Luis A. Bracero

Uterine artery Doppler velocimetry in pregnant women with hypertension

Uterine and umbilical artery velocimetry was carried out on 71 women with hypertensive disorders in pregnancy. Three categories of hypertensive disease were diagnosed: chronic hypertension, preeclampsia, and chronic hypertension with superimposed preeclampsia. Clinical classifications describe the severity of disease effectively, primarily because the classification is based on the appearance of abnormal physical or laboratory findings. Doppler velocimetry of the uterine arteries shows that normal pregnancy occurs when the systolic/diastolic ratio is less than or equal to 2.6. When the ratio exceeds this level and there is a notch in the waveform, the pregnancy is complicated by stillbirth, premature birth, intrauterine growth retardation, and maternal preeclampsia. The positive and negative predictive value of the examination is 93% and 91%, respectively. It appears that this new technology will be an essential ingredient of optimum pregnancy surveillance.

A classification of hypertension in pregnancy based on h Doppler velocimet

We studied 136 pregnant women with hypertension with Doppler velocimetry of the uterine and umbilical arteries. The patients were classified into four groups according to the values of the systolic/diastolic ratios. The first group had normal ratios in both the umbilical and uterine arteries. The second group had elevated umbilical ratios and normal ratios in the uterine arteries. The third group had elevated uterine artery systolic/diastolic ratios with normal umbilical artery values, and the fourth group had elevated systolic/diastolic ratios in both vessels. Women in the group with normal ratios in both the umbilical and uterine arteries were delivered of infants with a birth weight (mean +/- SD) of 3261 +/- 522 gm and gestational age of 39 +/- 2 weeks. The values for the three groups with abnormal velocimetry were: those with elevated umbilical ratios and normal ratios in the uterine arteries: body weight = 2098 +/- 811 gm, gestational age = 35.7 +/- 3.2 weeks; those with elevated uterine artery ratios with normal umbilical artery values: 2464 +/- 722 gm, gestational age = 36.3 +/- 3 weeks; and those with elevated systolic/diastolic ratios in both vessels: body weight = 1627 +/- 697 gm, gestational age = 33.3 +/- 2.7 weeks (p less than 0.01; p less than 0.001). There were 27 small for gestational age infants delivered during this study. Doppler velocimetry studies were abnormal in 26 of them (96%). Results show that Doppler-derived vascular patterns correlate well with normal and adverse perinatal outcome. A description of the uterine and umbilical systolic/diastolic ratios should be part of the clinical evaluation of all pregnant women with hypertension. This should lead to better treatment protocols and improved clinical outcome.

Surveillance of twin pregnancy with umbilical arterial velocimetry.

A continuous-wave Doppler system and a spectrum analyzer provide the tools for the measurement of systolic-diastolic velocity wave ratios in the umbilical arteries. In twins, each umbilical cord can be studied without imaging the fetuses. Results were tabulated by taking the average difference in the ratios between each fetus and plotting these values against the neonatal weight differences. In 43 twin pregnancies, the data revealed that ratio differences between fetuses that averaged 0.4 or more was predictive of a weight difference of greater than 349 gm. The sensitivity was 73% and specificity 82%. Two cases of twin transfusion syndrome were recognized by the simultaneous presence of high- and low-resistance values.

Doppler velocimetry and placental disease

Quantitative placental examinations were performed on 47 women who had Doppler flow velocity studies of the umbilical artery during their pregnancy. The systolic-diastolic ratio of the umbilical artery was used as the measurement parameter to divide the study population into two groups. Group 1 consisted of women with normal systolic-diastolic ratios (systolic-diastolic less than 3), and group 2 consisted of women with an elevated systolic-diastolic ratio (systolic-diastolic greater than or equal to 3). The group with an increase in systolic-diastolic ratio had more perinatal complications as demonstrated by two stillbirths, a higher incidence of cesarean deliveries for fetal distress, and more admissions to the neonatal intensive care unit. Significant differences were found when gestational age at delivery, placental weight, birth weight, and the number of small muscular arteries in the placenta were compared. Since gestational age may have accounted for the difference in placental findings, patients were matched for gestational age. The placental weights were comparable, but there were fewer small muscular arteries in those patients with an increase in systolic-diastolic ratio (p less than 0.001). In addition, when these findings were examined to determine the influence of diminished uterine flow velocity, none was found.

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.

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.

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 Whites classification, male gender, and third trimester mean glucose > or = 110 mg% identify the pregnancies at risk for diabetes-related morbidity.

Ultrasound Determination of Chorionicity and Perinatal Outcome in Twin Pregnancies Using Dividing Membrane Thickness

Objective: To assess the value of ultrasound measurement of twin dividing membrane thickness in predicting chorionicity and perinatal outcome. To compare magnified with unmagnified images, and measurements taken with dividing membranes parallel and perpendicular to the ultrasound beam. Methods: This was a prospective, observational cohort study of twin-pregnancy ultrasound examinations during the second and third trimesters with chorionicity confirmed by a pathologist. Ultrasound measurements of the dividing membrane thickness were recorded in 44 twin pregnancies using unmagnified and magnified images. Measurements were taken at various membrane sites either horizontal or vertical to the ultrasound beam, depending on the orientation of the dividing membrane. We compared the mean membrane thickness between monochorionic and dichorionic pregnancies as well as between pregnancies with good and adverse perinatal outcome. Results: Membranes were significantly thicker in dichorionic pregnancies when compared with the monochorionic pregnancies (2.35 vs. 1.69 mm, p = 0.021). A cut-off point of ≧2.0 mm provided a sensitivity of 75.7%, a specificity of 85.7%, a positive predictive value of 96.6%, and a negative predictive value of 40.0%, for determining dichorionicity. Two of 7 monochorionic and 24 of 37 dichorionic pregnancies (59.1%) had good perinatal outcome. These pregnancies had significantly thicker membranes (2.44 vs. 1.96 mm, p = 0.022). Even among the dichorionic pregnancies, a membrane thicker than 2.2 mm was associated with a significantly higher proportion with good perinatal outcome (80.0 vs. 47.1%, relative risk 1.7, p = 0.036). Magnified images obtained with the ultrasound beam parallel to the membrane identified adverse outcome more accurately than unmagnified and perpendicular images. A cut-off point of >2.2 mm for membrane thickness was found to be the best predictor of good outcome. Conclusions: Membrane thickness can be used to identify chorionicity and adverse perinatal outcome, particularly if the ultrasound images are magnified and parallel to the ultrasound beam.

Uterine-umbilical artery Doppler velocimetry in pregnant women with systemic lupus erythematosus.

We evaluated continuous wave uterine‐umbilical artery Doppler velocimetry for predicting pregnancy outcome in women with systemic lupus erythematosus (SLE). Lupus anticoagulant (LAC) and anticardiolipin (ACL) antibody status also were correlated with Doppler results and outcome. Three Doppler vascular patterns were identified in 27 pregnancies of 26 women with SLE. Patients with normal flow velocity in both vessels had normal outcomes (n = 18). Reduced flow velocity of the umbilical artery only was present in five women, whose newborn infants were of lesser gestational age and birthweight, two being small for gestational age. In four pregnancies reduced flow velocity was noted in both vessels. These cases had the poorest outcome, with three perinatal losses and all fetuses being small for gestational age. Doppler velocimetry showed 100% sensitivity and negative predictive value in the detection of the small for gestational age fetus and abnormal antepartum fetal heart rate tracing. Fourteen of 18 women with normal Doppler studies did not have preeclampsia or SLE flare‐ups, whereas all nine women with abnormal Doppler studies had such complications. In all 27 pregnancies the women were screened for LAC, and 21 women also were tested for the ACL antibody. Poor correlation was found between antiphospholipid antibody status and Doppler results in three of the six pregnancies with positive antibody testing the patients had normal Doppler studies and outcomes. Thus, Doppler velocimetry may help determine when these substances will affect the outcome adversely. In this study the umbilical‐placental vascular system was affected more often. Uterine‐umbilical arterial Doppler velocimetry uniquely identified the fetus at risk for adverse perinatal outcome in pregnancies complicated by SLE. Thus, it is a potentially valuable tool in clarifying the pathophysiology and in the management of SLE in pregnancy.

Analysis of antepartum fetal heart rate tracing by physician and computer.

OBJECTIVE To compare the interpretation of fetal heart rate (FHR) tracings by three obstetricians with that of a computer analysis program. METHODS Our study population consisted of high-risk pregnant women referred as outpatients for antepartum FHR monitoring. A total of 121 FHR tracings, from a series of 54 consecutive women, were interpreted by three physicians and a computer program (Oxford Sonicaid System 8000, Oxford Sonicaid Ltd., Chichester, UK). The physicians used a modified FHR scoring system to interpret the tracings. Total scores were categorized as 0-4: abnormal, 5-7: questionable, and 8-10: normal. The computer program used overall variation, categorized as normal: longer than 30 ms, abnormal: shorter than 20 ms, and questionable: 20-30 ms. RESULTS Significant differences were found among the physicians and between the physicians and the computer analysis for the individual elements of FHR tracings. There was very good agreement between two physicians and the computer in the assessment of the FHR baseline. When physicians used a FHR scoring system to classify the tracings as normal, questionable, or abnormal, the agreement was poor (kappa values ranged from -0.037 to 0.28). The computerized analysis identified two FHR tracings as questionable but both were classified as normal by all three physicians. CONCLUSIONS The level of agreement in the interpretation of FHR tracings was poor among physicians and between physicians and the computer analysis. A FHR scoring system did not improve the level of agreement between physicians.