Obstetrical Complications Flashcards
Preterm birth is defined as what?
Birth that occurs after 20 weeks but before 36 weeks and 6/7 days completed weeks of gestation
The diagnosis of preterm labor is defined as what events?
- Uterine contractions accompanied with cervical change
OR
- Cervical dilation of 2cm and/or 80% effaced
Which ethnicity is 2x more likely to experience pre-term labor?
African Americans 2x more likely than Caucasians
What 4 pathways are aimed at when preventing PTL?
- Infection (cervical)
- Placental-vascular
- Psychosocial stress and work strain
- Uterine stretch
What infections are associated with PTL?
bacterial vaginosis
group B strep
gonorrhea and chlamydia
There is a link between infection and progressive changes in cervical length and how is this related to preterm labor?
Risk of PTL ↑ as cervical length ↓
What are 2 screening tools that can be used to assess cervical length and to better predict risk of PTL?
- Ultrasound for routine screening of cervical length
- Fetal fibronectin (FFN) released from BM’s of fetal membranes in response to disruption of the membranes as w/ uterine activity, cervical shortening or infection
*negative predictive value is good; positive predictive value is low.
Alterations of any of the components of the placental-vascular pathway (immunologic component, vascular component, or low resistance connection of spiral arteries) is a risk factor for what?
results in poor fetal growth which is a risk factor for PTL as well as growth restriction and preeclampsia
Mental and physical stress are thought to induce a stress response that increases the release of what 2 things?
What is the effect of these 2 products?
Cortisol and catecholamines
Cortisol: released from the adrenal glands; stimulates early placental corticotrophin-releasing hormone (CRH) gene expression and increased CRH levels are known to assist in labor at term
Catecholamines: affect blood flow and can cause uterine contractions
The uterine stretch pathway in PTL is a risk factor in what women?
- polyhydramnios
- multiple gestations
What is the evaluation for PTL when a patient presents with any of the symptoms?
initial assessment done with cervical exam to assess dilation, effacement, and fetal presenting part
evaluate for any underlying correctable problems such as infection
external monitoring for uterine activity and fetal heart rate
reevaluate the cervix (usually at an hour) and during that hour oral or IV hydrate
cultures should be taken for GBS
also obtain an US
How is group B strep usually treated?
Antibiotics, typically penicillin, are given empirically to treat for GBS and usually discontinued if culture negative
Once you diagnose a patient with either 2 cm and/or 80% effacement or having made cervical change, what should you do next?
begin tocolysis (if gestational age is less than 34 weeks and there are no contraindications)
What are 3 tocolytic agents Whooten discussed?
Magnesium sulfate
Nifedipine
Prostaglandin Synthetase Inhibitors (indomethicin)
What is the MOA of magnesium sulfate?
it acts on the cellular level and competes with calcium for entry into the cell at the time of depolarization
What have some recent studies suggested about magnesium sulfate?
it may be more important in the role of neuroprotection
may offer prevention against cerebral palsy
What are the maternal side effects of magnesium sulfate?
feeling of warmth or flushing
nausea and vomiting
respiratory depression
cardiac conduction defects and arrest at high serum levels
What are the side effects in the neonate when mother is given magnesium sulfate?
loss of muscle tone
drowsiness
lower Apgar scores
What is Nifedipine
side effects
MOA
an oral agent effective in suppressing preterm labor
minimal maternal and fetal side effects
MOA: inhibits slow, inward current of calcium during the second phase of the action potential
What is the MOA of prostaglandin synthetase inhibitors?
What are the AEs of indomethacin?
they inhibit prostaglandin production that induce myometrial contractions
can cause oligohydramnios (decreases fetal renal function)
can cause premature closure of fetal ductus arteriosis and result in pulmonary hypertension and heart failure
infants exposed are at greater risk of necrotizing enterocolitis, intracranial hemorrhage
Which tocolytic used for PTL is only used on a short-term basis (mostly for extreme prematurity)?
Indomethacin
What are NSAIDs (Ibuprofen) used for in regards to PTL?
- Used to ↓ uterine activity
- NOT used for primary treatment of preterm labor