Flashcards in Week 2 Fetal & Neonatal Assessment (everything) Deck (151)
Normally, UA resistance to blood flow from the fetus to the placenta falls progressively throughout pregnancy, reflecting an increase in the number of tertiary stem vessels. Factors that affect placental vascular resistance include
gestational age, placental location, pregnancy complications (e.g., placental abruption, preeclampsia), and underlying maternal disease (chronic hypertension).
doppler velocimetry is used to evaluate
growth restricted fetuses or growth discordance in twin gestations
before in utero surgery can be recommended what must happen
a thorough evaluation must be performed (BOLD)
a thorough evaluation must be performed prior to utero surgery to evaluated
(1) precisely characterize the defect,
(2) exclude associated malformations,
(3) perform a fetal karyotype analysis, and
(4) eliminate the possibility that the condition can be treated using less aggressive technologies. Detailed counseling about the risks and benefits of the proposed procedure is required, and written informed consent is mandatory. Such a discussion must include a detailed review of the risks to both the fetus and the mother, including preterm PROM (28% to 100%), preterm labor and delivery (> 50%), maternal pulmonary edema (20% to 30%), placental abruption (5% to 10%), chorioamnionitis and sepsis (< 5%), and maternal death (rare).
the ideal case for fetal surgery consists of
a singleton pregnancy before fetal viability (before 23-24 weeks gestation)
in which the fetus has a normal karyotype and an isolated malformation that, if untreated, will result in fetal or neonatal demise.
what did the two randomized control trials publish
one on tracheal occlusion for the management of congenital diaphragmatic hernia
the other on rental versus postnatal repair of myelomeningocele
found little benefit to in utero surgery. although pediatric benefit with open maternal fetal surgery for myelomeningocele repair has been observed, there are significant risks including need for C section delivery with all future pregnancies- similar to that for women with a history of a classical c section delivery (BOLD)
when should repair of lesions such as cleft lip and palate be preformed
after delivery to minimize risk to the mother
Intrauterine fetal demise (IUFD)- known as
also known as stillbirth,
-defined as demise of the fetus after 20 weeks’ gestation and before delivery.
still birth rate in US
5.96 per 1000 live births in 2013- half occurring before 28 weeks.
Risk factors for still births include
extremes of maternal age,
prior unexplained IUFD,
umbilical cord and placental abnormalities, and
underlying maternal medical conditions (e.g., chronic hypertension, pregestational or gestational diabetes mellitus, autoimmune disorders, inherited or acquired thrombophilia).
Hydrops Fetalis is?
Hydrops fetalis (“edema of the fetus”) is a rare pathologic condition that complicates approximately 0.05% of all pregnancies.
Hydrops Fetalis US diagnosis requires...
abnormal accumulation of fluid in more than one fetal extravascular compartment, including ascites, pericardial effusion, pleural effusion, subcutaneous edema, and/or placental edema. (BOLD)
overall perinatal mortality rate in the setting of hydros fetalis exceeds what percent
prognosis depends on the underlying cause, severity and gestation age
in 50-75% of hydros fetalis what is seen
90% of hydros fetalis cases are a result of
non immune causes such as maternal infection (e.g., with parvovirus B19, cytomegalovirus, syphilis), massive fetal-maternal hemorrhage, and fetal abnormalities (e.g., congenital cardiac defects, fetal thalassemia, twin-to-twin transfusion syndrome).
hydros fetalis can be classically seen in fetuses with severe anemia - resulting form what
Rh isoimmunization, the introduction of Rh0(D) immune globulin has led to a substantial decrease in the incidence of immune hydrops
CHORIONIC VILLUS SAMPLING
Like that of amniocentesis, the goal of CVS is to provide fetal cells for genetic analysis, although in this case the cells are trophectoderm (placental) cells rather than amniocytes.
when is CVS best performed
10 and 12 weeks’ gestation. CVS performed before 10 weeks’ gestation has been associated with limb reduction defects
what is the most common complication of CVS
vaginal spotting, 10-25% of patients within the first few days after the procedure
is pregnancy loss associated with CVS
CVS appears to be associated with a higher risk for pregnancy loss than late amniocentesis
what is the most serious complication of CVS
spontaneous abortion (BOLD)
one complication unique to CVS involves
interpretation of the genetic test results (BOLD)
Amniotic fluid is composed of fetal urine, lung fluid, skin transudate, and water that is filtered across the amniotic membranes. It contains electrolytes, proteins, and desquamated fetal cells (amniocytes). Sampling of amniotic fluid (amniocentesis) can be used to measure various substances such as lecithin and sphingomyelin for assessing fetal lung maturity, to look for pathogenic bacteria for confirmation of an intra-amniotic infection, and to obtain fetal cells for determination of fetal karyotype or performance of specific genetic analyses.
The most common indication for second-trimester
amniocentesis is cytogenetic analysis of fetal cells, although on occasion it is performed to determine amniotic fluid AFP levels and acetylcholinesterase activity for the diagnosis of fetal open neural tube defects. Amniocentesis later in pregnancy is usually performed for nongenetic indications, such as (1) documentation of fetal pulmonary maturity before elective delivery before 39 weeks’ gestation, (2) amnioreduction in pregnancies complicated by severe polyhydramnios, (3) to confirm preterm premature rupture of membranes (PROM) (amniodye test), or (4) to exclude intra-amniotic infection.
Screening for Fetal Chromosomal Abnormalities
Fetal chromosomal abnormalities are a major cause of perinatal morbidity and mortality, accounting for 50% of first-trimester spontaneous abortions, 6% to 12% of all stillbirths and neonatal deaths, and 10% to 15% of structural anomalies in live-born infants. The most common aneuploidy (presence of an abnormal number of chromosomes instead of usual 46) encountered during pregnancy (autosomal trisomy) results primarily from nondisjunction during meiosis
women greater than 35 years are at higher risk for what
having a pregnancy complicated by fetal aneuploidy and are routinely offered noninvasive prenatal screening and an invasive diagnostic procedure (either amniocentesis or chorionic villus sampling [CVS]). (BOLD)
screening for fetal chromosomal abnormalities continued- random states-
which is the most common disorder
should all women be offered anurploidy?
However, because only 8% to 12% of all births occur in women 35 years of age and older, at most 20% to 25% of all cases of trisomy 21 (Down syndrome) would be identified if all women of advanced maternal age agreed to amniocentesis.101 Klinefelter syndrome (47, XXY) is the most common sex chromosome aneuploidy with a prevalence of 1 : 500 males, and Turner syndrome (45, X) is the only viable monosomy. Many older women are now opting for serum analyte screening for fetal aneuploidy, which is equally accurate in older women. All women, regardless of age, should be offered aneuploidy screening during early gestation.
high-frequency sound waves that are directed into the body by a transducer, reflected by maternal and fetal tissue, detected receiver, processed and displayed on a screen
Standard evaluation with perinatal US
involves determination of fetal number, presentation, amniotic fluid volume, cardiac activity, placental position, fetal biometry, and an anatomic survey.