PCB and DDT levels do not appear to have enhanced the mortality of striped dolphins (Stenella coeruleoalba) in the 2007 Mediterranean epizootic

In 2007, 17 years after the first reported Mediterranean epizootic of striped dolphins (Stenella coeruleoalba), a new strain of the morbillivirus caused the deaths of dozens of striped dolphins that appeared dead on Western Mediterranean beaches. DDT and PCB levels were determined in these dolphins, and in individuals from sporadic strandings in the surrounding years. Comparison between the two epidemic events showed that organochlorine (OC) levels in the dolphins from 1990 epizootic were more than 10-fold higher for tPCB and 6-fold higher for tDDT than levels in dolphins from the 2007 outbreak. In contrast to what occurred in 1990, OCs from individuals affected by the second outburst fit well with curves of OC trends in the Mediterranean. Because the virulence of the 2007 epizootic was much lower, and the deceased dolphins affected by it did not present OC concentrations that were more elevated than in presumably healthy individuals, this second outburst is not believed to have been enhanced by OC pollutants.

Organochlorine residues in South American sea lions, Otaria flavescens (Shaw, 1800): bioaccumulation and time trends

Blubber from stranded South American sea lions (Otaria flavescens) was sampled between 1991 and 2005 on the Peninsula Valdés in Argentina and analyzed for organochlorine (OC) pollutants. Mean blubber concentrations, expressed on an extractable basis, were 686 (SD = 1,060) ng g(-1) for dichlorodiphenyl trichloroethane (tDDT) and 735 (SD = 787) ng g(-1) for polychlorinated byphenils (PCB). The OC levels were well below those associated with adverse sublethal effects and lethality in mammals. OC concentrations showed statistically significant associations with age that were positive in males and negative in females. These trends are consistent with the majority of marine mammal populations studied. There were no trends in the levels of tDDT or PCB over time. In spite of the low levels detected, OC contamination was present consistently over the 14-year period, suggesting continuous inputs from geographic redistribution.

Abnormal first-trimester ductus venosus blood flow: a marker of cardiac defects in fetuses with normal karyotype and nuchal translucency

OBJECTIVE

To evaluate the independent contribution of ductus venosus (DV) blood flow assessment at 11-14 weeks' gestation to the prediction of congenital heart defects (CHD) in chromosomally normal fetuses, irrespective of the value of the nuchal translucency thickness (NT).

METHODS

During a 4-year period, all singleton pregnancies from 11 + 0 to 13 + 6 weeks' gestation were scanned for NT and DV blood flow in a tertiary center. Abnormal DV blood flow was defined as either absent or reversed flow during atrial contraction (AR-DV). Fetal echocardiography was performed in all cases with either NT > 99(th) percentile or AR-DV. Follow-up was assessed by postnatal examination or autopsy in cases of termination of pregnancy or perinatal death.

RESULTS

A total of 6120 pregnancies were scanned at a median gestational age of 12 weeks, and 45 cases of CHD were detected. AR-DV was found in 206 fetuses, of which 145 (70.4%) had a normal karyotype. Among fetuses with AR-DV and normal karyotype, 11 cases of CHD were diagnosed, giving a sensitivity of 24.4%, a positive predictive value of 7.6% and an odds ratio of 9.8. Increased NT (> 99(th) centile) was present in 55 of the 145 (37.9%) cases with AR-DV and normal karyotype, and in 6/11 (54.5%) of those with CHD. Thus, the group of 90 fetuses with abnormal DV blood flow and normal NT contained five cases of CHD, for a sensitivity of 11.1%, a positive predictive value of 5.5% and an odds ratio of 8.5. Right-heart anomalies were predominant in those cases with isolated AR-DV (4/5), but no specific CHD pattern was found in those with increased NT. The detection rate of CHD by the combined use of increased NT and/or AR-DV in the first trimester improved from 28.9% (13/45) to 40.0% (18/45).

CONCLUSIONS

In experienced hands, abnormal DV blood flow in the first trimester is an independent predictor of CHD and should constitute an indication for early echocardiography. In this study, the use of DV blood flow assessment increased early detection of CHD by 11% with respect to the use of NT measurement alone.

Prevalence and perinatal outcome of dichorionic and monochorionic twins with nuchal translucency above the 99(th) percentile and normal karyotype

OBJECTIVE

To evaluate the prevalence of and perinatal outcome associated with increased nuchal translucency thickness (NT) > 99(th) percentile in dichorionic and monochorionic twins with normal karyotype.

METHODS

Two hundred and six consecutive twin pregnancies (166 dichorionic and 40 monochorionic) underwent an NT scan during a 4-year period. In those with NT > 99(th) percentile and normal karyotype, we performed first- and second-trimester anomaly scans, fetal echocardiography at 14-16 and 20-22 weeks, maternal serology and, in monochorionic pregnancies, serial ultrasound examinations every other week. Perinatal outcome was recorded.

RESULTS

There were 10 (4.95%) pregnancies in which one of the fetuses had NT > 99(th) percentile and normal karyotype, including five fetuses (1.5%) in dichorionic and five (6.25%) in monochorionic pregnancies. During the same period the prevalence of NT > 99(th) percentile and normal karyotype in singleton pregnancies studied in our center was 2.6%. Among the 10 twins affected, six (60%) were diagnosed with structural abnormalities (three dichorionic and three monochorionic), and two intrauterine fetal demises occurred (one dichorionic and one monochorionic). Thus, the perinatal outcome was normal in only two of the pregnancies, one dichorionic and one monochorionic.

CONCLUSIONS

The prevalence of NT > 99(th) percentile in dichorionic twins with a normal karyotype is similar to that in singletons. In monochorionic twins we confirmed previous studies reporting an increased prevalence compared with singletons. NT > 99(th) percentile with a normal karyotype in twins was associated with a high rate of fetal abnormalities and/or fetal demise (overall 80%) irrespective of chorionicity.

Ductus venosus pulsatility index as an antenatal screening marker for Down's syndrome: use with the Combined and Integrated tests

OBJECTIVES

To assess the value of ductus venosus blood flow (expressed as pulsatility index, DVPI) in antenatal Down's syndrome screening when used with the Combined and Integrated tests.

METHODS

DVPI measurements between 10 and 13 weeks' gestation in 66 Down's syndrome and 7184 unaffected pregnancies were collected from women attending the Hospital Clinic, Barcelona, for antenatal care from 1999 to 2007 and combined with the Serum Urine and Ultrasound Screening Study (SURUSS) data to model screening performance, safety and cost-effectiveness of the screening tests with and without DVPI.

RESULTS

The median DVPI multiple of the normal median in Down's syndrome pregnancies was 1.55 (95% CI 1.36-1.73). As a single screening marker without using maternal age, DVPI has a 62% detection rate for a 5% false-positive rate. At a 90% detection rate (first trimester measurements at 11 weeks' gestation) the addition of DVPI reduced the false-positive rate of the Combined test from 8.5% to 4.6% and the Integrated test from 2.0% to 1.1%, with a corresponding reduction in fetal losses from diagnostic procedures. There was no material loss of cost-effectiveness.

CONCLUSION

Addition of DVPI measurements to the Combined and Integrated tests substantially improves the efficacy and safety of antenatal Down's syndrome screening.

Combining fetal nuchal fold thickness with second-trimester biochemistry to screen for trisomy 21

OBJECTIVE

To assess second-trimester screening for trisomy 21 by combining ultrasound nuchal fold (NF) measurement with maternal serum biochemistry.

METHODS

NF, maternal serum alpha-fetoprotein (AFP) and free beta-human chorionic gonadotropin (beta-hCG) were determined concurrently at 14-19 weeks' gestation in a study population comprising 1813 women with singleton pregnancies, including 1257 unselected women undergoing serum screening for trisomy 21 (1999-2002), and 556 high-risk pregnancies prior to amniocentesis (2003-2005), 402 of whom had positive serum screening tests. The results were expressed in multiples of the gestation-specific normal median (MoMs).

RESULTS

There were 1799 unaffected singleton pregnancies, and their NF values approximately fitted a log Gaussian distribution over a wide range. There was a weak but statistically significant correlation between log NF and log AFP (r = - 0.069, P < 0.005) and the correlation coefficient between log NF and log free beta-hCG was even smaller and not statistically significant (r = 0.038, P = 0.11). Among the seven trisomy 21 pregnancies, the median NF level was 1.53 MoM (geometric mean 1.75 MoM), a highly statistically significant increase compared with unaffected pregnancies (P < 0.0001, one-tail Wilcoxon Rank Sum Test). In pregnancies referred because of positive serum screening tests (391 unaffected, seven cases of trisomy 21, one of monosomy X and three other chromosomal anomalies) the use of NF to modify the serum screening risk would have reduced the invasive procedures in unaffected pregnancies by 46% without affecting the detection rate of trisomy 21 or other anomalies. Statistical modeling predicted that adding NF to AFP and free beta-hCG would increase detection more than would adding unconjugated estriol as well as inhibin-A, an analyte that is difficult to measure with precision.

CONCLUSIONS

The addition of NF measurement to second-trimester biochemical markers improves screening performance, and could overcome drawbacks in the implementation of inhibin-A assay in clinical practice.

Organochlorine concentrations declined during 1987-2002 in western Mediterranean bottlenose dolphins, a coastal top predator

We collected blubber samples from bottlenose dolphins stranded on Spain's Mediterranean coasts over a 25-year period (1978-2002). Samples were analyzed to determine time trends in levels of: HCB (hexachlorobenzene), PCB (polychlorinated biphenyls) and tDDT (dichlorodiphenyltrichloroethane and its metabolites). Overall, levels were high relative to other areas. This reflects both the ubiquity of organochlorine pollution in the western Mediterranean and the sampled species' coastal habit. There was a significant decline over the study period in the concentrations of all the compounds analyzed. However, the DDE/tDDT, which is indicative of DDT ageing, significantly increased. This suggests there has been no significant use of HCB, DDT or PCB in the region for a long time. It also indicates that the pollutant loads in the environment are gradually being reduced; either by degradation or by migration of the compounds to other regions. A comparison with dolphin species that have an oceanic distribution suggests that PCB decline at a comparable pace in coastal and offshore water bodies. However, the decline of tDDT is faster near the coast.

Sorghum stay-green QTL individually reduce post-flowering drought-induced leaf senescence

Sorghum is an important source of food, feed, and biofuel, especially in the semi-arid tropics because this cereal is well adapted to harsh, drought-prone environments. Post-flowering drought adaptation in sorghum is associated with the stay-green phenotype. Alleles that contribute to this complex trait have been mapped to four major QTL, Stg1-Stg4, using a population derived from BTx642 and RTx7000. Near-isogenic RTx7000 lines containing BTx642 DNA spanning one or more of the four stay-green QTL were constructed. The size and location of BTx642 DNA regions in each RTx7000 NIL were analysed using 62 DNA markers spanning the four stay-green QTL. RTx7000 NILs were identified that contained BTx642 DNA completely or partially spanning Stg1, Stg2, Stg3, or Stg4. NILs were also identified that contained sub-portions of each QTL and various combinations of the four major stay-green QTL. Physiological analysis of four RTx7000 NILs containing only Stg1, Stg2, Stg3, or Stg4 showed that BTx642 alleles in each of these loci could contribute to the stay-green phenotype. RTx7000 NILs containing BTx642 DNA corresponding to Stg2 retained more green leaf area at maturity under terminal drought conditions than RTx7000 or the other RTx7000 NILs. Under post-anthesis water deficit, a trend for delayed onset of leaf senescence compared with RTx7000 was also exhibited by the Stg2, Stg3, and Stg4 NILs, while significantly lower rates of leaf senescence in relation to RTx7000 were displayed by all of the Stg NILs to varying degrees, but particularly by the Stg2 NIL. Greener leaves at anthesis relative to RTx7000, indicated by higher SPAD values, were exhibited by the Stg1 and Stg4 NILs. The RTx7000 NILs created in this study provide the starting point for in-depth analysis of stay-green physiology, interaction among stay-green QTL and map-based cloning of the genes that underlie this trait.

Organochlorine compounds and stable isotopes indicate bottlenose dolphin subpopulation structure around the Iberian Peninsula

Isotopic signatures and organochlorine pollutant loads of organisms reflect the characteristics of the waters in which they live and feed. To investigate population structure of bottlenose dolphins around the Iberian Peninsula we determined delta(13)C and delta(15)N in the skin and organochlorine (OC) levels in the blubber of stranded bottlenose dolphins inhabiting the Mediterranean (Catalonia, Valencia and Balearic Islands) and adjacent Atlantic waters (Huelva and Portugal). OC levels were high in all regions, reflecting the predatory habits of the species, its coastal distribution and the existence of intense agricultural and industrial activity throughout the region. PCB congeners showed a gradient from the relatively more chlorinated forms to those that are less so, and followed a northeast to northwest direction across the Iberian Peninsula. This suggests that PCB inputs are more recent in the temperate latitudes of the eastern Atlantic Ocean than in the western Mediterranean Sea. Comparatively, OC ratios and isotopic signatures proved to be more efficient ways of discriminating groups than did raw OC concentrations. Significant differences in delta(13)C and in PCB congener profiles indicate that dolphins from the Atlantic and the Mediterranean do not intermingle. In addition, the two Atlantic groups differed in delta(15)N signature, tDDT concentration, DDT/PCB ratio and the PCB congener profile, which also suggests some degree of isolation between them. In the Mediterranean, dolphins from Catalonia and Valencia were indistinguishable, suggesting a common distribution area. However, dolphins from the Balearic Islands differed from those of the Peninsula in their DDT/PCB ratio and from all the other sample groups in their PCB congener profiles, which supports the hypothesis that the deep waters between the Islands and the Peninsula represent an effective barrier for the species.

Asthma, chronic bronchitis, and exposure to irritant agents in occupational domestic cleaning: a nested case-control study

BACKGROUND

Women employed in domestic cleaning are at increased risk for symptoms of obstructive lung disease, but the agents responsible are unknown.

AIMS

To investigate common tasks and products in occupational domestic cleaning in relation to respiratory morbidity.

METHODS

Case-control study in domestic cleaning women nested within a large population based survey of women aged 30-65 years; 160 domestic cleaning women with asthma symptoms, chronic bronchitis symptoms, or both and 386 without a history of respiratory symptoms were identified. Detailed exposures were evaluated for 40 cases who reported still having symptoms at the recruitment interview, and 155 controls who reported not having symptoms. All tasks performed and products used when cleaning houses were determined in a face-to-face interview. Lung function, methacholine challenge, and serum IgE testing were performed. Personal exposure measurements of airborne chlorine and ammonia were performed in a subsample. Associations between asthma, chronic bronchitis, and cleaning exposures were evaluated using multiple logistic regression analysis.

RESULTS

Airborne chlorine (median level 0-0.4 ppm) and ammonia (0.6-6.4 ppm) were detectable during occupational domestic cleaning activities. Cases used bleach more frequently than controls; adjusted odds ratio (OR) for intermediate exposure was 3.3 (95% CI 0.9 to 11) and for high exposure 4.9 (1.5 to 15). Other independent associations included accidental inhalation of vapours and gases from cleaning agents and washing dishes. These associations were more pronounced for cases with asthma symptoms than for those with symptoms of chronic bronchitis, but were not related to sensitisation to common allergens.

CONCLUSIONS

Asthma symptoms in domestic cleaning women are associated with exposure to bleach and possibly other irritant agents. The public health impact of the use of irritant cleaning products could be widespread since the use of these products is common both in the workplace and at home.

DDT and PCB reduction in the western Mediterranean from 1987 to 2002, as shown by levels in striped dolphins (Stenella coeruleoalba)

Temporal trends in DDT and PCB contamination were recorded in the offshore waters of the western Mediterranean Sea during 1987-2002 using striped dolphins (Stenella coeruleoalba) as indicators. Despite the fact that the use of DDT and PCB was banned at the end of the 1970s-early 1980s, dolphins were still found to carry moderate to high levels of these chemicals in their tissues, reflecting their ubiquity and environmental persistence. Concentrations of both groups of compounds have slowly decreased, although the decline in PCB has been steeper than that of DDT. Consequently, the tDDT/PCB ratio increased significantly. Indices of metabolisation of both DDT and PCB substantiated progressive aging of pollutant loads and degradation, suggesting that the offshore marine environment has not been exposed to significant releases of these contaminants in recent years. This all indicates a decline in organochlorine pollution in oceanic waters which is consistent, albeit not always, with trends observed in coastal surveys. Dolphins and other top predators are thus confirmed as useful indicators to assess long-term trends of pollutants in oceanic ecosystems and large water masses.

Differences in DDT and PCB residues between common and striped dolphins from the southwestern Mediterranean

Organochlorine concentrations (OCs) and stable isotopes were investigated in the blubber of common dolphins (Delphinus delphis) and striped dolphins (Stenella coeruleoalba) from the southwestern Mediterranean. Samples were obtained from dolphins entangled in fishing nets during the 1992-1994 fishing season and from biopsies taken in 1992. Intrapopulation variations were studied, but because most of the dolphins were juveniles or calves (90%), no significant differences were found on the basis of reproductive condition or sex. Only mature male common dolphins showed significantly higher levels of most of the compounds studied than immature individuals did. There were quantitative and qualitative interspecific differences in organochlorine compounds profile. As compared to common dolphins, striped dolphins carried higher concentrations of organochlorine concentrations (OCs), their %DDE/tDDT and PCB/tDDT ratios were significantly higher, and recalcitrant PCB congeners were more abundant. Distribution and information on composition of stomach contents would in principle support a higher exposure to OCs in common dolphins as compared to striped dolphins, thus apparently contradicting the observed results. However, stable isotopes showed that striped dolphins exploit a higher trophic level, thus explaining observed differences. Interspecific dissimilarities in metabolic capacity to handle OCs may be an added factor. Although in the two species OC concentrations exceeded levels considered to be ineffective in marine mammals, pollution-induced effects on populations could not be properly assessed.

Levels of organochlorine compounds in spotted dolphins from the Coiba archipelago, Panama

Blubber and skin samples from 63 spotted dolphins (Stenella attenuata) (18 males, 40 females and 5 of unknown sex) were collected by biopsy techniques in the waters of the Coiba archipelago. Blubber was analyzed for organochlorine compounds and skin for gender determination. Mean levels of HCB (hexachlorobenzene), tPCB (polychlorinated biphenyls) and tDDT (dichlorodiphenyltrichloroethane) were 0.064, 2.30 and 6.4 mgkg(-1), respectively. These levels are low and are not considered to represent a threat to the S. attenuata population. No significant differences either in concentrations of HCB, tPCB and tDDT or in PCB profiles were observed between males and females. The ratio tDDT/tPCB was 2.69, indicating predominantly agrarian versus industrial activities in the area. The ratio ppDDE/tDDT was 0.83, a high figure that suggests both a local reduction of DDT inputs and a high rate of DDT degradation. Significant quantitative and qualitative differences were observed between two schools, suggesting intra-population heterogeneity in organochlorine exposure possibly due to demographic segregation.

Jugular vein and carotid artery blood flow in fetuses with increased nuchal translucency at 10-14 weeks' gestation

OBJECTIVE

The aim of our study was to obtain measurements of the jugular vein and carotid artery pulsatility index (PI) at 10-14 weeks' gestation in chromosomally normal and abnormal fetuses with or without increased nuchal translucency (NT), in order to explore whether a relationship exists between increased NT and overperfusion of the head.

METHODS

This was a prospective study involving 179 pregnant women at high risk for chromosomal anomalies or structural malformations who were referred for chorionic villus sampling or first-trimester ultrasound examination at 10-14 weeks' gestation, respectively. Color and pulsed Doppler ultrasound were used to obtain jugular vein and carotid artery blood flow velocity waveforms at the level of the mid-neck. All Doppler measurements were obtained by a single investigator. The PIs of the jugular vein and carotid artery were correlated with NT measurement and fetal karyotype.

RESULTS

Doppler measurements of the jugular vein and carotid artery were successfully obtained in 90.5% of the fetuses. The fetal karyotype was abnormal in 13 cases, including three trisomies 21 and two trisomies 18, and normal in 149 cases. In the group with normal karyotype the NT was above the 95th percentile in 22 cases (15%). No correlation between the jugular vein or the carotid artery PI and the thickness of the NT was found. There were no significant differences when comparing the values of the jugular vein and carotid artery PI between the group with normal NT and the group with increased NT, or between the group with a normal karyotype and an abnormal karyotype.

CONCLUSION

Our results suggest that NT is not related to blood flow impedance in either the carotid artery or the jugular vein. Overperfusion and venous congestion of the head do not appear to be a causative pathophysiological mechanism involved in increased NT.

Prenatal diagnosis of hypoplastic left heart syndrome and trisomy 18 in a fetus with normal nuchal translucency and abnormal ductus venosus blood flow at 13 weeks of gestation

We describe a case of early prenatal diagnosis of a major congenital heart anomaly and trisomy 18 in a low-risk pregnant woman. Nuchal translucency (NT) measurement at 13 weeks' gestation was 1.2 mm and Doppler evaluation of the ductus venosus detected a persistent reversed flow during atrial contraction. This finding prompted us to perform fetal echocardiography which showed hypoplastic left heart syndrome. Karyotyping following chorionic villus sampling diagnosed trisomy 18. Review of the recent literature suggests that the finding of an abnormal ductus venosus Doppler pattern in the late first trimester of pregnancy may be an early sign of either congenital cardiac or chromosomal abnormality, even in the presence of normal NT screening.

Cardiac defects in chromosomally normal fetuses with increased nuchal translucency at 10-14 weeks of gestation

OBJECTIVE

To examine the prevalence, distribution and spectrum of cardiac defects in chromosomally normal fetuses with increased nuchal translucency thickness.

PATIENTS AND METHODS

During a 4-year period, targeted fetal echocardiography was used in 353 chromosomally normal fetuses with increased nuchal translucency thickness at 10-14 weeks' gestation. The cardiac scan was performed at 18-22 weeks. In the last 138 cases enrolled, an additional scan at 12-16 weeks was carried out. The follow-up included the findings at necropsy or in the pediatric examination. A complete follow-up was achieved in 97%.

RESULTS

Cardiac defects were present in 32 (9.1%) cases, increasing from 5.3% in those with a nuchal translucency thickness of > or = 95th centile (3.9 mm) to 24% when thickness > or = 6 mm (p < 0.001). In 31 cases (97%), the cardiac defect was diagnosed antenatally; in 24 cases (77%) this diagnosis was confirmed later. In the remaining seven cases, the autopsy examination was not available. A wide range of cardiac defects was observed, with the most common being atrioventricular septal defect and tricuspid atresia.

CONCLUSIONS

Euploid fetuses with increased nuchal translucency thickness have a significantly increased risk of cardiac defects. This is a marker of different types of heart anomalies and constitutes an additional indication for targeted fetal echocardiography. Most of the cardiac defects can be detected by fetal echocardiography.

Global distribution of halogenated dimethyl bipyrroles in marine mammal blubber

Four halogenated dimethyl bipyrroles (HDBPs), hypothesized to be naturally produced, were quantitated in marine mammal blubber from a number of species obtained from various locations worldwide. HDBPs were found in samples from all locations studied. Concentrations of total HDBPs (SigmaHDBPs) ranged from 0.4 ng/g lipid weight in ringed seals (Phoca hispida) from the White Sea to 2,540 ng/g lipid weight in Dall's porpoise (Phocoenoides dalli) from the northwestern North Pacific Ocean. At their highest levels, SigmaHDBPs made up 11% of the total quantitated organohalogen body burden of adult male Dall's porpoises. In two beluga (Delphinapterus leucas) data subsets, it was found that males contained significantly higher concentrations of SigmaHDBPs than females. No significant effects of age or sex on SigmaHDBPs were observed in harbor seal (Phoca vitulina) and bowhead whale (Balaena mysticetus) data subsets. The geographical distribution of concentrations did not resemble that of the ubiquitous anthropogenic organohalogen, polychlorinated biphenyl congener CB-153. Higher concentrations of HDBPs and different patterns of congeners were observed in samples from Pacific as opposed to non-Pacific Ocean influenced environments. Concentrations of HDBPs in beluga from the Arctic and St. Lawrence River were similar. Their high abundance in north Pacific Ocean biota and widespread occurrence suggest that HDBPs undergo extensive transport from a source located primarily in the Pacific Ocean. Evidence from HDBP congener patterns indicates that both ocean currents and atmospheric transport likely play a role in the movement of HDBPs. These results imply that HDBPs and anthropogenic organohalogens have different sources and support the natural production hypothesis.

Early prenatal diagnosis of major cardiac anomalies in a high-risk population

OBJECTIVE

To examine the accuracy of early fetal echocardiography performed in a high-risk population combining transvaginal and transabdominal routes.

METHODS

A series of 330 high-risk pregnancies were screened by transvaginal and transabdominal scan at 12-17 weeks' gestation in a prospective multicentre trial in Spain between September 1999 and May 2001. A total of 334 fetal heart examinations were performed, including four twin pregnancies. Maternal age ranged from 17 to 46 years (mean 33 years with 36% of women over 34 years). The median gestational age at scan was 14.2 weeks (range 12-17 weeks). For each fetus, visualization of the four-chamber view, the origin of the great arteries, aortic and ductal arches and systemic venous return was attempted in a segmental approach. B-mode and colour/pulsed Doppler flow imaging were used in all cases. The duration of complete heart examination was less than 30 minutes. The examinations were performed by three experienced operators. Reliability was assessed by conventional transabdominal echocardiography at 20-22 weeks, by postnatal follow-up in the first three months of life, and/or by autopsy in cases of termination of pregnancy.

RESULTS

The rate of successful visualization of the fetal heart was 94.6% (316/334). In 48 out of 334 (14.4%) fetuses the final diagnosis was abnormal. In 38 out of 48 (79.2%) cases with heart defects the diagnosis was suspected at early echocardiography. In the group with congenital heart defects, 27 cases had an abnormal karyotype (56.3%) and 31 cases showed extracardiac anomalies (64.6%). There were 10 false-negative cases at early scan. There were no false-positive diagnoses.

CONCLUSIONS

This experience stresses the usefulness of early fetal echocardiography when performed by expert operators on fetuses specifically at risk for cardiac disease. The high rate of successful visualization of the fetal heart provides a reliable diagnosis of major cardiac defects at this early stage of pregnancy.