Genetic amniocentesis: a risk factor for preterm delivery?

Second trimester amniocentesis is not a risk factor for very low birth weight and extremely low birth weight

Objectives. To assess the risk of very low birth weight (VLBW) and extremely low birth weight (ELBW) attributable to second trimester amniocentesis. Methods. Records of 4,877 consecutive amniocentesis, performed between 1997 and 2003, were analyzed. Only VLBW and ELBW in the study population (exposed) and in the control group (unexposed) were evaluated. Comparisons were made between the amniocentesis group versus nonexposed. Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated for VLBW and ELBW classes. Results. In the study population, the VLBW were 35 (0.71%) and the ELBW were 20 (0.41%). In the control group, the VLBW were 220 (0.67%) and the ELBW were 112 (0.34%). The Odds ratios of the VLBW between the study and the control group did not show any statistical significant risk (OR = 1.07, 95% CI = 0.72–1.54). Also in ELBW odds ratios between study and control group were not statistically significant (OR = 1.20, 95% CI = 0.7–1.95). Conclusions. No effect of the second trimester amniocentesis was noted on VLBW and ELBW.

Epidemiology and environmental factors in preterm labour

An epidemiological and environmental approach is the appropriate starting point to understanding preterm labour. Although there are multiple aetiologies it seems likely that anthropometric and environmental risk factors in combination with inherent genetic susceptibilities contribute to an increased risk of preterm labour for certain women. Poct 2pulation-based studies identifying risk factors and quantifying outcomes facilitate informed counselling and provide a framework for developing prediction tools. Carefully conducted case-control and cohort studies identify associations that may contribute to an understanding of causation. A combined approach encompassing epidemiology, pathophysiology and clinical research is required to understand the aetiologies, prevention and optimal management of preterm labour. This review focuses on the epidemiology of preterm labour and the role of environmental factors.

Prenatal screening and diagnosis of congenital toxoplasmosis: a review of safety issues and psychological consequences for women who undergo screening

As part of the EUROTOXO initiative, this review focuses on the potential risks associated with prenatal testing for congenital toxoplasmosis. We first review the evidence on the risks of adverse events associated with amniocentesis, which is required for definitive diagnosis of toxoplasmosis infection in the fetus, and for which the most important risk is fetal loss. To date, there has been only one randomized trial to document risks associated with amniocentesis. This trial, which was conducted in 1986, reported a procedure-related rate of fetal loss of 1.0% (95% CI, 0.3-1.5). However, evidence from available controlled studies suggests that the pregnancy loss associated with mid-trimester amniocentesis may be lower. Potential psychological consequences of prenatal testing for congenital toxoplasmosis include parental anxiety due to false positive results and uncertainties related to prognosis of children with a prenatal diagnosis of congenital toxoplasmosis. Parental anxiety may be particularly important in screening strategies that include more frequent screenings, which may in turn entail substantial, and at times unnecessary, anxiety or other negative consequences for women and their families. These negative psychological outcomes should be balanced against the benefits of testing, which can allow women to make an informed choice regarding the pregnancy.

Are amniotic fluid C-reactive protein and glucose levels, and white blood cell counts at the time of genetic amniocentesis related with preterm delivery?

OBJECTIVE

To compare women with spontaneous preterm delivery before 37 weeks and women who delivered at term with respect to amniotic fluid C-reactive protein (CRP), glucose levels, and white blood cell counts at the time of genetic amniocentesis.

STUDY DESIGN

The study was conducted on 216 pregnant women who underwent genetic amniocentesis between the 15th and 18th weeks of gestation at Baskent University Obstetrics and Gynecology Department. All patients were followed until delivery for the occurrence of pregnancy complication. Indications for amniocentesis included abnormal triple test results showing increased risk for Down's syndrome, advanced maternal age and sonographic findings indicative for chromosomal abnormalities. The samples were carried immediately to the laboratory for cytogenetic and biochemical examination. Women with spontaneous preterm delivery before 37 weeks (n = 20) and those who delivered at term (n = 196) were compared with respect to some maternal and infant characteristics, amniotic fluid C-reactive protein, glucose levels, and amniotic fluid white blood cell counts.

RESULTS

During the study period 244 patients underwent amniocentesis. A chromosomal abnormality was present in 11 patients. 1 patient had a spontaneous pregnancy loss within 3 weeks after the procedure and 16 patients were delivered for fetal or maternal indications (preeclampsia, fetal growth restriction, placenta previa). The remaining 216 women were included in the study and investigated for the risk of preterm delivery. The prevalence of spontaneous preterm delivery before 37 weeks was 9.3% (20/216). There were no significant differences between the preterm delivery and the term delivery groups with respect to C-reactive protein levels and white blood cell counts. Mean amniotic glucose levels were significantly lower in the preterm delivery group (P<0.05). Amniotic fluid glucose levels of < or = 46 mg/dL had a sensitivity of 100% and NPV of 100%.

CONCLUSION

Amniotic fluid glucose levels at the time of genetic amniocentesis are lower in women with spontaneous preterm delivery before 37 weeks compared to those who delivered at term. Amniotic fluid glucose levels of < or = 46 mg/dL at the time of genetic amniocentesis may be more sensitive, cheaper and have higher negative predictive value than C-reactive protein levels and white blood cell counts for the prediction of patients in spontaneous preterm labor. The greatest benefit of amniotic fluid glucose testing might be when the physician judges the patient to be at low risk for preterm delivery.

Early invasive diagnostic techniques in pregnant women who are infected with the HIV: a multicenter case series

OBJECTIVE

Studies that mostly were conducted before the widespread use of combination antiretroviral treatments have reported that antenatal invasive procedures markedly increase the risk of human immunodeficiency virus vertical transmission. We aimed to evaluate the vertical transmission rate and other maternal and neonatal complications among women who were infected with human immunodeficiency virus who underwent antenatal invasive procedures during the second trimester of pregnancy and who were delivered after the advent of antiretroviral regimens.

STUDY DESIGN

We conducted a multicenter case series of women who were infected with human immunodeficiency virus who underwent amniocentesis or chorionic villus sampling or cordocentesis during the second trimester of pregnancy and who were delivered after January 1, 1997.

RESULTS

Sixty-three of 775 recruited women (8.1%) had performed early invasive diagnostic techniques . This rate has improved progressively from 4% in 1997 to 14%. Two of 60 viable infants (3.3%; 95% CI, 0.6%-10.1%) were infected with the human immunodeficiency virus. This rate did not differ significantly from the transmission rate that was observed in women who did not undergo antenatal invasive techniques (1.7%; P = .30).

CONCLUSION

The current risk of human immunodeficiency virus vertical transmission that is associated with early invasive diagnostic techniques is lower than previously reported.

Chorionic villus sampling and amniocentesis

PURPOSE OF REVIEW

The advantages and disadvantages of common invasive methods for prenatal diagnosis are presented in light of new investigations.

RECENT FINDINGS

Several aspects of first-trimester chorionic villus sampling and mid-trimester amniocentesis remain controversial, especially fetal loss rate, feto-maternal complications, and the extension of both sampling methods to less traditional gestational ages (early amniocentesis, late chorionic villus sampling), all of which complicate genetic counseling. A recent randomized trial involving early amniocentesis and late chorionic villus sampling has confirmed previous studies, leading to the unquestionable conclusion that transabdominal chorionic villus sampling is safer. The old dispute over whether limb reduction defects are caused by chorionic villus sampling gains new vigor, with a paper suggesting that this technique has distinctive teratogenic effects. The large experience involving maternal and fetal complications following mid-trimester amniocentesis allows a better estimate of risk for comparison with chorionic villus sampling.

SUMMARY

Transabdominal chorionic villus sampling, which appears to be the gold standard sampling method for genetic investigations between 10 and 15 completed weeks, permits rapid diagnosis in high-risk cases detected by first-trimester screening of aneuploidies. Sampling efficiency and karyotyping reliability are as high as in mid-trimester amniocentesis with fewer complications, provided the operator has the required training, skill and experience.