R.J. Benzie

Composition of the amniotic fluid and maternal serum in pregnancy

Abstract The following parameters in maternal serum and amniotic fluid were simultaneously estimated at varying periods of gestation by manual and automated techniques in 252 samples: bilirubin, sodium, potassium, chloride, total CO 2 , urea nitrogen, glucose, uric acid, creatinine, total protein, albumin, osmolality, alkaline phosphatase, acid phosphatase, lactic dehydrogenase, hydroxybutyric dehydrogenase, and creatine kinase. Analysis of the results established norms for several parameters and indicated areas of difference from results of other workers. Emphasis is placed on the need for further biochemical studies of this nature.

Nonimmunologic hydrops fetalis

Twenty cases of nonimmunologic hydrops fetalis were reviewed. The incidence of nonimmunologic hydrops fetalis was 1/2,029 (20 cases in 40,588 deliveries). The diverse etiologies of nonimmunologic hydrops fetalis are demonstrated. The incidence of erythroblastosis fetalis caused by Rh isoimmunization declined markedly. The perinatal mortality rate was 14/18 or 78%. Prematurity, the presence of congenital anomalies, and the severity of hydrops fetalis contribute to this poor prognosis. However, a better understanding of the pathophysiology of hydrops fetalis, along with early detection by ultrasonography, preterm delivery with the liberal use of cesarean section, and availability of high-risk perinatal units, may enable us to improve the prognosis. A precise diagnosis should be attempted by careful antenatal and postnatal evaluation, so that accurate genetic counseling can be offered.

Fetal cystic hygroma colli: antenatal diagnosis, significance, and management

Twenty-four cases of fetal cystic hygroma colli were diagnosed by ultrasound. In two patients, the diagnosis was not confirmed at autopsy. Ten of these were cases of Turners syndrome, one was a case of Turners mosaicism, three had other aneuploidies, four had normal chromosomes, and six had a failed chromosome culture. The diagnosis, management, and future counseling of these patients are discussed.

Genetic amniocentesis in seventy twin pregnancies

Genetic amniocenteses were performed in 70 twin pregnancies over an 11-year period. Both sacs were successfully sampled in 49 of 62 patients (79%). The success rate was decreased (68%) with two placentas (anterior and posterior) and was improved with gestational age greater than or equal to 17 weeks (88%) and with ultrasound visualization of the septum (86%). Of three spontaneous abortions, two were attributed to amniocentesis (chorioamnionitis). When twin pregnancy is diagnosed in a patient with an indication for genetic amniocentesis, a careful reevaluation and discussion of risk factors with the couple are recommended.

Amniotic fluid tests for fetal maturity in normal and abnormal pregnancies.

Amniotic fluid creatinine, percentage of lipid-positive cells, and L/S ratio were determined on 285 samples from normal pregnancies and 222 samples from abnormal pregnancy states (Rh isoimmunization, diabetes, hypertensive disorders, intrauterine growth retardation, and hydramnios). In normal pregnancy the coefficient of correlation between true gestational age and estimated period of gestation (EPG) based on the three parameters was 0.94, in Rh isoimmunization 0.77, in diabetes 0.67, and in hypertensive disorders 0.59. In intrauterine growth retardation both the L/S ratio and creatinine were depressed, the coefficient was 0.61, and the EPG was consistently less than the true gestational age. The mean L/S ratio in pre-eclampsia was slightly below the normal mean and in diabetes the mean L/S ratio was also depressed. In 150 samples taken within 48 hours of delivery L/S ratios were accurate in assessing fetal pulmonary maturity although there was a 20 per cent incidence over all of false-immature values. There were no false-mature values except in diabetes (2/9).

Amniotic fluid tests for fetal maturity

Abstract Eighteen biochemical parameters and one cytologic test (percentage of lipid-positive cells) in amniotic fluid were assessed for their value in establishing fetal maturity. Ten parameters showed a trend with gestation but the three best tests were percentage of lipid-positive cells, lecithin/sphingomyelin ratio (L/S), and creatinine. With the use of a graph containing the mean value of the three key parameters, an estimated period of gestation was produced which was 95 per cent accurate for any individual sample. With some minor deviations the three tests and the estimated period of gestation based on the three tests continued to be accurate in abnormal pregnancy states.

Amniotic fluid lecithin/sphingomyelin ratio, palmitic acid, palmitic acid/stearic acid ratio, total cortisol, creatinine, and percentage of lipid-positive cells in assessment of fetal maturity and fetal pulmonary maturity: A comparison

Lecithin/sphingomyelin (L/S) ratio, creatinine, percentage of lipid-positive cells, palmitic acid, palmitic acid/stearic acid (P/S) ratio, and total cortisol were analyzed as tests for fetal maturity and fetal pulmonary maturity in 164 samples of amniotic fluid from 121 patients. Fifty samples were taken within 72 hours of delivery. The best tests for fetal maturity (37 weeks) with differential percentages were L/S ratio, palmitic acid, and P/S ratio. In the assessment of fetal pulmonary maturity, we studied an additional 174 samples in which only L/S ratio, creatinine, and lipid-positive cells were analyzed. All tests showed a high predictive value of an immature (positive) result was much less for all six parameters; the three best tests were total cortisol (33%), lipid-positive cells (26%) and L/S ratio (14%).

Experience with an antenatal diagnostic genetic clinic.

Summary: A regionalized, multi‐disciplined approach to antenatal diagnosis of genetic disease is a significant and positive contribution to modern obstetrical care. The indications, pick‐up rate, pregnancy outcome, and complications in such a programme are described.