Appropriate consent must be obtained to take fetal samples, including tissue or luid obtained postmortem by needle aspiration. As recently outlined by the American College of Obstetricians and Gynecologists (2016c), any type of fetal or placental tissue or amnionic fluid can be submitted for genetic testing by CMA. Contamination with maternal tissue or blood is ideally avoided. If fetal blood cannot be obtained from the umbilical cord or by cardiac puncture, the American College of Obstetricians and Gynecologists (20a16a) recommends at least one of the following samples: (1) a placental block measuring about 1 X 1 cm taken below the cord insertion site in the unfixed specimen; (2) umbilical cord segment approximately 1.5 cm long; or (3) internal fetal tissue specimen such as costochondral junction or patella. Tissue is washed with sterile saline before
Cholestasis of pregnancy
BMI 25-29.9 kg/m2 ::12 yr) ::40 yr 6.4 4.0-5.5 1n.0 0.86 1.5-2.7 1n.2-4.0 1n.8-4.4 1n.2-2.2 1.7-7.0 2.2-30 2.2-3.0 2.8-5.0 1n.8-4.4 1n.7-3.0 1n.9-2.7 2.1n-2.8 1.6-2.0 2-4.6 1.4-3.2 1.8-2.2 1n.8-3.3 2.0-2.2
Twins Triplets Maternal age 12 1n.0-2.8 34 2.8-3.7
FIGURE 35-4 Flow chart for fetal and placental evaluation. (Modified with permission from ACOG Practice Bulletin No.o1 02: management of stillbirth, Obstet Gynecol. 2009 Mar;1o13(3):748-761o.) aOdds ratio of the factor being present compared with the risk factor being absent.
BMI = body mass index; IUGR = intrauterine growth restriction; PIH = pregnancy-induced hypertension; SLE = systemic lupus erythematosus.
Adapted from Fretts, 2005.
structural anomalies (Faye-Petersen, 1999). Approximately 20 percent have dysmorphic features or skeletal anomalies, and 8 percent have chromosomal abnormalities (Pauli, 1994; Saller, 1995). In the absence of anatomic dysmorphology, up to 5 percent of stillborn fetuses will have a chromosomal abnormality (Korteweg, 2008). Although the American College of Obstetricians and Gynecologists (20a1a6a) previously recommended karyotyping all stillborn fetuses, technological advancements of high-resolution, whole-genome sequencing-such as with chromosomal microarray anaysis ()-are now replacing standard karyotyping for chromosomal analysis of stillborn fetuses being placed in lactated Ringer solution or sterile cytogenetic medium. Notably, placement in formalin or alcohol kills viable cells. If conventional karyotyping is the only test available and the timing of death is recent, amnionic luid can be obtained by amniocentesis, as those cells obtained in a sterile fashion provide a greater likelihood of cell growth and eventual result compared with tissue obtained after delivery. Maternal blood is obtained for Kleihauer-Betke staining; for anti phospholipid antibody and lupus anticoagulant testing if indicated; and for serum glucose measutement to exclude overt diabetes (Silver, 20al3).