of the uterine arteries in pregnancies complicated by diabetes.

The aim of this study was to examine the association between uterine artery Doppler velocimetry discordance and perinatal outcome, specifically in pregnancies complicated by diabetes. We evaluated 265 women with singleton pregnancies complicated by diabetes who underwent Doppler ultrasonographic examinations of the right and left uterine arteries within 1 week before delivery. The absolute difference between the right and left uterine arteries was computed after measuring the uterine artery systolic-diastolic ratio. Adverse outcome was defined as still-birth, intrauterine growth restriction, delivery before 37 weeks' gestation, or cesarean delivery for fetal risk. The discordance between right and left uterine artery systolic-diastolic ratios ranged from 0 to 2.3, with a mean of 0.39 +/- 0.36 and a median of 0.30. The discordance was significantly larger in the 63 pregnancies with adverse outcome than in those with good outcome (0.48 versus 0.36, P = 0.018). Among the women with large uterine artery S/D ratio differences (> or = 0.60), a cesarean delivery for fetal risk was three times more likely (21.5% versus 7.5%, P = 0.002). In diabetic women with chronic hypertension (n = 36), the discordance was significantly larger than in the 201 normotensive women (0.54 versus 0.35, P = 0.001); yet for this subgroup uterine artery S/D ratio discordance was not predictive of adverse outcome. In conclusion, although considerable overlap in discordance exists between the good and adverse outcome groups, the uterine artery S/D ratio discordance added prognostic information on perinatal outcome for normotensive women with diabetes. The predictive value is independent of White's classification, third trimester glycemic control, sex of the infant, and umbilical artery Doppler waveform data.

Arteries↗
PubMed1996

Effect of gender on perinatal outcome in pregnancies complicated by diabetes.

The aim of this study was to determine whether there is a gender-related difference in the morbidity and mortality of infants of diabetic mothers. We also wanted to identify risk factors associated with adverse pregnancy outcome, and create a perinatal morbidity index. We performed a retrospective review of 107 women whose pregnancies were singleton and complicated by diabetes. The subjects were divided according to the gender of the infant. The morbidity, mortality and confounding variables between the two groups were compared. Logistic regression analysis was used to identify the independent factors associated with an adverse pregnancy outcome. The male group (n = 62) had higher morbidity than the female group (n = 45). This was due to a higher incidence of hypoglycemia (relative risk = 3.9, 95% CI 1.2-12.5, p = 0.011) and need to stay in the neonatal intensive care unit 2 or more days (relative risk = 1.8, 95% CI 1.1-2.9, p = 0.015). There was one female stillbirth due to an episode of ketoacidosis in the mother. Male gender (relative risk = 1.8, 95% CI 1.2-2.7, p = 0.002) was one of three independent predictors of poor outcome. There is a male disadvantage in infants of diabetic mothers with regards to perinatal morbidity. Advanced White's classification, male gender, and third trimester mean glucose > or = 110 mg% identify the pregnancies at risk for diabetes-related morbidity.

Female↗
PubMed1996

Confirmation of Borrelia burgdorferi spirochetes by polymerase chain reaction in placentas of women with reactive serology for Lyme antibodies.

The purpose of our study was to determine whether Borrelia burgdorferi spirochetes were present in placentas of asymptomatic women with reactive Lyme serology using a silver stain, and to confirm the identity of the spirochetes by polymerase chain reaction (PCR). Sixty placentas of asymptomatic women with ELISA-positive or-equivocal serology for Lyme antibodies during pregnancy were examined for spirochetes using a silver stain. The results of the ELISA serology were confirmed by Western blot analysis. PCR amplification for B. burgdorferi was performed on placentas identified to have spirochetes and on a group of placentas negative for spirochetes. Spirochetes were identified by silver staining in 3 (5%) of the 60 placentas. PCR confirmed B. burgdorferi nucleotide sequences in 2 of the placentas. The 5 women had equivocal Lyme ELISA and negative syphilis serology. The results of the Western blot analysis were negative in 2 cases and indeterminate in 1 case. Six controls were negative for spirochetes by silver staining and PCR. A normal perinatal outcome was observed in all cases. Spirochetes identified in placental tissue of pregnancies with reactive Lyme serology were confirmed by PCR to be B. burgdorferi. There was no relationship between the presence of placental spirochetes and the results of Lyme serology or the pregnancy outcome.

Blotting, Western↗
PubMed1996

Comparison of umbilical Doppler velocimetry, nonstress testing, and biophysical profile in pregnancies complicated by diabetes.

The purpose of this study was to determine which test is best for predicting adverse outcomes in pregnancies complicated by diabetes: the nonstress test, biophysical profile, or umbilical artery velocimetry. We evaluated 207 singleton pregnancies complicated by diabetes within 1 week of delivery using the afore-mentioned pregnancy surveillance tests. Adverse pregnancy outcome was defined as delivery before 37 weeks of gestation or the occurrence of fetal growth restriction, hypocalcemia, hypoglycemia, hyperbilirubinemia, respiratory distress syndrome, or fetal risk requiring cesarean delivery. The prognostic value of each of the three tests was assessed, after controlling for the mothers' White classification and third trimester glycosylated hemoglobin value. Among the 207 pregnancies, 75 (36.2%) had an adverse outcome. In pregnancies in which the umbilical artery systolic to diastolic ratio was > or = 3.0, the relative risk of adverse outcome was 2.6 (95% confidence interval: 1.9-3.5, P < 0.001). For those with a biophysical profile < or = 6 the relative risk was 1.7 (95% confidence interval: 0.9-2.9, P = 0.109). Patients with a nonreactive nonstress test had a relative risk of 1.7 (95% confidence interval: 1.2-2.5, P = 0.009). Umbilical artery Doppler velocimetry was superior to either the nonstress test or the biophysical profile in identifying the subgroup of pregnancies complicated by diabetes that resulted in an adverse outcome.

Female↗
PubMed1995

Endothelin-1 levels in the maternal-fetal dyad.

The aim of this study was to determine the distribution of ET-1 levels in the term maternal-fetal dyad. We also compared the levels of ET-1 between umbilical vessels and assessed the effect of labor on the concentration of ET-1. The ET-1 levels were measured in plasma from 18 term maternal-infant pairs. Amniotic fluid ET-1 levels were also measured in 9 of these pregnancies. The ET-1 levels were determined by radioimmunoassay (RIA) after extraction of plasma using Sep-Pak C18 cartridges. There were no significant differences in the ET-1 levels between the umbilical artery and vein. However, there were significant differences in the umbilical artery concentration in women who labored when compared with those delivered without labor (6.0 +/- 1.1 vs. 2.7 +/- 0.7 pg/ml; t test, p = 0.022). ET-1 levels were lowest in the maternal plasma (0.9 +/- 0.2 pg/ml) and highest in the amniotic fluid (83 +/- 15 pg/ml). Assuming that elevated plasma ET-1 levels reflect increased bioactivity, the higher mean ET-1 levels in the cord vessels and in the amniotic fluid when compared to maternal levels suggest a role for ET-1 in the regulation of the fetoplacental circulation and in the constriction of blood vessels in the uterus after parturition. The higher levels of ET-1 in the umbilical artery of women who underwent labor implies that ET-1 is released as a result of the stress of labor.

Amniotic Fluid↗
PubMed1994

Middle cerebral to umbilical artery Doppler ratio in post-date pregnancies.

OBJECTIVE: To determine which antepartum test is the best predictor of post-date-related adverse outcome among the amniotic fluid index (AFI), nonstress test (NST), biophysical profile, or middle cerebral artery to umbilical artery Doppler ratio. METHODS: Pregnant women of 41 or more weeks' gestation with singleton fetuses and vertex presentations underwent antepartum testing twice a week. Pulsed Doppler ultrasound was used to obtain the flow velocity waveforms from the umbilical and middle cerebral arteries. Adverse post-date-related outcome was defined as the occurrence of meconium aspiration syndrome, cesarean delivery for fetal distress, or fetal acidosis. The predictive values of an AFI equal to or less than 5 cm, a biophysical profile score equal to or greater than 6, a nonreactive NST, and a middle cerebral artery to umbilical artery ratio less than 1.05 in identifying adverse outcome were compared. RESULTS: Forty-nine women met the inclusion criteria; ten (20.4%) had an adverse outcome. A middle cerebral artery to umbilical artery ratio of less than 1.05 was found to be the best predictor of adverse outcome, with a sensitivity of 80%, specificity of 95%, positive predictive value of 80%, and negative predictive value of 95%. The other three diagnostic tests had sensitivities equal to or less than 40%. The middle cerebral artery to umbilical artery ratio was also a better discriminator of adverse outcome than either the umbilical artery systolic-diastolic (S/D) ratio or the middle cerebral artery S/D ratio. CONCLUSION: Although the sample size of our study was small, the results suggest that a middle cerebral artery to umbilical artery ratio of less than 1.05 is an accurate method of predicting post-date-related adverse outcome.

Adolescent↗
PubMed1993

Doppler velocimetry, placental morphology and outcome in insulin-dependent diabetes.

The purpose of this study was to determine the underlying cause of abnormal umbilical artery Doppler velocimetry in pregnancies complicated by insulin-dependent diabetes, by evaluating placental morphology and correlating Doppler results with pregnancy outcome. Our study population consisted of 14 pregnancies with normal Doppler results and 11 pregnancies with abnormal Doppler results. Quantitative placental examinations were performed. Maternal and perinatal characteristics were analyzed. Infants from the abnormal Doppler group had a statistically significantly higher incidence than those from the normal Doppler group of hyperbilirubinemia, Cesarean delivery for fetal distress, and neonatal intensive care stay of 2 or more days. Women with abnormal Doppler results delivered earlier (36 vs. 38 weeks) and had infants of lower birth weight (3079 vs. 3629 g). They were also three times more likely to have poor glycemic control (relative risk = 3.2; p = 0.0067). The placentae of both groups showed no statistically significant differences in placental weight, number of tertiary stem villi, number of small muscular arteries, or mean arterial width. Our findings suggest a functional rather than structural placental process as the cause of the abnormal Doppler results in pregnancies complicated by diabetes. An association between glycemic control and Doppler velocimetry is suggested.

Journal Article↗
PubMed1992

Diagnosis of intrauterine growth retardation as a two-step process with morphometric ultrasound and Doppler umbilical artery velocimetry.

Ultrasound and Doppler umbilical artery velocimetry have been used to diagnose the small-for-gestational-age (SGA) fetus. Both techniques are relatively inefficient for this diagnosis. The aim of the present study was to see whether their serial use improved diagnostic accuracy. Forty women with an ultrasound diagnosis of SGA within three weeks of delivery were studied with velocimetry, and the outcome was evaluated. Diagnostic accuracy was improved from 65% by ultrasonography alone to 92% by the addition of an abnormal umbilical artery waveform (P < .02). An abnormal waveform was associated with an adverse outcome in 62%, compared to 14% with normal velocimetry (P < .01). The majority of small fetuses have a normal outcome. The combination of ultrasonography and velocimetry improved diagnostic accuracy and identified those small fetuses truly at risk.

Female↗
PubMed1991

Doppler studies of the uteroplacental circulation in pregnancies complicated by diabetes.

The aim of this study was to evaluate the uteroplacental side of the circulation in pregnancies complicated by diabetes. A total of 54 women with pregnancies complicated by diabetes underwent uterine and umbilical artery Doppler studies. Uterine Doppler velocity waveforms were not obtained in two women. The prevalence of abnormal uterine artery velocity waveforms was much higher than in a non-diabetic population (15.4% vs. 2%, p < 0.001). Those eight women with abnormal uterine Doppler studies had a statistically higher incidence of poor glycemic control, chronic hypertension, polyhydramnios, vasculopathy, pre-eclampsia, Cesarean births for fetal distress and newborns with respiratory distress syndrome. In this group of patients, the umbilical circulation was not considered to be a contributing factor in the development of problems.

Journal Article↗
PubMed1991

Comparison of nifedipine and ritodrine for the treatment of preterm labor.

Treatment of preterm labor with beta-sympathomimetics has been questioned because of the many maternal and fetal complications associated with its use. Nifedipine, a calcium antagonist, has been shown to suppress uterine activity in vitro and in vivo. A randomized prospective study was performed to compare the efficacy of nifedipine to ritodrine in the suppression of preterm labor. Data obtained from 42 women, of which 19 were randomized to the ritodrine group and 23 to the nifedipine group, were analyzed. Ritodrine and nifedipine proved to be equally effective in the suppression of preterm labor. However, the nifedipine group had fewer maternal and fetal complications.

Adult↗