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.

An International Menopause Society study of vasomotor symptoms in Bangkok and Chiang Mai, Thailand.

OBJECTIVES: To examine relationships between location, demographics, lifestyle, beliefs, and experience of hot flushes and night sweats (HFNS) amongst women living in two cities in Thailand. METHODS: Cross-sectional study of peri- and postmenopausal women, aged 45-55 years, from Bangkok and Chiang Mai. Participants completed questionnaires (demographics, health, HFNS (prevalence, frequency and problem-rating) and beliefs about menopause). A sub-sample of women from each location was interviewed. RESULTS: A total of 632 women (320 Bangkok and 312 Chiang Mai) aged 50.88 (standard deviation 3.06) years, took part. The prevalence of HFNS was 65%, average HFNS frequency 8.7 (10.8) per week and problem rating 4.3/10. Women from Chiang Mai had significantly more problematic HFNS, but prevalence and frequency were similar in both sites. Poor general health predicted HFNS prevalence and frequency, while Chiang Mai location, HFNS frequency, age, diet and beliefs about menopause were associated with problematic HFNS. Location remained significant after controlling for education, occupation and age; location was partially explained by beliefs. Qualitative interview responses illustrated the differences in beliefs about menopause between locations. CONCLUSION: HFNS reports are prevalent with moderate frequency and problem-ratings in these urban centers in Thailand. The results will be included in the broader International Menopause Society study of Climate, Altitude and Temperature (IMS-CAT) of the impact of climate on HFNS.

Fetal splenic artery peak velocity (SPA-PSV) at mid-pregnancy as a predictor of Hb Bart's disease.

PURPOSE: To determine the accuracy of splenic artery peak systolic velocity (SPA-PSV) in predicting fetal hemoglobin (Hb) Bart's disease at mid-pregnancy among fetuses at risk. MATERIALS AND METHODS: Pregnant women at risk of having a fetus with Hb Bart's disease were recruited into the study at 18 - 22 weeks of gestation and underwent SPA-PSV measurement before cordocentesis. The final diagnosis used as a gold standard was based on fetal hemoglobin typing using high performance liquid chromatography (HPLC). RESULTS: A total of 136 fetuses from 132 singleton pregnancies and 2 twin pregnancies were recruited into the study. The mean maternal age was 28.7 ± 5.4 years, the mean gestational age was 19.1 ± 1.02 weeks, and the incidence of Hb Bart's disease was 23.5 % (32 fetuses). Using SPA-PSV above 1.51 Multiple of Median (MoM) as a cut-off point, the sensitivity, specificity, positive predictive value and negative predictive value of SPA-PSV to identify affected fetuses was 84.4 % (32 from 36 cases), 98.1 %, 93.1 % and 95.3 % respectively. Nearly all normal fetuses had a normal SPA-PSV. CONCLUSION: SPA-PSV assessment at mid-pregnancy may be used as an adjunct method to identify fetuses with Hb Bart's disease with high, but not perfect, accuracy and may reduce the risk from unnecessary cordocentesis in some fetuses.

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.

Identification of fetuses with hemoglobin Bart's disease using middle cerebral artery peak systolic velocity.

OBJECTIVES: To determine the sensitivity and specificity of middle cerebral artery peak systolic velocity (MCA-PSV) in mid-pregnancy for the identification of homozygous alpha-thalassemia-1 (hemoglobin (Hb) Bart's disease) in fetuses at risk of the disease. METHODS: A total of 88 pregnancies (91 fetuses) at risk of Hb Bart's disease and undergoing MCA-PSV measurement before cordocentesis at 18-22 weeks of gestation were recruited into the study. Definitive diagnosis was made using the gold standard technique of Hb typing by high-performance liquid chromatography. RESULTS: The mean +/- SD age of the 88 pregnant women recruited into the study was 28.3 +/- 5.7 years, the gestational age was 18.8 +/- 1.1 weeks and the incidence of Hb Bart's disease was 22% (20 fetuses). Using MCA-PSV above 1.5 multiples of the median as a cut-off point, the sensitivity of MCA-PSV for detecting affected fetuses was 85% (17/20 cases), with a specificity of 100%, and positive and negative predictive values of 100% and 95.9% respectively. Three of 20 fetuses with Hb Bart's disease had normal MCA-PSV. CONCLUSIONS: MCA-PSV assessment in mid-pregnancy is a useful method for identifying Hb Bart's disease with high sensitivity and specificity among fetuses at risk, and may allow avoidance of unnecessary cordocentesis in some cases.

Prenatal sonographic delineation of the complex cardiac anatomy of thoraco-omphalopagus twins.

We describe a case of thoraco-omphalopagus twins diagnosed at 18 weeks' gestation. Each twin had a separate set of anatomical structures except for a shared heart, upper liver and anterior chest wall. The heart was located at the center of the juncture, and consisted of three atria and two ventricles, each twin having a single ventricle and right atrium but a fused left atrium. A set of great arteries originated from each single ventricle and there was juxtaposition of the aortic and pulmonary valves. One twin had transposition of the great arteries, whereas in the other these were normal in configuration. There was only one umbilical cord which contained four vessels (two arteries and two veins). This case report demonstrates the possibility of using fetal echocardiography to delineate the cardiovascular complex of the conjoined heart.

Preimplantation genetic diagnostic protocols for alpha- and beta-thalassaemias using multiplex fluorescent PCR.

Haemoglobinopathies including alpha- and beta-thalassaemia are the world's most common class of single gene disorder. Prenatal diagnosis (PND) for beta-thalassaemia has been proven to be an effective strategy for controlling the incidence of new cases and is widely used in several countries where the disease is common. Successful preimplantation genetic diagnosis (PGD) protocols for beta-thalassaemia have been introduced using restriction fragment length polymorphism (RFLP), single-stranded conformation polymorphism (SSCP) and denaturing gradient gel electrophoresis (DGGE). However, contamination and allele dropout (ADO) remain an important concern for all of these strategies. In the present study two PGD protocols for detecting beta-thalassaemia mutations (codon 41-42 and IVSI-110) and one for alpha-thalassaemia (SEA mutation) have been designed and tested. These methods contain failsafe mechanisms to reduce the risk of misdiagnosis due to ADO or contamination and utilise multiplex fluorescent PCR (F-PCR). Interestingly, amplification efficiency and ADO were significantly affected by the choice of DNA polymerase and the freshness of the single cells used. The close similarity between the DNA sequences of beta-globin and delta-globin was also found to be an important issue that necessitated careful design of primers for the beta-globin gene.

A successful strategy for preimplantation genetic diagnosis of myotonic dystrophy using multiplex fluorescent PCR.

The most common form of inherited muscular dystrophy in adults is myotonic dystrophy (DM), an autosomal-dominant disease caused by the expansion of an unstable CTG repeat sequence in the 3' untranslated region of the myotonin protein kinase (DMPK) gene. Expanded (mutant) CTG repeat sequences are refractory to conventional PCR, but alleles with a number of repeats within the normal range can be readily amplified and detected. Preimplantation genetic diagnosis (PGD) of DM has been successfully applied. However, a misdiagnosis using the reported protocol was recently documented. Two new PGD protocols for DM have been developed which utilise multiplex fluorescent PCR. Ideally a linked polymorphic marker, APOC2, is amplified in addition to the normal DMPK alleles, thus providing a back-up diagnostic result. However, the two couples reported in the present study were not fully informative at the APOC2 locus and so an unlinked short tandem repeat (STR) marker, D21S1414, was substituted. The highly polymorphic nature of the D21S1414, DMPK and APOC2 loci means that a very simple genetic fingerprint can be generated by analyses of these loci. This allows most DNA contaminants to be detected. Contamination is a significant problem for PGD and is the primary reason for the inclusion of D21S1414 and APOC2 in this protocol. This paper reports the first clinical experience and pregnancies following PGD for DM using a multiplex fluorescent PCR protocol.

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.

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.

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.

Prenatal diagnosis of Meckel syndrome: a case report.

OBJECTIVE: To demonstrate the major sonographic findings associated with Meckel syndrome and to emphasize the importance of prenatal sonography in helping to establish the correct diagnosis. SUBJECTS: Two fetuses with prenatal diagnosis of Meckel syndrome were sonographically evaluated. RESULTS: Both fetuses were demonstrated to have evidence of renal cystic dysplasia, occipital cephalocele and postaxial polydactyly. One case was diagnosed at 16 weeks of gestation whereas the other was detected at 36 weeks. Of interest, the first case had only unilateral renal cystic dysplasia and contralateral renal agenesis and mild degree of oligohydramnios. The other related anomalies which were not detected prenatally included cerebellar hypoplasia in case 1 and micrognathia in case 2. CONCLUSION: The main sonographic findings included renal cystic dysplasia, occipital cephalocele and postaxial polydactyly.

Prenatal sonographic diagnosis of VATER association.

PURPOSE: We examined the potential role of sonography in the prenatal diagnosis of the VATER association, a spectrum of fetal anomalies that includes vertebral defects, imperforate anus, tracheoesophageal fistula, and radial and renal dysplasia. METHODS: The sonographic findings in 4 fetuses with prenatal diagnoses of VATER association were prospectively recorded, along with information on outcome and postnatal radiographic findings. RESULTS: VATER association was diagnosed in 4 fetuses at 20, 17, 21, and 29 weeks' menstrual age. All showed bilateral radial atresia and tracheoesophageal fistula, visible sonographically as a collapsed or absent stomach with polyhydramnios. Two fetuses had vertebral defects. Postnatal radiographic and macroscopic findings confirmed the prenatal diagnosis in all cases. Other associated anomalies detected prenatally included single umbilical arteries (2 cases), ventricular septal defect (1 case), and renal abnormalities (2 cases). Anal atresia, present in 3 of the 4 fetuses, was not detected prenatally. CONCLUSIONS: This small series suggests that the VATER association can be readily diagnosed in utero. Important clues include radial atresia, absent or collapsed stomach, and polyhydramnios. Prenatal diagnosis can contribute to clinical decisions regarding pregnancy and neonatal management.

Prenatal sonographic features of sacrococcygeal teratoma.

OBJECTIVE: To describe the potential role of ultrasound in prenatal diagnosis of fetal sacrococcygeal teratoma (SCT). SUBJECTS: A total of four fetuses with prenatal diagnosis of SCT were sonographically evaluated and followed-up. RESULTS: Fetal SCT was diagnosed at 13, 17, 26 and 27 weeks of gestation. Three of them had predominantly solid tumors with scattered cystic areas, whereas the other one had an entirely cystic tumor. One had a rapid growth tumor and finally developed early hydrops. Three had polyhydramnios and delivered prematurely. The diagnosis was posnatally confirmed in all cases. In the case with the large tumor, a cesarean section was done to avoid traumatic delivery. Two cases survived and the tumors were successfully resected, whereas the others died due to heart failure secondary to hydrops in one case and prematurity in the other one. CONCLUSION: This small series suggests that SCT be readily diagnosed in utero, possibly as early as first trimester. The important clue was an abnormal mass in the sacrococcygeal area. The prenatal diagnosis can contribute to changes in clinical decision.

The rapid biophysical profile for assessment of fetal well-being.

OBJECTIVE: To determine the efficacy of the rapid biophysical profile (BPP), the combination of amniotic fluid index (AFI) and sound-provoked fetal movement (SPFM) detected by ultrasound, in predicting intrapartum fetal distress in high-risk pregnancies, compared with the nonstress test (NST). STUDY DESIGN: The prospective study of diagnostic tests was conducted on a total of 1,069 high-risk singleton pregnancies, undergoing antepartum assessment of both the standard NST and the new rapid BPP, including AFI and SPFM detected by ultrasound. Intrapartum continuous fetal heart rate (FHR) monitoring was performed in all of them. The diagnostic indices of the NST and the rapid BPP was calculated in term of predicting intrapartum fetal distress. RESULTS: The rapid BPP was a reliable predictor of intrapartum fetal distress with higher sensitivity and specificity. Its accuracy was better than that of the NST. The incidence of fetal compromise among positive, equivocal, and negative tests of the rapid BPP are 78.57, 15.82 and 0.9%, respectively, whereas the incidence among nonreactive and reactive NST are 31.63 and 2.52%, respectively. CONCLUSIONS: The rapid BPP is an effective predictor of intrapartum fetal distress in high-risk pregnancies. It may suffice as an inexpensive and less time-consuming method of evaluating antepartum fetal well-being.

Comparison of vacuum extraction delivery between the conventional metal cup and the new soft rubber cup.

To compare the effectiveness and complications of vacuum extraction delivery between the conventional metal cup and the silicone rubber cup. A prospective randomized clinical trial of 90 pregnant women requiring assisted vaginal delivery who met the predetermined criteria for vacuum extraction were allocated to delivery by the Malstrom metal cup (46 cases) or the silicone rubber cup (44 cases). The two groups were similar in respect of age, parity gestational age and indications for assisted vaginal delivery. The mean and median numbers of tractions and time from cup application to delivery were not significantly different between the groups. The overall success rate was higher in the metal cup (89.1%) than in the rubber cup (79.5%) but not significantly different. The silicone cup was more likely to fail in cases of occiput posterior position, excessive caput, and severe degree of molding. There were no significant differences between groups in terms of Apgar scores, birth canal injury, and maternal blood loss. Scalp injuries occurred more frequently with the metal than with the rubber cup (P = 0.006). Vacuum extraction delivery with the silicone rubber cup is associated with reduced scalp injuries but has a greater tendency to fail when the fetus presents in occiput posterior position, has excessive caput or severe degree of molding.

Amniocentesis-related fetal loss: a cohort study.

OBJECTIVE: To assess the risk of fetal loss attributable to second-trimester amniocentesis. METHODS: A cohort study was undertaken among singleton pregnant women undergoing genetic amniocentesis and controls matched prospectively on a one-to-one basis, matched strictly for maternal age, parity, and socioeconomic status. Both groups were recruited at 15-24 weeks' gestation and observed until delivery. The fetal loss rates of the groups were compared. RESULTS: A total of 2256 pairs were recruited to the study. After excluding those pairs lost to follow-up, those with fetal malformation, and those later proven to have major chromosomal abnormalities, 2045 matched pairs were compared by pregnancy outcomes. There were no significant differences in fetal loss rates, premature deliveries, or placental abruptions between the study and control groups (P > .05). However, this study did not have enough statistical power to identify differences of less than 1%. CONCLUSION: Second-trimester amniocentesis is probably not associated with a greater fetal loss rate than that of matched controls.