Six consecutive false positive cases from cell-free fetal DNA testing in a single referring centre.

INTRODUCTION: recent studies have proposed the introduction of cell-free fetal DNA testing (NIPT-Non Invasive Prenatal Testing) in routine clinical practice emphasizing its high sensibility and specificity. In any case, false positive and false negative findings may result from placental mosaicism, because cell-free fetal DNA originates mainly from placenta. CASE: WE REPORT SIX CASES OF WOMEN WHO UNDERWENT CHORIONIC VILLUS SAMPLING (CVS) OR AMNIOCENTESIS TO CONFIRM THE RESULTS FROM NIPT: two Turner syndromes, two Triple X, one Patau syndrome, one Edward syndrome. RESULTS: using classic cytogenetic analysis and, also, Array - Comparative Genomic Hybridization (Array CGH) the karyotype of all 5 fetuses was found to be normal. CONCLUSION: results from NIPT must always be confirmed by invasive prenatal diagnosis. It is mandatory to inform the patient that the CVS and amniocentesis still represent the only form of prenatal diagnostic test available.

Retrospective study evaluating the performance of a first-trimester combined screening for trisomy 21 in an Italian unselected population.

OBJECTIVES: to assess the performance of a combined first-trimester screening for trisomy 21 in an unselected Italian population referred to a specialized private center for prenatal medicine. METHODS: a retrospective validation of first-trimester screening algorithms [risk calculation based on maternal age and nuchal translucency (NT) alone, maternal age and serum parameters (free ß-hCG and PAPP-A) alone and a combination of both] for fetal aneuploidies evaluated in an unselected Italian population at Artemisia Fetal-Maternal Medical Centre in Rome. All measurements were performed between 11(+0) and 13(+6) weeks of gestation, between April 2007 and December 2008. RESULTS: of 3,610 single fetuses included in the study, we had a complete follow-up on 2,984. Fourteen of 17 cases of trisomy 21 were detected when a cut-off of 1:300 was applied [detection rate (DR) 82.4%, 95% confidence interval (CI) 64.2-100; false-positive rate (FPR) 4.7%, 95% CI 3.9-5.4; false-negative rate (FNR) 17.6%, 95% CI 0-35.8%]. CONCLUSION: in our study population the detection rate for trisomy 21, using the combined risk calculation based on maternal age, fetal NT, maternal PAPP-A and free ß-hCG levels, was superior to the application of either parameter alone. The algorithm has been validated for first trimester screening in the Italian population.

Antibiotic prophylaxis before second-trimester genetic amniocentesis (APGA): a single-centre open randomised controlled trial.

OBJECTIVE: To compare procedure-related pregnancy loss after second-trimester genetic amniocentesis in women given an antibiotic prophylaxis and controls. METHODS: Prospective, open randomised controlled single-centre study between January 1999 and December 2005 at Artemisia Fetal Maternal Medical Centre. A follow-up within 4 weeks after the procedure was done.Of 36,347 eligible women, 1424 refused to participate and 34,923 were enrolled and randomised with unequal chance of selection, 21,991 were assigned to treatment group and 12,932 were assigned to the control group, and did not receive any placebo. Oral azithromycin, 500 mg per day, was administered 3 days before amniocentesis. The primary endpoint was the procedure-related pregnancy loss. The secondary endpoint was the rate of preterm premature rupture of membranes. RESULTS: The rate of abortion related to the amniocentesis was 7/21 219 women (0.03%, 95% CI 0.009-0.057) in the intervention group, and 36/12 529 (0.28%, 0.28-0.30) in controls (p = 0.0019). The rate of preterm premature rupture of membranes was 14/21 219 (0.06%, 0.031-0.101) in the intervention group, and 140/12 529 (1.12%, 0.94-1.30) in the control group (p = 0.001). CONCLUSIONS: Antibiotic prophylaxis before second-trimester amniocentesis reduced the risk of abortion and of rupture of the membranes.

Prenatal diagnosis of left isomerism with normal heart: a case report.

OBJECTIVE: Left isomerism, also called polysplenia, is a laterality disturbance associated with with paired leftsidedness viscera and multiple small spleens. Left isomerism, heart congenital abnormalities and gastrointestinal malformation are strongly associated. METHODS: We present a case of prenatal diagnosis of left isomerism in a fetus with a structurally normal heart. CONCLUSION: Left isomerism syndrone may coesist with a structurally normal heart. If prenatal left isomerism is suspected, even in presence of a normal heart, is mandatory to esclude sign of gastrointestinal abnormalities, as late poly hy dramnios, and cardiac rhytm disturbance during the pregnancy and neonatal age.

Prenatal screening of Cystic Fibrosis: a single centre experience.

OBJECTIVE: The gene responsible for the pathogenesis of cystic fibrosis has been known for over 15 years and represent the most common autosomal recessive disease in the european population. We aimed to investigate the incidence of this condition during fetal life. METHODS: In the past 10 years we examined in our centre 25393 fetuses of women underwent to amniocentesis. We carried out the examination of the most frequent mutations which enable, according to the literature data, the identification of almost 80% of the affected alleles. RESULT: We identified 922 heterozygous and 9 homozygous for the mutation. The frequency of heterozygousin the examined sample was 1/27,5 while that of the affected was 1/2821. CONCLUSION: We encourage new thoughts regarding the diagnostic validity of the most frequent panel of mutations among the italian population in order to exclude never encountered mutations and the insertion of other more significant mutations.

Amniotic fluid index and fetal bladder outlet obstruction. Do we really need more?

PURPOSE: With the constant advances in technology and expertise of prenatal diagnosis, necessity of early counseling in cases of bilateral obstructive uropathy has become of paramount importance. To better evaluate fetal renal function new biochemical (serum and urine) fetal markers have been introduced in the literature. However, they are only available at select centers and always requiring an invasive approach. Furthermore, paucity of normal controls sometimes makes interpretation of results difficult. Owing to this growing interest towards biochemical evaluation of fetal renal function, assessment of amniotic fluid, which is mostly expression of fetal urination, has progressively fallen into disrepute, and studies comparing the amount of amniotic fluid with renal function are scant. MATERIALS AND METHODS: In a 3-year period 28 cases of bilateral obstructive uropathy were seen prenatally at the Artemisia Medical Center. All cases were initially reviewed at 17 to 20 weeks of gestation when a distended fetal bladder with thickened wall and enlarged kidneys were visualized. At the same time ultrasonographic assessment of amniotic fluid was performed by calculating the amniotic fluid index. An amniotic fluid index less than the 25th percentile was considered below average and an index less below the 5th percentile was considered oligohydramnios, whereas an index between 50th and 75th percentiles was considered normal. All cases were subsequently evaluated for renal function up to age 1 year. Impaired renal function was defined as a serum creatinine greater than 1.2 mg/dl before age 1 year. RESULTS: Of the 28 cases 18 had an index of oligohydramnios (group 1) and 10 had a normal index (group 2). No significant variations were observed in amniotic fluid index at repeated consultations throughout pregnancy. Two cases in group 1 and 1 case in group 2 were lost to followup while in the other group 1 cases intrauterine death occurred. Bilateral obstructive uropathy was confirmed in all instances after birth as valves in 18 cases and urethral atresia in 3. Of the 12 surviving group 1 cases there were 3 neonatal deaths from severe lung hypoplasia, and in the remaining 9 cases mean serum creatinine at each evaluation before age 1 year was 1.3 +/- 0.2 mg/dl. All patients in group 2 survived with a mean serum creatinine at each evaluation of 0.6 +/- 0.1 mg/dl (p <0.05). CONCLUSIONS: Despite widespread use of prenatal biochemistry, evaluation of amniotic fluid by the amniotic fluid index remains a reproducible and inexpensive method to predict renal function in cases of bilateral obstructive uropathy of any origin. It retains its validity not only in severe, but also in milder reductions. Conversely, intact amniotic fluid mostly invariably predicts normal renal function at long-term evaluation. For a better understanding of the disease such information is to be promptly conveyed to the prospective parents at each prenatal consultation.