Fetal sex determination from maternal blood at 6 weeks of gestation when at risk for 21-hydroxylase deficiency

Abstract

Analysis of cell-free fetal deoxyribonucleic acid in maternal plasma for fetal sex determination might reduce the need for corticosteroid administration and CVS in women with fetuses at risk for 21-hydroxylase deficiency.

Quantification of Cell-Free DNA in Normal and Complicated Pregnancies: Overcoming Biological and Technical Issues

“…With the currently used approaches, placental DNA is accurately detectable in maternal plasma by the 6–11th week of gestation [7], [41], [42]. In one plasma sample obtained at 7.2 weeks gestation, we were able to amplify SRY but not RASSF1A with both PCR techniques.…”

Non-invasive prenatal diagnosis using cell-free fetal nucleic acids in maternal plasma: Progress overview beyond predictive and personalized diagnosis

“…Non-invasive prenatal fetal sex detection has also been suggested for the management of some endocrine disorders, such as congenital adrenal hyperplasia, where masculinization of the female fetus can be suppressed by maternal administration of dexamethasone from the 6th week of gestation [35, 40]. This approach can allow either for slightly delayed administration of maternal steroids to women reluctant to expose fetuses unnecessarily to the potential side effects of dexamethasone, or for prompt cessation of treatment if the fetus is confirmed to be male.…”

Cell‐free fetal DNA in maternal plasma: an important advance to link fetal genetics to obstetric ultrasound

“…In our study, we made a correct diagnosis of gender in 25 of 26 cases, with one false‐positive male result19. These results are having a huge impact in clinical practice for the management of X‐linked genetic disorders and the technique has even been used to guide fetal therapy in prenatal cases at risk of 21‐hydroxylase deficiency49–51. It is already possible to consider only undertaking an invasive test such as chorionic villus sampling (CVS) in order to show if a male is affected or not by the disease when the fetus is shown to be male by free fetal DNA.…”

“…CVS is usually not undertaken before 11 weeks' gestation, whereas fetal gender determination from maternal plasma is reliable from 7 weeks' gestation but male signals can be detected as early as 2 weeks postconception19. The diagnosis of fetal gender early in the first trimester may reduce anxiety for parents who are carriers of an X‐linked condition or avoid unnecessary exposure to steroids in pregnancies at risk of 21‐hydroxylase deficiency50.…”