Objective: To evaluate the outcome of fetuses with prenatally diagnosed omphalocele and to investigate the predictive value of the omphalocele circumference/abdominal circumference (OC/AC) ratio – a measure for the relative size of the omphalocele. Materials and Methods: This study includes all fetuses prenatally diagnosed with omphalocele at our centre between 1995 and 2007. Medical records and footage of ultrasound examinations were reviewed. Omphalocele was classified in four groups: isolated, chromosomal, syndromic, and multiple anomalies. Results: Eighty-eight cases were identified: 21 (24%) were isolated and 67 had additional structural anomalies. Of the 44 fetuses (50%) with chromosomal anomalies, 2 had omphalocele as a solitary finding. Fifty-three pregnancies (60%) were terminated because of the size of the lesion or associated structural or chromosomal anomalies. Twenty-one cases resulted in a live birth, of which 17 were vaginal deliveries (81%, all uncomplicated) including 3 cases of giant omphalocele (≧5 cm). The OC/AC ratio was found predictive for herniation of the liver, respiratory insufficiency and type of surgical reconstruction. Currently, 12/88 fetuses (14%) are alive and well, including 2 infants with multiple anomalies. Conclusion: Identification of omphalocele should arouse suspicion of genetic abnormalities, even in cases that appear isolated. The OC/AC ratio may influence counselling regarding the postnatal course.

Two cases of sirenomelia are described, detected in the 14th and 16th weeks of gestation by transvaginal ultrasonography. A hypothesis for the aetiology of sirenomelia and its associated anomalies is discussed.

Over a 6 1/2 year period, in 288 pregnancies a variety of fetal malformations were detected by ultrasound. Two hundred and ten fetuses (73 per cent) were karyotyped. Gestational age at detection ranged from 11 to 38 weeks. The incidence of an abnormal karyotype in the total series was 14 per cent and 14.7 per cent in the 210 pregnancies in which a karyotype was performed. Single structural anomalies were found in 149 cytogenetically investigated fetuses, of which 25 had a chromosomal abnormality (17 per cent). Multiple structural malformations were present in 61 fetuses, of which 16 had an abnormal karyotype (26 per cent). Trisomy 18 was the most frequent finding. The most constant ultrasound finding in cases of an abnormal karyotype was polyhydramnios and severe IUGR in combination with structural defects. There is a need for extensive detailed ultrasound examination in high-risk pregnancies.

ABSTRACT

Two case reports are presented of fetuses with malformations in the neck region, detected in the first trimester of pregnancy by transvaginal ultrasonography. In one fetus a septated cystic hygroma was visualized. Trisomy 18 was found. The other fetus presented with a cephalocele. The ultrasound diagnosis was confirmed at autopsy in both cases. Sonographic criteria to distinguish between cystic hygroma and occipital cephalocele in the first trimester of pregnancy are discussed.