Rudy E. Sabbagha

Genetic amniocentesis in twin gestations

Among 1,613 women studied with routine ultrasonography prior to genetic amniocentesis at Northwestern University Medical School, 25 of 26 multiple gestations were detected. Sampling of fluid from both amniotic sacs was requested by 20 women with twin gestations in which both fetuses were ultrasonographically determined to be viable and of normal size. Fluid was obtained successfully from both amniotic sacs in 19 of 20 cases. The conclusions are that (1) twin gestations can be reliably detected by the use of routine ultrasonography, (2) both amniotic sacs can usually be sampled, and (3) the complication rate appears to be minimal to the patient and the fetuses, although the sample size is still small.

Predictive value sensitivity, and specificity of ultrasonic targeted imaging for fetal anomalies in gravid women at high risk for birth defects

In this report the predictive value of ultrasonic targeted imaging for fetal anomalies (TIFFA) is defined. Six hundred fifteen pregnant women at high risk for birth defects were scanned from January, 1980, to December, 1983. Follow-up evaluation was available on 569 fetuses. The pregnancies were classified into five groups according to the indications used for ultrasonic targeted imaging studies. The largest number of women were placed in group 1 and were referred because of a variety of abnormalities in previous or ongoing pregnancies. The women classified in the other four groups were examined because of maternal or fetal reasons related to specific craniospinal (29%), urinary (7.9%), gastrointestinal (6.7%), and skeletal (3.7%) defects. In our series the predictive values of abnormal and normal ultrasonic targeted imaging studies were 95% and 99%, respectively. A detailed breakdown of the accuracy of ultrasonic targeted imaging in relation to each anatomic category is presented; these data are useful in counseling gravid women with anomalous fetuses.

Diminished growth in fetuses born preterm after spontaneous labor or rupture of membranes

We examined biparietal diameter, abdominal circumference, and birth weight in 148 preterm infants to assess fetal growth. A statistically significant proportion of preterm fetuses had biparietal diameter and abdominal circumference values below the fiftieth and tenth percentile levels as compared with that expected in normal fetuses. Similarly, birth weight of infants in the study fell significantly below the fiftieth and tenth percentiles relative to Brenners curve. We conclude that diminished fetal growth is associated with early delivery secondary to preterm labor or preterm premature rupture of membranes or both. Additionally, since biparietal diameters in preterm fetuses are smaller than those of normal fetuses the prediction of gestational age by cephalometry should be advanced by 7 to 10 days.

A simple estimated fetal weight equation based on real-time ultrasound measurements of fetuses less than thirty-four weeks' gestation

Based on ultrasonographic mensuration, a number of equations have previously been devised for the purpose of estimating fetal weights. The objective of this study was to develop a mathematical equation that is simple, accurate, and easy to use when applied to preterm or low-birth weight fetuses (less than 2,500 gm). Real-time ultrasound measurements of fetal biparietal diameters (BPDs) and abdominal circumferences (ACs) were obtained in 62 pregnant women within one week of premature delivery. Mean gestational age and mean birth weight +/- SD for this study group of neonates were 28.5 +/- 3.5 weeks and 1,135 +/- 343 gm, respectively. With the aid of computer analysis, a simple regression equation was derived: EFW = (BPD x AC x 9.337) - 229. When predicted estimated fetal weight (EFW) was compared with actual birth weight (ABW), multiple regression analysis demonstrated a correlation coefficient (R) of 0.957. Preliminary results on 19 patients of a prospective study showed an absolute mean difference between the computed EFWs and the ABWs to be within 7.0% of ABW (70 gm/kg of ABW). The standard deviation of the difference was 9.3% of ABW (93 gm/kg of ABW). Based on these data, this simple equation appears to be clinically reliable and easy to use when estimating weights of preterm or low-birth weight fetuses of less than 2,500 gm.

Sonar biparietal diameter

BPD measurements were obtained from 107 white and 91 black normal gravid women, with established dates, between weeks 16 to 40 of pregnancy. The sonar methodology used is uniform, employing nonpersistent image scanning with electronic calipers. It is noted that the BPD percentile growth patterns derived from these racially different fetuses are alike. Similarly, the fetal age distributions corresponding to white vs. black fetal BPDs show minor differences. From a clinical standpoint, therefore, one percentile curve is constructed for both populations. It is concluded that the BPD differences observed in the currently used growth curves, reported by different investigators, are related to nonuniformity in sonar BPD methodology.

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 ultra-sound 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.

Prenatal diagnosis of harlequin ichthyosis

We report the successful prenatal diagnosis of ichthyosis in the fetus of a woman whose previous liveborn child was affected with “harlequin ichthyosis”. The fetal diagnosis was established through analysis of ultrasonographically guided fetoscopic skin biopsies. These biopsies showed premature hyperkeratosis, most marked around hair follicles and sweat ducts, and forming plugs of hyperkeratotic debris. These observations were in distinct contrast to those in control fetuses, whose epidermis consists of squamous epithelium only a few cells in depth with minimal keratinization.

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).

Isolated hyperechoic fetal bowel: significance and implications for management.

OBJECTIVE The objective of this study was to determine the significance of isolated hyperechoic fetal bowel. STUDY DESIGN Forty-five cases with prospective, ultrasonographic diagnosis of isolated hyperechoic fetal bowel were reviewed. Fetal variables, including aneuploidy, deoxyribonucleic acid studies for cystic fibrosis, congenital infection, growth retardation, and intrauterine death were reported. RESULTS Thirty-four of the 45 cases (76%) resulted in live-born infants without detected abnormalities. However, hyperechoic bowel was associated with cystic fibrosis in two cases (4%), congenital infection in two cases (4%), and fetal alcohol syndrome in one case. Termination of pregnancy was elected in three cases and intrauterine fetal death occurred in three cases (7%). Growth retardation was observed in five of 39 (13%) live-born infants. CONCLUSION Isolated hyperechoic fetal bowel is associated with significant pathologic disorders. Women whose fetuses are diagnosed as having isolated hyperechoic bowel should be offered additional prenatal diagnostic options, including maternal serologic studies for congenital infection, fetal karyotype, and deoxyribonucleic acid testing for cystic fibrosis. In addition, continuing ultrasonographic evaluation of fetal growth and antenatal biophysical assessment should be considered.

Diabetic macrosomia: accuracy of third trimester ultrasound.

Sonar biparietal diameter, head circumference, and abdominal circumference percentile values obtained late in the third trimester were compared with birth weight percentile (relative to dates) in 147 diabetic mothers and 40 control fetuses of nondiabetics. Estimates of fetal weight by the method of Shepard et al were also calculated from these sonar data and compared with birth weight percentile. Abdominal circumference values greater than the 90th percentile correctly predicted macrosomia (defined as birth weight greater than 90th percentile) in 78% of cases. Biparietal diameter and head circumference percentiles were significantly less predictive of macrosomia. When analyzed in a similar manner, estimated fetal weights greater than the 90th percentile correctly predicted macrosomia at birth in 74% of cases. However, when both the abdominal circumference and the estimated fetal weight exceeded the 90th percentile, macrosomia was correctly diagnosed in 88.8% of pregnant women with diabetes mellitus.