Cordocentesis-associated fetal loss and risk factors: single-center experience with 6650 cases.

OBJECTIVES: To identify procedural risk factors associated with fetal loss following cordocentesis and to determine the rate of cordocentesis-related fetal loss associated with the current cordocentesis protocol used in our institution. METHODS: This was a retrospective cohort study of pregnancies that underwent midpregnancy cordocentesis in a single center (a tertiary hospital, teaching school), between 1992 and 2018, based on data retrieved from our prospective database. All consecutive cases were validated to retrieve those meeting the eligibility criteria, which included: singleton pregnancy without underlying maternal disease, normal fetus (no structural or chromosomal abnormality or severe disorder), gestational age between 16 and 24 weeks at the time of the procedure and availability of pregnancy outcome. Cases that resulted in termination of pregnancy were excluded. We assessed the effect of prior cordocentesis model training on the fetal-loss rate and procedure-related complications, and evaluated potential risk factors of fetal loss secondary to cordocentesis, including procedure difficulty, placenta penetration, prolonged bleeding, fetal bradycardia, puncture site and early gestational age at procedure. Pregnancy outcomes were compared between the study group and a control group of women, who did not undergo cordocentesis, selected randomly at a 1:1 ratio from our obstetric database. RESULTS: A total of 10 343 procedures were performed during the study period, of which 6650 met the eligibility criteria and were included in the analysis. The fetal-loss rate in the first 60 procedures (early practice) of six operators (n = 360 procedures), who did not have prior model training, was significantly higher than that during the early practice of 18 operators (n = 1080 procedures) with prior model training (6.9% vs 1.6%; P < 0.001); whereas the fetal-loss rate in the next 60 procedures of practice was comparable between the two groups. After excluding the first 360 procedures of the groups without prior model training, the overall fetal-loss rate in pregnancies that underwent cordocentesis was significantly higher than that in the control group (1.6% vs 1.0%; P < 0.001). Considering the fetal-loss rate in the normal controls as background loss, the incremental cordocentesis-associated fetal-loss rate was 0.6%. Penetration of the placenta (odds ratio (OR), 2.65 (95% CI, 1.71-4.10)), prolonged bleeding from the puncture site (OR, 10.85 (95% CI, 5.27-22.36)) and presence of fetal bradycardia (OR, 3.32 (95% CI, 1.83-6.04)) during cordocentesis were independent risk factors associated with fetal loss. CONCLUSIONS: Cordocentesis model training markedly reduces fetal loss during the early learning curve of practice. Thus, cordocentesis practice without prior model training should not be acceptable. Significant procedural risk factors for fetal loss secondary to cordocentesis are placental penetration, prolonged bleeding and fetal bradycardia. Cordocentesis-related fetal loss may be only 0.6%, much lower than the rate reported previously. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

Associations between maternal serum free beta human chorionic gonadotropin (ß-hCG) levels and adverse pregnancy outcomes.

The objective was to determine the strength of relationship between maternal free beta human chorionic gonadotropin (ß-hCG) concentrations and rates of adverse pregnancy outcomes. Consecutive records of the database of our Down screening project were assessed for free ß-hCG levels and pregnancy outcomes. Pregnancies with foetal chromosomal or structural anomalies and those with underlying disease were excluded. Free ß-hCG levels of < 0.5, > 0.5 and < 2.0, and ≥ 2.0 MoM were categorised as low, normal and high, respectively. Of 17,082 screened women, 13,620 were available for analysis. In the first trimester (n = 8150), low ß-hCG levels significantly increased risk for intrauterine growth restriction (IUGR), preterm birth, low birth weight (LBW) and low Apgar score with relative risk of 1.66, 1.43, 1.83 and 2.89; whereas high ß-hCG group had a significant decreased risk of preterm birth and GDM with relative risk of 0.73 and 0.62. In the second trimester (n = 5470), both low and high ß-hCG groups had significant increased risks of the most common adverse outcomes, i.e. spontaneous abortion, IUGR and preterm birth. In conclusion, abnormally low (< 0.5MoM) or high (> 2.0 MoM) free ß-hCG levels are generally associated with an increased risk of adverse pregnancy outcomes. Nevertheless, high free ß-hCG levels in the first trimester may possibly decrease risk of preterm delivery and GDM.

Fetal liver length measurement at mid-pregnancy among fetuses at risk as a predictor of hemoglobin Bart's disease.

OBJECTIVE: To assess the effectiveness of liver length measurement in predicting hemoglobin (Hb) Bart's disease among fetuses at risk at mid-pregnancy. STUDY DESIGN: Pregnant women at risk of fetal Hb Bart's disease at 18 to 22 weeks of gestation were enrolled in the study. All of them underwent liver length measurement just before cordocentesis for fetal blood analysis. The final diagnosis used as a gold standard was based on fetal Hb typing using high-performance liquid chromatography. RESULT: A total of 334 pregnant women were recruited into the study. The prevalence of fetal Hb Bart's disease was 26.1% (87 of 334 fetuses). The sensitivity, specificity, as well as positive and negative predictive values of liver length in the prediction of affected fetuses were 71.3, 95.5, 84.9 and 90.4%, respectively. Overall, 24 fetuses (27.6%) had some degree of early hydrops fetalis. Of these, 20 had hepatomegaly as well. CONCLUSION: Liver length measurements at mid-pregnancy may be helpful in predicting affected fetuses among pregnancies at risk. Normal liver length measurement is associated with a very low risk of the disease. This information may help couples decide on whether to opt for either invasive diagnosis or a noninvasive approach, especially when used as an adjunct to other tests.

Erythrocyte osmotic fragility test for screening of alpha-thalassemia-1 and beta-thalassemia trait in pregnancy.

OBJECTIVES: To evaluate the sensitivity and specificity of osmotic fragility test (OFT) as a screening test in predicting the severe thalassemia trait (alpha-thalassemia-1 & beta-thalassemia). METHODS: A descriptive analysis and diagnostic test of non-anemic pregnant women attending antenatal care clinic, Maharaj Nakorn Chiang Mai, during April, and July 2002 was made. Blood samples were collected from 446 singleton pregnancies with no obvious medical complication such as iron deficiency anemia. OFT was performed in the same day, using 0.45% glycerin saline solution and the cut-off value of less than 60% was used for an abnormal test. Quantitative HbA2 test and PCR (SEA type) were done as a gold standard to confirm the diagnosis of beta-thalassemia trait and alpha-thalassemia-1 trait, respectively. RESULTS: The main outcome measures were sensitivity, specificity, positive and negative predictive value of OFT. If the OFT cut-off value of less than 60% was considered positive, the test had a sensitivity, specificity, positive and negative predictive value of 97.6%, 72.9%, 33.6%, and 99.5%, respectively. CONCLUSION: OFT has high sensitivity in detection of alpha-thalassemia-1 trait or beta-thalassemia trait and due to its simplicity with very low cost it may, therefore, be considered as a screening test in a wide population.

Sonographic features of trisomy 13 at midpregnancy.

OBJECTIVES: To evaluate the sonographic characteristics, at 16-22 weeks of gestation, of fetuses later diagnosed with trisomy 13. METHODS: This descriptive analysis of a case series was conducted from June 1989 to May 2001 at the Department of Obstetrics and Gynecology, Faculty of Medicine, Chiang Mai University, Thailand. Women with abnormal sonographic findings at midpregnancy (16-22 weeks of gestation) underwent amniocentesis or cordocentesis for karyotyping, and the inclusion criterion was proven trisomy 13. RESULTS: Indications for sonographic examination at midpregnancy were a genetic risk, large- or small-for-date fetus, and other suspected anomalies. Fifteen fetuses were later diagnosed with trisomy 13. In all of these cases there was at least one abnormal sonographic finding. In only one case did the fetus show no structural abnormality (at 17 weeks), but polyhydramnios and fetal growth restriction were observed. Common sonographic findings included holoprosencephaly with associated facial anomalies, and abnormal feet and/or hands, especially polydactyly. Non-structural abnormal findings such as polyhydramnios or fetal growth restriction were seen in less than one third of the fetuses. CONCLUSIONS: Nearly all the fetuses with trisomy 13 had sonographic characteristics of abnormalities at midpregnancy although common findings had often not yet appeared or the findings were low-sensitive. Detailed ultrasound at midpregnancy could effectively screen for further genetic testing pregnancies at risk for trisomy 13.

Prenatal diagnosis of hemoglobin Bart's hydrops fetalis by HPLC analysis of hemoglobin in fetal blood samples.

Since HbF and HbA are not found in fetuses with Hb Bart's hydrops fetalis the feasibility of prenatal diagnosis of homozygous alpha-thalassemia 1 by fetal hemoglobin typing was examined. Blood samples were obtained from fetuses at 18 to 22 weeks of gestation by cordocentesis in 32 pregnant women at risk of having a child with homozygous alpha-thalassemia 1 (alpha-thal-1). The samples were analyzed by a PCR-based method for the diagnosis of alpha-thal-1 (SEA type) and the proportion of hemoglobin fractions were determined by automated HPLC. DNA analysis showed that 8 of the 32 fetuses were homozygotes for alpha-thal-1, 17 were heterozygous for alpha-thal-1 (alpha-thal-1 trait), and a normal complement of four a-globin genes was found in 7 cases. The Hb typing in fetuses with homozygous alpha-thal-1 showed a peak of unbound Hb (Hb Bart's and Hb Portland) and no HbF, HbA and HbA The alpha-thal-1 trait chromatograms showed unbound Hb, pre HbF, HbF and HbA peaks. The chromatogram of normal fetuses showed HbF and HbA peaks without HbA2. In these cases the HbA proportion is between 3% and 10% with no apparent differences between the 18h and 22nd week of gestation. As the analysis of fetal Hb types by HPLC is facile and speedy and the results correspond with those obtained by DNA analysis, fetal Hb typing by automated HPLC is a convenient prenatal diagnostic method for homozygous alpha-thal-1. The method is recommended for prenatal diagnosis in populations with a high frequency of alpha-thal-1.

Prenatal sonographic markers of trisomy 21.

OBJECTIVE: To describe the sonographic characteristics of fetuses with trisomy 21. DESIGN: A prospective descriptive analysis. SETTING: Department of Obstetrics and Gynecology, Faculty of Medicine, Maharaj Nakorn Chiang Mai Hospital, Chiang Mai University. SUBJECTS: Pregnancies at risk of trisomy 21 between 14-27 weeks' gestation. RESULTS: Thirty-six fetuses with subsequently proven trisomy 21 were prenatally evaluated by ultrasound in the second trimester. The main indications for detailed ultrasound examinations were advanced maternal age and abnormal findings on routine ultrasound. All of them had chromosome analysis by amniocentesis or cordocentesis. Nineteen (52.78%) had one or more abnormal findings. The common sonographic findings included thickened nuchal fold (33.33%), short femur (19.44%), and mild pyelectasis (22.22%). The other uncommon abnormalities included major anomalies (cardiac malformations, ventriculomegaly, duodenal atresia, esophageal atresia), hyperechoic bowel, echogenic intracardiac foci, abnormalities of extremities. In this study, rare minor markers but more specific markers including sandal gap, clinodactyly and mid-phalanx hypoplasia of the fifth finger were demonstrated. CONCLUSION: About half of the fetuses with trisomy 21 had abnormal sonographic findings in the second trimester. The most common marker was thickened nuchal fold. Although prenatal ultrasound can not permit a definite diagnosis of trisomy 21, about half of them have sonographic markers, warranting cytogenetic testing.

Sonographic morphology scores (SMS) for differentiation between benign and malignant ovarian tumor.

The objectives of this cross-sectional descriptive analysis are to determine the sensitivity and specificity of sonographic morphology scores (SMS) in distinguishing between benign and malignant ovarian tumors and to determine the best cut-off score. The study was conducted at the Department of Obstetrics and Gynecology, Faculty of Medicine, Chiang Mai University. Two hundred and forty eight nonpregnant patients scheduled for elective surgery for ovarian tumors between July, 1996 and March, 1998 were recruited into the study and were sonographically examined in 24 hours of surgery by the same sonographer to evaluate inner wall structure, wall thickness, septum, echogenicity and score of the tumors. The final diagnosis was pathologically confirmed as the gold standard. It was found that the score of 9 from reciever operating characteristic curve was the best cut-off score, giving the sensitivity of 93.1 per cent and specificity of 75.6 per cent. In conclusion, the SMS system is probably useful in distinguishing ovarian malignancy from benign ovarian tumor.

Fetal loss rate associated with cordocentesis at midgestation.

OBJECTIVE: The aim of this study was to assess the risk of fetal loss attributable to cordocentesis at midgestation. STUDY DESIGN: A cohort study was conducted during the period 1989-1999. Women undergoing cordocentesis between 16 and 24 weeks' gestation with singleton pregnancies without obvious fetal anomaly were recruited into the study group. The control subjects were selected prospectively on a one-to-one basis with strict matching for maternal age, parity, gestational age at recruitment, and socioeconomic status. Both groups were prospectively followed up until delivery. RESULTS: A total of 1281 women with successful cordocentesis and their matched control subjects were recruited to the study. After exclusion of some pairs because of loss to follow-up or fetal malformations or severe disease necessitating termination of pregnancy, 1020 matched pairs were available to be compared with respect to fetal loss rate and pregnancy outcomes. The fetal loss rate was significantly higher among the study group (3.2% vs. 1.8%; P <.05, McNemar test). However, there were no significant differences in other obstetric complications between the study and control groups. CONCLUSION: The incremental fetal loss rate associated with cordocentesis at midgestation was about 1.4%.

Prenatal eradication of Hb Bart's hydrops fetalis.

OBJECTIVE: To evaluate the effectiveness of prenatal prevention of Hb Bart's hydrops fetalis. STUDY DESIGN: The study was a prospective descriptive analysis of pregnant women attending an antenatal clinic between June 1990 and June 1998. The study consisted of two periods, the first half with no prenatal diagnosis (PND) (1990-1994) and the second half with PND. During the study period, all cases of Hb Bart's hydrops fetalis were prospectively collected and postnatally confirmed. In the second period, prenatal strategy to control severe thalassemia was introduced. The strategy included (1) carrier identification by retrospective (history review for known risk) and prospective screening (simple erythrocyte osmotic fragility test) in women without known risks, (2) the couples at risk were offered genetic counseling and cordocentesis, (3) analysis of fetal blood for diagnosis, and (4) counseling for termination of pregnancy. RESULTS: During the first half of the study, the prevalence of Hb Bart's hydrops fetalis was 0.305 (89 in 29,399 deliveries). There were no fetuses with Hb Bart's hydrops fetalis among 16,360 screened pregnancies in the second half. However, of 6,856 pregnancies in the second half not screened due to a late first visit, 10 (0.15%) fetuses had Hb Bart's hydrops fetalis. Among the screened group, cordocentesis was performed in 361 pregnancies at risk, 170 and 191 from retrospective and prospective screening, respectively; and 75 (20.8%) were proven to have Hb Bart's disease, which was diagnosed before hydropic changes occurred. CONCLUSION: The strategy proved effective in preventing Hb Bart's hydrops fetalis, and extensive experience with it suggests that it be considered an effective way to control severe thalassemia.

Conservation of DNA bend sites with identical superhelical twists among the human, mouse, bovine, rabbit and chicken beta-globin genes.

We reported previously that DNA bend sites appear in the human beta-globin locus at an average distance of 680 bp. The relative locations of the sites were conserved among the five active beta-like globin genes and one pseudogene. Here, we mapped the sites in the beta-like globin genes from various species and examined their conservation. The locations of the bend sites in the bovine, rabbit and chicken beta-globin genes mapped here showed marked conservation in their locations relative to the cap site and showed similar locations to the previously mapped sites in the human beta- and mouse betamaj-globin genes. Further analysis of the first bend sites from the cap site (B-1 sites) indicated that they contained tracts of adenines and thymines longer than or equal to two bases. This sequence feature contributed mostly to the curvature profiles revealed by gel assays and/or by computer-based TRIF analysis. TRIF analysis indicated that most of the B-1 sites showed right-handed superhelical twists accompanied by left handed twists. This was confirmed by the effect of ethidium bromide on the superhelical twists in the assays.

Prenatal diagnosis of campomelic dysplasia.

A pregnant woman of 24 weeks' gestation underwent ultrasound examination for fetal anomaly screening. The ultrasound findings revealed a single fetus with biparietal diameter of 61 mm, which was consistent with menstrual dates. The thoracic cage was small compared to the abdomen with hypoplastic scapulae and normally ossified unfractured ribs. All bony structures demonstrated normal echogenicity. The upper long bones were normal length and shape. Both femurs and tibiae were obviously bowed anteriorly, and slightly shortened. Bilateral talipes equinovarus were clearly demonstrated. A prenatal diagnosis of campomelic dysplasia was made and was confirmed by postnatal radiography and autopsy. The sonographic diagnosis in this case was based on the findings of small thorax, hypoplastic scapulae and bowed tibiae and femurs.

Cordocentesis at 16-24 weeks of gestation: experience of 1,320 cases.

The objective of this study was to assess the safety and efficacy of diagnostic cordocentesis at midpregnancy. 1,320 singleton pregnancies with no obvious congenital anomalies, a gestational age of 16-24 weeks, and proper indications underwent cordocentesis using the freehand technique. The results of each procedure was prospectively collected and subsequently analysed for the results and pregnancy outcomes. The mean maternal age was 31.1 years and the mean gestational age at the time of cordocentesis was 19.8 weeks. The most common indication was the risk of severe thalassaemia syndrome (69.8%) and was followed by rapid karyotyping. Of 1,320 cordocenteses, 1,281 (97%) were done successfully at the first attempt. The mean duration of the procedure was 10.5 min and was significantly longer in the first 50 cases of practice for each operator. The maternal blood contamination rate was higher when the cord insertion was targeted. The procedure-related complications included transient bleeding at puncture site (20.2%), transient fetal bradycardia (4. 3%), chorioamnionitis (two cases), and cord haematoma (one case). Of 1,281 successful cases, 184 fetuses had severe disease. The total fetal loss rate was 3.2% and the procedure-related loss was 1%. The other obstetric complications were comparable with those in the general population. We conclude that cordocentesis at midpregnancy is a useful, relatively safe, and effective procedure for prenatal diagnosis.

Prenatal control of severe thalassaemia: Chiang Mai strategy.

Prenatal diagnosis of severe thalassaemia is conventionally diagnosed by fetal DNA analysis but it can not be widely used due to its drawbacks of high cost and technical effort. This prospective study describes a new prenatal strategy in preventing severe thalassaemia by a more simple and inexpensive way. The strategy included: (1) genetic counselling; (2) identification of pregnancies at risk by retrospective screening (history of known risk) and prospective screening for asymptomatic women; (3) cordocentesis at 16-22 weeks' gestation; (4) fetal blood analysis with high performance liquid chromatography (HPLC); (5) termination of affected pregnancy. The prospective screening consisted of 2 min osmotic fragility (OF) and HbE screening test in women with no risk, and testing the husbands of the women with a positive result. If both of the couple had a positive result, the diagnostic test (HbA(2) level and PCR alpha-thal 1) for the carrier was needed. A pregnancy in which both of the couple were carriers was considered at risk. This strategy identified 181 and 108 couples at risk by prospective (from 7954 pregnancies) and retrospective screening, respectively. Two hundred and forty-two underwent cordocentesis, 108 from retrospective screening and 134 from prospective screening, and 62 were proven to have severe thalassaemia (29 and 33 in retrospective and prospective screening, respectively). The strategy identified nearly all, if not all, fetuses with severe thalassaemia without false positives among the screened couples. In conclusion, the strategy proves to be highly effective in the control of severe thalassaemia.

Prenatal diagnosis: 10-year experience.

To evaluate the indications and results of prenatal diagnosis of the high risk pregnant women attending the antenatal care clinic at Maharaj Nakorn Chiang Mai Hospital, Chiang Mai University during 1988-1998, we analysed 2,315 amniocenteses, 1,000 cordocenteses, and 11,895 obstetric ultrasound examinations. Among the amniocentesis group, 2,017 cases (87%) were done with the indication of advanced maternal age. The prevalence of major abnormal fetal chromosomes among high risk pregnancies was 1:58. Of 1,000 cases with cordocentesis, the most common indication was fetal risk of severe thalassemia (658 cases; 65.8%) and followed by fetal risk of chromosome abnormalities (272 cases; 27.2%). In the group of cordocentesis for diagnosis of thalassemia, 99 and 49 pregnancies were affected with Hb Bart's disease and homozygous beta-thalassemia, respectively. Thirty three cases with indication of chromosome analysis had fetuses with abnormal chromosomes. The major indications of ultrasonography included suspicion of intrauterine growth restriction (IUGR), determination of gestational age and screening anomalies, respectively. In conclusion, our extensive experience has enabled us to prenatally detect most fetuses with severe thalassemia, and fetuses with abnormal chromosomes as well as anomalies in a significant number, contributing a great deal to our population. Therefore, we recommend that systematic prenatal diagnosis, either amniocentesis, cordocentesis or ultrasound should be provided to every high risk pregnant woman for a healthy newborn.

Fetal sonographic cardiothoracic ratio at midpregnancy as a predictor of Hb Bart disease.

The objective of this study is to evaluate the efficacy of sonographic cardiothoracic ratio at midpregnancy in predicting fetal hemoglobin Bart disease. Among 17,254 pregnant women screened for severe thalassemia between June 1994 and November 1998, 345 pregnant women at risk for having a fetus with hemoglobin Bart disease underwent ultrasonographic examination and cordocentesis at 18 to 21 weeks' gestation. Before cordocentesis, the cardiothoracic ratio was determined and recorded. The definite fetal diagnosis was based on fetal blood analysis with high performance liquid chromatography. Among 345 pregnancies in which sonographic examination and cordocentesis were performed, 70 fetuses were affected by hemoglobin Bart disease. The mean cardiothoracic ratio was significantly higher than that of unaffected fetuses (0.55 versus 0.45, Student's t-test, P<0.001). The sensitivity and specificity of the cardiothoracic ratio in prediction were calculated for various cutoff values. On the basis of the receiver operating characteristic curve, the best cutoff value was 0.50 (greater than 0.50 considered abnormal), giving the sensitivity of 98.6% and a specificity of 98.9%. In conclusion, the cardiothoracic ratio has very high accuracy in predicting hemoglobin Bart disease in pregnancies at risk. This finding suggests that invasive diagnostic method should be reserved for only the fetuses who have a cardiothoracic ratio of 0.5 or more; however, further studies are needed to confirm this observation.