Monitoring Pregnancy Flashcards
3 ways pregnancy is confirmed
Clinical (signs and symptoms, enlarged uterus, etc)
Pregnancy test (urine or serum)
Ultrasound
hCG is produced by what cells
Placental tissue (the syncytiotrophoblasts)
Conversion between gestational and embryonic age
Gestational age = embryonic age + 2 weeks
3 ways to determine gestational age
- LMP
- Physical examination (clinical size of uterus)
- Ultrasound
Nagele’s rule
Estimated delivery date = LMP - 3 months + 7 days +1 year
What is the most accurate way to date a pregnancy?
Early ultrasound (7-14 weeks)
Using the crown rump length
Exception is IVF because we know the exact due date
Ideally offered to every patient
3 reasons accurate dating is important
Assessing impact regarding teratogenic exposures
Monitoring fetal growth
Timing obstetrical intervention
5 objectives in the first prenatal visit
Confirm pregnancy Obtain history* Complete physical exam Investigations (lab and ultrasound) Counseling
4 objectives in prenatal visits (not the first one)
History from last visit
Focused physical exam
Additional investigations
Counseling
GTPAL stands for…
Gravida: how many pregnancies a woman has had, including the current one
Term: number of pregnancies she has delivered at term
Preterm: 20-37 weeks
Abortus: before 20 weeks
Living: number of living children
G increases when you get pregnant, but the others increase when you deliver
Schedule of visits for low-risk pregnancies
Every 4 weeks until 28 weeks
Every 2 weeks from 28-36 weeks
Every week from 36 weeks on
3 things you really want to ask for in a focused history
Contractions
Bleeding
Fetal movement
3 things to measure in a focused physical exam
Blood pressure
Symphyseal fundal height (from pubis to top of uterus)
Listen to fetal heart rate
4 general screening tools
Maternal age (aneuploidy increases w age)
Serum biochemistry
Ultrasoun
NIPT
3 diagnostic tools
Amniocentesis
Chorionic villus sampling
Fetal blood sample
SIPS
Serum Integrated Prenatal Screen
Looks at maternal age and serum biochemistry
Screens for Down’s, NTDs, and trisomy 18
IPS
Integrated Prenatal Screen
Looks at maternal age, serum biochemistry, and nuchal translucency scan
Nuchal translucency scan
Special ultrasound technique
Looking at fluid accumulation in spinal cord
If it is enlarged there is an increased risk for Down’s
NIPT
Non-invasive prenatal testing
Measures cell-free fetal DNA in serum after 10 weeks
Screens for Down’s, trisomy 18, and 13
Second trimester detailed ultrasound
18-22 weeks (just to 20?)
Offered to all women
Focuses on fetal anatomy, fetal growth, amniotic fluid volume, placenta location, and may include soft markers of aneuploidy
Can see structures, but may not be able to tell how they are working
Third trimester ultrasounds
Not routine
May be considered based on risk factors
5 factors affecting the accuracy of ultrasound
Access to ultrasound Maternal body habits Number of fetuses Position of fetus Technical factors
Amniocentesis
Sample amniotic fluid to obtain fetal cells for testing
Invasive (risk of miscarriage)
Performed after 15 weeks
Chorionic villus sampling
Sample placental villi for testing
Invasive (risk of miscarriage)
Performed between 10-13 weeks
Fetal blood sample
Sample fetal blood from umbilical cord or heart
Rarely used as it’s extremely invasive
