Extracorporeal Membrane Oxygenation in Pregnancy

BACKGROUND

Safety and efficacy of extracorporeal membrane oxygenation (ECMO) in pregnancy is unknown.

CASE

A 33-year-old pregnant woman at 23 weeks of gestation presented with acute respiratory distress syndrome unresponsive to conventional mechanical ventilation. Early initiation of ECMO therapy along with protective mechanical ventilation strategy resulted in an excellent maternal and fetal outcome.

CONCLUSION

Extracorporeal membrane oxygenation can be life saving when initiated early in pregnant patients with severe acute respiratory insufficiency unresponsive to conventional mechanical ventilation.

Maternal Death After Second-Trimester Genetic Amniocentesis

BACKGROUND

We report a maternal death after a second-trimester amniocentesis.

CASE

An uncomplicated amniocentesis was performed using sterile technique and ultrasound guidance. A refrigerated amniotic fluid specimen demonstrated negative leukocyte esterase activity, negative Gram stain for bacteria and white blood cells, and normal glucose and interleukin-6. The patient died from Escherichia coli sepsis and disseminated intravascular coagulation 40 hours after the amniocentesis. The autopsy showed normal- appearing needle entries into the skin and uterus without evidence of bowel adhesion or a needle track through the bowel.

CONCLUSION

Genetic counselors and obstetric care providers should be aware of potential serious maternal morbidity and mortality that may occur subsequent to uncomplicated amniocentesis.

Diagnostic mid trimester amniocentesis: how safe?

OBJECTIVE

Genetic mid-trimester amniocentesis is a common invasive procedure. The origin of the commonly quoted 0.5% rate of procedure-related pregnancy loss after amniocentesis is obscure and is in conflict with the only randomized prospective study that reported a procedure-related rate of loss of 1.0%. This review was performed to establish an estimate of procedure-related pregnancy loss after mid-trimester amniocentesis. The impact of placental puncture on the rate of loss and the risk of direct needle injury to the fetus were also examined.

STUDY DESIGN

The National Library of Medicine database was used to identify English language reports of >1000 amniocenteses with sufficient detail and follow up data to allow the calculation of the rate of spontaneous pregnancy loss after amniocentesis but before 28 completed weeks. These reports were divided into 2 groups to assess the impact of the ultrasound technique. Group I described only preamniocentesis ultrasound evaluation; group II described primarily concurrent ultrasound needle guidance. Pregnancy loss between the 2 groups was compared. The impact of placental puncture and reported direct fetal trauma were examined. The significance of differences was tested using chi-square analysis, with significance at a probability value of < or =.05.

RESULTS

Twenty-nine reports that totaled 68,119 amniocenteses were examined. In a comparison of all studies in group I with all studies in group II, there was a lower rate of loss after amniocenteses with the use of concurrent guidance (1.4%) compared with the use of preamniocentesis ultrasound evaluation (2.1%) that was significant ( P <.001). Among only the 5 controlled studies that used preamniocentesis ultrasound evaluation, the difference in rate of loss between amniocentesis patients and control subjects was 0.6% ( P =.0042; 95% CI, 0.19, 1.03), which was identical to the difference in the rate of loss of 0.6% between amniocentesis patients and control subjects from the 5 controlled studies that used concurrent ultrasound needle guidance ( P <.0001; 95% CI, 0.31, 0.90). Multiple case reports and small series of presumed fetal needle trauma were reviewed, but most of these attributed causation to the amniocentesis needle based only on circumstantial association. Two cases with direct evidence of fetal needle trauma are discussed. Finally, the rate of loss after placental puncture from among 9 reports that provided this detail was 1.4% and not different from the overall rate of loss that was noted in group II.

CONCLUSION

This examination of experience with 68,119 amniocenteses from both controlled and uncontrolled studies provides a substantive basis for several conclusions: (1) Contemporary amniocentesis with concurrent ultrasound guidance in controlled studies appears to be associated with a procedure-related rate of excess pregnancy loss of 0.6% (95% CI, 0.31, 0.90). To determine the total rate of loss, this must be added to the reported natural rate of loss without amniocentesis among control patients of 1.08%. (2) The use of concurrent ultrasound guidance appears to reduce the number of punctures and the incidence of bloody fluid. Concurrent ultrasound guidance was associated with a reduced rate of loss when all studies were compared, but not among controlled studies. (3) Direct fetal needle trauma is rare, and rarely proved, but may occur more frequently than is reported because of a failure to diagnose and a failure of the consistent production of sequelae. (4) This experience does not substantiate an increased rate of pregnancy loss if placental puncture is required.

Failure of amniotic-fluid-cell growth: is it related to fetal aneuploidy?

We investigated outcome in patients whose amniotic-fluid-cell samples showed unexplained growth failure in culture. 32 of 7872 amniocentesis samples were classified as unexplained growth failures. 10 women did not have repeat cytogenetic testing, but among their pregnancies there were 4 abnormal outcomes (1 fetal bladder-outlet obstruction, 2 stillbirths, and 1 acardiac twin). Of the 22 patients who had repeat karyotypic analysis, 18 had normal fetal karyotypes. However, 4 fetuses were aneuploid (2 trisomy 21, 1 trisomy 13, and 1 Pallister-Killian syndrome).

Analysis of indications for referral to a multidisciplinary medical genetics clinic: implications for training programs in obstetrics and gynecology

Clinical genetics has become an integral component of obstetric training. Advances in prenatal screening (particularly maternal serum alpha-fetoprotein) and the clinical applications of molecular technologies have broadened the indications for referral to geneticists. During the study period, 1237 patients were referred for genetics consultation. A total of 596 (48%) were referred because of cytogenetic indications (576 for genetic amniocentesis); 252 (20%) because of multifactorial-developmental abnormalities; 204 (17%) because of risk of diseases attributable to single-gene mutations; 58 (5%) because of antenatal teratogen exposure(s); and 127 (10%) because of other reasons. Herein we summarize our experience as a multidisciplinary genetics unit and offer recommendations for broadening resident training curricula to meet current clinical needs. These data will be useful for enhancement of health care use and more effective direction of limited resources.

The hidden effect of time

It is customary to regard datasets as homogeneous with respect to the order of collection of the measurements. Examples are given in which this assumption is breached. Hidden time trends have implications for the design of studies, their analysis and interpretation. It is suggested that, if the order of observations is known, a plot by time should be performed, perhaps using a cusum.