#199 Use of Prophylactic Antibiotics in Labor and Delivery

Question 1

According to the CDC what % of antibiotics prescribed in acute care hospitals in the US are inappropriate?

Answer 1

20-50%

Question 2

A comparison of very-low-birth-weight neonates (<1500g) born between 1998 and 2000 and 1991 and 1993 showed increase, decrease, or same incidence of early-onset neonatal sepsis from GBS? For Sepsis caused by e coli?

Answer 2

Decrease incidence of neonatal sepsis from GBS. Increase in sepsis caused by E coli.

Question 3

Is sepsis in very-low-birth-weight neonates with ampicillin-resistant E coli more or less likely to be fatal than neonates with susceptible strains?

Answer 3

More likely to be fatal

Question 4

What % of GBS isolates are resistant to erythromycin and clindamycin?

Answer 4

Up to 30%

Question 5

What is the incidence of severe allergic reaction to penicillin? Less severe reactions?

Answer 5

1 in 2,500-25,000. 10% with less severe reactions

Question 6

What % of patients who receive antibiotic in hospital will have severe adverse reaction?

Answer 6

Approximately 5%

Question 7

What % of patients with a PCN allergy may react if given a cephalosporin?

Answer 7

Up to 10%

Question 8

What is the risk of skin reactions (urticaria, rash, pruritius) and anaphylaxis to cephalosporin administration?

Answer 8

Skin reaction: 1-3%

Anaphylaxis: 0.001-0.1%

Question 9

How does the physiologic state of pregnancy affect levels of antibiotics, how?

Answer 9

Increased GFR (decreases drug half-life, lower peak serum level), increased plasma volume (large volume of distribution), Hormone-mediated increases in binding proteins, decreased gastric emptying time and acidity (may change oral absorption of drugs)

Question 10

What antibiotics are known to reach fetal concentrations of 30-90% of maternal serum in the 2nd trimester and beyond?

Answer 10

Include ampicillin, cephalothin, clindamycin, vancomycin, azithromycin, and aminoglycosides

Question 11

What is the dose of cefazolin prior to cesarean section? Based on weight.

Answer 11

Can use standardized 2g dose.
If <80kg can do 1g.
In non ob patients can do 3g in patients 120kg or more, but not strongly supported in Ob literature.

Question 12

What effect does vaginal cleansing prior to cesarean section have for women who were in labor or those with ruptured membranes.

Answer 12

Reduced risk of endometritis and postoperative fever, but does not decrease risk of wound infection.

Question 13

What solutions can be used for vaginal preparation prior to cesarean section?

Answer 13

10% providone-iodine or chlorhexidine gluconate with 4% alcohol

Question 14

What is the single most important risk factor for infection in the postpartum period?

Answer 14

Cesarean section.

Question 15

What should you do if antibiotic prophylaxis was not able to be administered prior to start of cesearean section (eg stat delivery)?

Answer 15

Administer as soon as possible after incision is made

Question 16

What is alternative antibiotic regimen for pre op antibiotics for cesarean section if someone has a significant penicillin allergy?

Answer 16

Single-dose combination of clindamycin (900mg) with an aminoglycoside (5mg/kg)

Question 17

What does the current evidence say regarding azithromycin use for cesarean deliveries?

Answer 17

Supports use for women undergoing nonelective cesarean delivery

Question 18

How do surgical site infection rates compare after cesarean section if patients receive ancef within 1 hour of incision vs greater than 1 hour before incision?

Answer 18

Double the rate of SSI if more than 1 hour before incision

Question 19

When should patients in a cesarean section receive additional ancef?

Answer 19

If surgery >4 hours, if EBL >1500cc

Question 20

Does pre operative cesarean section antibiotics change if patient is known MRSA carrier?

Answer 20

Can consider adding vanc to regimen (vanc is not sufficient coverage by itself for cesarean delivery ppx)

Question 21

Does latency antibiotics for PPROM affect neonatal morbidity and mortality?

Answer 21

Reduces respiratory distress syndrome, necrotizing enterocoloitis, intraventricular hemorrhage, and early onset sepsis

Question 22

Does antibiotic prophylaxis after PPROM affect maternal infectious complications?

Answer 22

yes, reduces them

Question 23

Why is amoxicillin-clavulanic acid contraindicated for latency antibiotics for PPROM?

Answer 23

Increased risk of neonatal necrotizing enterocolitis

Question 24

If someone is tested for GBS in the setting of PPROM and results are negative, but patient delivers 6 wks later, what do you do?

Answer 24

Should retest prior to delivery if 5 or more weeks since negative baseline GBS test

Question 25

If someone is tested for GBS in the setting of PPROM and results are positive, but patient delivers 6 wks later, what do you do?

Answer 25

Test does not need to be repeated and patient should receive GBS prophylaxis

Question 26

Is infective endocarditis prophylaxis recommended for women with acquired or congenital structural heart disease for either vaginal or cesarean delivery?

Answer 26

No, only conditions associated with the highest risk of adverse outcomes from endocarditis are appropriate for prophylaxis [cyanotic heart dx, prosthestic valves, or both]

Question 27

What cardiac conditions have a high risk of endocarditis in the presence of bacteremia?

Answer 27

Prosthetic cardiac valve or prosthetic material used for valve repair, previous infectious endocarditis, patients with CHD [unrepaired cyanotic CHD, repaired CHD repaired with prosthetic material or device during first 6mo post op, repaired CHD with residual defects], cardiac transplant recipients with valve regurg d/t structurally abnormal valve

Question 28

What antibiotics can be used for infective endocarditis antibiotic prophylaxis regimens for high-risk women?

Answer 28

IV: ampicillin 2g IV or ancef 2g IV or ceftriaxone 1g IV
Allergic to PCN: ancef or ceftriaxone 1g or clindamycin 900mg
Oral: amoxicillin 2g
Oral, allergic to PCN: keflex 2g, clindamycin 60mg, azithromycin 500mg

Question 29

Is antibiotic prophylaxis appropriate for patients undergoing repair of 3rd degree or 4th degree lacerations?

Answer 29

A single dose of antibiotic at the time of repair is reasonable in the setting of OASIS

Question 30

Is antibiotic prophylaxis recommended for history-, ultrasonography-, or examination-indicated cervical cerclage?

Answer 30

Evidence insufficient to recommend antibiotic prophylaxis

Question 31

What is the risk (%) of preexisting chorioamnionitis as a cause of cervical insufficiency?

Answer 31

Approximately 33%. Often subclinical

Question 32

Are antibiotics recommended for manual removal of the placenta after vaginal delivery?

Answer 32

existing data do not support antibiotic use

Question 33

Are antibiotics recommended for postpartum dilation and curettage?

Answer 33

No data to recommend for or against prophylactic antibiotics

Question 34

Are antibiotics recommended for placement of indwelling intrauterine balloon catheter in setting of retained placenta or postpartum hemorrhage?

Answer 34

No data to recommend for or against prophylactic antibiotics

Question 35

Which patients do not need pre op antibiotic prophylaxis for cesarean section?

Answer 35

If already receiving an antibiotic regimen with equivalent broad-spectrum coverage (eg, for chorioamnionitis)

Question 36

Should antibiotic prophylaxis be used for pregnancy prolongation in women with preterm labor and intact membranes?

Answer 36

No

Question 37

Should all pregnant women receive MRSA screening?

Answer 37

No