L. Pijpers

Amniocentesis or chorionic villus sampling in multiple gestations? Experience with 500 cases

500 women with multiple pregnancies underwent amniocentesis or chorionic villus (CV) sampling at our department between January 1988 and July 1997. The aim of this retrospective study was to evaluate the laboratory aspects and the consequences of discordant results in these pregnancies in relation to the method of sampling. Uncertain results in one or both samples, requiring further investigation were more frequent in CV samples (eight times in 163 paired samples, 5 per cent) than in amniotic fluid (AF) samples (once in 298 paired samples, 0·3 per cent). Sampling one fetus twice (erroneous sampling) was seen only once among 163 pregnancies with two CV samples in our study. Cross contamination due to mixed sampling was discovered in two of seven pregnancies that underwent DNA diagnosis in CV and might be a rather regular occuring phenomenon. In none of the 500 pregnancies mixed sampling caused diagnostic dilemmas. A third sampling problem, maternal cell contamination caused a diagnostic problem once among the AF samples. Selective fetal reduction appeared safer after CV sampling than after amniocentesis. Subsequently, CV sampling instead of amniocentesis has become the method of choice for prenatal diagnosis in multiple pregnancies in our department. Copyright

Genetic amniocentesis in twin pregnancies.

Summary. Eighty‐three patients with twin pregnancies were seen at the University Hospital of Rotterdam between 1 January 1980 and 31 August 1985 for prenatal genetic studies. No abnormal karyotypes were found. Amniotic fluid was successfully obtained from both amniotic sacs in 77 patients. In two pregnancies elevated levels of alpha‐fetoprotein (AEP) were found in both sacs. One of these pregnancies was terminated and the other continued until term. One pregnancy miscarried 4 weeks after amniocentesis at 19 weeks gestation; three women were delivered between 23 and 28 weeks, 36 at between 28 and 37 weeks and 42 women after 37 weeks. The perinatal mortality rate was 55/1000 (9 of 164). These results show that genetic amniocentesis is a safe and reliable technique in twin pregnancy but the interpretation of elevated AFP levels is complicated by the fact that AFP diffuses across the amniotic membranes between the two sacs.

Noninvasive management of isolated bilateral fetal hydrothorax

Fetal outcome was studied in eight cases of isolated bilateral fetal hydrothorax. All patients were referred because of polyhydramnios. Spontaneous resolution of pleural effusion was observed twice. No remarkable change in the degree of hydrothorax was demonstrated in the remaining six cases. All eight cases resulted in the birth of a live infant without other abnormalities. Postnatal intubation, which was carried out in all six fetuses with hydrothorax, was always followed by spontaneous respiration. Subsequent thoracocentesis resulted in the collection of 50 to 500 ml of serous fluid. Sustained intubation (7 days) was necessary in only two infants because of developing respiratory distress as a result of prematurity or recurrent pleural fluid accumulation. All eight infants were alive and well at the age of 1 month. Although in the present study noninvasive management of isolated fetal hydrothorax seems to have been justified, a larger multicenter study is needed to compare survival with and without pleuroamniotic shunting.

Abnormal karyotypes in semi-direct chorionic villus preparations of women with different cytogenetic risks

Among 3499 cytogenetically investigated semi‐direct chorionic villus samples, 219 (6·3 per cent) abnormal karyotypes were encountered. The karyotypes were considered certainly abnormal (generalized abnormal with high probability) in 109 cases (3·1 per cent), and in 110 cases (3·1 per cent) uncertainly abnormal (potentially confined to the placenta), requiring further investigation. Of these 110 uncertain abnormalities, the cytogenetic result turned out to be finally abnormal representing generalized abnormality in 36 cases (32·7 per cent), finally normal representing confined placental mosaicism (CPM) in 69 cases (62·7 per cent), and remained undetermined in 5 instances (4·5 per cent). The rate of the numbers of certainly abnormal and all (certainly+uncertainly) abnormal results, the certainty rate, and that of generalized abnormalities and all abnormalities (generalized abnormalities+CPM cases), the predictive value, are strongly correlated with the cytogenetic risk. Therefore, we advise chorionic villus sampling for cytogenetic investigation only in women with a cytogenetic risk equal to or exceeding that of a 40‐year‐old pregnant woman. Because of the high rate of prenatal follow‐up investigations after the finding of uncertain results in semi‐direct villi, semi‐direct and cultured villi should be karyotyped simultaneously. Copyright

Pregnancy in a patient with diffuse cavernous hemangioma of the uterus

This is the first reported case of successful conservative treatment of a pregnant woman with a diffuse cavernous hemangioma of the uterus. Marked autotransfusion from the hemangioma during labor contractions was clinically apparent and was confirmed by invasive hemodynamic monitoring.

Prenatal detection of trisomy 18 caused by isochromosome 18p and 18q formation.

We report on the prenatal detection and further genetic studies in a case of trisomy 18 caused by isochromosome 18p [i(18p)] and 18q [i(18q)] formation. The diagnosis was made by standard cytogenetic techniques in amniotic fluid cells and confirmed by fluorescence in situ hybridization. The formation of the isochromosomes cannot be explained by a single model; centromere misdivision and meiosis II nondisjunction without recombination or mitotic misdivision are the most likely mechanisms of formation as indicated by DNA analysis.

Fetal Urinary Electrolytes in Bladder Outlet Obstruction

Ultrasound findings and urinary electrolytes in the fetus were correlated with fetal outcome and postmortem findings in 8 cases of fetal bladder outlet obstructions. One of the two fetuses, suggesting normal renal function according to urinary electrolytes, displayed renal dysplasia at birth. Six fetuses were predicted to have poor renal function, 5 of these were found to have renal dysplasia at autopsy. The interpretation of fetal urinary electrolytes as a prognostic indication for the presence or absence of renal dysplasia needs to be clarified.

FETAL RENAL ANOMALIES, A DIAGNOSTIC DILEMMA IN THE PRESENCE OF INTRAUTERINE GROWTH RETARDATION AND OLIGOHYDRAMNIOS

Measurement of the head-to-abdomen (H/A) ratio for differentiating between symmetrical and asymmetrical IUGR may be difficult in the presence of marked oligohydramnios. A total of 76 cases of IUGR with various degrees of oligohydramnios was studied. Sixteen (59%) out of 27 structural defects represented bilateral renal agenesis, 11 of which were diagnosed prenatally. When only the H/A ratio was measured (n = 29) the sensitivity in picking up a structural defect was 50%. Calculation of the pulsatility index in the umbilical artery and fetal internal carotid artery (n = 47), whether or not combined with amnioinfusion (n = 5), resulted in a sensitivity of 76%. It is suggested that the latter two techniques may provide valuable additional information as to the cause of IUGR.

Effect of Amnioinfusion on the Umbilical Doppler Flow Velocity Waveform: A Case Report

A case of intrauterine growth retardation with marked oligohydramnios is presented in which, following amnioinfusion of 200 ml of a 5% glucose solution, the diagnosis of bilateral renal agenesis was established. Doppler flow study in the umbilical artery revealed a high resistance flow velocity waveform which became normal following amnioinfusion, suggesting cord compression rather than poor uteroplacental perfusion. Abnormal Doppler flow velocity waveforms in the umbilical artery in the presence of severe oligohydramnios should be interpreted with caution.

Selective Birth in a Dyzygotic Twin Pregnancy with Discordancy for Down’s Syndrome

The discovery of a twin pregnancy by ultrasound at the intake procedure for chorionic villus sampling or amniocentesis is not unusual because of the raised incidence of dizygotic twins at increased maternal age. Since the conception of dizygotic twins is genetically a separate and unrelated event, the risk of abnormalities in each twin is independent, but additive. In advanced maternal age, the risk of chromosomal aneuploidy in one of both fetuses varies between 2 and 6% [1]. This case report discusses the early prenatal diagnosis of twins discordant for Downs syndrome.