Ch 9 Prenatal Diagnosis & Fetal Assessment

screening

• standard!

• used to identify ppl who have a higher likelihood of abnormality/disease

• not 100% accurate

  • false-negatives/positives

    • bc of many factors - weight, timing, etc

• done via blood sample

diagnostics

• done after positive screening result

• more precise for a given condition

• gives yes/no answers abt a condition/abnormality

• makes a diff in mother’s pregnancy

  • keeping and/or future plans

ultrasound

• diff depending on trimester

• 2 types

  • abdominal

  • transvaginal

abdominal ultrasound

• through belly w/ gel

transvaginal ultrasound

• using want vaginally → cervix

first trimester ultrasounds

• transvaginal!

• visualization to confirm pregnancy

• identification of ectopic pregnancies

• molar pregnancy confirmation

• confirmation of cardiac fxn in pregnancy

  • investigates troubles/concerns

second trimester ultrasounds

• abt 18-20wks in

• congenital malformation identification

• looking for multifetal pregnancies

• verifying dates & growth

• when gender is learned

• anatomic ultrasound !

anatomic ultrasound

• growth

• organs

• movements

• amniotic fluid

• placenta & blood flow

third trimester ultrasound

• @ abt 34wks +

• evaluate fetal size & growth

• help guide amniocentesis

• help determine health r/t early delivery choices

doppler flow studies

• examine flow of blood in blood vessels

  • from mom → placenta

comprehensive fetal well-being assessment

• monitoringgg!

  • fetal growth

  • placental fxns

  • central venous pressure

  • cardiac fxn

alpha-fetoprotein analysis

• aka AFA

• detect neural tube defects (spina bifida) or down syndrome/trisomy issues

  • w/ defect, more escapes into amniotic fluid from fetus → enters maternal circulation thru placental crossing

• not required, but suggested

• high incidence of false positive → diagnostic testing

• required when pregnant ages 30-50+

• blood test - non invasive

alpha-fetoprotein analysis timing

• 2nd trimester! (16-18wks)

• multiple-marker screening!

alpha-fetoprotein

• glycoprotein made initially by yolk sac & fetal gut

  • later made mainly be fetal liver

AFA diagnostic

• amniocentesis

  • much more definitive!

AFP elevation causes

• open neural tube defects

• underestimation of gestational age

• presence of multiple fetuses

• GI defects

• low birth weight

• oligohydramnios

• maternal age

• diabetes

• decreased maternal weight

• fetal death

low AFP causes

• molar pregnancy

• increased maternal weight

• maternal T1D

• down syndrome

• trisomy 18

chorionic villus

• in placenta

  • finger-like projections of placental tissue that share same genetic makeup as fetus

chorionic villus sampling

• check cells from placenta (identical to cells from fetus) to check for chromosomal abnormality

  • ie: down syndrome

• gives results like amniocentesis, but done earlier

• ultrasound guidance

• transcervical or transabdominal

• nurse responsibility to give education after!

chorionic villus sampling timing

• pretty early on

• btwn weeks 10-13

chorionic villus sampling & ultrasound

• used as guidance

  • esp bc cells are from placenta

• completely sterile procedure

chorionic villus sampling procedure

• sample taken

  • 10-30mL aspirated into syringe w/ culture medium

chorionic villus sampling education

• vaginal bleeding

  • abt 2 days

  • light!

• cramping

• take it easy - no strain for 24hrs

• report heavy bleeding, clots/tissue, contractions, fluid leaking, fever

amniocentesis

• transabdominal puncture of amniotic sac

  • obtaining fluid for analysis

• detection of chromosomal a