Cervical Insufficiency

Question 1

Cervical insufficiency definition

Answer 1

The inability of the uterine cervix to retain a pregnancy in the second trimester, in the absence of uterine contractions

Question 2

Risk factors

Answer 2

Cervical:

• collagen abnormalities
• uterine anomalies
• biological variation (but some deliver at term still even if congenital)

Past Obs. Hx:
-recurrent mid-trimester preganancy losses
Previous PPROM <32
Prior pregnancy with a cervical length measurement of <25mm prior to 27 weeks

Acquired:

• cervical trauma
• mechanical dilatation
• treatment of CIN

Question 3

Conservative Managment with risk factors for cervical insufficiency but no history of previous loss

Answer 3

Urine MC&S
HVS
TV cervical length at anatomy

> 30mm=no follow up
25 to 29mm= 2 weekly TVS up until 24 weeks
-consider cerclage if further evidence
<24mm=commence progesterone, consider steroids at 24/40

Question 4

conservative management with a previous 2nd trimester loss or a previous preterm delivery before 34/40

Answer 4

Urine MC&S
HVS
Consider progesterone at booking

USS cervical length from 14 weeks 2 weekly until 24

Cervical length >25mm- continue scanning until 24/40
Evidence of shortening <24mm - should be on progesterone, consider steroids at 24/40, if further shortening, consider cerclage

Question 5

Surgical management (3 or more preterm births < 34 weeks (with progressively earlier del) and/or second trimester losses)

Answer 5

Urine MC&S
HVS
Cerclage at 12-14 weeks
2 weekly TVS until 24 weeks gestation
If ongoing shortening despite cerclage, consider progesterone
Steroids at 23/40

Question 6

Acute presentation with suspected cervical insufficiency

Answer 6

Hx: rule out infection or PTL, mat Obs, exam, VE only if birth thought imminent

Invx: MSU, HVS and Vulvo-vaginal swab, FBC, CRP
Consider USS- TV cervical length; TA for fetal wellbeing, unless birth imminent

Management: if no contractions and no signs of infection and cervical os fully effaced and more than 1 cm dilated —>cerclage
Steroids if >24/40

Question 7

USS measurement guidelines

Answer 7

Empty bladder
Vaginal probe in anterior fornix
Length oof endocervical canal measured from the internal to external cervical os
3 measurements should be made over 5 minutes given cervix is dynamic

Question 8

Progesterone (vaginal)

Answer 8

High bioavailability and few systemic side effects; some vaginal irritation
100 or 200mg

Reduces risk of preterm birth
Evidence of improved perinatal outcomes