Allan S. Nadel

Birth weight as a predictor of brachial plexus injury

Objective To examine the relationship between birth weight and brachial plexus injury and estimate the number of cesareans needed to reduce such injuries. Methods All 80 neonatal records coded for brachial plexus injury from October 1985 to September 1993 at the Brigham and Womens Hospital in Boston, Massachusetts, were studied along with linked maternal files. Birth weight, method of delivery, presence or absence of shoulder dystocia, and any diagnosis of maternal gestational or nongestational diabetes were abstracted. Data for the group with brachial plexus injury were compared with data for live-born infants without this injury during the same period. The sensitivity and specificity of birth weight as a predictor of brachial plexus injury were calculated. Further, the number of cesarean deliveries necessary to prevent a single brachial plexus injury was estimated using various weight cutoffs (4000, 4500, and 5000 g) for elective cesarean delivery. Results Among 77,616 consecutive deliveries, there were 80 brachial plexus injuries identified, for an incidence of 1.03 per 1000 live births. The incidence of brachial plexus injury increased with increasing birth weight, operative vaginal delivery, and the presence of glucose intolerance. In the group of women without diabetes, between 19 and 162 cesarean deliveries would have been necessary to prevent a single immediate brachial plexus injury. Among women with diabetes, between five and 48 additional cesareans would have been required. Conclusion Although birth weight is a predictor of brachial plexus injury, the number of cesarean deliveries necessary to prevent a single injury is high at most birth weights. Because of the large number of cesarean deliveries needed to prevent a single brachial plexus injury in infants born to women without diabetes, it is difficult to recommend routine cesarean delivery for suspected macrosomia in these women.

Improved birth weight table for neonates developed from gestations dated by early ultrasonography.

Most previously published tables of birth weight percentiles as a function of gestational age have been derived from neonates with imprecise gestational dating. In order to improve the accuracy of neonatal birth weight percentiles, we developed a birth weight table based on measurements from a group of neonates who had accurate gestational dating by prenatal first trimester ultrasonography. By matching a database of obstetrical ultrasonograms over a 5 year period to birth records at our institution, 3718 newborn infants with gestational dating by first trimester ultrasonography were identified. Statistical smoothing and regression techniques were applied to gestational age at birth and birth weight data to develop a table for the 10th, 50th, 90th, and other weight percentiles for 25 weeks of gestation onward. The weight table developed from our population has lower 50th and 90th percentile weights, and narrower 10th to 90th percentile ranges, at 25 to 35 weeks than in prior tables. At 39 to 43 weeks, our 10th, 50th, and 90th percentile weights are higher than those in previous tables. Our weight table for newborn infants, based on measurements from neonates with accurate dating, permits improved assignment of weight percentiles for gestational age and more accurate diagnosis of growth disorders in fetuses and neonates.

First-trimester nasal bone evaluation for aneuploidy in the general population

OBJECTIVE: To evaluate the role of fetal nasal bone imaging at 10 3/7 to 13 6/7 weeks as a screening tool for aneuploidy, in a prospective multicenter trial. METHODS: Unselected patients from the general population with viable singleton pregnancies at 10 3/7 to 13 6/7 weeks were recruited at 15 U.S. centers. All had screening with nuchal translucency (NT) ultrasound by specially trained sonographers. In the last 8 months of this trial, first trimester nasal bone evaluation was added to the screening protocol. Nasal bones were described as present, absent, or unable to determine. RESULTS: A total of 38,189 patients completed first trimester NT screening, of whom 6,324 also underwent nasal bone sonography. An acceptable nasal image was obtained in 4,801 cases (76%), with nasal bones described as present in 4,779 (99.5%), and absent in 22 (0.5%). There were 11 identified cases of trisomy-21 in the population of 6,324 patients. In 9 of the 11 cases (82%) the nasal bones were described as present, and 2 cases were described as unable to determine. The only other aneuploidies were 2 cases of trisomy-18, in 1 of which the nasal bones were described as absent, and in 1 present. Absence of nasal bones had sensitivity for aneuploidy of 7.7%, false-positive rate 0.3%, and positive predictive value 4.5%. CONCLUSION: First-trimester nasal bone evaluation was not a useful test for population screening for trisomy-21 and added little to first-trimester NT screening. The difficulty in performing first-trimester nasal bone sonography consistently, in the general population setting, will significantly limit the usefulness of this aneuploidy screening technique. LEVEL OF EVIDENCE: III

Absence of Need for Amniocentesis in Patients with Elevated Levels of Maternal Serum Alpha-Fetoprotein and Normal Ultrasonographic Examinations

Abstract Background. Recent improvements in the accuracy of sonographic diagnosis of neural-tube and ventral-wall defects have raised a question about the wisdom of routinely offering amniocentesis to women who have elevated levels of maternal serum alpha-fetoprotein with a structurally normal fetus as determined by ultrasonography. Methods. We reviewed the ultrasound findings in 51 consecutive fetuses with spina bifida, encephalocele, gastroschisis, or omphalocele that were delivered or aborted at a single hospital, to estimate the sensitivity of ultrasonography for these diagnoses. In all cases, the mothers had undergone prenatal sonography at one facility between 16 and 24 weeks after the last menstrual period. We used these data to calculate the probability of an affected fetus in a woman with a given level of maternal serum alpha-fetoprotein and a normal sonogram. Results. These four types of anomalies were correctly identified in all 51 cases, yielding a sensitivity of 100 percent (95 percent confid...

Prematurity among insulin-requiring diabetic gravid women.

From Jan. 1, 1983, through Dec. 31, 1987, 420 gravidas with insulin-requiring diabetes antedating pregnancy delivered on the Joslin Clinic service. Among them, 110 pregnancies (26.2% of the total) delivered before 37 completed weeks of gestation compared with a 9.7% incidence (906/9368) for the general population at the Brigham and Womens Hospital during calendar year 1985. Thirty-three percent of all premature deliveries were the result of the development of preeclampsia. The relative risk of prematurity for diabetic patients with any hypertensive complication was 2.0 (95% confidence interval, 1.40 to 2.87) compared with normotensive diabetic subjects. Compared with the general population, most of the excess risk of prematurity was confined to hypertensive diabetics and normotensive patients of more advanced White class. A history of having had a previous premature delivery, increasing duration of diabetes antedating pregnancy, and carrying a male fetus in the index pregnancy were significantly associated with premature delivery. Future efforts to reduce the incidence of prematurity among diabetic gravidas should be directed toward reducing the incidence of preeclampsia.

Levorotation of the fetal cardiac axis: A clue for the presence of congenital heart disease

Objective To evaluate the use of the cardiac axis within the chest for the prenatal detection of congenital heart defects. Methods We reviewed retrospectively the sonographic findings of all fetuses scanned between 17 and 40 weeks gestation and diagnosed prenatally as having heart defects. The cardiac diagnoses were confirmed postnatally. The control group consisted of 75 consecutive fetuses with normal fetal surveys and newborn follow-up examinations. The cardiac axes were measured retrospectively using an image of the four-chamber view of the heart and measuring the angle between the interventricular septum and a line bisecting the chest. Mean and standard deviations (SDs) of the axis measurements in normal and abnormal fetuses were compared by Student t test. Results The 75 fetuses with heart defects diagnosed by prenatal sonogram had a mean cardiac axis of 56 ± 13°, compared with 43 ± 7° in normal fetuses (P < .001). Using 57° (two SDs above the mean for normal fetuses) as the upper limit of normal, 33 of 75 (44%) abnormal fetuses versus none of 75 normal fetuses were identified. The frequency of cardiac rotation was greater in fetuses with truncus arteriosus, Ebsteins anomaly, pulmonic stenosis, coarctation of the aorta, and tetralogy of Fallot. Conclusion The presence of a cardiac axis exceeding 57° in the fetal chest is associated with a substantial risk of congenital heart defects. The finding of an abnormal axis should prompt further evaluation of the fetal heart.

Lateral ventricular atrium: larger in male than female fetuses

Objective: To attempt to detect the presence of a gender difference in the size of the fetal lateral ventricular atrium. Methods: The width of the lateral ventricular atrium was measured sonographically on 543 consecutive fetuses scanned at 17–40 weeks, with a normal structural survey and documented gender assignment. Lateral ventricular measurements of male and female fetuses were compared. Results: The mean width (± S.D.) of the lateral ventricular atrium for the entire study population of 543 fetuses was 6.5 ± 1.4 mm. The measurement was 6.7 ± 1.3 in male and 6.3 ± 1.4 in female fetuses (P < 0.001). The atrial measurements were ≥ 8.5 mm in 10% of the male and 7% of the female fetuses (P > 0.05, NS). Conclusion: Male fetuses have slightly larger cerebral lateral ventricles than female fetuses.

Management of isoimmunized pregnancy by use of intravascular techniques

Twenty-two patients who had 23 pregnancies complicated by isoimmunization were managed by the use of intravascular methods on an outpatient basis. Nine patients underwent 30 percutaneous fetal blood sampling procedures to determine fetal blood type or hematocrit, without complication. Thirteen patients underwent 45 intrauterine fetal transfusions via the umbilical vessels and 16 intraperitoneal fetal transfusions. The overall survival rate in this series was 85.7%. Survival among fetuses that were hydropic at initial evaluation was 83.3%. The procedure-related perinatal mortality rate for intravascular intrauterine transfusions was 2.2%. Knowledge of fetal blood type and hematocrit allowed treatment individualized to the specific needs of each patient. In particular, the ability to transfuse blood directly into the vascular system of the hydropic fetus proved to be lifesaving in those patients.

An unusual variant of congenital dyserythropoietic anaemia with mild maternal and lethal fetal disease

Summary. An unusual variant of congenital dyserythropoietic anaemia is described presenting as mild haemolytic anaemia with multinucleated erythroblasts in the marrow of the proband. The outcome of her non‐consanguineous pregnancy was a third trimester, in utero, fetal demise. The hydropic fetus had dyserythropoiesis with circulating multi‐nucleated erythroblasts, and haemosiderosis. Re‐evaluation of the proband revealed a variant of congenital dyserythropoietic anaemia with an inheritance pattern, and with morphological, serological and biochemical features which are not consistent with any of the three described variants of congenital dyserythropoietic anaemias.

Does previa location matter? Surgical morbidity associated with location of a placenta previa

Objective:To evaluate the effect of placenta previa location (anterior vs posterior) on cesarean morbidity.Study Design:Retrospective cohort of women undergoing cesarean for placenta previa. The rate of hysterectomy and blood transfusion in the setting of anterior previa was compared with posterior previa. Planned stratified analysis based on delivery history was performed. Logistic regression was performed to control for potential confounders.Result:Two hundred and eighty-five women undergoing cesarean delivery for placenta previa were identified. Women undergoing primary cesareans with an anterior previa had higher rates of blood transfusion (adjusted odds ratio (aOR) 3.13 95% confidence interval (CI) (1.18 to 8.36) and hysterectomy (7.4% vs 0, P=0.001) compared with those with a posterior previa; similarly, women undergoing repeat cesarean with anterior previa had higher rates of hysterectomy (aOR 4.60 95% CI (1.02 to 20.7). The majority of hysterectomies (93.8%) were due to abnormal placentation.Conclusion:An anterior placenta previa increases the risk of hysterectomy for both primary and repeat cesareans due to abnormal placentation. In the absence of accreta, blood transfusion remained a significant cause of maternal morbidity in both anterior and posterior placenta previas. This information may be useful for operative planning.