100%(2)2 out of 2 people found this document helpful
This preview shows page 19 - 21 out of 60 pages.
oEstimation of fetal weight can be measured using the Loepold's maneuver, measuring fundal height, or ultrasound biometry (the more methods used, the more accurate measurement)-> Fetal Fibronectin (fFN)oIt is a fetal glycoprotein produced by the trophoblast and other fetal tissuesoThe absence of cervicovaginal fFN between 20 and 34 weeks gestationhas been shown to be a strong predictor of a woman not experiencing preterm labor birth due to spontaneous preterm labor and premature ROM.oPositive findings of this protein = birth within the net 2 weeksoVaginal examinations, sexual intercourse within the previous 24 hours, vaginal creams, and some medications can cause false findings --> should be AVOIDED prior to fFN testing-> Evaluation of Fetal Lung MaturityoVERY IMPORTANT BEFORE BIRTH CAN PROGRESS!oThe alveoli of the lungs are lined with surfactant(which is composed of phospholipids) oSurfactant is needed to maintain stability in the lungs by lowering the surface tension in the alveoli (the greater the surface tension, the harder it is to have adequate oxygen)oLecithin/Sphingomylin Ratio= two components of surfactantWant 2:1 ratio(usually seen at 35 weeks)–-> indicates that serfactin has been releasedWhen at least 2 times as much lecithin begins to exceed that of sphingomyelin is found in the amniotic fluid, RDS is very unlikelyA delay is lung maturationis often seen in infants with mother's that have diabetes, nonhypertensive renal disease, or isoimmunizationAcceleration of lung maturitycan be seen with prolonged ROM (over 24 hours) by approximately 1 week, therefore having a protective effectL/S ratio results are NOT accurate when blood or meconium contaminates the amniotic fluidIf preterm delivery is progressing:oMom will get a shot of Betamethasone or Dexamethasone – steroids to delay delivery by 24 hours or more so steroid has time to workoPhosphatidyglycerol Levels (PG)
OB study guide20= The second most abundant phospholipid in surfactantAPPEARS at about 36 weeks gestation and increases in amount until termMay be present before 35 weeks in those with diabetes, PROM, vascular disease, or sever preeclampsiaPRESENCE of this = low risk of RDS (absence = risk of RDS)Useful in blood-contaminated specimens and vaginal specimensoFluorescence PolarizationMeasures the ratio of surfactant to albumin in uncentrifuged amniotic fluidoShake Test and Foam Stability Test (ethanol, saline, amniotic fluid) -->shake x 15 sec...wait 15 minutes -->some amniotic fluid is withdrawn and put it in a test tube with ethanol and saline. It is shaken up and if a ring of bubbles occurs at the top of the fluid then it means there is surfactant in the amniotic fluid. o-> Chorionic Villus Sampling (CVS)-Detects genetic, metabolic, and DNA disorders in the 1sttrimester (between 8-12 weeks = when the villi is present)--> Benefit is this is done early in case parents are potentially considering termination if a problem exists-->Obtains a small sample of chorionic villi from edge of placenta.