RNC-OB: Questions With Expert-Level Solutions
What is the fetal development sequence? Correct Answer -
fertilization of egg by sperm-> blastocyst-> uterine implantation->
embryonic stage -> fetal stage
What is Naegele's rule? Correct Answer - Add 7 days to the
first day of the LMP and subtract 3 months to estimate a woman's
EDC
What is alternative method to Naegele's rule? Correct Answer -
determine date of onset from LMP and count 40 weeks from that
date
Mothers who are Rh-negative and isoimmunized should receive
what? Correct Answer - 300 mg IM Rh immune globulin prior
to procedures as prophylaxis
When are invasive prenatal diagnosis procedures recommended?
Correct Answer - abnormal prenatal screening results, thickened
nucchal translucency >3 mm, one or both parents are carriers for a
significant genetic condition, or a fetal anomaly is visualized on U/S
What are some examples of invasive prenatal screening tests?
Correct Answer - amniocentesis, CVS and PUBS
What is chorionic villus sampling? Correct Answer - Sampling
cells from the placenta (used to obtain trophoblast cells for analysis)
When is chorionic villus sampling obtained? Correct Answer -
between 10 and 13 weeks gestation
How can CVS be obtained? Correct Answer - transvaginal
(transcervical) or transabdominally
,What are some contraindications for transcervical CVS? Correct
Answer - Maternal Rh sensitization, active vaginal/ceervical
infection, uterine fibroids, hx of vaginal bleeding within the last 2
weeks, and marked retorverterd, retroflexed uterus
What is another word for Cordocentesis? Correct Answer -
percutaneous umbilical blood samplings (PUBS)
When is cordocentesis performed? Correct Answer - After 17
weeks gestation
How is blood confirmed to be fetal? Correct Answer - by MCV >
100
What is cordocentesis used for? Correct Answer - Used to
detect fetal infections, blood disorders and chromosomal
abnormalities
What can a cordocentesis NOT tell you? Correct Answer -
neural tube defects
Where is a cordocentesis sampled from? Correct Answer -
where the cord enters the placenta (umbilical vein preferred due to
less risk of fetal bradycardia
What needs to be performed before and during CVS sampling?
Correct Answer - U/S
What do both CVS sampling and cordocentesis increase the risk of?
Correct Answer - miscarriage
, What is the most common complication of cordocentesis? Correct
Answer - bleeding from the cord puncture site
s/s of first trimester of pregnancy Correct Answer -
amenorrhea, N/V, weight gain, mood swings, food cravings, breast
changes
Dx tests of pregnancy Correct Answer - positive Hegar,
Chadwick and Goodell signs, hCG, transvaginal or abd US
Hegar sign Correct Answer - lower uterine softening
Chadwick sign Correct Answer - Change of labia, cervical and
vaginal color from pink to bluish violet
Goodell sign Correct Answer - softening of the cervix due to
increased vascularization
When does Hegar sign appear? Correct Answer - earliest at
week 4 and lasts until week 12
When does Chadwick sign usually appear? Correct Answer - as
early as 6 weeks after conception
What is the first trimester? Correct Answer - Defined as the
time from fertilization to the end of the 12th week of pregnancy
What embryonic stages are included in the first trimester? Correct
Answer - weeks 3-8
What are some major occurrences in the first trimester of
pregnancy? Correct Answer - implantation, major organ
development, bone and tooth bud development, sexual organs
distinguishable, nail beds form, spontaneous fetal movements begin,
What is the fetal development sequence? Correct Answer -
fertilization of egg by sperm-> blastocyst-> uterine implantation->
embryonic stage -> fetal stage
What is Naegele's rule? Correct Answer - Add 7 days to the
first day of the LMP and subtract 3 months to estimate a woman's
EDC
What is alternative method to Naegele's rule? Correct Answer -
determine date of onset from LMP and count 40 weeks from that
date
Mothers who are Rh-negative and isoimmunized should receive
what? Correct Answer - 300 mg IM Rh immune globulin prior
to procedures as prophylaxis
When are invasive prenatal diagnosis procedures recommended?
Correct Answer - abnormal prenatal screening results, thickened
nucchal translucency >3 mm, one or both parents are carriers for a
significant genetic condition, or a fetal anomaly is visualized on U/S
What are some examples of invasive prenatal screening tests?
Correct Answer - amniocentesis, CVS and PUBS
What is chorionic villus sampling? Correct Answer - Sampling
cells from the placenta (used to obtain trophoblast cells for analysis)
When is chorionic villus sampling obtained? Correct Answer -
between 10 and 13 weeks gestation
How can CVS be obtained? Correct Answer - transvaginal
(transcervical) or transabdominally
,What are some contraindications for transcervical CVS? Correct
Answer - Maternal Rh sensitization, active vaginal/ceervical
infection, uterine fibroids, hx of vaginal bleeding within the last 2
weeks, and marked retorverterd, retroflexed uterus
What is another word for Cordocentesis? Correct Answer -
percutaneous umbilical blood samplings (PUBS)
When is cordocentesis performed? Correct Answer - After 17
weeks gestation
How is blood confirmed to be fetal? Correct Answer - by MCV >
100
What is cordocentesis used for? Correct Answer - Used to
detect fetal infections, blood disorders and chromosomal
abnormalities
What can a cordocentesis NOT tell you? Correct Answer -
neural tube defects
Where is a cordocentesis sampled from? Correct Answer -
where the cord enters the placenta (umbilical vein preferred due to
less risk of fetal bradycardia
What needs to be performed before and during CVS sampling?
Correct Answer - U/S
What do both CVS sampling and cordocentesis increase the risk of?
Correct Answer - miscarriage
, What is the most common complication of cordocentesis? Correct
Answer - bleeding from the cord puncture site
s/s of first trimester of pregnancy Correct Answer -
amenorrhea, N/V, weight gain, mood swings, food cravings, breast
changes
Dx tests of pregnancy Correct Answer - positive Hegar,
Chadwick and Goodell signs, hCG, transvaginal or abd US
Hegar sign Correct Answer - lower uterine softening
Chadwick sign Correct Answer - Change of labia, cervical and
vaginal color from pink to bluish violet
Goodell sign Correct Answer - softening of the cervix due to
increased vascularization
When does Hegar sign appear? Correct Answer - earliest at
week 4 and lasts until week 12
When does Chadwick sign usually appear? Correct Answer - as
early as 6 weeks after conception
What is the first trimester? Correct Answer - Defined as the
time from fertilization to the end of the 12th week of pregnancy
What embryonic stages are included in the first trimester? Correct
Answer - weeks 3-8
What are some major occurrences in the first trimester of
pregnancy? Correct Answer - implantation, major organ
development, bone and tooth bud development, sexual organs
distinguishable, nail beds form, spontaneous fetal movements begin,
