Assessing Pregnancy Status & Ultrasound Detection of Heartbeat Flashcards
what can US detection of baby’s hearbeat confirm?
pregnancy (later on)
what do most common pregnancy tests (panel A) measure concentrations of in urine
- human chorionic gonadotropin (hCG) hormone
what 2 things can hCG be measured in to detect pregnancy
- urine
- blood
what is the chorion
- membrane that develops from trophoblast cells (of outer layer of embryo / blastocyst)
____ layers in early placenta release hCG from ~_ days after conception
- chorion
- ~8 days
why is hCG critical for successful pregnancy
- hCG signals corpus luteum in ovary to stay alive & hence making progesterone (thus endometrium does not shed, ovulation not occur)
from how many days after conception (day 0) can hCG be detected in urine and in blood respectively
~12-14 days in urine
~11 days in blood
when do concentrations of hCG in maternal urine and blood peak during pregnancy
~8-11 weeks into pregnancy
- then decline
what kind of US can detect baby’s heartbeat in a normally-developing pregnancy
transvaginal US
at how many weeks since last menstrual period & how many weeks after conception - can transvaginal US detect baby’s heartbeat
- 6-7 wks from last menstrual period
- 4-5 wks after conception
how many weeks after foetal heart begins to pump blood thru the developing circulation can heartbeat be detected on transvaginal US
1-2wks after
how many days after conception does foetal heart beat rhythmically
~22 days after conception
how many days after conception foes foetal heart begin to pump blood around
~24-25 days after conception
absence of a detectable heartbeat in embryo longer than _mm is diagnostic of pregnancy failure
7mm
how is heart rate (bpm) of foetal heartbeat determined in transvaginal US
- timing of changes in distances between heart tissue layers
