Subarachnoid space diameter in chromosomally abnormal fetuses at 11–13 weeks’ gestation

Objectives: To examine the subarachnoid space diameters in chromosomally abnormal fetuses at 11–13 weeks’ gestation.

Methods: Stored three-dimensional (3D) ultrasound volumes of the fetal head at 11–13 weeks’ gestation from 407 euploid and 88 chromosomally abnormal fetuses (trisomy 21, n?=?40; trisomy 18, n?=?19; trisomy 13, n?=?7; triploidy, n?=?14; Turner syndrome, n?=?8) were analyzed. The subarachnoid space diameters, measured in the sagittal and transverse planes of the fetal head, in relation to biparietal diameter (BPD) in each group of aneuploidies was compared to that in euploid fetuses. A total of 20 head volumes were randomly selected and all the measurements were recorded by two different observers to examine the interobserver variability in measurements.

Results: In euploid fetuses, the anteroposterior, transverse and sagittal diameters of the subarachnoid space increased with BPD. The median of the observed to expected diameters for BPD were significantly increased in triploidy and trisomy 13 but were not significantly altered in trisomies 21 and 18 or Turner syndrome. In triploidy, the subarachnoid space diameters for BPD were above the 95th centile of euploid fetuses in 92.9% (13 of 14) cases. The intraclass reliability or agreement was excellent for all three subarachnoid space diameters.

Conclusion: Most fetuses with triploidy at 11–13 weeks’ gestation demonstrate increased subarachnoid space diameters.     

Role of First‐Trimester Sonography in the Diagnosis of Aneuploidy and Structural Fetal Anomalies

Objective. We sought to determine the sensitivity of the first‐trimester scan in the early diagnosis of aneuploidy and structural fetal anomalies in an unselected low‐risk population. Methods. This was a retrospective chart review of all patients having first‐trimester scans between 2002 and 2009. At our center, a survey of fetal anatomy is performed at the time of nuchal translucency assessment at 11 weeks to 13 weeks 6 days. A second‐trimester scan is done at 20 to 23 weeks and a third‐trimester scan at 32 to 35 weeks. Isolated sonographic findings of choroid plexus cysts and echogenic intracardiac foci were excluded. Lethal anomalies and those requiring immediate surgical intervention at birth were considered major structural anomalies. All scans were performed by a single sonologist certified by the Fetal Medicine Foundation. All neonates were examined at birth by a pediatrician. Results. Our study included 1370 fetuses. Six cases of aneuploidy (0.4%) were detected. The first‐trimester scan detected 5 of 6 cases of aneuploidy (83%), confirmed by karyotype. There were 36 cases of structural fetal anomalies (2.6%); 20 (1.5%) were major anomalies. The first‐trimester scan detected 16 of 36 (44%); 20 (56%) were identified by second‐ or third‐trimester scans. The first‐trimester scan detection rate for major structural anomalies was 14 of 20 (70%). The 5 that were missed by the first‐trimester scan were detected by a second‐trimester scan. Conclusions. Our study emphasizes the importance of the first‐trimester scan in the early detection of aneuploidy and structural fetal anomalies. In this small unselected low‐risk population, the first‐trimester scan detected 83% of aneuploidies and 70% of major structural anomalies. Our results are comparable to previously published studies from other centers and further exemplify the invaluable role of the first‐trimester scan in the early detection of aneuploidy and structural anomalies in an unselected low‐risk population.     

手术终止妊娠对早孕妇女外周血中游离胎儿DNA的影响

目的检测在孕早期手术终止妊娠是否会对母体外周血浆中的胎儿DNA水平造成影响。方法选择孕6~9w妇女36例(自愿要求终止妊娠,无禁忌症,胎儿性别为男性),在其终止妊娠前后分别采取外周静脉血5m l,对其血浆中的游离胎儿DNA的SRY基因行荧光定量分析。结果在36例血浆标本中,术前有31例检测到胎儿DNA,术后全部检测到胎儿DNA。其浓度平均分别为62.40±21.70(31.80~128.00Eq/m l),101.04±37.40(58.20~209.70Eq/m l),术前与术后胎儿DNA含量有统计学差异(P<0.01)。结论①孕妇外周血中游离胎儿DNA最早在孕45天即可检测到。②外周血中游离胎儿DNA的水平在妊娠终止后很快升高。③孕妇外周血中的游离胎儿DNA很可能来源于母胎之间出血。     

The effect of cigarette or sheesha smoking on first-trimester markers of Down syndrome

Objective  To investigate the influence of cigarette or sheesha smoking on first-trimester markers of Down syndrome.
Design  A prospective observational study.
Setting  Primary care centres and antenatal clinics of Maternity and Children Hospital, King Abdulaziz University Hospital and New Jeddah Clinic Hospital, Jeddah, Saudi Arabia.
Population  Women with a singleton pregnancy who were either nonsmokers ( n = 1736) or cigarette smokers ( n = 420) or sheesha smokers ( n = 181).
Methods  Fetal nuchal translucency thickness (fetal NT), maternal serum free beta-human chorionic gonadotrophin (free β-hCG) and pregnancy-associated plasma protein-A (PAPP-A) were measured at 11 weeks 0 days to 13 weeks 6 days of gestation in all women. Women were grouped according to smoking status, confirmed by maternal serum cotinine measurements, and analyte levels between groups were compared.
Main outcome measures  Fetal NT, maternal serum free β-hCG, PAPP-A and cotinine measurements.
Results  Compared with nonsmoking women, fetal NT was significantly increased and free β-hCG and PAPP-A levels were significantly decreased in both cigarette and sheesha smokers. There were significant relationships between all three markers and the number of sheeshas consumed per day.
Conclusions  Cigarette and sheesha smoking significantly affect first-trimester markers of Down syndrome (fetal NT, free β-hCG and PAPP-A). Correction for this effect in women who smoke might improve the effectiveness of first-trimester screening for Down syndrome in these women. The underlying mechanism(s) relating smoking to the changes in first-trimester markers require further studies.     

Ectopia Cordis in a First‐Trimester Sonographic Screening Program for Aneuploidy

We review the sonographic features, antenatal course, and perinatal outcomes in 7 cases of ectopia cordis diagnosed in the first trimester. Four cases were associated with a large omphalocele (pentalogy of Cantrell) and 2 with a body stalk anomaly. The remaining fetus had isolated thoracic ectopia cordis. Two pregnancies were terminated; 2 fetuses died in utero; 2 infants died after delivery; and 1 died at 3 months of age. We conclude that the diagnosis of ectopia cordis can easily be established during the first trimester. In agreement with the currently available literature, the prognosis of ectopia cordis in our series was uniformly poor.