Fetal Laboratory Medicine: On the Frontier of Maternal–Fetal Medicine

Determination of organic pollutants in meconium and its relationship with fetal growth. Case control study in Northwestern Spain

OBJECTIVES

Antenatal exposure to organic pollutants is a leading public health problem. Meconium is a unique matrix to perform prenatal studies because it enables us to retrospectively evaluate fetal exposure accumulated during the second and third trimester. The aim of the present study was to evaluate associations between organic pollutant levels in meconium and birth weight in NW Spain.

METHODS

In this study, we quantify the concentrations of 50 organic pollutants together with the total values of the most important chemical groups in meconium using gas chromatography coupled to tandem mass spectrometry.

RESULTS

Organochlorine pesticides, polychlorinated biphenyls and polybrominated diphenyl ethers were detected with the highest levels in meconium from small for gestational age newborns. It was estimated that several congeners were statistically significant (p<0.05). However, organophosphorus pesticides attained higher concentrations in newborns with an appropriate weight.

CONCLUSIONS

The occurrence of transplacental transfer can be confirmed. Prenatal exposure to organic pollutants was associated with a decrease in birth weight and, therefore, organic pollutants could have an impact on fetal growth. Nevertheless, these results need validation in larger sample sized studies.

Red Blood Cell Alloimmunization in the Pregnant Patient

Alloimmunization to red blood cell (RBC) antigens represents a challenge for physicians caring for women of child bearing potential. Exposure to non-self RBC antigens may occur during transfusion or pregnancy leading to the development of antibodies. If a subsequent fetus bears that antigen, maternal antibodies may attack the fetal red blood cells causing red cell destruction and clinically significant hemolytic disease of the fetus and newborn (HDFN). In the most severe cases, HDFN may result in intrauterine fetal demise due to high output cardiac failure, effusions and ascites, known as "hydrops fetalis". This article reviews strategies for management and prevention of RBC alloimmunization in women of child bearing potential.

Recognition and nursing management of sepsis in early infancy

Neonatal sepsis describes serious bacterial or viral infections that manifest in the first 28 days of life, causing significant morbidity and mortality. Although most babies with early-onset neonatal sepsis are born and managed in hospital, some are born in the community, or discharged early from postnatal wards. Consequently, emergency department (ED) nurses and other healthcare professionals need to be able to identify and treat these infants effectively to improve long-term outcomes. This article discusses neonatal sepsis, including causative organisms, types of neonatal sepsis and why neonates are vulnerable to infection. The National Institute for Health and Care Excellence 2012 and 2014 guidance is also discussed in relation to management of neonatal sepsis and a case study is included to illustrate some of the challenges that ED nurses may encounter.

Do toxic metals and trace elements have a role in the pathogenesis of conotruncal heart malformations?

OBJECTIVE

The aim of the present study was to determine the role of toxic elements and trace elements in the pathogenesis of conotruncal heart defects by measuring their concentrations in the first meconium specimens of the affected newborns.

METHODS

Concentrations of lead, cadmium, iron, zinc, and copper were measured in 1st-day meconium specimens that were collected from 60 newborns with conotruncal heart defects (Group I) and 72 healthy newborns (Group II).

RESULTS

The newborns with conotruncal defects and the healthy newborns had statistically similar demographic and clinical characteristics. When compared with healthy newborns, mean concentrations of lead, cadmium, iron, zinc, and copper were significantly higher in newborns with conotruncal heart defects (p=0.001 for each). In total, 51 newborns with conotruncal heart defects had normal karyotype. These newborns had significantly higher concentrations of lead, cadmium, iron, zinc, and copper when compared with healthy newborns. There were significant and positive correlations between the concentrations of lead and cadmium (r=0.618, p=0.001), lead and iron (r=0.368, p=0.001), lead and zinc (r=0.245, p=0.005), lead and copper (r=0.291, p=0.001), cadmium and iron (r=0.485, p=0.001), cadmium and zinc (r=0.386, p=0.001), and cadmium and copper (r=0.329, p=0.001).

CONCLUSION

Toxic metals and trace elements may disturb DNA repair mechanisms by impairing DNA methylation profiles, and thus have a role in the pathogenesis of conotruncal heart defects.

Fetal blood sampling

OBJECTIVE

We sought to review indications, technical aspects, risks, and recommendations for fetal blood sampling (FBS).

METHODS

A systematic review was performed using MEDLINE, PubMed, EMBASE, and Cochrane Library using the terms "fetal blood sampling," "percutaneous umbilical blood sampling," and "cordocentesis." The search was restricted to English-language articles published from 1966 through July 2012. Priority was given to articles reporting original research, in particular randomized controlled trials, although review articles and commentaries also were consulted. Abstracts of research presented at symposia and scientific conferences were not considered adequate for inclusion in this document. Evidence reports and guidelines published by organizations or institutions such as the National Institutes of Health, Agency for Health Research and Quality, American Congress of Obstetricians and Gynecologists, and Society for Maternal-Fetal Medicine were also reviewed, and additional studies were located by reviewing bibliographies of identified articles. Grade (Grading of Recommendations Assessment, Development, and Evaluation) methodology was employed for defining strength of recommendations and rating quality of evidence. Consistent with US Preventive Task Force guidelines, references were evaluated for quality based on the highest level of evidence.

RESULTS AND RECOMMENDATIONS

Ultrasound-guided FBS is the only procedure that provides direct access to the fetal circulation. When invasive testing is planned for suspected severe fetal anemia or thrombocytopenia, we recommend FBS as the procedure of choice, with availability of immediate transfusion if confirmed. We recommend against the use of FBS for indications in which other less invasive, and therefore lower risk, alternatives are available. The overall success rate of FBS is high, and blood samples can be obtained in >98% of patients. We suggest that counseling for FBS include discussion about the potential risk of FBS that may include, but may not be limited to: bleeding from puncture site (20-30%); fetal bradycardia (5-10%); pregnancy loss (≥1.3%, depending on indication, gestational age, and placental penetration); and vertical transmission of hepatitis or human immunodeficiency virus. We recommend that FBS be performed by experienced operators at centers with expertise in invasive fetal procedures when feasible.