RESUMO

AIM: The aim of this study was to evaluate the passage of fetal erythrocytes into the maternal circulation after invasive obstetric procedures, using the Kleihauer-Betke test, flow cytometry and α-fetoprotein concentration in maternal blood. MATERIAL AND METHODS: This was a prospective descriptive study on patients who underwent: amniocentesis, cordocentesis, chorionic villus sample, amniotic infusion, bladder drainage and ventricular-amniotic shunt to investigate the karyotype; treatment for hydrocephalus, oligohydramnios, obstructive uropathy and polyhydramnios; and investigation of lung maturity. Maternal blood samples were collected before and 60 min after the invasive obstetric procedure in order to evaluate the passage of fetal erythrocytes using the Kleihauer-Betke test, flow cytometry and α-fetoprotein concentration. RESULTS: In total, 43 invasive obstetric procedures were performed. The procedures performed were: 27 cases of amniocentesis (62.7%), seven cases of cordocentesis (16.2%), four chorionic villus samples (9.4%), two amniotic infusions (4.7%), two ventricular-amniotic shunts and one bladder drainage (2.3%). After one case of cordocentesis with two puncture attempts via the placenta, a significant increase in fetal erythrocytes was detected using the three methods. After another cordocentesis with one puncture via the placenta, a significant increase in fetal erythrocytes was detected using flow cytometry and α-fetoprotein concentration, but not through the Kleihauer-Betke test. The other 41 samples did not show any significant increase in fetal erythrocytes in the maternal blood. CONCLUSION: Invasive obstetric procedures performed during prenatal care are safe when performed by experienced professionals with the proper technique, with minimal chance of passage of fetal erythrocytes into the maternal compartment.

Assuntos

RESUMO

Esta revisão sistemática teve como objetivo avaliar se a realização da ultrassonografia (US) de rotina em gestações de baixo risco colabora com a diminuição da mortalidade materna e neonatal. Foi realizada uma revisão criteriosa da literatura dos últimos 20 anos, analisamos 121 estudos e deu-se preferência às revisões e aos ensaios clínicos randomizados, sendo esses estudos classificados segundo os níveis de evidência da Associação Médica Brasileira. Resultados: A US precoce possibilita melhor datação da gestação, evitando pós-datismo e induções desnecessárias, diagnostica gestações múltiplas com estabelecimento da corionicidade, e em lugares e casos em que a interrupção da gestação é permitida, diminui a mortalidade perinatal. A US morfológica do primeiro e segundo trimestres tem boa sensibilidade para detectar anomalias fetais, e o morfológico de segundo trimestre mostrou-se com razoável relação custo-benefício. A US após 24 semanas não demonstrou nenhum benefício claro para a mãe ou para o feto, a exceção da avaliação da maturidade placentária que parece reduzir a mortalidade perinatal. Conclusões: O tema continua controverso, necessitando de mais estudos que avaliem seu benefício em longo prazo. Como os estudos demonstram maior benefício antes de 24 semanas, algumas sociedades recomendam a realização de 2 exames: um ao redor de 12 semanas e o morfológico de segundo trimestre.

This systematic review aimed to assess whether the implementation of ultrasound (US) in routine low-risk pregnancies collaborates with decreasing maternal and neonatal mortality. We conducted a careful review of the literature of the last 20 years and analyzed 121 studies, and preference was given to the reviews and randomized clinical trials. These studies were classified according to the levels of evidence from the Brazilian Medical Association. Results: The early US allows: early dating of pregnancy avoiding post-term pregnancy and unnecessary inductions, diagnosis of multiple pregnancies and the establishment of chorionicity and reduce perinatal mortality in places and circumstances in which termination of pregnancy is allowed. The first and second trimester US screening have good sensitivity for detecting fetal abnormalities, and the second trimester US proved to be a reasonable cost-benefit analysis. The US after 24 weeks showed no clear benefit to the mother or the fetus, except for the evaluation of placental maturity that seems to reduce perinatal mortality. Conclusions: The issue remains controversial, requiring further studies to evaluate its long-term benefit. As the studies show more benefit before 24 weeks, some guidelines recommend performing 2 tests: 1 around 12 weeks and the second trimester screening.

Assuntos