Genetic sonography as the preferred option of prenatal diagnosis in patients with pregnancies following intracytoplasmic sperm injection

Down's syndrome screening at 11-14 weeks' gestation using prenasal thickness and nasal bone length

PURPOSE

To perform a multicenter prospective study of ultrasound prenasal thickness (PT), and nasal bone length (NBL) measurement at 11-14 weeks' gestation.

METHODS

Ultrasound PT and NBL determination was performed in 504 normal fetuses and 17 fetuses with Down's syndrome (DS). Measurements were made from mid-sagittal 2D images acquired using a standardized technique during nuchal translucency (NT) examination. PT and NBL values were expressed in multiples of the gestation-specific normal median (MoM) and as the PT/NBL ratio. Information on PT and NBL MoMs was also combined using logistic regression. Results were classified as positive according to whether they were greater than the normal 95th centile for PT, PT/NBL and the DS risk from logistic regression equation or below the 5th centile for NBL.

RESULTS

The median value in DS cases and unaffected controls were: PT 1.26 and 0.996 MoM; and NBL 0.596 and 0.993 MoM. The proportion of DS fetuses with positive results was 41% for PT, 65% for NBL, and 82% for both the PT/NBL ratio and DS risk from the logistic regression equation. PT/NBL levels did not vary according to gestational age.

CONCLUSION

The PT/NBL ratio is a valuable first trimester DS screening marker that can be easily determined concomitant with the NT measurement.

Nuchal translucency measurement, free β-hCG and PAPP-A concentrations in IVF/ICSI pregnancies: systematic review and meta-analysis

So far, data on the effect of assisted reproductive technologies (ART) on the components of first trimester combined screening for Down syndrome are still controversial. A systematic search of the literature was performed in order to identify the effect of ART, particularly in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) with fresh embryo transfer, on the nuchal translucency, free beta-human chorionic gonadotrophin and pregnancy-associated plasma protein-A measurements. Moreover, a meta-analysis and a descriptive graphical representation of the ratios between ART and spontaneous pregnancies (controls) values of median of the multiple of median (m₀ MoM) were performed. Free beta-human chorionic gonadotrophin test showed slightly higher values in the ICSI group than controls (RR = 1.09, 95%CI: 1.03-1.16) but not in the IVF group (RR = 1.03, 95%CI: 0.94-1.12). Pregnancy-associated plasma protein-A values for IVF/ICSI, IVF and ICSI showed lower values in comparison with controls (RR, 95%CI 0.85, 0.80-0.90; 0.82, 0.74-0.89 and 0.83, 0.79-0.86, respectively). The nuchal translucency measurement did not show any statistical differences between study groups (IVF and ICSI) and controls (RR = 1.00, 95%CI: 0.94-1.08 and RR = 1.01, 95%CI: 0.97-1.05, respectively). These results may be due to alterations in the placentation of ART pregnancies. Differentiating further subgroups of ART pregnancies may explain the differences in biomarker concentrations, in prenatal behavior and in obstetric outcomes between ART and spontaneous pregnancies. © 2017 John Wiley & Sons, Ltd.

Nuchal translucency in twins according to mode of assisted conception and chorionicity

OBJECTIVES

The impact of nuchal translucency (NT) screening in twins conceived after use of assisted reproduction technology (ART) has not been addressed properly in the literature. The aim of the current study was to assess, in a large cohort from a single center, NT in twins following various modes of ART as compared with NT in spontaneously-conceived twins and to differentiate results with regard to chorionicity.

METHODS

Retrospective data from 825 twin pregnancies were available for this study. All pregnant women underwent NT screening and chorionicity determination between 11 + 0 and 13 + 6 weeks' gestation in our center. Information about mode of conception and pregnancy outcome was obtained from hospital records and by telephone interviews. Twins were classified as having been conceived after in-vitro fertilization (IVF) with the woman's own or a donated embryo, after non-IVF ART or spontaneously. NT distribution in subgroups of fetuses was compared on the basis of the multiple of the normal median (MoM), SD of log10 MoM estimated by the 90(th) -10(th) centile range divided by 2.563 and the proportion of NT values exceeding the normal 95(th) centile which was 1.641 MoM in the singletons.

RESULTS

NT values were statistically significantly higher in ART pregnancies as compared with spontaneously-conceived pregnancies (Wilcoxon rank-sum test, P < 0.05) with medians of 1.073 and 1.038 MoM, respectively, but the proportion with values above the normal 95(th) percentile did not differ (chi-square test, P = 0.89). Among the ART twins, NT values were significantly higher for those conceived using IVF methods (P < 0.005), with a median of 1.082 MoM, compared with a median of 1.022 MoM using other methods. However, although a greater proportion exceeded the 95(th) centile (7.3% compared with 4.8%) this difference did not reach statistical significance (P = 0.17). There were no differences in NT values according to chorionicity (Wilcoxon rank-sum test, P = 0.75). The standard deviation of log10 NT was similar for all subgroups of twins. The correlation coefficient between fetuses in ART pregnancies was statistically significantly lower than that in spontaneously-conceived pregnancies (P < 0.05) but no significant differences were found between types of ART or according to chorionicity.

CONCLUSIONS

There was a small but significant increase in NT levels among ART pregnancies, which appeared to be confined to those conceived using IVF, and a small reduction in the correlation between fetuses. These effects probably have little impact on the estimated risk based on algorithms in use today.

Low uptake of prenatal diagnosis after established carrier status of a balanced structural chromosome abnormality in couples with recurrent miscarriage

OBJECTIVE

To evaluate to what extent couples carrying a balanced structural chromosome abnormality follow up the advice to opt for invasive prenatal diagnosis (PND) in subsequent pregnancies.

DESIGN

Index-control study.

SETTING

Six centers for Clinical Genetics in The Netherlands.

PATIENT(S)

Couples referred for chromosome analysis after recurrent miscarriage between 1992 and 2001 and with at least one pregnancy after disclosure; 239 carrier couples and 389 noncarrier couples.

INTERVENTION(S)

Questionnaire, medical record checking.

MAIN OUTCOME MEASURE(S)

Uptake of invasive PND.

RESULT(S)

Only 53 of 239 (22%) carrier couples underwent a PND procedure (CVS or amniocentesis) in all subsequent pregnancies. A relatively high number, 105 (44%) carrier couples, refrained from PND in all subsequent pregnancies. More carrier couples with maternal age >or=36 years (20/33 = 61%) refrained from PND, compared with carrier couples with maternal age <36 years (85/206 = 41%). In women >or=36 years, an equal proportion of carrier and noncarrier couples refrained from PND (61% vs. 54%).

CONCLUSION(S)

The advice to opt for invasive PND in carrier couples is poorly followed, especially in carrier couples with maternal age >or=36 years. The motivations of carrier couples to opt for or refrain from invasive PND procedures should be the topic for further research to optimize clinical care and informative decision making.

First-trimester screening markers are altered in pregnancies conceived after IVF/ICSI

OBJECTIVES

To determine the levels of first-trimester screening markers and to assess the false-positive rate for first-trimester combined screening for Down syndrome in a large national population of women pregnant after assisted reproductive technology (ART), in order to decide whether or not to correct risk calculation for mode of conception.

METHODS

A national prospective cohort study of 1000 pregnancies achieved after ART was compared with a control group of 2543 pregnancies conceived spontaneously. All women completed a first-trimester combined screening program. Risk calculation was performed retrospectively based on the screening parameters to avoid bias due to the use of different algorithms of risk calculation.

RESULTS

In chromosomally normal pregnancies conceived after in-vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI), the pregnancy-associated plasma protein-A multiples of the median value was significantly decreased when compared with that of pregnancies conceived spontaneously (0.78 and 0.79 vs. 0.98), while there was no difference in the group treated by frozen embryo replacement. There was no difference in the level of free beta-human chorionic gonadotropin between groups. The median nuchal translucency thickness was smaller in the overall ART group compared with controls. The false-positive rate of first-trimester combined screening in the overall ART group, adjusted for maternal age, was significantly higher when compared with controls (9.0% vs. 6.0%).

CONCLUSIONS

It seems advisable to use a population of IVF/ICSI pregnancies to establish median curves for the first-trimester serum screening parameters and perhaps also for nuchal translucency thickness. However, care must be taken, as different ART treatment methods and aspects of medical history seem to alter the screening parameters in different ways.

A model for second-trimester Down syndrome sonographic screening based on facial landmarks and digit length measurement

OBJECTIVE

To determine whether Down syndrome can be detected by combining measurements of fetal nasal bone (NB) length, prenasal thickness (PT) and digits 2 and 3 of the hand.

METHODS

Two hundred and fifty-four normal and 25 Down-syndrome fetuses were scanned between 15 and 33 weeks' gestation. Physicians performing the scans were not blinded to the fetal karyotype. Both PT and NB were measured in a mid-sagittal plane. For PT measurement calipers were placed between the frontonasal angle and the outer skin edge. Digits 2 and 3 of one hand were also measured. The results (except for PT/NB ratio) were expressed in multiples of the normal gestation-specific median (MoM). A logistic regression model was used to estimate the odds of the fetus having Down syndrome given different combinations of NB, PT, PT/NB ratio, and digits 2 and 3 measurements. The odds were used to calculate the risk of Down syndrome for each pregnant woman from her age and measurements.

RESULTS

The median PT MoM for unaffected fetuses and Down-syndrome fetuses was 1.12 vs. 1.35 (P < 0.0001). The median NB MoM for unaffected and Down-syndrome fetuses was 1.03 vs. 0.81 (P < 0.001) and the PT/NB ratio MoM for unaffected and Down-syndrome fetuses was 0.63 vs. 0.96 (P < 0.001). The respective median MoM values for digits 2 and 3 of the Down-syndrome fetuses were significantly smaller (0.81 vs. 0.93 and 0.89 vs. 0.95, respectively, P = 0.003). Only the PT/NB ratio and digit 2 were finally included in the logistic regression equation. Using a 1 in 200 risk cut-off, the observed sensitivity and false-positive rate were 76% and 6.7%, respectively.

CONCLUSION

Combining the PT/NB ratio and digit 2 measurements yielded a promising screening detection rate. Confirmation of our findings in a prospective study is needed before the method can be used clinically.

Antenatal care in singleton pregnancies after ICSI as compared to spontaneous conception: data from a prospective controlled cohort study in Germany

BACKGROUND

The aim was to compare the antenatal care and the intake of vitamins and medications of infertility patients with singleton pregnancies after ICSI to women with a spontaneously conceived singleton pregnancy.

METHODS

The data on the antenatal care of 2055 singleton pregnancies after ICSI from a prospective controlled multicentre study in Germany were analysed. The prospectively collected data of the control group of 7861 singletons were retrospectively assessed for the present analysis.

RESULTS

The ICSI patients were significantly older (32.9 versus 27.0 years, P<0.019) and more likely to be obese (body mass index>or=30 kg/m2: 13.9 versus 4.8%, P<0.001) than the controls. The control mothers were significantly more likely to smoke (19.2%) or to consume alcohol (23.5%) during pregnancy than the ICSI mothers (7.4 and 0.6% respectively). Only 38.1% of ICSI patients took folic acid before conception. Only 61.7% of ICSI patients received an iodine supplementation at some point during pregnancy. ICSI patients went more regularly to the routine antenatal care consultations at the gynaecologist and had ultrasound examinations performed more regularly than the controls. The absolute number of ultrasound examinations was significantly higher in the ICSI group (13.6+/-6.0 versus 4.1+/-2.4).

CONCLUSION

In spite of the intensive use of antenatal medical care by patients pregnant after ICSI, simple methods, such as the use of supplementary iodine and periconceptional folic acid, were used rarely. This indicates that counselling pregnant patients after ICSI about periconceptional and antenatal care seems to be insufficient in Germany and must be improved.

Targeted first-trimester prenatal diagnosis before fetal reduction in triplet gestations and subsequent outcome

OBJECTIVE

To assess the feasibility of targeted first-trimester ultrasound evaluation in triplet gestations and to report the outcome in reduced and expectantly managed triplets.

METHODS

This was a retrospective analysis of 127 triplets at 11-14 weeks with targeted ultrasound examination including nuchal translucency (NT) screening.

RESULTS

One or more abnormal findings were observed in 33 of 381 fetuses (8.7%), including increased NT (n = 18), malformations (n = 4), aneuploidy (n = 3), relative intrauterine growth restriction (n = 2) or spontaneous demise (n = 13). Of 63 patients (49%) who chose reduction, selective termination due to abnormal findings was performed in 13 fetuses. The rates of complete abortion <24 weeks were 9.8% and 3.2% for those with expectant management and fetal reduction, respectively. Expectantly managed triplets delivered significantly earlier (31.1 +/- 3.8 vs. 35.6 +/- 3.3 weeks) (P < 0.01) with a lower mean birth weight (1483 +/- 552 g vs. 2305 +/- 557 g) (P < 0.01) and a lower number of liveborn fetuses (85.6% vs. 97.4%) (P < 0.01) than those reduced.

CONCLUSION

Targeted first-trimester ultrasound is feasible and reliable in triplet gestations and should be an integral part of the counseling process. It results in more accurate selection for those who consider fetal reduction. Our data further support fetal reduction as a valuable strategy to improve perinatal outcome in triplet pregnancies.

All five digits of the hands of fetuses with Down syndrome are short

OBJECTIVE

To compare mid-gestation sonographic measurements of all five digits of the hands of fetuses with Down syndrome with those of normal controls.

METHODS

Twenty-nine fetuses between 17 and 26 weeks' gestation which had been confirmed by karyotyping to have Down syndrome were included in this prospective study. Each fetus was scanned once and the digits of only one hand were measured. Measurements were compared with those of 302 previously reported normal controls matched for gestational age. All measurements were expressed in multiples of the gestation-specific normal median (MoM) for each digit.

RESULTS

Compared to 1 MoM for the length of Digits 1 to 5 from the normal population, the respective values in the Down syndrome digits were: 0.94, 0.85, 0.92, 0.88 and 0.85 MoM, representing values significantly lower than normal (P < 0.05; t-test).

CONCLUSIONS

All five digits of the hands of fetuses with Down syndrome are shorter than are those of euploid fetuses. Integration of fetal digit measurement into the antenatal assessment of selected high-risk cases may be of value although confirmation of our findings should be obtained before this measurement is incorporated into Down syndrome screening in the general population.

Different preferences for prenatal diagnosis in pregnancies following assisted reproduction versus spontaneous conception

The uptake of prenatal diagnosis in 436 singleton and 146 twin pregnancies following assisted reproduction was compared with a matched group of spontaneous conceptions. The first and second trimester ultrasound examination included target fetal anatomic evaluation and screening by specific markers described for fetal aneuploidy. Women with assisted conception attended significantly more often for first trimester prenatal diagnosis (57.9 versus 34.9%, P < 0.01), but had fewer examinations in the early second trimester at 15-18 weeks (37.8 versus 48.8%, P < 0.01) than those with spontaneous conception. Screen positive results of 6.5 and 6.9% for first trimester examination and 6.0 and 7.3% for second trimester examination were found in assisted conceptions and controls respectively. A significantly higher rate of invasive prenatal diagnosis was observed in the second trimester for spontaneous conceptions, 20.0 versus 11.8% (P < 0.01) compared with assisted conceptions. This was attributed to the higher rate of invasive procedures in advanced maternal age >/=35 years of 40.7 versus 28.6% (P = 0.01) in spontaneous and assisted conceptions respectively. With the purpose of avoiding invasive testing, women with assisted conception were more likely to use the results of the ultrasound examination to guide their final decision about invasive testing, rather than undergo genetic amniocentesis as a first option.

First trimester screening with free beta-hCG, PAPP-A and nuchal translucency in pregnancies conceived with assisted reproduction

OBJECTIVE

To evaluate the effect of in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) on free beta-human chorionic gonadotrophin (beta-hCG), pregnancy-associated plasma protein A (PAPP-A) and nuchal translucency (NT).

METHODS

First trimester maternal dried whole blood specimens from 74 singleton pregnancies (32 by IVF and 42 by ICSI) and 30 twin pregnancies (16 by IVF and 14 by ICSI) in which conception was achieved with assisted reproduction techniques were matched with five controls resulting in 370 singleton controls and 150 twin controls. NT was measured using the Fetal Medicine Foundation protocol. Free beta-hCG, PAPP-A and NT levels were compared between the IVF and control groups and between the ICSI and control groups using the Mann-Whitney U test.

RESULTS

In singleton pregnancies, the only significant difference was a 21% (95% CI: -35%--7%) reduction in PAPP-A in IVF cases. In twin pregnancies, the only significant difference was a 12% (95% CI: -34%--3%) reduction in NT in IVF cases. In singleton pregnancies, the false-positive rate for Down syndrome screening was 1.4% and 1.9% greater for the IVF and ICSI groups, respectively, compared to controls for a general screening population.

CONCLUSIONS

Patients undergoing assisted reproduction techniques should be counseled about the possibility of increased false-positive rates. Larger studies are needed to confirm this observation and to develop appropriate adjustment factors to reduce false-positive rates.

Prenatal age-specific reference intervals for measuring all five digits of the fetal hand

OBJECTIVE

To construct prenatal age-specific reference intervals for measurement of five digits in normal fetuses.

PATIENTS AND METHODS

Prospective cross-sectional study of fetuses assessed at an antenatal ultrasound unit in a university-affiliated general hospital. The study cohort comprised 302 pregnant women attending our clinic for routine fetal biometry or anomaly scan between December 1997 and June 2000. They all fulfilled the study inclusion criteria: singleton fetuses with normal anatomy, accurate gestational age and no medical complications of pregnancy. Each fetus was scanned once only and the finger measurements of one hand were obtained. Electronic calipers were placed on the outer margin of the proximal phalanx to the outer margin of the distal phalanx level. Those measurements and the relevant gestational age were registered in a computerized database.

RESULTS

The linear increase of size of each of the five fingers was plotted across the evaluated range of gestation (P < 0.001; r2 between 0.85 and 0.86 for fingers I to V). Tables showing the 5th, 50th and 95th centiles of finger lengths between 14 and 27 weeks' gestation were created based on the reference interval charts.

CONCLUSIONS

Second-trimester measurement of all five digits of the fetal hand is feasible. This may assist in the evaluation of fetuses that are primarily suspected of having genetic abnormalities that might be expressed by deviation in finger length.

Prenatal diagnosis and management of fetal cardiovascular malformations

Screening for fetal cardiovascular malformations is widely performed. Its accuracy is not yet satisfactory, but better training of ultrasonographers and extension from the four-chamber view to the study of the outflow tract are probably clues to an improvement. The main impact of prenatal diagnosis is still the termination of pregnancy for severe malformations and for those associated with chromosomal or extracardiac anomalies. There is now evidence that prenatal diagnosis improves perinatal morbidity or mortality for some malformations. New information about the molecular genetic basis of congenital heart disease will help in management and counselling.