Genetic amniocentesis at 7–14 weeks of gestation

Genetic amniocentesis performed at 7–14 weeks of gestation was studied in a series of 138 patients of whom 50 wanted termination of pregnancy (⩽ 12 weeks). The material for analysis consisted of 132 samples due to two sampling failures and four samples being handled incorrectly. Forty-eight samples (36 per cent) were taken at 7–12 weeks of gestation, mainly transvaginally (36/48:75 per cent). The success rate of culture and karyotyping increased with the duration of pregnancy, but was only satisfactory from week 11 onwards. The time until harvest was then 14–15 days. The transvaginal approach is easy to perform and was accepted by the women, but we experienced bacterial or fungal overgrowth in 17 per cent of these samples, whereas no infection occurred in the samples taken transabdominally (n = 96). We conclude that genetic amniocentesis is feasible from week 11, but further studies concerning side effects, especially focusing on the procedure-related abortion risk, should be carried out before early amniocentesis is routinely applied.     

Isolated fetal hydronephrosis: Beware the effect of bladder filling

The aim was to assess the role that fetal bladder size has in the determination of fetal hydronephrosis. Forty-three fetuses were evaluated for fetal hydronephrosis in the second trimester of pregnancy. Anteroposterior measurements of the renal pelvis were obtained with a full bladder and again when the bladder emptied in each fetus. Statistical analysis was performed using the Spearman rank order correlation coefficient to assess the relationship between bladder status and renal dilation. The anteroposterior size of the fetal renal pelvis diminished from 6.8 ± 1.8 mm on a full bladder scan to 4.5 ± 1.6 mm when the bladder was emptied (P<0.001). Fifty-three per cent of the fetuses whose renal pelvic measurements were 5 mm or more on a full bladder scan had normal-appearing renal pelvises when their bladders emptied. The status of the fetal bladder should be considered when evaluating fetal hydronephrosis.     

Prediction of an abnormal karyotype in fetuses with omphalocele

The aim of this study was to assess the value of ultrasonographic evaluation in predicting abnormal karyotypes in fetuses with omphalocele. Forty fetuses with antenatally diagnosed omphalocele and available karyotype results were reviewed. Ultrasound evaluation included herniation contents and size, and the detection of other anomalies. Nine of 40 consecutive fetuses had abnormal karyotypes: trisomy 18 (n = 5), trisomy 13 (n = 3), 47,XXX (n = 1). Only 1/25 with an extracorporeal liver versus 8/15 with an intracorporeal liver had abnormal chromosomes [P = 0·0006, RR = 0·14 (0·02 < RR <0·9)]. Small defects (<3 cm) were associated with abnormal karyotypes [P = 0·01, RR = 4·7 (1·4<RR <15·6)]. Finding concurrent malformations was highly associated with chromosomal anomalies [P = 0·00004, RR = 4·4 (2·3 < RR < 8·5)]. The presence of associated malformations, an intracorporeal liver, and a small herniation size are highly suggestive of an associated abnormal karyotype.     

Prenatal diagnosis of gall bladder anomalies—report of 17 cases

We describe here 17 cases of fetal gall bladder anomalies, detected as early as the 14th week of gestation, out of 10 016 fetal systemic examinations performed by us in the last 6 years (015 per cent). In seven cases, agenesis of the fetal gall bladder was detected. The diagnosis was confirmed by post-abortal examination in five cases and in two post-partum. In six other cases, a left-sided gall bladder and in one case, a ‘floating’ gall bladder were detected at 15 weeks' gestation. In two cases, a septated or bilobed gall bladder was visualized. None of these 15 cases was dyskaryotic, but in five cases, two with agenesis and three left-sided gall bladders were associated with other fetal malformations. In two other cases, the gall bladder appeared dysmorphic on sonographic examination and in both of them intrauterine growth retardation and other anomalies were detected. Trisomy 18 was diagnosed by amniocentesis in one of them. According to our experience, failure to visualize the fetal gall bladder by the 15th gestational week is diagnostic of its absence and should raise the differential diagnosis between gall bladder atresia, which has a good prognosis, and external biliary atresia, which has a poor prognosis. Further experience is needed to characterize the various gall bladder malformations and their prognosis.     

Ultrasound screening for chromosomal anomalies in the first trimester of pregnancy

For the last 6 years, sonographic signs for excessive fluid accumulation in the backs of 10- to 12-week-old fetuses have been looked for prior to transabdominal chorionic biopsy. In 1400 pregnancies, subsequent karyotype analyses revealed 28 cases of Down syndrome. In 15 ( = 54 per cent), a large fluid cushion over most of the back had been documented at the time of biopsy. Only a few chromosomally normal fetuses with the same peculiarity were observed. The cushion was also present in fetuses with trisomies 18 and 13 , and in Turner syndrome. Systematic first-trimester screening for nuchal fluid accumulation seems to be a recommended method for the detection of Down syndrome and other chromosome anomalies in young pregnant women at low risk. It compares favourably with current methods of maternal serum screening performed at 16–18 weeks which require a higher number of invasive procedures.     

Apparent segregation of null alleles ascribed to deletions of the ornithine transcarbamylase gene in congenital hyperammonaemia

Ornithine transcarbamylase (OTC) deficiency is an X-linked disorder of the urea cycle mapped to chromosome Xp21.1. Here, we show that apparent segregation of null alleles at the OTC locus and flanking polymorphic loci mimicked false maternity or false paternity in three affected families. Based on these observations, we suggest giving consideration to gene deletion when dealing with segregation of null alleles in OTC deficiency.     

Prenatal diagnosis and investigation of a fetus with chondrodysplasia punctata,ichthyosis, and Kallmann syndrome due to an Xp deletion

We report the prenatal diagnosis of a male fetus with X-linked recessive chondrodysplasia punctata (CDPX), steroid sulphatase (STS) deficiency, X-linked Kallmann syndrome (KAL), and a chromosome deletion at Xp22.31. Biochemical analysis of bone from this case indicates that CDPX is not a defect of vitamin K metabolism. Immunocytochemical study of the brain suggests that KAL is a defect in neuronal migration.     

Prenatal diagnosis of familial congenital pyloric atresia

Familial congenital pyloric atresia is a rare malformation of the fetal gastrointestinal tract. It usually manifests as maternal polyhydramnios and enlarged fetal stomach on ultrasound scan. Sonographic prenatal diagnosis and management of a pregnancy complicated by familial congenital pyloric atresia are presented.     

Antenatal diagnosis of a congenital nasolacrimal duct cyst by ultrasonography: A case report

With proximal and distal obstruction to the lacrimal drainage system, mucus accumulates forming a cyst. In order to diagnose a nasolacrimal duct cyst antenatally, the sonographer must image the region adjacent to the orbits.