Flashcards in Preterm Labor Deck (55):
the action of giving birth
What is preterm, generally?
Birth less than 37
What is late preterm?
What is early preterm?
Less than 34
What is the definition of term?
[37 - 42)
What is early term?
[37 - 39)
What is full term?
[39 - 42)
What is post term?
Greater than 42
What is the leading cause of neonatal death?
What is the definition of SGA? LGA?
SGA = Less than the 10th percentile
LGA = Greater than the 90th percentile
What is the definition of low birthweight?
Less than 2500 g
What is the definition of very low birthweight?
Less than 1500g
What is the definition of extremely low birthweight?
Less than 1000g
True or false: SGA = preterm
False--related but not equivalents
True or false: once infants survive prematurity, they have the same survival rate
What are the two major adverse pulmonary events associated with prematurity? (2)
What are the CV adverse effects of prematurity? (3)
What are the major adverse GI effects of prematurity? (3)
What are the major adverse ophthalmological effects of prematurity? Why?
Retinopathy of prematurity d/t the need to ventilation and O2
What (potentially) is the long term risk factor for neonatal hypoglycemic episodes?
What is the pathophysiology behind the retinopathy of prematurity?
Giving Oxygen to premies encourages growth of blood vessels in the retina (which would have been fully formed if born at term). This causes proliferation, and regression once oxygen is stopped, leading the vessels to die. Death of vessels is a inciting factor for retinal detachment
What histological changes occur within the uterus that allows for contractions?
Increased connectivity d/t increase in Connexins, and gap junctions
What is the hormone that sets off uterine contractions?
How useful is a single measurement of CRH in determining the timing of the "fetal clock"?
Not very--need multiple to define a function
True or false: CRH levels, and thus the fetal clock, appear to be set at the level of implantation
What are the A and B isoforms of progesterone receptors? What happens to the ratio of these when labor occurs?
A = Contraction
B = quiescent
A becomes more predominant as labor approaches
True or false: only a small fraction of preterm labor is recurrent
True or false: a mother who was preterm is more likely to have a preterm child
The risk of preterm labor is (__)x for african americans than for white
Is prior stillbirth a risk factor for spontaneous preterm birth
Any women with abdominal or pelvic pain after how many weeks gestation should be suspected of preterm labor?
What is the strongest predictor of having a preterm birth?
Having had a preterm birth before
How often is preterm labor accurately diagnosed?
What are the early s/sx of premature labor?
What dilation size indicates labor?
What percent of cervical effacement indicates labor?
What is the cornerstone of the diagnosis of preterm labor?
What defines a shortened cervix?
Less than 3 cm
What is the length of the cervix that indicates imminent (days to a week) delivery?
Less than 1 cm
What is fetal fibronectin (fFN), and what role does it play in pregnancy?
Glycoprotein component of the ECM, that may be involved in the adhesion of fetal membranes to decidua.
Declines after 24 weeks
How do you obtain fFN? Why?
Swab BEFORE doing a pelvic exam or using a speculum, o/w cannot obtain for 24 hours
What is the utility of measuring fetal fibronectin (fFN)?
If negative, unlikely that the women will deliver in the next few weeks.
If positive, then not useful
What are the two measurements that aid in identifying when labor is imminent?
US + fFN
What is the cervical length that indicates that it is safe to d/c the patient? What indicates that the patient will probably go into labor?
More than 30 mm
Less than 20 mm
If a pt is between 20-29 mm in cervical length, and has a positive fFN, what should be done? What about a negative?
Positive = will go into labor
Negative = consider observation
What is the effect of nifedipine on uterine contractions?
BLocks Ca channels to block contractions
What is the medication of choice that inhibits prostaglandin action on myometrial cells to inhibit contraction?
What is the MOA of terbutaline in the uterus?
Inhibits beta receptors on the uterus to inhibit contractions
Using terbutaline in twin pregnancies results in what?
What is the MOA of prostaglandins to stimulate uterine contractions?
Increases Ca levels, and gap junction formations
What is the MOA of MgSO4 in prevent uterine contractions?
decreases Ca influx
Giving Mg prior to delivery does what for a preterm baby?
Protects the blood vessels within the developing brain
Is bed rest indicated for pregnant women?
No--increases muscle atrophy and risk for VTE
What can't you use indomethacin as a tocolytic after 34 weeks?
Risk closing the ductus arteriosus