Objective To assess the value of antenatally determined observed to expected fetal lung area to head circumference ratio (LHR) in the prediction of postnatal survival in isolated, congenital diaphragmatic hernia (CDH). Methods Results In both the normal fetuses and those with CDH the LHR increased but the observed to expected LHR did not change significantly with gestational age. In normal fetuses the mean observed to expected LHR in the left lung was 100% (95% CI, 61-139%) and in the right lung it was 100% (95% CI, 67-133%). In fetuses with CDH the mean observed to expected LHR was 39% (range 7-79%). Regression analysis demonstrated that significant predictors of survival were the observed to expected LHR (odds ratio (OR) 1.09, 95% CI, side of CDH (left side OR 11.14, 95% CI, and gestational age at delivery (OR 1.18, 95% CI,). ConclusionIn CDH, the LHR increases while observed to expected LHR is independent of gestational age. In fetuses with both left-and right-sided CDH, measurement of the observed to expected LHR provides a useful prediction of subsequent survival.

K E Y W O R D S:

Objective: The purpose of this study was to determine the perinatal outcome in monoamniotic twin pregnancies and to review the recently published literature about the topic. Methods: This retrospective study examined the records of prenatally diagnosed monoamniotic twin pregnancy casese in our institution between January 1997 and April 2010. Results: Among 1,112 twin pregnancies, there were 15 (1.3%) monoamnionic twins, including 2 conjoined twin pregnancies. Twelve (80%), 9 (60%), 5 (33.3%), and 4 pregnancies (26.7%) delivered after 20, 30, 32, and 34 weeks, respectively. Among 12 pregnancies that continued after 20 weeks of gestation, three cases showed one-fetal death and one, both-fetal death. The perinatal mortality rate (from 20 weeks of gestation to 28 days after birth) was 37.5%. The incidence of lethal anomalies and congenital heart anomalies was 20% and 23.3%, respectively. The mean gestational age at delivery was 31.4±4.53 weeks; 16 of 18 neonates (84.2%) were admitted to the neonatal intensive care unit (NICU). Three neonates expired on the first day after birth. The mean duration of the NICU stays for 13 live neonates was 32.0±29.3 days (range, 3 to 114 days). The main causes of perinatal deaths were preterm birth, congenital anomalies, pregnancy loss before 20 weeks, and intrauterine fetal demise that might have resulted form cord entanglement. Conclusion: Perinatal mortality in monoamniotic twins was still very high and the survival rate after 32 weeks of gestation is approximately one-third. Further studies are needed to improve the perinatal mortality.

Blood plasma of pregnant women contains circulating cell-free fetal DNA (ccffDNA), originating from the placenta. The use of this DNA for non-invasive detection of fetal aneuploidies using massively parallel sequencing (MPS)-by-synthesis has been proven previously. Sequence performance may, however, depend on the MPS platform and therefore we have explored the possibility for multiplex MPS-by-ligation, using the Applied Biosystems SOLiD(™) 4 system. DNA isolated from plasma samples from 52 pregnant women, carrying normal or aneuploid fetuses, was sequenced in multiplex runs of 4, 8 or 16 samples simultaneously. The sequence reads were mapped to the human reference genome and quantified according to their genomic location. In case of a fetal aneuploidy, the number of reads of the aberrant chromosome is expected to be higher or lower than in normal reference samples. To statistically determine this, Z-scores per chromosome were calculated as described previously, with thresholds for aneuploidies set at > +3.0 and < -3.0 for chromosomal over- or underrepresentation, respectively. All samples from fetal aneuploidies yielded Z-scores outside the thresholds for the aberrant chromosomes, with no false negative or positive results. Full-blown fetal aneuploidies can thus be reliably detected in maternal plasma using a multiplex MPS-by-ligation approach. Furthermore, the results obtained with a sample from a pregnancy with 45,X in the cytotrophoblastic cell layer and 46,XX in the mesenchymal core cells show that ccffDNA originates from the cytotrophoblastic cell layer. Discrepancies between the genetic constitution of this cell layer and the fetus itself are well known, and therefore, care should be taken when translating results to the fetus itself.