OB Test 2 Flashcards
What are the broad categories associated with factors of high risk pregnancies?
- Biophysical - factors that originate within the mother or fetus and affect the development or functioning of either one or both (ex. genetic, nutritional)
- Psychosocial - maternal behaviors and adverse life events that have a negative effect on the health of the mother or fetus (ex. emotional distress, depression, drinking, substance abuse)
- Sociodemographic - the context in which the mother and family live (ex. low income, lack of prenatal care)
- Environmental - hazards in the workplace and the woman’s general environment and may include environmental chemicals (ex. anesthetic gases, radiation)
What are the possible risks of smoking to the fetus?
low birth weight
higher neonatal mortality rates
increased miscarriage rate
increased incidence of prelabor rupture of membranes
What are the possible risks of caffeine to the fetus?
> 200mg caffeine daily (about 12 ounces coffee/day) may increase the risk for giving birth to infants with intrauterine growth restriction (IUGR)
What are the possible risks of alcohol to the fetus?
fetal alcohol syndrome
fetal alcohol effects
learning disabilities
hyperactivity
What are the possible risks of drugs to the fetus?
teratogenic effects
metabolic disturbances
chemical effects
depression or alteration of central nervous system
What are the possible risks of psychologic status to the fetus?
birth complications related to emotional stress
How many fetal kicks warrant further evaluation by a non stress test?
fewer than 3 in 1 hour
What is a transvaginal ultrasound used for?
Used in the first trimester to detect ectopic pregnancies, monitor the developing embryo, help identify abnormalities, and establish gestational age.
(full bladder is not needed)
(can be used in second and third trimester along with abdominal scanning to evaluate preterm labor.)
What is an abdominal ultrasound used for?
Used after the first trimester once the uterus has become an abdominal organ to assess the fetus.
(full bladder is needed to displace the uterus upward to provide a better image.)
What is gestational dating by ultrasonography indicated for?
conditions such as uncertainty regarding the date of the last normal menstrual period, recent discontinuation of oral contraceptives, bleeding episode during the first trimester, uterine size that does not correlate with dates, and other high risk conditions.
What standard set of measurements have been accepted as being the most useful for determining gestational age in the first trimester?
crown-rump length biparietal diameter (BPD) head circumference abdominal circumference femur length
After what week of gestation is ultrasound dating less reliable and why?
after 22 weeks of gestation because of variability in fetal size
At what rate is average fetal growth?
1 cm per week
What physiological parameters of the fetus can be assessed with ultrasound?
Amniotic fluid volume (AFV) Vascular waveforms from fetal circulation Heart motion Fetal breathing movements (FBMs) Fetal urine production Fetal limb and head movements
How is the blood flow in a fetus and placenta studied?
Through a doppler blood flow analysis
How does doppler blood flow analysis work?
It uses systolic/diastolic flow ratios and resistance indices to estimate blood flow in various arteries.
What are the vessels that are most often studied through doppler blood flow analysis?
the fetal umbilical and middle cerebral arteries and the maternal uterine arteries.
What is severe restriction of umbilical artery blood flow as indicated by absent or reversed flow during diastole associated with?
IUGR (intrauterine growth restriction)
What does significantly increased peak systolic velocity in the middle cerebral artery predict?
moderate to severe fetal anemia
What does abnormal maternal uterine artery doppler waveforms predict?
fetal growth restriction
What amniotic fluid volume is considered to be healthy?
2.5 or greater
What are subjective determinants of oligohydramnios? objective?
Subjective - fundal height that is small for gestational age and fetus that is easily palpated.
Objective - the maximum vertical pocket of amniotic fluid is less than 1 to 2 cm.
What are subjective determinants of polyhydramnios? objective?
Subjective - fundal height that is large for gestational age and fetus that cannot easily be palpated or that is ballotable.
Objective - pockets of amniotic fluid measuring more than 8 cm.
How is the total AFV (amniotic fluid volume) evaluated?
by a method in which the vertical depths (in cm) of the largest pocket of amniotic fluid in all four quadrants surrounding the maternal umbilicus are totaled, providing an amniotic fluid index (AFI).