-
Dating...EXTREMELY IMPORTANT!
Duration of pregnancy typically lasts 280days or 40weeks Gestational Age: Dating begins with the first day of last menstrual period
Negele's rule:
add 7 days to first day of LMP, count back 3 months Embryologists/Reproductive biologists study ovulatory age -
-
At missed menses, detection limit of 12.5 mIU/mL rin urine equired to dose 95 percent of pregnancies Cole et. al (2004) evaluated effectiveness of 18 different HPTs.
First Result, Ealy Response the only proven to detect at time of missed menses Qualitative hCG typically orderdd within 1 week - 10day of HPT -
Most extensive workup (3 categories)Blood work: HCT, T+SInfections: RPR, Rubella, HepB, G+C/PAP, PPD, U/A and Cxs, VZV titer, HIV
-
Chorionic Villus Sampling Benefits:
Genetic testing: Downs/Cystic Fibrosis...
Paternity testing
Results in 1-7 Days Disadvantage:
Cannot evaluate NT defects
Miscarriage rate of about 1:100 -
-
First Tri Screen:
evaluates NT, hCG, PAPP-A in combination with maternal age and risk factors Pos Test
-Increase in nuchal translucency as measured in mm
-Low PAPP-A levels
-High hCG levels Advantage:
looks for chromosomal abnormalities (t21,t18...)
Identifies about 85/100 abnormal individuals
5% of normals have a positive test
test positive: 1/100-1/300 chance of abnormality- f/u with CVS or amnio ACOG pamphlet -
Amniocentesis
Detects chromosomal abnormalities, genetic defects, neural tube defects
+Paternity testing Disadvantage:
miscarriage: 1/200-1/400 = risk equivalent to age > 35
infection, LOF, preterm labor -
Triple Screen:
AFP (fetal)
hCG(placenta)
Estriol(fetal and placenta)35 yo, 80% sensitivity
increased MSAFP: increased NTD, or GI/abd wall abn. Add Inhibin-A for Quad screen:
more accurate test for t21 -
Anatomy scan at 18-22 weeks
-
26-28 weeks GCT:
no prep, not fasting
1 hour glucose >130 abnormal GTT
must eat at least 150mg carbs for 3 days prior
fast 14 hours prior
100g oral glucose load cannot be above these cutoffs
fasting 90
1hr 180
2hr 155
3hr 140 -
for Rh - mothers
-
BPP: at greater than 32 weeks -NST (20-30 min)
-U/S
breathing
movement
tone
hr
Amniotic fluid -
Broup B strep culture 5 weeks prior to delevery
with Abx tx, 1:4000 risk of baby with GBS
25% of all healthy adult women are carriers -
HCT, RPR, HIV