dx of pregnancy Flashcards
A 16 yo girl, LMP 10 weeks ago, presents for a pregnancy test. The pregnancy test is positive. She requests a blood test because she has heard “those pee tests aren’t reliable”.
After examining the patient and after auscultating a fetal heartbeat, you counsel the patient about your findings, and about her options regarding the pregnancy. She goes home to think things over and to reach a decision after talking to her boyfriend and her mother
quickening
-never use this to dx pregnancy
-The first fetal movements perceived by the patient
-Primigravidas: 20 weeks GA
-Multigravidas: 16-20 weeks GA
-Considered by Aristotle and by the Abrahamic religions to be the time of “ensoulment” of the fetus
-Not used to make diagnosis of pregnancy
PE findings that were previously used to dx pregnancy
-Chadwick’s sign (pic)
-Cyanosis of cervix and vagina at 6-8 weeks
-blood is going to the pelvis
-so much blood it looks purple
-normal but looks hypoxic
-Hegar’s sign
-Softening of uterine corpus at 6-8 weeks
-Both of these entities are commonly included on the PANCE and PANRE!
methods of absolutely dx pregnancy without urine or blood
-auscultation or measurements of fetal heart rate while measuring maternal heart rate:
-2 different heart rates indicate pregnancy
-the corollary is also important
-in cases of maternal tachycardia, be certain to document 2 separate and distinct heart rates
-clinician palpates fetal movements
-radiologic evidence of fetus:
-U/S
-flat plate of abdomen or CT scan
-often obtained in trauma
urine pregnancy tests
-extremely accurate and reliable (>99% accurate)
-often positive days after conception
-should be positive by 1st missed period
-a positive result corresponds to a serum quantitative bHCG of at least 20mlU/ml
false positive pregnancy tests
-may be caused by:
-Recent pregnancy (usually within one month of conclusion of pregnancy)
-Mixed samples
-Exogenous bHCG administered as part of infertility treatment
-Choriocarcinoma (malignancy arising from the placenta)
-May represent initial presentation, or recurrence of disease
false negative pregnancy tests
-may be caused by:
-very early pregnancy
-mixed samples
reasons to obtain a serum bHCG
-almost never necessary to obtain serum to dx pregnancy
-MC reason to order quantitative serum bHCG is to rule out ectopic gestation
-normally bHCG doubles every 48 hrs in 1st trimester (ectopic normally wont do that)
-a normal intrauterine pregnancy will demonstrate this pattern
-if serum bHCG levels plateau or fall, consider these dx:
-ectopic or impending abortion
-intrauterine pregnancy can be seen (yolk sac, fetal pole) via transvaginal US with bHCG > 1500 or via transabdominal US with bHCG >6000 -> this is known as the DISCRIMINATORY ZONE
-by 2000 you should see on US
ectopic pregnancies are generally located in the fallopian tube
-but can be elsewhere
-in the cervix
-in an old c section scare (very rare)
-in the ovary
-abdominal
lithopedion
-stone + child
-fetus dies in the abdomen and is found on accident
in which of the following circumstances should an intrauterine gestational sac be visible on transvaginal US
-HCG of 260
-HCG of 730
-HCG of 1150
-HCG of 2120
