Spontaneous abortion rate and advanced maternal age: consequences for prenatal diagnosis

Association between serum vitamin D level during pregnancy and recurrent spontaneous abortion: a systematic review and meta-analysis

PROBLEM

Previous studies had shown that there might be an association between serum vitamin D concentrations and the occurrence of recurrent spontaneous abortion (RSA). However, the conclusions remained controversial. The objective of this study was to systematically review the evidence for an epidemiological association between vitamin D and RSA.

METHOD OF STUDY

The literature search was performed in the following databases: PubMed, Web of Science, Embase and Chinese databases. The I² statistic was used to evaluate heterogeneity. Effect sizes were calculated using fixed or random effects models, including standardized mean difference (SMD), odds ratios (OR) and their 95% confidence intervals (95%CI). Then we performed subgroup analysis, sensitivity analysis and publication bias analysis.

RESULTS

Fourteen studies from five countries were included. Based on the results, patients with RSA had lower vitamin D levels than controls (SMD = -1.48, 95%CI: -2.01, -0.94, P<0.001), and pregnant women with vitamin D deficiency (VDD) had a higher risk of developing RSA (OR = 4.02, 95%CI: 2.23, 7.25, P<0.001). There was remarkable heterogeneity between studies (I² _SMD = 97.3%, P<0.001; I² _OR = 82.2%, P<0.001). The results of the subgroup analysis suggested that heterogeneity may be caused by the assay method, age and region. Sensitivity analysis showed the analysis results were robust.

CONCLUSION

Patients with RSA had lower serum vitamin D levels than normal pregnant women, and pregnant women with VDD might be at higher risk for RSA. This article is protected by copyright. All rights reserved.

The risk of intrapartum cesarean delivery in advanced maternal age

OBJECTIVE

We aimed to investigate the association of advanced maternal age with intrapartum cesarean delivery and to assess its risk factors and perinatal outcomes.

STUDY DESIGN

A retrospective cohort study of all women with singleton pregnancies who attempted a trial of labor (≥24 + 0 weeks of gestation) in a single center (2011-2017). The study population was stratified by parity (nulliparous or multiparous) and further sub-categorized into three cohorts: (1) women <35 years at birth (reference group), (2) women aged 35-40 years, and (3) women >40 years. Labor and delivery characteristics and neonatal outcomes were compared.

RESULTS

Overall, 55,089 women were included: 39, 192 (71.1%) were under 35 years old, 15,90712,892 (28.923.4%) were 35-40 y and 3,015 (5.5%) were >40 y. For nulliparas, the rate of intrapartum Cesarean deliveries increased with maternal age and approached 25.3% in those >40 y as compared to 8.9% for those <35 y. The positive association between Cesarean section rates and maternal age extends beyond nulliparas and is also seen in multiparas, although to a smaller degree. After adjusting for confounders, maternal age was significantly and independently associated with intrapartum cesarean delivery in a dose-dependent manner in nulliparous women, [adjusted Odd Ratio (aOR) 1.56 (95% Confidence Interval (CI) 1.39-1.76) and 2.53 (2.07-3.09)] among women aged 35-40 y and >40 y, respectively. Maternal age was not significantly associated with adverse neonatal outcome.

CONCLUSION

Advanced maternal age is an independent risk factor for intrapartum Cesarean delivery. Yet, the majority of older gravidae who attempt a trial of labor, even if nulliparous, deliver vaginally without an increase in adverse neonatal outcome.

A survey of influencing factors of missed abortion during the two-child peak period

This study aimed to investigate the influencing factors of missed abortion during the two-child peak period in China. 220 pregnant women were divided into observation (presence of missed abortion, 100 cases) and control group (no presence of missed abortion, 120 cases). The single factor analysis of clinical data showed that, advanced age, premarital examination, genitalia abnormality, luteal insufficiency, spouse semen abnormality, mycoplasma infection, chlamydia infection, sexually transmitted diseases, perm or dyeing hair in pregnancy, radiation overload, primipara, spontaneous abortion history, smoking, drinking and overly intimate with pets had significant difference between observation and control group (p < .05). The logistic regression analysis results showed that, the advanced age, genital abnormality, luteal insufficiency, spouse sperm abnormality, pregnancy infection, primipara, spontaneous abortion history and bad life habits were the main risk factors of missed abortion. In the intervention for prevention of missed abortion, these factors should be paid more attention.Impact statementWhat is already known on this subject? There are many complex factors affecting the embryonic development and causing the missed abortion.What do the results of this study add? The advanced age, genital abnormality, luteal insufficiency, spouse sperm abnormality, pregnancy infection, primipara, spontaneous abortion history and bad life habits are the main risk factors of missed abortion.What are the implications of these findings for clinical practice and/or further research? These findings can provide a theoretical basis for the further prevention of missed abortion.

Miscarriage is associated with cervical ribs in thoracic outlet syndrome patients

The constancy of the number of cervical vertebrae in mammals is probably the result of selection against associated variations. A survey among patients with and without cervical ribs showed an association between miscarriage and the presence of cervical ribs. This supports the hypothesized selection against variations in cervical vertebral number.

Cost-effectiveness of prenatal screening and diagnostic strategies for Down syndrome: A microsimulation modeling analysis

Objectives

Down syndrome (DS) is the most frequently occurring fetal chromosomal abnormality and different prenatal screening strategies are used for determining risk of DS worldwide. New non-invasive prenatal testing (NIPT), which uses cell-free fetal DNA in maternal blood can provide benefits due to its higher sensitivity and specificity in comparison to conventional screening tests. This study aimed to assess the cost-effectiveness of using population-level NIPT in fetal aneuploidy screening for DS.

Methods

We developed a microsimulation decision-analytic model to perform a probabilistic cost-effectiveness analysis (CEA) of prenatal screening and diagnostic strategies for DS. The model followed individual simulated pregnant women through the pregnancy pathway. The comparators were serum-only screening, contingent NIPT (i.e., NIPT as a second-tier screening test) and universal NIPT (i.e., NIPT as a first-tier screening test). To address uncertainty around the model parameters, the expected values of costs and quality-adjusted life-years (QALYs) in the base case and all scenario analyses were obtained through probabilistic analysis from a Monte Carlo simulation.

Results

Base case and scenario analyses were conducted by repeating the micro-simulation 1,000 times for a sample of 45,605 pregnant women per the population of British Columbia, Canada (N = 4.8 million). Preliminary results of the sequential CEAs showed that contingent NIPT was a dominant strategy compared to serum-only screening. Compared with contingent NIPT, universal NIPT at the current test price was not cost-effective with an incremental cost-effectiveness ratio over $100,000/QALY. Contingent NIPT also had the lowest cost per DS case detected among these three strategies.

Conclusion

Including NIPT in existing prenatal screening for DS is shown to be beneficial over conventional testing. However, at current prices, implementation of NIPT as a second-tier screening test is more cost-effective than deploying it as a universal test.

Total pregnancy loss after chorionic villus sampling and amniocentesis: a cohort study

OBJECTIVES

To identify maternal-, operator- and procedure-related variables that affect procedure-related pregnancy loss after transcervical (TC) and transabdominal (TA) chorionic villus sampling (CVS) and amniocentesis and to estimate the rates of spontaneous and procedure-related loss in comparable subgroups of women.

METHODS

This was a retrospective cohort study conducted at the University Medical Center Groningen and the Academic Medical Center, The Netherlands. Databases of both centers were searched to identify singleton pregnancies that had undergone a combined test and/or anomaly scan at around 20 weeks' gestation, or an invasive procedure (CVS and/or amniocentesis) between January 2001 and December 2011. Maternal characteristics, obstetric history, technical aspects of the invasive procedure, ultrasound examinations and fetal and neonatal outcomes were available for 29 201 cases. Women were categorized, according to the type of examination they had received, into the following five groups: first-trimester combined test (and 20-week anomaly scan); 20-week anomaly scan only; CVS; amniocentesis; amniocentesis after unsuccessful CVS. Rates of fetal loss were compared between groups.

RESULTS

Variables significantly associated with a higher rate of fetal loss were, for CVS, repeat attempts during the procedure, use of TC cannula instead of biopsy forceps, gestational age at procedure ≥ 13 weeks and a pregnancy after assisted reproductive techniques, and, for amniocentesis, if indication was fetal anomaly or family history of anomalies and repeat attempts during the procedure. In women aged ≥ 36 years who did not undergo an invasive procedure, spontaneous fetal loss rate (FLR) after first-trimester combined test was 1.40%, whereas after CVS, FLR was 2.76% and 2.43% for a TC and TA approach, respectively. The additional risk of fetal loss with TC-CVS was therefore 1.36% (1 : 74), which varied according to the instrument used (0.27% for forceps and 3.12% for cannula), and with TA-CVS was 1.03% (1 : 97). In women aged ≥ 36 years who underwent a 20-week anomaly scan only, spontaneous FLR was 0.63%. In women who underwent amniocentesis solely because of advanced maternal age, FLR was 1.11%. The additional risk of fetal loss with amniocentesis was 0.48% (1 : 208).

CONCLUSION

The total rate of procedure-related fetal loss after TA- and TC-CVS and amniocentesis appears lower than the risks on which women are currently counseled. There was a trend for a decrease in risk when the level of experience of the operator increased. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Damaging effects of multi-walled carbon nanotubes on pregnant mice with different pregnancy times

The mechanism by which nanoparticles cross the placental barrier was studied by using isotopic tracers. The abortion rates and other related data were counted and analysed in pregnant mice with different pregnancy times. Results showed that oxidised multi-walled carbon nanotubes (oMWCNTs) crossed the placental barrier and entered the foetus body. The abortion rates in the pregnant mice depended on pregnancy times. The abortion rates in the first-time, second-time and fourth-time pregnant mice were 70%, 40% and 50%, respectively. The maternal body weight gain was inhibited until gestational ages of 13, 10 and 11 d. oMWCNTs decreased the serum progesterone level and increased the serum oestradiol level in a dose- and time-dependent manner. However, this effect decreased with gestational age. The histology and vascular endothelial growth factor/reactive oxygen species content in the placenta showed that oMWCNTs narrowed the blood vessel and decreased the number of blood vessels in the placenta.

Evolutionary medicine: its scope, interest and potential

This review is aimed at readers seeking an introductory overview, teaching courses and interested in visionary ideas. It first describes the range of topics covered by evolutionary medicine, which include human genetic variation, mismatches to modernity, reproductive medicine, degenerative disease, host-pathogen interactions and insights from comparisons with other species. It then discusses priorities for translational research, basic research and health management. Its conclusions are that evolutionary thinking should not displace other approaches to medical science, such as molecular medicine and cell and developmental biology, but that evolutionary insights can combine with and complement established approaches to reduce suffering and save lives. Because we are on the cusp of so much new research and innovative insights, it is hard to estimate how much impact evolutionary thinking will have on medicine, but it is already clear that its potential is enormous.

The Effect of Chorionic Villus Sampling on Fetal Heart Rate

OBJECTIVE

Fetal heart rate (FHR) variation during chorionic villus sampling (CVS) is a controversial topic. Limited studies have been published on this subject. Our study intended to evaluate the effects of CVS on the FHR.

METHOD

One hundred and sixty-five patients undergoing first-trimester elective CVS for prenatal diagnosis of beta-thalassemia were entered into a prospective study. M-mode FHR was obtained before and immediately after CVS in the patients. Potentially confounding variables also recorded included: gestational age, number of needle passes and placental location.

RESULTS

FHR values before and after CVS were compared using the paired t test and showed no statistically significant differences by 95% confidence. No differences were found in data analyzing gestational age, number of needle passes or placental location.

CONCLUSION

We were unable to detect any significant change in FHR after performing CVS. It seems that FHR is generally not altered by CVS.

Cytogenetic Abnormalities in Products of Conception: A Relationship Revisited

OBJECTIVES

Cytogenetic evaluation of product of conception (POC) is essential to determine the cause of pregnancy loss and aid the prenatal diagnosis of subsequent pregnancies. The purpose of this study is twofold. (1) To profile cytogenetic abnormalities, their relationship with maternal and gestational age and analyze sex ratios in our case series of 2052 consecutive samples of POC referred to the Baystate Medical Center, Laboratory Genetics between January 1992 and January 1999. (2) To present a comprehensive review of such data published in the last 15 years, in order to study temporal differences in the above parameters and make this information readily available for cytogeneticists and genetic counselors.

MATERIALS AND METHODS

Data was entered and analyzed in Epi Info version 6.0 using the Z-test, chi-square test of significance and linear correlation coefficient.

RESULTS AND CONCLUSIONS

The profile of cytogenetic abnormalities detected in POC has not changes significantly over time. The mean maternal age in our study (overall and for trisomies) was higher than that reported previously, which is consistent with the noted trend of increasing age at pregnancy in recent years. Our study provides evidence that abnormal karyotypes are aborted earlier and that tetraploidies have the least survival amongst all abnormalities. The higher mean gestational age for trisomic abortions in our study, as compared with previously reported figures, can be attributed to the increasing practice of active maternal screening with subsequent therapeutic abortions. Analysis of sex ratios may reaffirm a female specific developmental disadvantage in early stages of pregnancy.

Long-term follow-up of infants after transcervical chorionic villus sampling and after amniocentesis to compare congenital abnormalities and health status

OBJECTIVES

Next to procedure-related fetal loss, other adverse effects of invasive prenatal diagnosis have been reported: limb defects after chorionic villus sampling (CVS) or early amniocentesis and respiratory distress after amniocentesis (AC). Because minor abnormalities may be overlooked in routine follow-up, we obtained long-term follow-up data after CVS and AC.

METHODS

1509 women with a singleton pregnancy who had transcervical CVS were matched by age and season of conception with 1509 women with singleton pregnancies who had AC. All procedures were performed during 1985-1991 for advanced maternal age >35 years. Data regarding congenital malformations (classified according Eurocat), neonatal and paediatric morbidity and complications of motor development, speech, hearing and visual function were obtained by questionnaire in 1993-1995.

RESULTS

Short-term outcome was known in all but ten infants. Questionnaires with a structured design were mailed to all women with a surviving infant (n=2810); 86.7% responded. No difference was detected between infants after CVS compared with infants after AC regarding congenital malformations (7.2% versus 6.3%), neonatal morbidity (15.1% versus 15.9%), paediatric morbidity with clinical treatment (7.7% versus 6.3%) or outpatient treatment only (43.9% versus 40.3%) and evident function disturbance (2.0% versus 2.0%) or doubtful function disturbance (6.3% versus 6.8%). The number of infants with physical growth <10th centile for Dutch infants was equal (10.1%). Sub-analysis for limb abnormalities or respiratory complications did not demonstrate differences between infants after CVS and AC. Only 10% of all congenital malformations were already known through routine post-partum follow-up.

CONCLUSIONS

An extensive long-term survey could not demonstrate differences of health status between infants after prenatal diagnosis by transcervical CVS and AC.

Intermediate but not low doses of aspirin can suppress angiotensin-converting enzyme inhibitor-induced cough

This self-matched control study aimed to compare the efficiency of two different regimens of active treatment: aspirin in low (100 mg daily) versus intermediate (500 mg daily) doses in abolishing angiotensin-converting enzyme inhibitor (ACEI)-induced cough. A dry bothersome cough is the most common adverse class effect of all angiotensin-converting enzyme inhibitors. Prostaglandins (PG) have been pinpointed as playing a leading role in the genesis of ACEI-associated cough. The role of different doses of the most commonly used PG inhibitor-aspirin-in ACEI cough modification was not yet elucidated. Of 350 consecutive ACEI-treated patients, we identified 34 (9.7%) nonsmoking ACEI-related coughers. Patients with lung disease, nonsteroidal anti-inflammatory drug (NSAID) treatment, and those who did not agree to participate in the study were excluded. In the remaining 14 ACEI coughers (eight men, six women; mean age, 63 +/- 11 years), the treatment was discontinued; the dry cough completely disappeared, but returned in all patients within 1 week after ACEI reintroduction. At the end of the rechallenge period, patients started a low dose of aspirin for 1 week, switching thereafter to the intermediate dose of aspirin for an additional week. On each visit the cough severity (CS, 0-4) and frequency (CF, 0-10) scores were registered. Low doses of aspirin were ineffective in suppressing ACEI-induced cough, whereas intermediate doses completely abolished cough in five patients and reduced coughing in all but one patient; CS and CF decreased, respectively, from 2.5 +/- 1.0 to 0.9 +/- 1.1, P < .002 and from 6.6 +/- 2.4 to 2.4 +/- 1.1, P < .0002. Overall, intermediate doses of aspirin beneficially modified cough scores in 13 (93%) patients, enabling nine (64%) to continue ACEI treatment. Aspirin did not influence blood pressure control either in hypertensives or in postinfarction patients. We conclude that intermediate but not low doses of aspirin probably can suppress ACEI-induced cough. These findings propose a new alternative therapeutic approach for patients with ACEI-related cough, especially those in whom ACEI treatment seems to be essential.

Transabdominal chorionic villus sampling in the second and third trimesters of high-risk pregnancies

Late chorionic villus sampling (placental biopsy) under ultrasound guidance was carried out in 800 (80 per cent) cases in the second trimester and 200 (20 per cent) cases in the third trimester of pregnancy. Out of 1000 placental biopsies, 250 (25 per cent) were performed because of suspicious ultrasonographic findings. Colour Doppler was used to investigate the uteroplacental and fetal vessels in 300 (30 per cent) pregnancies before and after late chorionic villus sampling (CVS). In the same group, mean serum alpha-fetoprotein (AFP) levels increased after sampling in 20 (6.7 per cent) patients. In 20 patients (2 per cent), complications between sampling and delivery were found. A placental haematoma measuring 0.5-1 ml was seen at the sampling site in 4 (0.4 per cent) patients in the second trimester of pregnancy and in 3 (0.3 per cent) in the third trimester. Two (0.2 per cent) demonstrated fever, but there were no instances of chorioamnionitis. There were only three (0.3 per cent) spontaneous abortions 4-6 weeks after late CVS. However, there was no correlation between AFP elevation, placental haematoma, Doppler measurements, and spontaneous abortion. Cytogenetic findings were obtained in 990 (99 per cent) of 1000 placental samplings. We found 60 (6.0 per cent) chromosomal abnormalities. In the group with suspicious ultrasonic findings (250 cases), we found significant oligohydramnios in 125 (50 per cent) and significant polyhydramnios in 60 (24 per cent), and 45 (18 per cent) had chromosomal abnormalities. Among the 60 patients with chromosomal abnormalities, ultrasonographic findings in 10 (16.7 per cent) were detected after the 20th week of pregnancy. There were no significant differences in mean pulsatility index (PI) in the uteroplacental and fetal vessels before and after late CVS. Preliminary data from five trisomic fetuses (three trisomy 21 and two trisomy 18) showed abnormally increased umbilical PI and abnormally decreased middle cerebral artery PI.

Chorionic villus sampling by biopsy forceps. Results of 1580 procedures from a single centre

The results of a prospective series of 1580 chorionic villus sampling (CVS) procedures using biopsy forceps are presented. Most of the procedures (1442), including 11 sets of twins, were performed by the transcervical approach (TC-CVS), using a curved-shank thin forceps, and 138 by the transabdominal approach (TA-CVS), using a trocar-guided straight thin forceps. The mean gestational age for TC-CVS was 10.9 weeks, and in 233 cases (16 per cent) the procedure was carried out between the 12th and 14th weeks. The mean gestational age for TA-CVS was 16.7 weeks. The major indication for CVS was advanced maternal age (92.7 per cent in the TC and 91.8 per cent in the TA approach), and indications for abnormal ultrasound findings were more common in the TA approach (4.5 per cent) than in TC-CVS (0.07 per cent). Although sampling was apparently accomplished in all the procedures, in 3.1 per cent of the TC-CVS and 2.2 per cent of TA-CVS procedures, the samples were less than 1 mg after dissection. A cytogenic report was obtained in 96.1 per cent of the TC-CVS and 90.6 per cent of the TA-CVS. Maternal serum alpha-fetoprotein (MSAFP) was measured before and after TC-CVS and the post-CVS MSAFP was positively correlated with the sample weight. Second-trimester amniocentesis following CVS was required in 5.2 per cent (TC-CVS) and 6.5 per cent (TA-CVS), due to the failure to obtain a cytogenetic report or diagnostic confirmation. The follow-up to the 20th week was 100 per cent by ultrasound scan, and 88.6 per cent from the 21st week to 1 week after delivery. Fetal loss rates within 2 weeks of the procedure were 1.7 per cent (TC-CVS) and 0.8 per cent (TA-CVS) and total fetal loss accumulated to 1 week after delivery was 4.6 per cent (TC-CVS) and 5.9 per cent (TA-CVS). Factors found to increase significantly fetal loss in the TC-CVS series were maternal age and the collection of very small samples, but not the number of forceps insertions.

Predictive factors in recurrent spontaneous aborters--a multicenter study

PROBLEM

Compare data from several centers relating to success rates in recurrent spontaneous miscarriage and assess the significance of indicators of subsequent pregnancy loss.

METHOD

Data from 777 couples with unexplained recurrent spontaneous abortion from independent studies at seven centers were analyzed using logistic regression analysis. The following covariates were considered: age of patient, number of previous spontaneous abortions, length of previous abortions history, sub-fertility index (defined as the product of the number of spontaneous abortions and the abortion history), whether a patient was a primary or secondary aborter, and whether a patient had received leukocyte immunotherapy.

RESULTS

There was a highly significant difference between the seven centers in success rates in the subsequent pregnancy and a highly significant association between success rate and each of the following covariates: the number of previous abortions, the length of the previous abortion history and the sub-fertility index. In particular, for each increase of 10 units in the value of the sub-fertility index, up to a value of 30, the odds in favor of a successful pregnancy decreased by a factor of 0.6, i.e., 40%. There was, however, little evidence of an association between the success rate in the subsequent pregnancy and age, parity, or immunization with cells from the husband.

CONCLUSIONS

The sub-fertility index may be a useful measure of likelihood of success in a subsequent pregnancy.

The association between alpha-fetoprotein and beta hCG levels prior to and following chorionic villus sampling in cases that spontaneously miscarried

Maternal serum alpha-fetoprotein (AFP) and beta-human chorionic gonadotropin (beta hCG) measurements taken prior to chorionic villus sampling (CVS) in 21 patients who subsequently miscarried were compared with measurements in a control group of 113 patients with uneventful pregnancies. Patients with AFP levels of 10 iu/ml or more prior to the CVS had a 4.3 times greater risk of miscarriage (95 per cent confidence interval 1.3-13.6). AFP levels obtained 1 week after the CVS in the 13 patients with late miscarriages were higher than in the control group (P = 0.06). Patients miscarrying had a greater rise in AFP (P = 0.06) and a greater fall in beta hCG levels (P = 0.04) following the CVS procedure, compared with the control subjects. Each 10-unit change in the difference between AFP or beta hCG levels prior to and 1 week following the CVS was associated with a significantly increased risk for late miscarriage. Elevated maternal serum AFP levels early in pregnancy and changes in AFP and beta hCG levels following CVS may predict an increased risk for subsequent miscarriage.

Pregnancy outcome following ultrasound-detected fetal cardiac activity in women with a history of multiple spontaneous abortions

OBJECTIVE

To determine whether women with two or more previous spontaneous abortions of unknown etiology, by conventional testing criteria, have a different rate of subsequent fetal loss than controls after ultrasonic documentation of fetal cardiac activity.

METHODS

Medical records were reviewed from 185 women with spontaneous abortion of unknown etiology. Of these women, 91.9% were found to have evidence of cellular immunity to trophoblast and were treated with progesterone for immunosuppression. Ultrasound evaluation was obtained at 5-6 weeks' gestation to document fetal cardiac activity. A control group of 63 women was also studied. All women were followed for pregnancy outcome.

RESULTS

A total of 248 pregnancies were identified from the 185 study patients with multiple spontaneous abortions. Fetal cardiac activity was visualized by ultrasound in 209 pregnancies from 171 study subjects; of these, the outcomes of 208 pregnancies were known. The rate of spontaneous abortion after ultrasound documentation of fetal cardiac activity was 22.7%. Neither maternal age nor number of previous losses was associated with an increased incidence of spontaneous abortion following documentation of fetal cardiac activity. The rate of spontaneous abortion in the control group after documentation of fetal cardiac activity was 3.3%.

CONCLUSION

These data may help clinicians give couples who have experienced recurrent pregnancy loss a more realistic prognosis for pregnancy success once fetal cardiac activity has been confirmed.

Randomized trial comparing first-trimester transcervical chorionic villus sampling and second-trimester amniocentesis

A total of 800 patients were randomized at the 9th to 11th week of pregnancy either for transcervical chorionic villus sampling (CVS) on the day of trial entry or for amniocentesis (AC) at the 16th week. The indication for fetal karyotyping was maternal age in 94 per cent of the cases; the mean maternal age was 39.2 years. An adequate sample was obtained in 98.3 per cent of the cases in the CVS group and in all cases in the AC group. Retesting was indicated in 3.3 per cent of the CVS cases. An abnormal karyotype was found in 6.1 per cent of the CV samples and in 4.5 per cent of the amniotic fluid samples. There was one false-positive chromosome result in both groups. Twelve (3.1 per cent) miscarriages occurred by the 22nd week of pregnancy in the CVS group in pregnancies intended to continue. No difference was seen between the groups for total fetal loss rates. The number of surviving infants in the CVS group was 92.2 per cent and in the AC group 91.7 per cent (rate difference 0.5 per cent (95 per cent confidence interval -3.3 to 4.3)). In our study, both the diagnostic accuracy and the risk of fetal loss were equal in the CVS and AC groups.

Testing for fetal abnormality in routine antenatal care

The detection of fetal abnormality is a major component of routine antenatal care. A variety of techniques are now in use, although these are constantly being modified in the pursuit of more accurate and earlier detection. In this paper we draw attention to the distinction between screening and diagnostic tests, and describe the techniques which have been most commonly used in the UK: serum-screening for neural tube defects; screening for Down's syndrome; ultrasound scanning; amniocentesis and chorionic villus sampling.

The predictive value of uterine artery flow velocity waveforms in miscarriage in older women

OBJECTIVE

To determine whether uterine artery blood flow velocity measurements can predict miscarriage in older women.

DESIGN

Prospective study.

SUBJECTS

Three hundred and ninety-three women aged 35 years and older in the first trimester of pregnancy.

MAIN OUTCOME MEASURES

Miscarriage, genetic abortion, pulsatility index (PI), maternal age, gestational age at intake.

RESULTS

Twenty women miscarried; 10 pregnancies were terminated because of chromosomal anomalies. Maternal age and gestational age at intake were significantly associated with miscarriage rate (P = 0.01 and P = 0.001, respectively). Uterine artery PI values declined significantly during the first trimester (P = 0.001). However, no association was found between uterine artery PI values and miscarriage rate. PI, maternal age and gestational age at intake were not essentially different between women who miscarried before or after chorionic villus sampling. No association was found between PI, maternal age, and gestational age at intake and genetic abortion rate.

CONCLUSIONS

Uterine artery blood flow velocity waveforms, as expressed by the pulsatility index, bear no relation to miscarriage.

Importance of complete follow-up of spontaneous fetal loss after amniocentesis and chorion villus sampling

Women who are the most difficult to trace after amniocentesis or chorion villus sampling are often those who have had an adverse pregnancy outcome. To calculate total fetal loss figures for use in prenatal counselling we have followed in a multicentre study 100% of women who had undergone these procedures. Early spontaneous loss (within three weeks of the procedure) and total spontaneous loss were much lower after amniocentesis (0.2% and 1.3%, respectively) than after chorion villus sampling (1.2% and 2.9%). Four spontaneous fetal losses among the 20 pregnancies that were the most difficult to follow-up increased the loss rate by 0.5% for chorion villus sampling. Risk of early fetal loss after chorion villus sampling was related to experience of the operator (relative risk [RR] 4.3, p = 0.003), and total fetal loss was lower in pregnancies tested at 10 weeks' or more gestational age compared with those tested before 10 weeks' (RR 0.4, p = 0.01). A table showing the frequency of each of the seven possible outcomes after amniocentesis and chorion villus sampling is useful in counselling those considering one or other test.

Analyses of 95 first-trimester spontaneous abortions by chorionic villus sampling and karyotype

PURPOSE

Our purpose was to determine the incidence of chromosomal aneuploidy in first-trimester pregnancy losses using chorionic villus sampling (CVS).

STUDY DESIGN

All patients presenting for CVS with no fetal cardiac activity were offered CVS.

RESULTS

Cytogenetic results were completed in 95 of 96 cases (99%). Eighty-three percent of the karyotypes were aneuploid. The 16 euploid fetuses had no excess of females.

CONCLUSION

CVS is the most reliable method of determining the karyotype of spontaneously aborted fetuses. The incidence of aneuploidy is much greater than in previous reports that analyzed passed products of conception. CVS should be offered to women who present with first-trimester spontaneous abortions.

Transabdominal chorionic villus sampling: fetal loss rate in relation to maternal and gestational age

In this paper we report the fetal loss rate in relation to both maternal and gestational age in 1764 pregnant women who underwent transabdominal chorionic villus sampling (TA-CVS) between January 1986 and August 1990. The fetal loss rate, considered as a proportion of continuing pregnancies, decreased with advancing gestational age at sampling from 4.3 per cent before 9 weeks to 0.4 per cent at or after 13 weeks, the difference being statistically significant (p < 0.025). The fetal loss rate increased from 1.6 per cent in women under 30 to 2.4 per cent in women of 40 years or over, but the difference was not statistically significant. Considering that the total fetal loss rate before 28 weeks' gestation was on average 1.91 per cent (1.3 per cent under 35 years and 2.8 per cent in women of 35 or over), we believe that TA-CVS is a safe and effective technique for prenatal diagnosis of genetic diseases.

Reproductive behaviour following spontaneous loss of pregnancy after prenatal diagnosis

One hundred and fifty-eight women of advanced maternal age with complete follow up who experienced spontaneous fetal loss after prenatal diagnosis were studied for reproductive behaviour as well as prenatal diagnosis in a subsequent pregnancy. A higher rate of subsequent pregnancies amongst women who experienced an early spontaneous abortion after chorionic villus sampling (CVS) was expected compared with women who lost a pregnancy later during pregnancy after amniocentesis. Of the 92 women who underwent CVS in a previous pregnancy, 57 (62%) became pregnant again. Of the 66 women who underwent amniocentesis in the pregnancy that ended in fetal loss, 34 women (52%) had a subsequent pregnancy. The cumulative incidence of subsequent pregnancies was significantly influenced by maternal age but not by parity or the method of prenatal testing. Most women who decided on a new pregnancy opted for prenatal diagnosis. There was a preference for amniocentesis if the patient had previously undergone CVS. However, the reverse was not the case.

The role of abnormal fetal heart rate in scheduling chorionic villus sampling

OBJECTIVE

To assess the value of fetal heart rate (FHR) measurements in predicting spontaneous fetal loss in pregnancies scheduled for chorionic villus sampling (CVS).

DESIGN

A prospective descriptive study.

SETTING

Two hospital departments of obstetrics and gynaecology in Israel.

SUBJECTS

114 women between 9 and 11 weeks gestation scheduled for chorionic villus sampling (CVS).

INTERVENTIONS

Fetal heart rate was measured by transvaginal Doppler ultrasound and compared with a monogram established from 75 fetuses. Whenever a normal FHR was recorded, CVS was performed immediately.

RESULTS

106 women had a normal FHR and underwent CVS; two of these pregnancies ended in miscarriage. In five pregnancies no fetal heart beats could be identified and fetal death was diagnosed. In three pregnancies an abnormal FHR was recorded and CVS was postponed; all three pregnancies ended in miscarriage within 2 weeks.

CONCLUSION

Determination of FHR correlated with crown-rump length could be useful in predicting spontaneous miscarriage before performing any invasive procedure late in the first trimester.

Effect of chorionic villus sampling on utilization of prenatal diagnosis in women of advanced maternal age

The effect of the introduction of chorionic villus sampling on the utilization rate of prenatal diagnosis in advanced maternal age was studied during the period 1 January 1985-1 January 1991. On the first of January 1985, the age limit for prenatal diagnosis in The Netherlands was lowered from 38 to 36 years of age. The overall uptake rate during the studied period increased significantly, but only because of the increased uptake rate in the group 36 and 37 years. In the maternal age group of 42 years and older, an uptake rate as low as 15.9% was established. This was mainly determined by the relatively high percentage (73.0%) of women from ethnic minorities in this age group. The number of CVS procedures increased significantly during the study period, but the utilization rate was not influenced, since the number of amniocenteses decreased accordingly. An increase in acceptability of prenatal diagnosis by women of advanced maternal age due to early testing and early termination of pregnancy could not be substantiated in the present study.

Prenatal diagnosis in advanced maternal age. Amniocentesis or CVS, a patient's choice or lack of information?

Ninety-six women of advanced maternal age were interviewed about the way they obtained information on prenatal diagnosis and about how the decision was made as to what procedure was to be performed (transabdominal chorionic villus sampling (TA-CVS) or amniocentesis). In the CVS group, women visited their physician or midwife earlier in pregnancy (mean 7.1 weeks) than those in the amniocentesis group (mean 10.7 weeks). The availability of prenatal diagnosis was not mentioned during the first antenatal visit in 55 per cent of women from the amniocentesis group as opposed to 25 per cent from the TA-CVS group. Approximately 40 per cent of women eligible for prenatal diagnosis did not receive any information from the referring body prior to counselling at our centre. Only 29 per cent of women who underwent amniocentesis had actually chosen this procedure; 71 per cent were too late to undergo TA-CVS at 12 weeks. It is concluded that information to the patient must be improved in order to ensure early referral for prenatal diagnosis.