Prenatal ultrasonographic fetal rib length measurement: correlation with gestational age

The availability of normal data on fetal rib bone length would be of value in a variety of circumstances under which ultrasound examinations are performed. Fetal rib length measurements were obtained in 257 singleton fetuses in a prospective cross-sectional study. The study population consisted of pregnancies between 14 and 40 weeks with no evidence of growth disturbances, or structural or karyotypic abnormalities. Fetal rib length, as a function of gestational age, was expressed by the regression equation: RL = -0.5834 + 0.2030 (GA), where RL is the rib length in centimeters and GA the gestational age in weeks. The correlation was R = 0.94 (p < 0.0001). The normal limits of fetal rib length are defined, and a high correlation between fetal rib length, gestational age, and other standard determinants of fetal growth is demonstrated. Our results indicate that fetal rib length can be a useful adjunct in determining normal fetal growth and in the management of the pregnancy with fetal skeletal dysplasia.

Antenatal diagnosis and treatment of fetal goitrous hypothyroidism: case report and review of the literature

The recognition and treatment of fetal hypothyroidism are believed to be important to optimize growth and intellectual development in affected fetuses. We present a case of fetal goiter diagnosed by ultrasonography in the second trimester of pregnancy. Cordocentesis performed at 28 weeks confirmed the presence of fetal hypothyroidism. Fetal therapy was performed with weekly intra-amniotic injections of thyroxine from 29 to 36 weeks. A repeat cordocentesis at 35 weeks showed normalization of fetal thyroid function. The fetal goiter decreased rapidly in size following fetal treatment. Amniotic fluid levels of thyroid stimulating hormone (TSH) and free thyroxine were obtained with each amniocentesis. Sulfated iodothyronine concentrations in maternal blood were obtained before and after fetal thyroxine treatment. This report discusses the role of amniotic fluid levels of TSH and free thyroxine and maternal levels of sulfated iodothyronine in the diagnosis and management of fetal hypothyroidism. A review of the English literature is presented.

A non-human primate model for the in utero chronic catheterization of the umbilical vein. A preliminary report

Short-term ultrasound-guided fetal umbilical cord catheterization in humans has been reported. However, before chronic umbilical vein catheterization is attempted in humans the technique must be tested in the non-human primate model. If the fetus was to tolerate this procedure, chronic fetal umbilical vein catheterization could be used for drug administration, parenteral fetal nutrition or to monitor the changes of hematologic parameters during and after open or endoscopic fetal surgery. In this study, 4 pregnant baboons were used to test the feasibility of ultrasound-guided umbilical vein catheterization. Although the umbilical vein was successfully catheterized in all the animals, only 1 fetus survived the postoperative period. The 3 immediate fetal deaths were due to a fetal intra-amniotic hemorrhage, while the most likely cause of death of the 4th animal was infection. In the surviving fetus and mother, blood was sampled once a day. Neither fetomaternal hemorrhage nor thrombosis could be documented. We conclude that ultrasound-guided transplacental umbilical vein chronic catheterization is technically difficult but feasible in the baboon model. Further studies in this model are needed to improve the catheterization technique and to monitor the extent of time that the catheter may be tolerated within the umbilical vein.

Ultrasonographic growth and Doppler hemodynamic evaluation of fetuses of obese women

All fetuses benefit from ultrasonographic estimation of gestational age and evaluation of growth patterns. Monitoring the pregnancies of obese women is perceived as more difficult than monitoring those of nonobese women. The aim of this study was to determine if maternal obesity affects the growth and Doppler resistance indices (RI) of the fetus. Twenty-eight women with a preconception weight > 90.7 kg underwent obstetric ultrasonographic evaluations from the 20th week of gestation. Their ultrasonographic data were compared with those of controls. Ten of the obese women developed gestational diabetes and had lower umbilical artery RIs for a given gestational age (P < .0001) than did those obese women without other medical complications, those with medically controlled pregnancy-induced hypertension or those from the control population. The relation between fetal unit weight and umbilical artery RIs was established. The pattern of RI changes was similar in all groups when estimated fetal weight instead of gestational age was used as the covariant. Fetal growth and Doppler velocimetry can be monitored adequately in obese women. Gestational diabetes significantly influences the pattern of fetal growth and the impedance to flow in the umbilical artery.

Ultrasonic prediction of discordant growth in twin pregnancies

In this prospective study conducted from 1984 through 1987, the ability to correctly predict growth discordancy in twin gestations by ultrasonic estimated fetal weights is examined. Discordancy was defined as an intertwin birth weight difference of 25% or greater. This method resulted in a sensitivity rate of 77% and a specificity rate of 92%. The positive predictive value of an abnormal test (i.e. discordant growth) was 67% and the negative predictive value of a normal test (i.e. concordant growth) was 95%. The perinatal mortality rate of 217/1,000 in discordant twin fetuses was significantly higher than 29/1,000 in the concordant twins in this study population (p < 0.01) and even more of a contrast to the rate of 10/1,000 in our singleton population. Accurate prediction of discordant twin pregnancies which are at high risk for poor outcome opens the opportunity for potential in utero treatment modalities.

Sonographic measurement of the fetal iliac bone: growth and relation to femur length in assessment of gestational age

Diagnostic ultrasonography has given us the opportunity to diagnose several congenital malformations in utero. Skeletal dysplasias is a heterogeneous group of disorders of the skeleton. Although disorders of bone growth are often diagnosed in utero, it is usually a general diagnosis because the exact syndrome cannot be specified. This is due to the fact that many anomalies of the skeleton have similar features. The wing of the iliac bone can be either affected or normal in skeletal dysplasias and its appearance may help in the differential diagnosis. This study was undertaken to establish values for the width of the iliac bone wing during normal gestations and thus enable us to use it in the evaluation of fetal growth and the recognition of specific congenital anomalies.

Fetoplacental and uteroplacental Doppler blood flow velocity analysis in premature rupture of membranes

The value of Doppler velocimetry in predicting fetal distress or perinatal infection was investigated in 60 patients with premature rupture of the membranes (PROM) between 25 and 38 weeks of gestation. Studies were performed in the umbilical and uterine arteries after admission to the hospital and repeated every 24 to 76 hours until delivery. Results of the last study, performed less than 24 hours before delivery and comparison between longitudinal studies in the same patient, failed to disclose statistical differences between patients who did or did not develop the perinatal complications under study. We conclude that Doppler velocimetry is not a sensitive enough means of predicting fetal distress or infection in PROM.

Twin pregnancy. Ultrasonographically observed changes in fetal presentation

The changes in fetal presentation throughout pregnancy were observed ultrasonographically in 332 sets of twins. Seventy-eight percent of the leading twins were vertex at 26-30 weeks' gestational age, 75% at 31-34 weeks and 81% at 35-38 weeks. The incidence of nonvertex presentation for either twin was 73.0%, 64.5% and 59.5% at the same gestational ages. The results are not significantly different from those on concordant twins delivered at the same gestations. Thus, one can counsel parents of twins at all gestational ages in regard to the potential for malpresentation.

Antenatal classification of hydrops fetalis

Among 12,572 pregnant women referred for ultrasound examination from 1985-1990, 76 fetuses had ultrasonographic findings of hydrops fetalis, ten immune and 66 nonimmune. Fetuses with cystic hygroma (20), heart defects or arrhythmias (13), or other congenital anomalies (15) accounted for the majority of the nonimmune cases. Antenatal chromosomal studies were available in 42 fetuses with nonimmune hydrops, of which 14 (34%) were abnormal with seven monosomes and six trisomies. Seventeen cases of hydrops (22%) were classified as idiopathic because they had no recognizable etiology. It is concluded that: 1) The ultrasonographic incidence of fetal hydrops in referral centers can be as high as one in 165 pregnancies; 2) most cases of fetal hydrops are of the nonimmune type, which can occur in a low-risk population and can be detected with early second-trimester ultrasound screening; and 3) the complexity of this condition and the high rate of chromosomal abnormalities require referral to a high-risk center for evaluation and pregnancy management.

Transvaginal color Doppler imaging in the assessment of uteroplacental blood flow in the normal first-trimester pregnancy

Characteristic changes of low resistance and high diastolic blood flow velocity were identified by Doppler studies starting in the early phase of the second trimester. These changes were attributed by some authors to trophoblastic invasion of the uterine vasculature converting the uterus into a low-resistance organ. Because of technical limitations previous studies were confined to the uterine artery and its main branches. With the development of color Doppler and transvaginal ultrasonography we can now identify blood flow in various small vessels in the placental bed. This study was performed to assess the ability of color Doppler ultrasonography to evaluate subtrophoblastic blood flow by color identification in the early phase of normal pregnancy from 5 to 9 weeks' gestation. Results show that the characteristic increase in diastolic blood flow is evident as early as 5 weeks' gestation.

Death due to high-output cardiac failure in fetal sacrococcygeal teratoma

Fetal sacrococcygeal teratoma (SCT) is being recognized with increasing frequency. Placentomegaly and hydrops fetalis are preterminal events, and it has been suggested that fetal death may be due to high-output cardiac failure from arteriovenous shunting through the tumor. We had a chance to examine this hypothesis when a 21-week fetus presented with a huge sacrococcygeal teratoma. There were marked placentomegaly, cardiomegaly, hyperdynamic ventricles, and a pericardial effusion. Doppler studies showed tremendous flow through the SCT with extreme enlargement of the inferior vena cava, consistent with congestive heart failure from increased flow through the tumor. Hydrops developed, and the fetus was delivered because of placental abruption. This case provides supportive evidence that the teratoma acts as a large arteriovenous shunt, causing high-output cardiac failure. We have now collected 18 more cases of sacrococcygeal teratoma diagnosed in utero. Of the total 45 cases of fetal SCT, 9 had placentomegaly and/or fetal hydrops and all 9 fetuses died in utero or shortly after birth. We conclude that the only hope for survival in these severely affected fetuses is to reduce blood flow to the tumor before birth.

Placental histology in fetuses between 18 and 23 weeks' gestation with abnormal karyotype

Placentas from karyotypically abnormal fetuses (18 to 23 weeks' gestation) were analyzed prospectively at the light microscopic level. Group I consisted of 14 control placentas. Group II consisted of 14 placentas from fetuses with an abnormal karyotype. Secondary and tertiary stem villi counts, small muscular artery counts, and total vessel counts were determined per 100 x field. There were no differences in secondary and tertiary stem villi counts between groups. A significant decrease in small muscular artery counts (p less than 0.01) and total vessel counts (p less than 0.01) was noted in group II. Placental and fetal weights were comparable between groups. This undervascularization may represent placental immaturity as a result of arrested or delayed angiopoiesis. It appears that this abnormality is established before the third trimester and may be enhanced by late vascular obliteration as reported by others. These data substantiate the concept that the structure and function of the placenta is determined to a great degree by fetal karyotype and may help explain the morbidity and mortality seen in these fetuses.

Combined intravascular-intraperitoneal transfusions in hydropic twins due to Rh (D) alloimmunization

Fetal hydrops due to Rh (D) alloimmunization can be reversed by ultrasound-guided intravascular transfusions with improvement in perinatal morbidity and mortality. We report a case of in utero intravascular transfusion in hydropic twins which reversed all the hydropic findings within 3 days. A simple intraperitoneal transfusion was performed in each twin 2 weeks later, and only one neonatal exchange transfusion was required for the ultimate survival of both twins.

Ultrasonographic measurement of fetal femur length in growth disturbances

Ultrasonographic measurement of fetal femur length is a recognized technique for determination of gestational age and fetal growth. A total of 280 pregnant women were studied, each of whom had pathologies with the potential to either accelerate or delay fetal growth. There were 1000 measurements of the fetal femur length performed on these 280 fetuses. A total of 125 fetuses were found to have a growth disturbance-91 with asymmetrical intrauterine growth retardation and 34 with macrosomia. Comparison of fetuses with either intrauterine growth retardation or macrosomia with appropriate-for-gestational-age fetuses showed that the femur length is not statistically affected by intrauterine growth abnormalities.

Congenital cystic hygroma of the neck diagnosed prenatally: outcome with normal and abnormal karyotype

Twenty-two cases of cystic hygromas were diagnosed prenatally at Eastern Virginia Medical School and followed through the neonatal period. Our series was combined with 131 cases which have been described in the literature. Karyotypes were obtained in 110 fetuses and 80 (72.7 per cent) were abnormal. Fifty-one were not terminated: 30 with abnormal and 21 with normal karyotypes. There were no neonatal survivors in the group with abnormal karyotypes. There were five survivors in the 21 with normal karyotypes but only 2/21 without severe medical complications. Combining our series with those previously reported in the literature would suggest only a 2-3 per cent rate of intact survivors when fetal cystic hygromas are diagnosed in utero. This information should be helpful when counselling patients whose pregnancies carry this diagnosis.

Lower limb movements and urologic function in fetuses with neural tube and other central nervous system defects

Lower limb movements and urologic systems were evaluated by prenatal ultrasound in 120 fetuses with either neural tube defects or intracranial anomalies. Despite anticipated major lower extremity and bladder dysfunction, lower limb movements were seen in 100% of the fetuses with anencephaly and encephaloceles, 93% with isolated spina bifida, 60% with complex spina bifida and 90% with abnormal intracranial findings. In all the cases except those with cloacal exstrophy, fetal bladder and collecting systems appeared normal. Therefore, fetal lower limb movements and urinary tract integrity appear to have no diagnostic or prognostic value in fetuses with neural tube defects or other central nervous system anomalies. These diagnoses can only be made by direct ultrasound observation of the lesion itself.

Fetal sacrococcygeal teratoma

Early prenatal diagnosis of fetal sacrococcygeal teratoma (SCT) has enabled the perinatal team to institute management of this condition during the perinatal period. We report 2 additional cases to our previous 27 cases including 1 which represents the earliest diagnosis of SCT. Fetal SCT behaves in a different manner than neonatal SCT. In utero manipulation of fetal SCT may be possible if diagnosis is made during the second trimester.

Ultrasound diagnosis of intrauterine growth retardation

Intrauterine growth retardation is associated with increased perinatal morbidity and mortality. Assuming an accurately dated pregnancy, ultrasonic estimations of fetal weight can be used to predict intrauterine growth retardation. Antenatal detection of this condition will have an impact on management and ideally may improve outcome.

Midtrimester amniotic fluid delta optical density at 450 nm in normal pregnancies

Spectrophotometric analysis of amniotic fluid has become the standard for assessing the fetal condition in Rh-immunized pregnancies. Serial amniocentesis is usually started at 28 to 29 weeks of gestation unless the antibody titer or history indicates it should be done earlier. This study presents the values from 14 to 20 weeks in normal pregnancies, which will also assist in evaluating pathologically elevated values.

Fetal sacrococcygeal teratoma

Sacrococcygeal teratoma (SCT) is being diagnosed before birth with increasing frequency. We were recently consulted about management of a 22-week fetus with SCT and reviewed our experience (6 cases) and the literature. We found that most fetal SCT present from 22 to 34 weeks gestation with a uterus enlarged by the tumor and/or associated polyhydramnios; although the American Academy of Pediatrics Surgical Section clinical classification is an important prognostic indicator in neonatal SCT, it does not appear to predict outcome in fetal SCT; associated chromosomal abnormalities or life threatening anomalies are rare; presentation after 30-weeks gestation is a relatively good prognostic sign with fetal survival, after planned cesarean delivery, in 6 of 8 cases; and hydrops and/or placentomegaly in association with fetal SCT predicts fetal demise soon after diagnosis with 7 of 7 cases dying in utero.

In utero diagnosis of congenital diaphragmatic hernia by CT amniography

Congenital diaphragmatic hernia (CDH) was diagnosed using CT following intraamniotic contrast medium injection. Computed tomographic amniography may be helpful when the sonographic diagnosis of CDH is uncertain or prenatal surgical repair is being considered.

Comparison of fetal weight estimation formulas with and without head measurements

Most published sonographic techniques for estimating fetal weight use measurements of the biparietal diameter (BPD) and abdominal circumference. In many clinical situations, however, accurate head measurements cannot be obtained. One hundred one patients were scanned within 72 hours of delivery. Using multiple stepwise regression analysis, a best-fit formula was developed using abdominal circumference and femur length, or femur length alone. The mean error was 109 g/kg fetal weight for abdominal circumference and femur length that was comparable with BPD and abdominal circumference formulas for estimated fetal weight. The mean error when femur length was used alone was 129 g/kg fetal weight. When these models were tested prospectively on 67 patients and compared with published formulas, they yielded results that were similar in accuracy. Among these additional patients, the model using one parameter (femur length) had an average error of 114 g/kg, whereas the femur length and abdominal circumference showed a mean error of 125 g/kg.

Routine ultrasound screening for antenatal detection of intrauterine growth retardation

This prospective screening program of a large obstetric population was designed to determine the effectiveness of ultrasonic biometry to diagnose intrauterine growth retardation. The results of 3616 pregnancies were analyzed. All pregnancies were dated before the 24th week by ultrasonic measurements. The study compared the effectiveness of three ultrasonic growth parameters: biparietal diameter (BPD), head circumference, and abdominal circumference, to detect intrauterine growth retardation and to determine the optimal gestational age to perform the scan for this purpose. To maintain a high sensitivity required in a screening program, all ultrasonic measurements below the 25th percentile for gestational age were considered abnormal. The predictive value of a positive test in this situation ranged from 0.25 to 0.55, depending on the week of gestation in which the scan was performed. Accuracy of predictions improved greatly when the scans were performed within two weeks of delivery. Abdominal circumference measurements were more predictive of intrauterine growth retardation than either head circumference or BPD measurements or the combination of these parameters. In view of the sensitivity of the test and the prevalence of the disorder, it is concluded that 34 +/- 1 weeks of gestation is the optimal time to screen patients ultrasonically for intrauterine growth retardation.

Oral ritodrine and preterm premature rupture of membranes

A prospective randomized study was performed to determine whether or not oral ritodrine therapy significantly prolonged the latent period in patients with prematurely ruptured membranes. Compared with a control group of similar patients, those treated had a significantly prolonged mean latent period. In addition, 47.6% of the treatment group versus 14.2% of the control group had a latent period of more than one week.

Endocervical curettage as a routine part of colposcopic examinations for abnormal cervical cytology

Two hundred seven consecutive patients with adequate colposcopy and routine endocervical curettage (ECC) were evaluated for abnormal cervical cytology. A positive ECC was found in 31 patients (15.0%). In patients with grade III cervical intraepithelial neoplasia (CIN), ECC was positive 260% more often than in patients with CIN 1 and 2 (P less than .005). The ECC was the only evidence of dysplasia in three instances. The data suggest that routine ECC should be an integral part of the colposcopic examination of patients with abnormal cytology.

Routine ultrasound screening for the prediction of gestational age

In a technician-oriented routine ultrasound program, the value of screening an entire obstetric population for predicting gestational age based on a single measurement was evaluated over selective scans performed on the basis of uncertain menstrual history. Consecutive pregnancies of 4527 women were scanned, and the results were analyzed. Gestational ages were determined by both menstrual history and ultrasonic crown-rump length or biparietal diameter (BPD) measurements. The estimated date of confinement based on ultrasound measurements was compared with menstrual history in its ability to predict the actual onset of spontaneous labor. Of patients with optimal menstrual history, 84.7% delivered within +/- two weeks of the date predicted. Only 69.7% delivered within +/- two weeks of the estimate date of confinement based on suspect menstrual history. Crown-rump length measurements were as predictive (84.6%) as optimal menstrual history. Biparietal diameter measurements done between 12 and 18 weeks' gestation were significantly more accurate in gestational predictions (89.4%) than those based on menstrual history (P less than .001). It is concluded that ultrasound cephalometry before 18 weeks is the single best dating parameter.

The management of severe rhesus isoimmunization by fetoscopic intravascular transfusions

Twenty-five severely rhesus-isoimmunized fetuses, including 15 with hydrops fetalis, underwent a total of 77 intrauterine transfusions between 19 and 32 weeks' gestation. Fifty-eight of the procedures were fetoscopically directed intravascular transfusions, nine were ultrasound-guided intraperitoneal transfusions, and 10 were a combination of intravascular transfusion, fetal paracentesis, and intraperitoneal transfusion. The average number of antenatal procedures per patient was three (range, one to five). The survival rate for the 19 fetuses that received their initial intrauterine transfusion at or before 25 weeks' gestation was 84%; 11 of the 13 hydropic fetuses and five of the six fetuses without antenatal evidence of hydrops survived. In six cases hydrops fetalis was reversed in utero. The outcome in patients referred after 25 weeks' gestation was poor; neither of the two hydropic fetuses and only two of the four nonhydropic ones survived, which suggests the importance of early referral to a team experienced in the management of this problem. However, most of these fetal losses occurred early in the series. Seven of the 20 neonates were hydropic, and nine had severe thrombocytopenia (platelet count, less than 50,000 X 10(6)/L). The mean cord blood hematocrit and bilirubin of the neonates were 25.1% and 82 mumol/L, respectively. The babies required a total of 69 exchange transfusions (range, 0 to 9) and 68 simple transfusions (range, 0 to 25). One newborn infant who had had ultrasound evidence of hydrops fetalis at 22 weeks' gestation did not require any exchange transfusions. Nine patients required intermittent positive pressure ventilation (eight had respiratory distress syndrome and one had apnea) for a range of 1 to 86 days. The neonatal survival rate was 90% (18/20).

Medical and surgical treatment of inflammatory bowel disease in pregnancy

Inflammatory bowel disease is a relatively common spectrum of disorders of the gastrointestinal tract in women of the reproductive age group. Although Crohn's disease may decrease fertility, female reproductive ability is normal in UC. In general, IBD is not a contraindication to pregnancy or vaginal delivery and is not an indication for therapeutic abortion. Pregnancy will have a variable effect on IBD, and the patient's experience in previous pregnancies is not prognostic of future pregnancies. Whenever possible, pregnancies should be planned when IBD is quiescent and the patient is on a minimal drug regimen. The treatment of IBD is essentially the same regardless of pregnancy. Aggressive medical management with supportive therapy, corticosteroids, and sulfasalazine is effective in the treatment for this disorder. Sulfasalazine is effective in preventing recurrence of UC. Surgical treatment may be necessary in pregnancy. An enlarged uterus may make recognition of acute complications difficult, and fear of radiation may decrease the number of diagnostic x-ray studies performed. A proctocolectomy and ileostomy is curative for UC, but no procedure will cure Crohn's disease. In pregnancy, a limited surgical procedure may be necessary. There is a high incidence of fetal loss if surgery is required in IBD. This fetal loss is probably caused by the fulminant nature of the disease rather than surgery itself. If surgery is indicated, however, it should be performed for maternal indications despite the risk to the fetus. As can be seen, management of IBD in pregnancy is not to be taken lightly and requires extensive collaboration between obstetrician, gastroenterologist, surgeon, and other support personnel.

The present place of routine ultrasound screening

The value of routine ultrasound examinations is illustrated in Table 3. Ultrasound examination may of course be indicated in early pregnancy on clinical grounds. If it is not, we recommend that all patients should have measurement of the BPD between 16 to 18 weeks' gestation even if they have optimal menstrual histories. It is preferable to have a routine ultrasound service if a MSAFP programme is offered because, although it is possible to scan only patients with a raised MSAFP, prior knowledge of gestational age helps in the timing of the sample and prevents concern in patients with inaccurate dates. At 16 to 18 weeks' gestation multiple pregnancies can be diagnosed reliably and many structural abnormalities can be detected even when the routine examination is performed by non-medically trained personnel. A fundal placenta at 16 to 18 weeks' gestation excludes the possibility of placenta praevia. Seeing the fetus on the ultrasound screen and watching fetal movements strengthens parental feelings towards pregnancy. A repeat ultrasound examination in the third trimester to measure AC is superior to clinical means of detecting growth retardation. Placental localization at this gestation is accurate and has removed the need for the hazardous 'examination under anaesthetic'. If facilities are available we recommend that every patient has a repeat scan in the third trimester. If facilities are insufficient then we recommend that high risk patients have serial scans and that other patients have SFH measurement at each antenatal visit, and that only those that have a low SFH should have repeat ultrasound examinations. Until the day arrives when there is sufficiently trained personnel, adequate equipment and time to perform detailed examinations of all fetuses at 16 to 18 weeks' gestation, together with serial examination and measurement of all growth parameters, we feel the above schema makes the best use of available facilities.

An evaluation of two equations for predicting fetal weight by ultrasound

In an earlier study we presented a method of determining fetal weight from ultrasound measurements of abdominal circumference (AC) and biparietal diameter (BPD). From an equation with these two measurements as independent variables we generated tables of estimated fetal weights (E1). Although these tables have been very useful, we had the impression we were underestimating fetal weight. Therefore, we reconsidered an earlier unpublished table generated from a different equation (E2). While most estimates from E1 and E2 were likely to be within 10% of actual weight, there was significant underestimation with E1. E2 provides a better balance between the distribution of overestimations and underestimations.

Prenatal diagnosis of congenital adrenal hyperplasia

In patients with congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency, the concentrations of the cortisol precursor 17-alpha hydroxyprogesterone (17-OHP) and its metabolite delta 4-androstenedione (delta 4 A) are increased. CAH was diagnosed in twins by measurement of 17-OHP and delta 4 A concentrations in amniotic fluid obtained by amniocentesis from both amniotic cavities at 17 weeks' gestation. Both prenatal karyotypes were 46,XX. Spontaneous labor and delivery of 2 nonviable fetuses with genital masculinization occurred at 26 weeks' gestation. It is concluded that delta 4 A measurement, like 17-OHP quantitation, is valuable in the prenatal diagnosis of CAH; that both methods appear useful in prediction of CAH in twin fetuses; and that abnormal adrenal-mediated masculinization in female CAH is well established before the end of the second trimester.

The estimation of fetal weight by computer-assisted analysis

The need for a quick and easy method for estimating fetal weight in utero has been clearly established. Estimates by abdominal palpation and fetal hormone production have proved to be of limited value. Eight-five patients, ranging from 17 to 41 weeks' gestation, were ultrasonically scanned within 48 hours of delivery. Statistical analysis and multiple multivariant linear regressions were performed employing the BMD statistical packages. Our results show that birth weight is a logarithmic function of fetal body parameters and that the abdominal circumference has the single best correlation with the log10 birth weight. Our best linear regression with the use of two fetal dimensions (abdominal circumference and biparietal diameter) had a standard deviation of 106 grams per kilogram fetal weight. Since this derived formula is very cumbersome to manipulate, tables have been prepared with computer assistance to read the estimated fetal weight directly. Prospective estimates in 32 cases of both normal and pathologic gestations have proved to be within our expected accuracy.