Prenatal care Flashcards
When do you test for GBS?
After 36 weeks typically - they are valid for 5 weeeks and given most will deliver by 41 weeks covers most women
Why do we care about GBS?
To prevent early onset GBS sepsis in newborns
What if women’s urine grows GBS?
GBS bacteriuria is present in any amountat any time during pregnancy, this is considered a positive result (proxy for heavy colonization), and thus repeat screening is not necessary.
What about GBS in preterm women who have not been tested?
In the case of prematurity, treatment should begin while awaiting screen results.
What is the gold standard for GBS treatment?
gold standard for the treatment of GBS colonization intrapartum to reduce risk to neonates for early-onset disease is penicillin G.
loading dose of 5 million units loading, then 2.5-3 million units IV every 4 hours until delivery.
How long do you need for GBS tx to work?
Studies done with PCN or ampicillin prophylaxis demonstrate that 4 or more hours pf prophylaxis is preferable, though 2 hours has been shown to reduce GBS count and decrease neonatal sepsis. That said, obstetric intervention should not be delayed solely to provide 4 hours of antibiotic administration., when it is indicated.
What if patient is PCN allergy with positive GBS?
- ask about allergies
- low risk: ancef; high risk: clinda
- try and do allergy testing during pregnancy
- get susceptibiltiy testing in the lab if no testing
(Clindamycin should only be utilized if culture results have shown susceptibility)
When to pursue GBS tx in preterm labor? What risk factor
- Prematurity or PPROM (< 36 weeks 6 days)
- History of a prior newborn affected by GBS disease
- Amniotic membrane rupture > 18 hours duration
- Presence of intrapartum fever > 100.4F (38 C)
- If known GBS positive result in a previous pregnancy (may engage in shared decision making in this clinical scenario).
What are the two kinds of testing for GBS?
culture (takes longer) vs rapid test (shorter)
When can you NOT treat for GBS bacteriuria?
If asymptomatic GBS bacteriuria is present at >10^5 CFU/mL, treatment should be considered as you would for any other form of ASB. If at less than 10^5 CFU, no correlation has been found between treatment of this lower-level bacteriuria and improved maternal or neonatal outcomes; however, it should still be noted that this patient would be considered GBS positive.
When should RhoGam be given?
At 28 weeks, post-delivery within 72 hours, and sensitizing bleeding events in either 1st/2nd vs 3rd trimester
- RhIg should also be given within 72 hours of a sensitizing event – that is, one that causes or potentially causes bleeding at the fetal-maternal interface.
What is alloimmunization?
formation of maternal antibodies against blood group antigens not possessed by the mother
What are the tests we use to give amount of RhoGam?
KB test measures the amount of fetal hemoglobin in the mother’s circulation, and thus estimates the amount of RhIg needed to prevent alloimmunization.
What is the half-life of RhoGam, and when can you hold off on redosing?
• RhIg has a half life of about 23 days, and thus a 300mcg dose is detectable for approximately 12 weeks.
- Redosing may be held if delivery or subsequent sensitizing events occur within 3 weeks (or 1 half life) of a dose; redosing should be more strongly considered after this interval.
How does Rh hemolytic disease of the newborn get started?
Generally, a sensitizing pregnancy (1st event) is unaffected as antibodies are created in maternal serum from the first exposure to Rh(+) antigen.
Subsequent infants with Rh(+) types will be affected by disease as antibodies in maternal serum cross and attack fetal red cells.
