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Biomedical subjects

E Pajkrt

Publications and source records attributed to E Pajkrt.

At least 19 recordsLinked to original sources
PubMed2004

Disappearance of enlarged nuchal translucency before 14 weeks' gestation: relationship with chromosomal abnormalities and pregnancy outcome.

OBJECTIVE: The aim of this study was to investigate the natural course of enlarged nuchal translucency (NT) and to determine if its disappearance before 14 weeks' gestation is a favorable prognostic sign in relation to fetal karyotype and pregnancy outcome. METHODS: A total of 147 women with increased NT (> 95th centile) at first measurement were included in this study. A second measurement was performed in all cases, at an interval of at least 2 days. Both measurements were taken between 10 + 3 and 14 + 0 weeks. All women underwent chorionic villus sampling or amniocentesis for subsequent karyotyping. In those women with a normal karyotype, a fetal anomaly scan was performed at 20 weeks' gestation. Pregnancy outcome was recorded in all cases. The finding of persistent or disappearing NT enlargement was analyzed in relation to fetal karyotype and pregnancy outcome. RESULTS: Of the 147 paired measurements, NT remained enlarged at the second measurement in 121 (82%) cases. An abnormal karyotype was found in 35% of these cases. In 26 (18%) fetuses the NT measurement was found to be below the 95th percentile at the second measurement and in only two of them an abnormal karyotype was found (8%). In the 103 chromosomally normal fetuses an adverse outcome (i.e. fetal loss or structural defects) was recorded in 22 fetuses with persistent enlargement (28%) and in four fetuses with disappearing enlargement (17%). CONCLUSIONS: Disappearance of an enlarged NT before 14 weeks' gestation is not a rare phenomenon and seems to be a favorable prognostic sign with respect to fetal karyotype. Overall, no significant difference in pregnancy outcome was found between chromosomally normal fetuses with persisting or disappearing NT enlargement.

Abortion, Spontaneous↗
PubMed2002

[Ultrasound screening for Down's syndrome early in pregnancy: nuchal translucency thickness].

Screening for Down's syndrome (DS) in the Netherlands is based on maternal age. Women aged 36 years or above are offered amniocentesis or chorionic villus sampling to determine if the foetus has Down's syndrome or other chromosomal abnormalities. Disadvantages of this method are a low detection rate of affected pregnancies (no more than 15%) and iatrogenic miscarriages (0.5-1%). Pregnant women under the age of 36 are not eligible for screening, even though 70% of the children with Down's syndrome are born in this age group. Screening by measuring nuchal translucency thickness, an early ultrasound marker for Down's syndrome carried out in the first trimester of pregnancy, has a higher detection rate with a less invasive method and therefore fewer iatrogenic miscarriages. However, Dutch law prohibits the offer of screening to women with a low individual risk of DS (Population Screening Act), because of the anxiety this may provoke in these women. The Dutch Health Council's Prenatal Screening Committee has advised the minister of Public Health, Welfare and Sport that risk-assessment screening, in particular the triple test, should no longer be postponed and that research into (other) screening options should be stimulated.

Adult↗
PubMed2001

Outcome of fetuses with increased nuchal translucency.

Recent reports on nuchal translucency screening in unselected patient populations show results that are comparable with those reported by the thus far largest series on screening for Down's syndrome based on maternal age and nuchal translucency measurement. Much interest is focused on the prognostic value of increased nuchal translucency in fetuses with normal chromosomes. Increased nuchal translucency is regarded as a clear sign of declining fetal health, which can be associated with fetal demise, structural anomalies, rare genetic syndromes, and in particular congenital heart defects. A clear association is demonstrated between nuchal translucency above the 99th centile and congenital cardiac defects. Such a finding should prompt specialized echocardiography. However, on the whole the sensitivity of nuchal translucency screening is too low to consider this as the sole criterion to screen for critical heart defects.

Chromosome Aberrations↗
PubMed2000

Intra- and interoperator repeatability of the nuchal translucency measurement.

OBJECTIVE: The aim of this study was to assess the repeatability of nuchal translucency measurement by well-trained sonographers either experienced or inexperienced with the measurement. METHODS: The nuchal translucency was measured three times by two out of nine operators in 161 pregnant women attending two teaching hospitals. Intra-operator and inter-operator variation was assessed by calculating the standard deviation (SD). Intraclass Correlation Coefficients (ICC) with a 95% lower confidence limit (95% CL) were calculated for each operator and for pairs of operators. Intra- and inter-operator kappa statistics were calculated, after dichotomising the results into a nuchal translucency smaller or larger than 3 mm. RESULTS: The SD of intra-operator difference was 0.35 mm. The intra-operator repeatability showed ICCs varying from 0.83 to 0.95 for the experienced operators and from 0.47 to 0.83 for the inexperienced. The SD of inter-operator differences was 0.56 mm, 0.46 mm and 0.44 mm, based on one, two and three measurements, respectively. The inter-operator repeatability showed a variation in ICC from 0.74 to 0.95 in pairs of experienced sonographers to 0.51 in one pair inexperienced with the measurement. The kappa value expressing the intra and inter-operator repeatability as being > 3 mm or < 3 mm was 0.88 and 0.85, respectively. CONCLUSION: This study supports the finding that the nuchal translucency measurement is reproducible, as long as it is performed by sonographers well trained in the technique of this measurement.

Down Syndrome↗
PubMed2000

Co-variables in first trimester maternal serum screening.

The objective of this study was to determined the influence of maternal weight, maternal smoking habits, gravidity, parity and fetal gender on the level of maternal serum marker used in first trimester screening for Down syndrome. A total of 2449 singleton unaffected pregnancies from two centres were studied. Maternal serum free beta-human chorionic gonadotrophin (hCG) and alpha-fetoprotein (AFP) concentrations had been measured in all pregnancies, and pregnancy associated plasma protein (PAPP)-A levels had been measured in 924. All results were expressed as multiples of the gestation specific median (MoM) values after regression, using each centre's own medians. Information on maternal weight was available in 2259 pregnancies, on self-reported current cigarette smoking in 1364 (of whom 117 (8.6%) were smokers), on gravidity in 1371, parity in 1303 and fetal gender in 253. All three markers showed a statistically significant negative association with maternal weight (p<0.0005) and in the subsequent analyses MoM values were weight adjusted using standard methods. The median PAPP-A level in smokers was 0.81 MoM, a significant reduction (p<0.005); free beta-hCG was also reduced (median 0.89 MoM) but not significantly (p=0.17), and AFP was unaltered. The median AFP level in primagravidas was highly significantly greater than that in gravid women (p<0.0005). In PAPP-A the reverse effect was seen but it did not reach statistical significance (p=0.15) and there was no effect for free beta-hCG. Results of a similar magnitude and direction were found for parity. The median level of free beta-hCG was higher (p=0.0005), and the median AFP lower in female pregnancies. Maternal weight and, for PAPP-A, maternal smoking are important first trimester screening co-variables. Gravidity, parity and fetal gender also seem to influence one or more first trimester markers.

Body Weight↗
PubMed1999

Early pregnancy screening for fetal aneuploidy with serum markers and nuchal translucency.

We determined the aneuploidy detection rate achievable by early pregnancy screening with pregnancy associated plasma protein (PAPP)-A, free beta human chorionic gonadotrophin (hCG) and ultrasound nuchal translucency (NT) measurement. Women having prenatal diagnosis were scanned, and a blood sample was taken and stored. Stored samples were tested and a total of 37 were found to have Down syndrome, 8 to have Edwards syndrome and 255 were controls. Results were expressed in multiples of the gestation-specific median (MOM) value in the controls after regression and, for the serum markers, maternal weight adjustment. In Down syndrome the medians were for PAPP-A 0.63 MOM (95 per cent confidence interval (CI) 0.45-0.87); free beta-hCG 1.88 MOM (1.33-2.66); and NT 2.34 MOM (1.70-3.22). Using these parameters the expected detection rate for a 5 per cent false-positive rate for different marker combinations were: 55.3 per cent for PAPP-A and free beta-hCG; 68.4 per cent for NT alone; and 84.6 per cent for PAPP-A, free beta-hCG and NT. The median values for Edwards syndrome were: 0.17 MOM for PAPP-A; 0.18 MOM for free beta-hCG; and 2.64 MOM for NT. Early pregnancy screening with the combined measurement of maternal serum PAPP-A and free beta-hCG and fetal nuchal translucency could achieve a high Down syndrome detection rate.

Aneuploidy↗
PubMed1999

Pregnancy outcome and nuchal translucency measurements in fetuses with a normal karyotype.

The aim of this study was to examine the relationship between nuchal translucency thickness and pregnancy and fetal outcome in fetuses with a normal karyotype and without structural malformations. Fetal nuchal translucency measurements were performed in 2088 chromosomally and structurally normal fetuses. In all fetuses the karyotype and pregnancy outcome were known. Likelihood ratios for different outcome measures were calculated. Spontaneous abortion, intra-uterine and neonatal death occurred in 2.4, 1.1 and 0.5 per cent respectively. The incidence of immature delivery was 1.1 per cent and of premature delivery 6.0 per cent. The only adverse pregnancy outcome recorded that was associated with increased nuchal translucency was spontaneous abortion. The likelihood ratio for the occurrence of a spontaneous abortion was 3.1 for measurements between 3.0 and 3.9 mm, and 6.8 for measurements>/=4 mm. Increased lethality in fetuses with enlarged nuchal translucency and normal chromosomes may provide evidence that the same insult causing excessive fluid collection in the nuchal region may also be responsible for fetal demise.

Abortion, Spontaneous↗
PubMed1999

Effect of study design on the association between nuchal translucency measurement and Down syndrome.

OBJECTIVE: To evaluate the effect of verification bias on the accuracy of first-trimester nuchal translucency measurement for Down syndrome detection. METHODS: We used MEDLINE and EMBASE to identify all papers relating the results of nuchal translucency measurement to fetal karyotype. The detected studies were scored for verification bias. Fifteen studies without and ten with verification bias were included. RESULTS: Sensitivity and specificity were calculated for each study. For studies with verification bias, adjusted estimates of the sensitivity were calculated assuming a fetal loss rate for Down syndrome pregnancies of 48%. The sample size weighted sensitivity was 55% in studies without and 77% in those with verification bias, for specificities of 96% and 97%, respectively. After adjustment for verification bias, the sample size weighted sensitivity changed from 77% to 63%. CONCLUSION: Studies with verification bias reported higher sensitivities, but also slightly higher specificities of nuchal translucency measurement than studies without verification bias. The difference in sensitivity is greater than could be explained by verification bias. We postulate that the experience of the sonographist might be an explanation for the differences.

Down Syndrome↗
PubMed1999

Enlarged nuchal translucency and low serum protein concentrations as possible markers for Zellweger syndrome.

We present a case of a fetus in which an enlarged nuchal translucency was detected at 12 weeks' gestation. The karyotype was normal. Subsequent ultrasound examination showed no obvious fetal abnormalities apart from a mild pericardial effusion. Serum screening revealed very low concentrations of estriol and human chorionic gonadotropin. After birth the diagnosis of Zellweger syndrome was made. Nuchal translucency screening, estriol level identification and detailed ultrasound scanning may help to identify fetuses affected by this syndrome.

Adult↗
PubMed1999

Use of the disutility ratio in prenatal screening for Down's syndrome.

OBJECTIVE: To assess the value of the triple test incorporating individual differences in parental evaluation of outcomes of pregnancy. DESIGN: Decision analysis. SAMPLE: Monte Carlo simulation of triple test results in 25,000 women with a normal pregnancy and 25,000 women with a pregnancy affected by Down's syndrome. METHODS: A decision model was developed for women who were 16 weeks pregnant. Three strategies were evaluated: 1. no prenatal testing; 2. amniocentesis; and 3. the triple test followed by amniocentesis if the risk of a pregnancy with Down's syndrome, based on maternal age and the triple test results (post-test risk), was above the woman's threshold risk for amniocentesis. MAIN OUTCOME MEASURES: The outcomes considered were: 1. birth of a child without Down's syndrome; 2. birth of a child with Down's syndrome; and 3. pregnancy loss, either spontaneously, or as a result of termination. The values of these pregnancy outcomes were expressed on a disutility scale in units of 'lost pregnancy equivalents'. The birth of a normal child brings no disutility. The disutility of the birth of a child with Down's syndrome is consequently specified by the ratio of the expected parental distress after the birth of a child with Down's syndrome to the expected parental distress after the loss of the pregnancy (disutility ratio). RESULTS: The value of the triple test depends strongly on maternal age as well as on the individual evaluation of the outcome of pregnancy. The triple test is of considerable value for all women > 38 years; its value for women between 27 and 38 years depends on the disutility ratio, and it is of little value for women < 27 years. CONCLUSION: The value of the triple test depends on the parental evaluation of outcome of pregnancy for a large group of pregnant women. The disutility ratio, as introduced in this study, might be an instrument to elicit these values for individual women in clinical practice.

Abortion, Induced↗
PubMed1998

Weekly nuchal translucency measurements in normal fetuses.

OBJECTIVE: To examine the longitudinal course of nuchal translucency thickness by weekly measurements between 10 and 15 weeks' gestation in normal fetuses. METHODS: Nuchal translucency was measured weekly from 10 to 15 weeks' gestation in 64 fetuses with normal pregnancy outcome. The median and the fifth, 25th, 75th, and 95th percentiles were calculated. RESULTS: Nuchal translucency measurements varied considerably with gestational age; this variation followed a fetus-specific pattern. In 94% of cases, we observed an increase followed by a steady decrease in nuchal translucency measurement. A visible nuchal translucency was found after 76 and 86 days' gestation in 97% (95% confidence interval [CI] 89, 100) and 100% (95% CI 94, 100) of the fetuses, respectively. The median nuchal translucency increased from 0.7 mm at 70 days' gestation to 1.7 mm at 91 days' gestation, after which it declined to 1.0 mm at 105 days' gestation. CONCLUSION: A progressive increase and subsequent decrease in nuchal translucency thickness occurs with advancing gestation in most fetuses, but the timing of the peak thickening appears to be fetus-specific. In this study, each fetus developed a visible nuchal translucency. If the nuchal translucency measurement is 0 mm before 12 weeks, it may be advisable to repeat the measurement at 12 weeks' gestation. In contrast, a nuchal translucency that cannot be measured from 12 weeks' gestation onward suggests that this temporary anatomic entity is already in its waning phase.

Adult↗
PubMed1998

Outcome of fetuses with enlarged nuchal translucency and normal karyotype.

The aim of this study was to examine the relationship between nuchal translucency measurements and outcome of pregnancy with special regard to fetuses with an enlarged nuchal translucency and a normal karyotype. Fetal nuchal translucency measurements were performed on consecutive mothers attending the prenatal diagnosis center of our hospital. A complete follow-up was obtained in 88.4% of the cases. Of the 74 fetuses (4.4%) with an enlarged nuchal translucency (> or = 3 mm), 25 (33.8%) had an abnormal karyotype. Two pregnancies ended in a spontaneous abortion before karyotyping was performed. In the remaining 47 eukaryotic fetuses with enlarged nuchal translucency, five (10.6%) had a structural anomaly, two were affected by genetic syndromes (4.2%) and an additional four fetuses (8.5%) were affected by a single-gene disorder. A spontaneous abortion or an intrauterine death occurred in 6.4% and in 2.1% of these fetuses, respectively. The total incidence of an unfavorable outcome in the group of chromosomally normal fetuses with enlarged nuchal translucency was 32%. In contrast, in the group with a normal nuchal translucency (< 3 mm), the incidence of an unfavorable outcome was 7.5%. There is a strong association between enlarged nuchal translucency measurements and congenital (structural and genetic) abnormalities, as assessed by receiver operator characteristic analysis. This may represent, in fetuses with a normal karyotype, a non-specific sign of a disturbance in the developmental process. In these cases, detailed ultrasound surveillance is recommended.

Adult↗
PubMed1998

Screening for Down's syndrome by fetal nuchal translucency measurement in a high-risk population.

OBJECTIVE: To examine the discriminative capacity of nuchal translucency measurement in the detection of trisomy 21 and other chromosomal anomalies. DESIGN: Prospective cohort study. SUBJECTS: A total of 2247 women with viable singleton pregnancies between 10 and 14 weeks' gestation attending a prenatal diagnosis center for fetal karyotyping. METHODS: The fetal nuchal translucency was measured transabdominally in all women before invasive prenatal testing. RESULTS: Chromosomal abnormalities were found in 63 fetuses, including 36 with Down's syndrome. The likelihood of the presence of chromosomal abnormalities increased with larger nuchal translucency thickness. A nuchal translucency of 3 mm or more identified 25 out of 36 fetuses (69%) with trisomy 21 at the expense of a 4.0% false-positive rate. Correction of nuchal translucency measurements for differences due to variation of the measurement with gestational age, either by using the 'delta-value' or multiples of the median (MoM), did not improve the detection rate in our patient data set. CONCLUSIONS: The discriminative capacity of nuchal translucency measurement makes it a useful tool in screening for trisomy 21 and other chromosomal anomalies.

Adult↗
PubMed1998

Screening for Down's syndrome by fetal nuchal translucency measurement in a general obstetric population.

OBJECTIVE: To examine the effectiveness of nuchal translucency measurement in the detection of trisomy 21 in a low-risk population. DESIGN: Prospective cohort study. SUBJECTS: A total of 1473 women with viable singleton pregnancies between 10 and 14 weeks' gestation attending an antenatal clinic for routine obstetric care. METHODS: The fetal nuchal translucency was measured in all women. Fetal karyotyping was performed for the usual indications and in cases of a nuchal translucency measurement > or = 3 mm. RESULTS: Down's syndrome was found in nine fetuses (0.6%). Screening by maternal age would have diagnosed six out of nine fetuses (67%) with trisomy 21 for an invasive testing rate of 24%. Because the actual uptake of prenatal diagnosis for maternal age was 79%, only 44% of the Down's syndrome fetuses would have been detected prenatally by this screening method. A nuchal translucency of 3 mm or more identified 67% of the fetuses with trisomy 21, for an invasive testing rate of 2.2%. The combination of nuchal translucency thickness, corrected for the influence of gestation by 'delta-value' and maternal age performs differently according to the chosen cut-off point for adjusted risk. A minimum risk of 1 : 100 would detect 78% of the Down's syndrome fetuses for a testing rate of 8.1%. By offering karyotyping to all women with a post-test risk of 1 : 300, the detection rate would increase to 100% with an invasive testing rate of 19.8%. This is lower than the invasive testing rate of maternal age screening. CONCLUSIONS: These data suggest that nuchal translucency measurement is an effective screening method for trisomy 21 in an unselected obstetric population.

Adolescent↗