Faculty Bibliography

OBJECTIVE: To examine the effects of meperidine and nalbuphine on intrapartum fetal heart rate (FHR) tracings using computer analysis. METHODS: We studied 28 women with uncomplicated pregnancies in early labor at term with reactive FHR tracings. The women were randomized to receive either meperidine 50 mg or nalbuphine 10 mg intravenously on request. One-hour FHR recordings were obtained before and immediately after administration of the medications. RESULTS: There were no significant differences in the FHR characteristics of the two groups during the pre-treatment period. Nalbuphine significantly decreased the number of accelerations of 10 beats per minute (17 versus 4, P = .003) and 15 beats per minute (10 versus 1.5, P = .001), time spent in episodes of high variation (35.5 versus 10 minutes, P = .004), long-term variation (47 versus 29.8 milliseconds, P = .002), and short-term variation (8.4 versus 6.4 milliseconds, P = .03). Meperidine had no significant effect on any FHR characteristic. CONCLUSION: In the early intrapartum period of normal term pregnancies and at commonly used dosages, nalbuphine had a significant effect on FHR tracings, whereas meperidine had no effect, as determined by computer analysis

Ultrasonographic evaluation of the cervix in pregnancy has provided some insight into premature delivery and pregnancy wastage. Its use has led to the development of cervical length nomograms in uncomplicated singleton pregnancies and to the realization that varying degrees of cervical incompetence exist. In some instances the internal os has been observed to dilate and funnel in the early second trimester while in others these changes occur gradually into the third trimester. Transient cervical changes have been linked to premature delivery and extended ultrasonographic inspection is required for their detection. Although sonography may allow the identification of women who deliver prematurely, it has not demonstrated enough discriminatory power to recommend its routine use for this purpose. Pre- and postoperative inspection of the cervix in elective and emergency cerclage procedures may become influential in outpatient management. A method of functional evaluation of the cervix using transfundal pressure (TFP) has been introduced which may lead to earlier diagnosis of cervical incompetence. The significance of descent of the membranes in response to TFP and sonographic findings consistent with premature cervical changes have not been validated because of surgical intervention performed in response to these findings. Our review concludes that, although sonography of the cervix may be useful in selective cases, more information on the natural history of abnormal cervical sonographic findings and controlled randomized trials are needed before recommendations on surgical intervention can be made

The placental lesions of the very low birthweight (VLBW) infant were investigated in relation to clinical complications leading to preterm birth and evidence of growth impairment. The 249 singleton gestations yielding infants less than 1500 g were grouped according to the clinical complications leading to preterm birth as premature membrane rupture (116/249, 47%) preterm labor (55/249, 22%), pregnancy-induced hypertension (PIH, 54/249, 22%), and normotensive abruption (ABR, 24/249, 10%). Specifically excluded from this data set were cases with greater than 2 weeks discordance, fetal congenital anomalies, placenta previa, and maternal medical or gestational diseases such as chronic hypertension and diabetes mellitus, and intrauterine growth retardation (IUGR) as a primary indication for delivery. Placental weight and lesions including decidual vasculopathy and related villous lesions, chronic villitis/intervillositis, and decidual plasmacytosis were considered as variables in analyses in which raw birthweight was the dependent variable and gestational age a confounder. Of the 195 VLBW, 79 (41%) infants from normotensive mothers had lesions of decidual vasculopathy or chronic inflammation. In the VLBW infants from hypertensive mothers, growth restriction was related to markers of decidual vasculopathy. In the absence of maternal hypertension the growth restriction was independently associated with chronic villitis. Decidual vasculopathy (characteristic of PIH) and chronic intrauterine inflammation underlie the complications of many normotensive VLBW infants. The placental lesions in VLBW-IUGR depend on the presence or absence of maternal hypertension. In the absence of maternal hypertension, VLBW-IUGR is associated with chronic inflammation and is independent of decidual vasculopathy. In the presence of maternal hypertension, VLBW-IUGR is directly related to decidual vasculopathy

OBJECTIVE:Our purpose was to establish the sensitivity and specificity of various ultrasonographic markers of trisomy 21 in the second trimester of pregnancy on the basis of literature review and to generate tables that would allow adjusting the risk for trisomy 21, and therefore the need for genetic amniocentesis, depending on the presence or absence of these markers. STUDY DESIGN/METHODS:A computer search was performed of the English literature, including the years 1983 through 1993, of studies that used second-trimester ultrasonography to detect fetuses with trisomy 21. After statistical analysis of the reported studies was performed, the average sensitivity and specificity of the following ultrasonographic markers were determined: structural malformations, short femur, short humerus, combination of short femur and short humerus, pyelectasis, nuchal fold thickening, echogenic bowel, and short ear length. After the average sensitivity and specificity of these ultrasonographic markers were established, appropriate tables were generated by Bayes' theorem to adjust the risk for trisomy 21 in the second trimester depending on the presence or absence of these markers. Statistical analyses were performed with the statistical package Excel on a personal computer. RESULTS:The average detection rate (sensitivity) of structural fetal malformations was 28%, short femur 31%, short humerus 33%, short femur and humerus 32%, nuchal fold thickening 32%, echogenic bowel 7%, and short ear length 71%. The nuchal fold thickening had the highest specificity (99.5%). Isolated pyelectasis was not associated with an increased risk for trisomy 21. However the risk was increased when pyelectasis was associated with other markers. In the presence of normal ultrasonographic results, the negative prediction can be combined with maternal age-related or biochemical prediction of trisomy 21 to help in the informed consent process in counseling women about the benefits and harms of genetic amniocentesis. Genetic amniocentesis should be considered in women of any age when second-trimester ultrasonography reveals the presence of one or more of the following: fetal structural malformations, short femur (determined by biparietal diameter-to-femur length ratio), combination of short femur and humerus, abnormal (> or = 6 mm) nuchal fold thickening, echogenic bowel, or short ear length. CONCLUSION/CONCLUSIONS:In experienced hands second-trimester ultrasonography may be used to adjust the priori risk of both high and low-risk women for trisomy 21 and therefore the need for genetic amniocentesis.

OBJECTIVE: To use a meta-analysis of all published randomized trials to determine whether the use of continuous electronic fetal heart rate monitoring (EFM) as the main method of intrapartum fetal surveillance is associated with improved pregnancy outcome compared to intermittent auscultation. DATA SOURCES: We used the MEDLINE data base and reference lists of articles to identify all published randomized trials of EFM versus intermittent auscultation. METHODS OF STUDY SELECTION: A total of nine randomized trials published in peer-review journals were identified. The selection criterion was the use of EFM or intermittent auscultation as the main intrapartum fetal surveillance technique. DATA EXTRACTION AND SYNTHESIS: A total of 18,561 patients were included in the nine published randomized trials, 9398 in the EFM group and 9163 in the auscultation group. Measures of pregnancy outcome included cesarean delivery, cesarean for suspected fetal distress, overall use of forceps or vacuum, use of forceps or vacuum for suspected fetal distress, overall perinatal mortality, and perinatal mortality due to fetal hypoxia (intrapartum or early neonatal death) attributable to the method of intrapartum monitoring. The meta-analysis showed that the patients monitored electronically had a significantly higher overall cesarean rate (odds ratio [OR] 1.53, 95% confidence interval [CI] 1.17-2.01), higher cesarean rate for fetal distress (OR 2.55, 95% CI 1.81-3.53), overall increased use of forceps or vacuum (OR 1.23, 95% CI 1.02-1.49), increased use of forceps or vacuum for suspected fetal distress (OR 2.50, 95% CI 1.97-3.18), and decreased perinatal mortality due to fetal hypoxia (OR 0.41, 95% CI 0.17-0.98). CONCLUSION: Electronic fetal monitoring is associated with increased rates of surgical intervention and decreased perinatal mortality due to fetal hypoxia

Transabdominal ultrasonography in obese pregnant women is often unsatisfactory because of the poor transmission of ultrasound through a thickened abdominal wall. We report our experience with the placement of a transvaginal probe in the umbilicus to improve resolution in obese pregnant patients. The technique, which involves filling the umbilicus with ultrasound transmission gel and inserting the transvaginal probe into the umbilicus, was applied in 25 consecutive obese patients who had unsatisfactory fetal imaging by the standard transabdominal approach. The most frequent reason for incomplete fetal survey by the standard transabdominal approach was unsatisfactory imaging of the fetal heart (19 of 25 cases, 76%). The transumbilical approach resulted in improved resolution and satisfactory cardiac examination in 18 of these 19 cases (95%). In two cases, color and pulsed Doppler interrogation of intrafetal vessels become possible. A complete fetal survey was accomplished in 96% of the cases

Available data on the relationship of multiple parameter biophysical testing and fetal acid-base status suggest that a nonreactive nonstress test and absent fetal breathing are the first manifestations of fetal compromise, whereas absent body movement and tone are associated with more advanced degrees of fetal compromise.