The Normal Pregnancy Flashcards
What are 2 things to be done for prenatal care to decrease birth defects?
Starting folic acid at least 1 mo. prior to conception (reduces risk of spina bifida and anencephaly)
Adequate glucose control in patients with DM
How much folic acid should be given to women in their first pregnancy vs. subsequent preganncies?
No history: 0.4 mg
History: 4.0 mg
Gravity and Parity (4)
Gravity: number of times a woman has been pregnant
Parity: number of pregnancies that led to a birth at or beyond 20 wks or >500 g.
-includes full-term, pre-term, abortions, living
Normal findings associated with pregnancy include… (6)
Systolic murmurs (splitting and S3)
Palmer erythema
Spider angiomas
Linea nigra
Striae gravidarum
Chadwick’s sign (bluish hue of vagina on pelvic exam)
Labs/vaccines done at 1st visit (9)
CBC
Type and screen (Rh)
Rubella vaccine if not immune
Syphilis
Hep B sAg
HIV
Cervical cytology and Gonorrhea and Chlamydia
DM screening
Urine culture
What are 2 lab abnormalities in pregnancy?
Increased fibrinogen and clotting factors
Decreased Hct and Hb due to diluted volume
Most important thing to establish on first visit is…
Approximate due date
When can hCG be detected on pregnancy test?
What levels suggest it is negative vs. positive?
What is the level at menses?
6-8 days post ovulation
Negative: <5 IU/L
Positive: >25 IU/L
Approx 100 IU/L at menses
How frequently does hCG double in the first 30 days of pregnancy?
hCG doubles every 2ish days in the first 30 days
When is gestational sac seen?
When hCG is 1500-2000 IU/L
How can gestational age and due date be estimated? (3)
LMP - Naegel’s rule: minus 3 mo. and 7 days = due date (does not work if pt’s cycles are irregular or cannot remember, etc.)
PE - size of uterus
US
- crown rump length (CRL) between 6-11 wks can determine due date within 7 days
- 12-20 wks measuring femur length, biparietal diameter and abdominal circumference can determine due date within 10 days
- 3rd trimester can be off by +/- 3 wks
Women >35 y/o are at an increased risk…
Autosomal trisomies (13, 18, or 21) or sex chromosome abnormalities
Which recessive disease should be genetically screened for in all pregnant women?
CF, because up to 15% of carriers are undetected
Which 2 sex-linked disorders should be genetically screened for?
*Fragile X syndrome: most common form of inherited mental retardation
Duchenne muscular dystrophy
What is the most common inherited multifactorial disorder?
Neural tube defects (1/1000 live births)
What are 4 parts of the first trimester screening (up to 14 weeks)?
Maternal age
Fetal nuchal translucency (NT) thickness (echo free area at the back of the fetal neck from 10-14 wks)
Maternal serum b-hCG
Pregnancy associated plasma protein-A (PAPP-A)*
Which 2 screens are done in the second trimester (weeks 14-28)? What do they test for?
Triple screen: b-hCG, maternal serum alpha fetoprotein (AFP) biochemical markers. Done between 16-20 wks. 70% detection rate of trisomy 21.
Quadruple screen: b-hCG, estriol, AFP and inhibin A. 80% detection rate of trisomy 21.
What is the better way to do prenatal testing in high risk patients?
Cell-free fetal DNA testing
When is cell-free fetal DNA testing done?
Where does the DNA come from?
What should it NOT be used for?
9-10 weeks (can be done in first or second trimester)
Apoptosis of trophoblastic cells that have entered maternal circulation
NTD - evaluate maternal-AFP instead
Which patients should Cell-free fetal DNA testing be done? (5)
High maternal age
H/O pregnancy with a trisomy
FH of chromosomal abnormalities
US findings suggestive of aneuploidy
Positive serum screening in first trimester or triple/quad screening (second trimester)
*due to high cost
If a cell-free fetal DNA test is positive, what is the next step?
Invasive diagnostic test to confirm - amniocentesis or CVS (second trimester diagnostic procedures)
When can amniocentesis and CVS be done? What are their miscarriage rates?
Amniocentesis: 16-20 weeks, 0.3% miscarriage rate
CVS: 11 weeks, 1% miscarriage rate
Historical important teratogen:
Thalomide, which causes phocomelia
FDA classification of drugs in pregnancy (A, B, C, D, X)
A - no risk in any trimester
B - studies reveal no risk, however studies might not be adequate
C - animal studies show an adverse effect, but no studies done on pregnant women
D - there is a demonstrated risk to fetus, but the benefits may outweigh the risks on occasion
X - contraindicated - do not use!
Out-dated and not used anymore
What is the newer way drugs used in pregnancy are evaluated? What 3 subsections do they evaluate?
Pregnancy and lactation labeling rule (PLLR)
Pregnancy
Lactation
F/M reproductive potential
What time is the fetus most vulnerable to teratogens? Why?
What happens from the 4th month onward?
Day 17-56 post-conception, due to organogesis.
From 4th month to the end is mainly increasing organ size, not development.
What are the major teratogens? (9)
Alcohol - most common
Smoking
Anti-anxiety meds
Anti-neoplastic (aminopterin and MTX)
Anti-coagulants - do not use Coumadin, must use Heparin instead
Anti-convulsants
Illicit drugs
Infectious agents
Radiation
What is thought to be a possible risk of estrogen-progesterone combos in pregnancy?
Masculinization of female external genitalia
What is the dose dependent aspect of radiation exposure in pregnancy?
When is the critical period for its use?
What is exposure is before 2 weeks?
In most cases, diagnostic levels of radiation…
What is the rule of thumb for determining no risk?
Risk increases with dosage
2-6 wks is critical period
Lethal effect or no effect at all < 2 wks
Does not have a teratogenic risk
Rule of thumb: <5 rads of exposure = no risk
Frequency of office visits in pregnancy from:
Until 28 wks
28-36 wks
Until delivery
Until 28 wks: every 4 wks
28-36 wks: every 2 wks
Until delivery: weekly
What is done at routine office visits during pregnancy? (5)
BP
Weight
Urine protein
Uterine measurement (20 wks at umbilicus)
Fetal HR (doppler at 12 wks and fetoscope from 18-20 wks)
How much weight should be gained for the following BMIs?
<19
19-25
>25
<19: 28-40 lbs
19-25: 25-35 lbs
>25: 15-25 lbs
How can fetal movement be assessed?
Kick counting: 10 movements in 2 hrs
When near term, what 2 things should be evaluated?
Evaluate fetal lie (longitudinal, oblique, transverse)
Evaluate fetal position (vertex, breech)
Screening done at:
20 weeks (1)
28 weeks (4)
35 weeks (1)
20 weeks: fetal survey US
28 weeks: gestational DM, and repeat Hb and Hct, Rhogam, Tdap (27-36 wks)
35 weeks: screening for group B strep carrier with vaginal culture
What is a reactive non-stress test (NST)?
What does a non-reactive non-stress test require (positive test)?
2 accelerations of at least 15 beats above baseline lasting at least 15 sec. during 20 min of monitoring
Further evaluation with a contraction stress test or biophysical profile
What is the contraction stress test (CST)?
What is a positive test?
Give oxytocin to establish at least 3 contractions in a 10 min period.
If decelerations are noted with the majority of contractions the test is positive and delivery is needed.
What 5 biophysical variables are included in determining the biophysical profile?
What do the following scores mean?
8-10
6
<4
Non-stress test Fetal breathing movements Fetal movements Fetal tone Amniotic fluid volume
8-10: reassuring
6: equivocal, deliver if at term
<4: non-reassuring, consider delivery
