Early genetic amniocentesis and its relationship to respiratory difficulties in paediatric patients: a report of findings in patients and matched controls 3-5 years post-procedure

Early amniocentesis with the filtration technique: neonatal outcome in 123 singleton pregnancies

OBJECTIVE

To evaluate results of a prospective study of pregnancies in which early amniocentesis with the filtration technique was performed at 10-13 weeks' gestation (mean 12.3 weeks' gestation).

METHODS

123 singleton pregnancies in which early amniocentesis with the modified filtration technique was performed at 10-13 weeks' gestation (mean 12.3 weeks' gestation). The amniotic fluid was aspirated into the syringe and reinjected through the filter.

RESULTS

All the procedures were performed successfully by a single needle insertion. Neither dry taps nor filtration failures occurred. The mean time of amniocentesis was 4.02 min (95% confidence interval, 3 min and 36 s to 4 min and 18 s). The karyotyping success rate was 99.2%. Temporary amniotic fluid leakage occurred in three women (2.4%). There were 110 (89.4%) live births. Two cases of stillbirth occurred at week 38 and week 40. Two unintended losses occurred within three weeks after sampling (1.62%). Another additional unintended fetal death was notified at the 20-week screening ultrasonography. The total fetal-loss rate was 10.6%. In one case, talipes equinovarus was detected at the 20-week screening ultrasound study.

CONCLUSIONS

Further studies are needed to determine the risk of amniotic leakage and its relation to duration of the procedure in patients undergoing early amnifiltration.

First trimester prenatal diagnosis: amniocentesis

Twenty years after midtrimester genetic amniocentesis was first used, first trimester invasive prenatal procedures were introduced. Chorionic villous sampling presents some disadvantages that entitled many centers to look into an alternative for first trimester diagnosis. Early amniocentesis (EA) can be performed effectively, as shown over the years in many observational studies and partially randomized and randomized trials. Recently, a multicenter randomized trial (Canadian Early and Midtrimester Amniocentesis Trial) reported a higher total pregnancy loss, a significant increased incidence of musculoskeletal foot deformities, a significant increased culture failure rate, and an increased postamniocentesis rate of leakage in the EA group compared with midtrimester amniocentesis. These results concerning EA procedures from 11w(+0) to 12w(+6) should be included in any pre-EA counseling. However, further trials have started to evaluate EA procedures between 13w(+0) to 14w(+6).

Randomised trial to assess safety and fetal outcome of early and midtrimester amniocentesis. The Canadian Early and Mid-trimester Amniocentesis Trial (CEMAT) Group

BACKGROUND

Most published reports on early amniocentesis are of cohort studies rather than randomised trials. This study was designed to assess the safety and cytogenetic accuracy of early amniocentesis in-contrast to midtrimester amniocentesis in a randomised multicentre setting.

METHODS

Pregnant women were randomly allocated early amniocentesis (between 11(+0) and 12(+6) gestational weeks(days)) or midtrimester (between 15(+0) and 16(+6) gestational weeks(days)) amniocentesis. A detailed fetal ultrasound examination was done between 15 and 20 gestational weeks in all women. All amniocenteses were done under continuous ultrasound guidance: 11 mL (early amniocentesis) or 20 mL (midtrimester amniocentesis) of amniotic fluid were removed for cytogenic analysis. No more than two needle insertions were done on the same day. All fetal losses (spontaneous or induced abortions) were counted as outcome events and post-procedural losses had cytogenic analysis. Maternal and fetal health were assessed at 20-22 weeks and 5 weeks after delivery. Logistic regression analysis was used to assess the significance of the differences between the early amniocentesis and midtrimester amniocentesis groups.

FINDINGS

4374 pregnant women took part in the study. 1916 (87.8%) of 2183 women in the early amniocentesis group had their amniocentesis before 13 gestational weeks. 1775 (81.2%) of 2185 women in the midtrimester group had their amniocentesis after 15 gestational weeks. There was a significant difference in total fetal losses for early amniocentesis compared with midtrimester amniocentesis (7.6% vs 5.9%; difference 1.7%, one-sided CI 2.98%, p = 0.012). There was a significant increase in talipes equinovarus in the early amniocentesis group compared with the midtrimester amniocentesis group (1.3% vs 0.1%, p = 0.0001). There was a significant difference in postprocedural amniotic-fluid leakage (early amniocentesis 3.5% vs midtrimester amniocentesis 1.7%, p = 0.0007).

INTERPRETATION

Our study shows that early amniocentesis is associated with an increased risk of fetal loss and talipes equinovarus. Our results should be taken into consideration when invasive prenatal diagnosis is being offered.

First trimester invasive procedures: effects on symptom status and lung volume in very young children

First trimester procedures have been associated with perinatal lung function abnormalities that may suggest subsequent respiratory problems. Our aim was, therefore, to assess the impact of first trimester invasive procedures [early amniocentesis (EA) and chorion villus sampling (CVS)] on respiratory morbidity in very young children. A questionnaire was issued to parents of 439 EA and 453 CVS (subjects), and 435 controls (their mothers had undergone no invasive procedures) when their children were one year old. Data were also obtained from diary cards issued to a subset of 278 of the EA, 262 of the CVS, and 264 of the control infants followed prospectively. Functional residual capacity (FRC) was measured at a median age of 5 months (range: 0.25-24) in 159 children whose mothers had undergone EA, 168 following CVS and in 165 controls. Analysis of the one-year questionnaire demonstrated an excess of symptomatic infants in the EA group (31%) compared to the CVS (22%; P < 0.01) and control groups (17%; P < 0.01). Findings from the prospective follow-up study confirmed those results and also demonstrated an increase in chest-related hospital admissions in the EA group (3%) compared to the controls (0.4%; P < 0.05). Logistic regression analysis revealed that positive symptom status related significantly to EA and CVS interventions (P < 0.0001), bottle feeding (P < 0.001), parental smoking (P < 0.01), a family history of atopy (P < 0.01), and immaturity (P < 0.01). In the control group, FRC correlated best with weight (r = 0.92). The mean FRC of the EA and CVS groups was higher than that of the controls (P < 0.01). A higher proportion of children had an FRC two standard deviations above the controls' mean in the EA group (n = 14) compared to the CVS group (n = 3; P < 0.01). The symptomatic infants tended to have higher FRCs than the asymptomatic children. We conclude that first trimester procedures are associated with increased respiratory morbidity in very young children.

Early amniocentesis: a clinical review

Early amniocentesis at less than 14 weeks gestation is becoming more common in prenatal diagnosis populations. Randomized studies are minimal and have not had the power to determine the accuracy and safety of the procedure compared to chorionic villus sampling or mid-trimester amniocentesis. Procedures at 11+0-12+6 weeks should be considered experimental. This clinical review considers the ethics, embryology, and clinical experience (cytogenetics, AFP, AChE, procedure and cytogenetic failures, spontaneous and therapeutic pregnancy losses, congenital anomalies) of early amniocentesis.