Obstetric Analgesia and anesthesia

Question 1

Rate of PTB

Answer 1

10%

• 50% of which followed PTC
• 25% after PPROM
• 25% due to IOL for complications

Question 2

Modifiable risk factors for PTB

Answer 2

low maternal prepregnancy weight
smoking
substance abuse
SIP (<18m)

Question 3

non-modifiable risk factors for PTB

Answer 3

• # prior PTB
• UTI’s and STIs (including BV)
• treatment of these do not decrease your risk of PTB
• pyelo though is an independent risk factor and it further increases PTB rates. So you want to treat UTIs
• cervical length (<25mm at 16-24w gestation)

Question 4

Stratgiesto assess risk for PTB include:

Answer 4

• cervical length via TVUS
• optimize whatever condition got them into preterm labor last time
• (treating asymptomatic BV doens’t help them
• FFN isn’t recommended as a primary screening test given the amount of false positives

Question 5

cervical length guidelines

Answer 5

• in a singleton with no prior PTB: TVUS/ABUS at 18-22.6 weeks conducted as part of anatomy scan (though cost benefit unclear)
• singleton preg with prior PTB: serial TVUS 16w with serial repeats until 24.0 is recommended. should be repeated 1-4 week intervals
• Multiple gestations: limited data, only do one scan at anatomy scan with TVUS of cerical length

Question 6

strategies to reduce PTD risk:

Answer 6

• vaginal progesterone 200mg daily from point of dx of shortened cervix until 36-37w for asymptomatic pt (okay for twins, but data limited)
• 17 OH progesterone IM is not recommended to prevent PTD in those without prior PTD
• US cervical cerclage without hx of PTD is only helpful for Beverly shortened cervixes (<10m). No benefit if between 10-25mm
• Exam indicated cerclage for pt’s dilated in 2nd trimester is unclear, counsel on risk for perivialbe baby
• cervical pessary use isn’t recommended