Amniotic Fluid Aspiration Research Articles

Development of a novel method for amniotic fluid stem cell storage

Background aimsCurrent procedures for collection of human amniotic fluid stem cells (hAFSCs) indicate that cells cultured in a flask for 2 weeks can then be used for research. However, hAFSCs can be retrieved directly from a small amount of amniotic fluid that can be obtained at the time of diagnostic amniocentesis. The aim of this study was to determine whether direct freezing of amniotic fluid cells is able to maintain or improve the potential of a sub-population of stem cells. MethodsWe compared the potential of the hAFSCs regarding timing of freezing, cells obtained directly from amniotic fluid aspiration (D samples) and cells cultured in a flask before freezing (C samples). Colony-forming-unit ability, proliferation, morphology, stemness-related marker expression, senescence, apoptosis and differentiation potential of C and D samples were compared. ResultshAFSCs isolated from D samples expressed mesenchymal stem cells markers until later passages, had a good proliferation rate and exhibited differentiation capacity similar to hAFSCs of C samples. Interestingly, direct freezing induced a higher concentration of cells positive for pluripotency stem cell markers, without teratoma formation in vivo. ConclusionsThis study suggests that minimal processing may be adequate for the banking of amniotic fluid cells, avoiding in vitro passages before the storage and exposure to high oxygen concentration, which affect stem cell properties. This technique might be a cost-effective and reasonable approach to the process of Good Manufacturing Process accreditation for stem-cell banks.

Meconium exposure and autism risk.

This study aims to determine whether fetal meconium passage is associated with autism. This retrospective birth cohort analysis of 9 945 896 children born in California 1991 to 2008 linked discharge diagnosis and procedure codes for prenatal stressors, meconium-stained amniotic fluid (MSAF) and meconium aspiration syndrome (MAS) with autism diagnoses for 47 277 children through 2012. We assessed the relative risk of autism by meconium status using logistic regression, adjusting for demographic and clinical features. Children exposed to meconium (MSAF and MAS) were more likely to be diagnosed with autism in comparison with unexposed children (0.60% and 0.52%, vs 0.47%, respectively). In adjusted analyses, there was a small increase in autism risk associated with MSAF exposure (adjusted relative risk (aRR) 1.18, 95% confidence interval (CI) 1.12 to 1.25), and a marginal association that failed to achieve significance between MAS and autism (aRR 1.08, 95% CI 0.98 to 1.20). Resuscitation of neonates with respiratory compromise from in utero meconium exposure may mitigate long-term neurodevelopmental damage.

Early Neonatal Morbidity after Term Delivery: How should We respond?

ABSTRACT Aim The aim of this retrospective study was to investigate the influence of gestational age and mode of delivery at term on early neonatal morbidity and mortality in a tertiary maternity center in a 10-year period. Materials and methods The data were derived from the medical records between January 1, 2005, and December 31, 2014, from the University Hospital “Sveti Duh,” Zagreb, Croatia. There were 30,363 live born term infants included in the study. The data from the medical records have been used to analyze their mode of delivery, morbidity, and mortality. Results Term newborn infants delivered by cesarean section (CS) had increased prevalence of lower Apgar scores, resuscitation, neonatal convulsions, and neonatal encephalopathy, respiratory pathology (except for amniotic fluid aspiration), and mechanical ventilation. Early and late neonatal deaths were more prevalent in term infants delivered by CS. The prevalence of birth trauma (except for facial nerve palsy) and hyperbilirubinemia was significantly increased in vaginally born neonates. The prevalence of perinatal infections was equal in both groups of infants. Morbidity and mortality of term newborn infants presented as prevalence per 1,000 live born, regardless of the mode of a delivery week by week from 37 through 41 weeks of gestation, were also investigated. The highest prevalence for most of the observed parameters were at 37 to 41 weeks of gestation, while the lowest prevalence was observed at a gestational age between 39 and 40 weeks. This was not the case for the 1st and the 5th minute 4 to 7 Apgar scores, birth injuries, respiratory pathology, and late neonatal deaths. Conclusion Early-term delivery was connected with more morbidity and mortality in the early neonatal period. It seems that the best gestational age to be born is at 39 to 40 weeks of gestation. Mode of delivery at term counts as well, showing that vaginal delivery at term had the lowest risk of morbidity and mortality. How to cite this article Stanojevic M, Leko L. Early Neonatal Morbidity after Term Delivery: How should We respond? Donald School J Ultrasound Obstet Gynecol 2016;10(2):180-184.

Current Concepts in the Management of Meconium Aspiration Syndrome.

In developing countries, meconium aspiration syndrome (MAS) is an important cause of morbidity and mortality among neonates. The concepts of pathophysiology and management of meconium stained amniotic fluid (MSAF) and meconium aspiration syndrome have undergone tremendous change in recent years. Routine intranatal and postnatal endotracheal suctioning of meconium in vigorous infants is no longer recommended. Recent studies have challenged its role even in non-vigorous infants. Supportive therapy like oxygen supplementation, mechanical ventilation and intravenous fluids are the cornerstone in the management of meconium aspiration syndrome. Availability of surfactant, inhaled nitric oxide, high frequency ventilators and extracorporeal membrane oxygenation has made it possible to salvage more infants with meconium aspiration syndrome. In this review the authors have discussed the current concepts in the pathophysiology and management of MAS. Drugs in trials and future therapeutic targets are also discussed briefly.

Droplet digital PCR, a new approach to analyze fetal DNA from maternal blood: application to the determination of fetal RHD genotype.

The discovery of free fetal DNA in the maternal circulation has inaugurated the era of non-invasive prenatal diagnosis. The latter has the advantage of avoiding the use of conventional obstetric procedures, such as chorionic villus sampling or aspiration of amniotic fluid, thus limiting the risks of miscarriage they induce. However, as free fetal DNA accounts for about 10% of cell-free DNA in maternal plasma, the presence of ambient maternal DNA can make it difficult to detect fetal alleles of paternal origin. Digital Droplet PCR (ddPCR) is a very sensitive method derived from quantitative real-time PCR (qPCR) for the detection of rare alleles and their absolute quantification by removing the necessity of standards. Here we show that this new technology can be applied in routine prenatal fetal RHD genotyping from maternal blood. In conclusion, the use of quantitative properties of digital PCR, in terms of accuracy, sensitivity and specificity, allows one to consider extending the applications of this new technology in non-invasive prenatal diagnosis of many diseases such as autosomal monogenic diseases, either dominant or recessive.

Droplet digital PCR combined with minisequencing, a new approach to analyze fetal DNA from maternal blood: application to the non-invasive prenatal diagnosis of achondroplasia.

Achondroplasia is generally detected by abnormal prenatal ultrasound findings in the third trimester of pregnancy and then confirmed by molecular genetic testing of fetal genomic DNA obtained by aspiration of amniotic fluid. This invasive procedure presents a small but significant risk for both the fetus and mother. Therefore, non-invasive procedures using cell-free fetal DNA in maternal plasma have been developed for the detection of the fetal achondroplasia mutations. To determine whether the fetus carries the de novo mis-sense genetic mutation at nucleotide 1138 in FGFR3 gene involved in >99% of achondroplasia cases, we developed two independent methods: digital-droplet PCR combined with minisequencing, which are very sensitive methods allowing detection of rare alleles. We collected 26 plasmatic samples from women carrying fetus at risk of achondroplasia and diagnosed to date a total of five affected fetuses in maternal blood. The sensitivity and specificity of our test are respectively 100% [95% confidence interval, 56.6-100%] and 100% [95% confidence interval, 84.5-100%]. This novel, original strategy for non-invasive prenatal diagnosis of achondroplasia is suitable for implementation in routine clinical testing and allows considering extending the applications of these technologies in non-invasive prenatal diagnosis of many other monogenic diseases. © 2016 John Wiley & Sons, Ltd.

Comparison of group B streptococci colonization in vaginal and rectal specimens by culture method and polymerase chain reaction technique

BackgroundStreptococcus agalactiae (group B streptococci, GBS) is a colonizing microorganism in pregnant women and without causing symptoms. Colonization of GBS in the rectovaginal region in late of pregnancy is a risk factor for newborn diseases. GBS infection in newborn babies is acquired by the aspiration of infected amniotic fluid or vertical transmission during delivery through the birth canal. The aim of this study was determination of GBS prevalence among vaginal and anorectal specimens at gestation females by polymerase chain reaction (PCR) and culture-based methods. MethodsIn this study, 137 rectal and vaginal swabs were separately collected from women with gestational age 35–37 weeks from July 2013 to March 2014 at the teaching hospital of Razi, Ahvaz, Iran. All samples were enrichment in selective culture media Todd–Hewitt broth for 24 hours and recognized by standard culture using blood agar, phenotypic tests, and amplification of the CFB gene. ResultsAge range was 16–45 years (mean, 28.34 ± 0.7 years). Of rectal samples, 42 (30.7%) were positive based on culture method and 57 (41.6%) samples were positive by PCR. Of 137 vaginal samples, 38 (27.7%) were positive by culture and 60 (43.8%) samples were positive by PCR. The chance of colonization with GBS was increased in women with a history of urinary tract infection. ConclusionThe frequency of GBS culture from rectal samples was higher than vaginal samples. However, the detection percentage of GBS using PCR from vaginal samples was higher than rectal samples. By contrast, the culture is a time-consuming method requiring at least 48 hours for GBS fully identification but PCR is a sensitive and rapid technique in detection of GBS, with the result was acquired during 3 hours.

Congenital miliary tuberculosis in an 18-day-old boy

Congenital tuberculosis (TB) is a rare disease that is associated with high mortality. Mycobacterium tuberculosis, the causative agent, may be transmitted from the infected mother to the fetus by the transplacental route or by aspiration of infected amniotic fluid. Clinical symptoms and signs are not specific. Miliary patterns are the most common findings in the chest X-rays of many infants with congenital TB. In this case, an 18-day-old boy had jaundice on the fifth day of birth, and fever and respiratory distress appeared on the 18th day. Chest X-ray showed diffuse fine bilateral infiltration. Clinically, pneumonia or sepsis was suspected. Respiratory symptoms and chest X-ray findings worsened despite empirical antibiotic therapy. The lungs showed miliary infiltration suggestive of TB. Gastric aspirates were positive for M. tuberculosis. Respiratory distress and fever were gradually improved after anti-TB medication. Congenital TB is difficult to detect because of minimal or no symptoms during pregnancy and nonspecific symptoms in neonates. Hence, clinicians should suspect the possibility of TB infection even if neonates have non-specific symptoms. Early diagnosis and meticulous treatment are required for the survival of neonates with TB.

Risk Factors and Outcome of Neonates Born through Meconium Stained Amniotic Fluid in a Tertiary Hospital of Nepal

Introduction: The incidence of meconium aspiration syndrome is still high in the developing world contributing significantly to the neonatal mortality. The study was aimed to know the risk factors contributing to meconium aspiration syndrome and neonatal outcome in a tertiary government hospital of the country.Materials and Methods: It was a hospital based cross sectional study done over a period of three months. All live newborns born through meconium stained liquor were enrolled and all the details regarding mother, neonate were recorded. Odd’s ratio and bivariate analysis was done to assess the risk factors for meconium aspiration syndrome.Result: Out of all the deliveries 14.6% were meconium stained amniotic fluid and meconium aspiration syndrome developed in 6.6% of the neonates. Low Apgar score and premature rupture of membranes was significantly associated with the risk of occurrence of meconium aspiration syndrome. Neonates who developed meconium aspiration syndrome had mortality of 11.3%.Conclusion: Perinatal asphyxia and premature rupture of membranes were significantly associated with the development of meconium aspiration syndrome and neonates who developed meconium aspiration syndrome had high mortality.J Nepal Paediatr Soc 2015;35(1):44-48

Fatal pneumonia in a newborn caused by Oerskovia xanthineolytica

A premature child was born at 34–35 weeks gestation with aspiration of amniotic fluid. Rupture of the amniotic sac occurred 3 day before delivery. Two days later the child died. From the lungs, after 24 hours cultivation on blood agar, a pure culture of small yellow pigmented colonies was isolated. All other organs remained sterile. Gram stain revealed Gram-positive rods. The strain was catalase positive and motile. The phospholipid and fatty acid compositions were studied. Final identification was done using ApiCoryne (BioMerieux) and the strain was proved as Oerskovia xanthineolytica. Disk diffusion and E test were performed for antimicrobial susceptibility testing. The strain was susceptible to vancomycin, imipenem and cotrimoxazole. This report demonstrates the first fatal case with isolation of this microorganism from the lungs of newborn.

How to perform an amniocentesis.

Amniocentesis is a technique for withdrawing amniotic fluid from the uterine cavity using a needle, via a transabdominal approach and under continuous ultrasound guidance, in order to obtain a sample of fetal exfoliated cells, transudates, urine or secretions. It can be performed from 16 weeks of pregnancy onwards, with various chromosomal, biochemical, molecular and microbial studies being performed on the amniotic fluid sample. The most common reasons for the procedure are to enable prenatal diagnosis of chromosomal abnormalities, single gene disorders, fetal infection and intra-amniotic inflammation, as well as to assess fetal lung maturity and blood or platelet type. The procedure has a risk of fetal loss of approximately 0.5% (range, 0.06–1%)1 when performed in the second trimester, after the amniotic membrane has fused with the chorion; there is also a risk of amniotic fluid leakage (approximately 0.3% of cases) and other rare complications, such as placental hemorrhage, intra-amniotic infection, abdominal wall hematoma and fetal lesion. There is an important lack of good-quality evidence to support most recommendations for the procedure, and a recent review suggested that operators should use those methods and technique modifications with which they are most familiar when performing an amniocentesis2. The aim of this summary article and the full version, included as supplementary material online, is to describe the amniocentesis technique, presenting a practical guideline for its performance. We also describe the use of a Vacutainer® (BD Vacutainer Systems, Plymouth, UK) aspiration system in order to produce a continuous vacuum for amniotic fluid aspiration as an alternative to using manually operated syringes.

Inhaled Surfactant Therapy in Newborns in Artificial Lung Ventilation

Objective: to evaluate the efficiency of inhaled surfactant therapy in neonatal infants with respiratory failure. Subjects and methods . The trial enrolled 13 premature neonatal infants; their mean gestational age was 31.8±2.8 weeks and the birth weight was 1825±600.9 g. They had a oneminute Apgar score of 4.3±1.4. All the neonates needed mechanical ventilation (MV) at birth because the leading clinical sign was respiratory failure caused by acute intranatal hypoxia, neonatal amniotic fluid aspiration, respiratory distress syndrome (RDS), and cerebral ischemia. Curosurf was injected in a dose of 174.7±21 mg/kg in the infants with neonatal RDS at 35 minutes of life. All the babies included in the study were noted to have severe disease and prolonged MV. After stabilization of their status, the neonates received combination therapy involving surfactantBL inhalation to reduce the duration of MV. The dose of the agent was 75 mg. Results . After surfactantBL inhalation, effective spon taneous respiration occurred in 69.2% of the newborn infants; successful extubation was carried out. The median duration of MV after surfactant BL inhalation was 22 hours (4—68 hours). There were no reintubated cases after inhalation therapy. Following surfactantBL inhalation, 4 (30.8%) patients remained to be on MV as a control regimen; 3 of them had highfre quency MV. SurfactantBL inhalation made it possible to change the respiratory support regimen and to reduce MV parame ters in these babies.

PO-0736 Preliminary Experience With The Use Of Neurally Adjusted Ventilatory Assist In The Neonate

<h3>Background and aims</h3> Invasive and non-invasive ventilation of the neonate may be associated with local and systemic complications due to mechanical trauma to lung tissues and their inflammatory response. A key objective of mechanical ventilation is to reduce its duration and side effects. Neurally Adjusted Ventilatory Assist (NAVA), a method that uses the electrical activity of the diaphragm (EAdi) as a signal to trigger the mechanical ventilatory breaths, may improve synchronisation between patient and ventilator and optimise the gas volume delivered to the lungs, according to the patient needs, eventually reducing volu- and biotrauma. We aimed to test the effectiveness of NAVA in the neonate. <h3>Methods</h3> We present three preterm babies with severe respiratory distress syndrome that failed several attempts of weaning and extubation, and two full-term new-borns with amniotic fluid aspiration that could be successfully managed after changing from conventional ventilation to NAVA. <h3>Results</h3> Our most frequent observations were a reduction in the Peak Inspiratory Pressure and in the need of FiO₂, after changing from S-IMV, A/C or Pressure Regulated Volume Control to NAVA. We also observed a reduction in respiratory rate and an increase in the patients’ comfort. After extubation, during NIV-NAVA, the patients remained stable and confortable, even with the presence of air-leaks up to 90%. No patient required reintubation. <h3>Conclusions</h3> NAVA is effective in weaning and extubation of neonates and seems to provide more comfort to the patients. Further studies are needed to assess whether short-term benefits are reflected in better outcomes in the long run.

Neonatal Respiratory Distress Syndrome: Early Diagnosis, Prevention, and Treatment

to improve treatment results in premature infants with neonatal respiratory distress syndrome (NRDS), by establishing developmental mechanisms and elaborating methods for its early diagnosis, treatment, and prevention. Material and methods . The paper analyzes the results of a clinical observation and laboratory, instrumental, immunological, morphological, and radiological studies of 320 premature neonates at 26—35 weeks gestational age. The following groups of neonates were identified: 1) 40 premature neonatal infants without NRDS and with the physiological course of an early neonatal period (a comparison group); 2) 190 premature neonates with severe NRDS in whom the efficiency of therapy with exogenous surfactants, such as surfactant BL versus curosurf, was evaluated; 3) 90 premature newborn infants who had died from NRDS at its different stages. Results . The poor maternal somatic, obstetric, and gynecological histories in the early periods of the current pregnancy create prerequisites for its termination, favor the development of severe acute gestosis, and cause abnormal placental changes. Each gestational age is marked by certain placental changes that promote impaired uterineplacentalfetal blood flow and premature birth. Alveolar and bronchial epithelial damages, including those ante and intranatally, microcircula tory disorders play a leading role in the tanatogenesis of NRDS. Intranatal hypoxia and amniotic fluid aspiration are one of the important factors contributing to alveolar epithelial damage and NRDS in premature neonates. Exogenous surfactants prevent the development of hyaline membranes and are useful in the normalization of ventilation-perfusion relationships and lung biomechanical properties. Conclusion. This study could improve the diagnosis and treatment of NRDS, which assisted in reducing the duration of mechanical ventilation from 130±7.6 to 65±11.6 hours, the number of complications (the incidence of intragastric hemorrhages decreased from 28.8 to 9%), the stay length of the neonates in an intensive care unit, and early neonatal mortality rates from 9.3 to 0.9‰ and in improving demographic indicators.

Evaluation of specific marker CK13 and CK10/13 combined with APM staining for the diagnosis of amniotic fluid embolism and aspiration

ObjectiveTo explore the value of CK13 (Rab) and CK10/13(Mab) as objective and specific biomarkers combined with Alcian-Phloxine-Martius yellow (APM) staining for the diagnosis of amniotic fluid embolism (AFE) and amniotic fluid aspiration (AFA). MethodsA retrospective study of forensic autopsy cases of 148 neonatal deaths and 19 maternal deaths in the perinatal stage was conducted at the Institute of Pathology and Forensic Medicine, Zhejiang University. Medical records were reviewed and monoclonal antibody for CK13 (Rab) and CK10/13 (Mab) as immunostaining of amniotic fluid squamous cells, APM staining, and Hematoxylin and Eosin (HE) staining were used to diagnose the AFE and AFA. Descriptive statistics of the patient population were analyzed using SPSS 20.0 software. ResultsImmunoreactivity of CK13 and CK10/13 specifically identified squamous cells of all the AFE and AFA cases. The amniotic fluid squamous cells were stained positive in a deep brown color with the monoclonal antibody to CK 13 and CK10/13 whereas the endothelial cells and alveolar epithelial cells were negative. There was no CK13 or CK10/13 expression in the non-AFE and non-AFA cases. With APM staining keratinized squamous cells were pink and mucus was blue-green in marked contrast with the surrounding tissue, which improved the detection rates of both keratinized squamous cells and mucus. ConclusionsCK13 (Rab) and CK10/13 (Mab) are valuable and reliable biomarkers of amniotic fluid squamous cells. APM reveals enriched mucus and keratinized squamous cells of amniotic fluid. Immunohistochemical detection of CK13 and CK10/13 combined with APM staining can improve the accuracy and reduce the difficulty in the diagnosis of AFE and AFA.

A Young Lady with Acute Pulmonary Embolism after Caesarean Section - A Case Report

The presentation of acute dyspnea after pregnancy is rare, but should bring a number of important conditions to the mind of the attending physician. Pulmonary embolism, amniotic fluid embolism, pneumonia,aspiration pneumonia and pulmonary edema are some of the potentially devastating causes that must be considered. We report a 29 years young lady who presented with progressive severe dyspnoea, haemoptysis with right leg swelling and H/O lower uteraine caesarean section(LUCS) followed by mymectomy one and half months back , initially her ECG, chest –X-ray &amp; echocardiographic findings revealed evidence of pulmonary embolism we treated her with dramatic improvement. Birdem Med J 2013; 3(2): 116-120 DOI: http://dx.doi.org/10.3329/birdem.v3i2.17218

Acute Postpartum Pulmonary Edema in a 32-Year-Old Woman Five Days after Cesarean Delivery

Acute dyspnea after pregnancy is a rare presentation, and a number of important conditions may accompany it. Pulmonary embolism, amniotic fluid embolism, pneumonia, aspiration and pulmonary edema are some of the potential causes that must be considered. The percentage of pregnancies that are complicated by acute pulmonary edema has been estimated 0.08%. The most common contributing factors include the administration of tocolytic agents, underlying cardiac disease, iatrogenic fluid overload and preeclampsia. Here we report a case of 32- year-old woman of 5th postpartum day following lower uterine cesarean section with acute dyspnea from her first pregnancy who was admitted in coronary care unit with history of one episode of raised blood pressure 160/90 mm Hg and cough on 1st postoperative day. Clinical examination and relevant investigations explored that it was a case of bilateral pulmonary edema. Patient was kept in ventilator and was treated with nitroglycerine (GTN), frusemide and ACE inhibitor. After diuresis, considerable improvement was observed in her respiratory status. From the 4th day, the patient became hemodynamically stable and was weaned off the ventilator. After five days, all the biochemical parameters became normal and she had no dyspnea. Journal of Enam Medical College; Vol 3 No 2 July 2013; Page 113-116 DOI: http://dx.doi.org/10.3329/jemc.v3i2.16135

Research on screening specific biomarkers for pathological diagnosis and differential diagnosis of amniotic fluid embolism and amniotic fluid aspiration

羊水吸入和羊水栓塞的诊断和鉴别诊断主要依赖HE染色形态学的判断,同时结合临床经过及全身其他脏器改变作出诊断.这种方法在一定程度上依赖于病理医师的形态观察,具有一定的主观性.羊水吸入和羊水栓塞发病迅猛,患者常在发病数小时内死亡[1].再者,由于各种原因,病理检查不能及时进行,导致组织自溶/使典型材料缺乏,或血管内皮和(或)肺泡上皮脱落干扰使形态学特征不典型,或由于栓塞于脏器小血管内的羊水成分数量较少,极易出现漏诊或误诊,临床常因缺少可供客观判断的标志物而导致医疗纠纷.我们利用近年发展起来的兔单抗标记技术,结合常规鼠单抗标记方法,旨在研究和筛选出特异性羊水角化细胞标志,为羊水吸入和羊水栓塞的病理诊断提供客观检测依据。

Adrenal fusion anomaly

CASE REPORT A 35­year­old female, G2P1L1, underwent an antenatal scan at 36 weeks. Large thoraco­lumbar neural tube defect and Arnold­Chiari malformation type II were detected in the fetus. A female fetus weighing two kg was delivered following induction for termination of pregnancy. Autopsy confirmed Arnold­ Chiari malformation, and meningomyelocele at thoraco­ lumbar region. Histology showed features suggestive of amniotic fluid aspiration in non­aerated lungs. A transverse band of tissue across the midline was noted above the kidneys, posterior to aorta. No separate adrenals were identified in superior poles of kidney (Figure 1A, B). Histologic examination of transverse band of tissue showed a capsulated tissue with cells displayed in zonal pattern. A compact cellular layer formed outer layer, columns of paler cells in the middle and smaller cells in cords on inner side consistent with adrenal gland morphology (Figure 2). This confirmed the diagnosis of adrenal fusion anomaly. DISCUSSION Adrenal gland agenesis, hypoplasia and accessory gland are common congenital anomalies of adrenal CLINICAL IMAGES OPEN ACCESS

Operator experience reduces the risk of second trimester amniocentesis-related adverse outcomes

ObjectiveTo investigate the impact of operator experience on amniocentesis-related adverse outcomes. Study designRetrospective study of mid-trimester amniocenteses performed by the same operator on singleton pregnancies in a single private institution during 1994–2007. Outcomes were hemorrhagic or dark amniotic fluid aspiration, insufficient volume aspiration, repeated puncture and fetal loss. Rates were estimated annually, as well as for every 10% of procedures up to the total number. The association of each outcome with epidemiological aspects was also examined. ResultsIn total, 5913 amniocenteses were performed. The overall rate of adverse outcomes was 5.4%. The total adverse outcome rate reduced from 10.2% in the first 10% of cases to 3.0% in the last 10% (P=.001). The rate of hemorrhagic fluid gradually decreased from 4.4% to 1.5% (P=.05) over the same intervals. The fetal loss rate was also reduced from 0.5% during the first half to 0.3% in the second half of the study period (P=NS). Logistic regression analysis indicated no significant correlations between adverse outcomes with any of epidemiological parameters of women undergoing amniocentesis. ConclusionOperator experience has a beneficial impact on preventing procedure-related adverse outcomes.