Diprosopus associated with neural tube defect and facial cleft in the first trimester.

We report a case of diprosopus presenting with increased nuchal translucency of 5.3 mm at 14 weeks of gestation. Ultrasonographically, the fetus presented with micrognathia, anterior indentation of the cephalic pole, abnormal cerebral hemispheres with a cystic 4th ventricle and angulation of the spine. The fetal karyotype was normal (46,XX). Following termination of pregnancy, postmortem examination established the diagnosis of diprosopus tetraophthalmus with facial cleft of the 2 faces.

Fetal karyotyping after 28 weeks of gestation for late ultrasound findings in a low risk population.

OBJECTIVE: To analyze the indications and the results of invasive testing for fetal karyotyping for ultrasound abnormality in the third trimester of pregnancy, when first- and second-trimester screening tests were negative. METHODS: Retrospective study of 171 consecutive pregnancies that underwent invasive testing after 28 weeks of gestation in 2 institutions between January 1999 and December 2001. Forty-one patients did not have any form of screening for fetal aneuploidy beforehand. One hundred and thirty of them had a normal first-trimester scan and a low risk of fetal aneuploidy by nuchal translucency and/or maternal serum screening and were included in the statistical analysis. RESULTS: Mean maternal age, gestational age at diagnosis and at invasive testing were 30.5 years; 29.3 weeks and 32.5 weeks respectively. Amniocentesis and fetal blood sampling were performed in 97 and 33 cases respectively. The most frequent indications for invasive testing in the third trimester were major fetal malformations (51%) and intrauterine growth restriction (19%) detected on routine second- or third-trimester ultrasound examination. Ultrasound markers of aneuploidy and polyhydramnios accounted for 17 and 11% of the indications respectively. Fetal karyotype was normal in 121/130 cases. A gene mutation was found in one case. The karyotype was abnormal in nine cases, including seven cases of aneuploidy (one Turner syndrome, three trisomy 18, and three trisomy 21) and two cases of structural chromosomal abnormalities (46,XX, del 4 p16.1 and 46,XX, dup1). One hundred cases resulted in the delivery of a normal baby. Thirty cases led to termination of pregnancy or intrauterine death due to major fetal malformations (N = 25), abnormal karyotype in six of these, and severe IUGR (N = 5) with normal karyotype. Fetal US markers of aneuploidy and isolated polyhydramnios were associated with a favorable outcome in all cases.A significant increase in the risk of chromosomal anomaly was seen when two or more anomalies were found, rising from 2% with one anomaly to 21% when two or more anomalies were present. CONCLUSION: In low risk patients, fetal karyotyping in the third trimester may be justified when the diagnosis of fetal malformation is made in the third trimester of pregnancy. Two or more anomalies increase the risk of fetal aneuploidy even with a negative-screening test in the first and second trimester of pregnancy.

A new clue to the prenatal diagnosis of lobar holoprosencephaly: the abnormal pathway of the anterior cerebral artery crawling under the skull.

We report a case of a 24-week-old fetus with cerebral anomalies suggestive of lobar holoprosencephaly including an unusual course of the anterior cerebral artery on Doppler examination. This abnormal trajectory of the anterior cerebral artery in holoprosencephalic brains has been described by pathologists, neurosurgeons and radiologists but our case indicates that this finding may be a useful adjunct to confirm such a difficult diagnosis prenatally.