2 - preterm labour

Question 1

when is extreme preterm?

Answer 1

22 - 26 wks

Question 2

when is early preterm?

Answer 2

26 - 34 wks

Question 3

when is preterm?

Answer 3

34 - 36 wks

Question 4

what are some factors that increase risk preterm birth?

Answer 4

• smoking (doubles risk)
• maternal age <18
• domestic violence
• UTI (send MSU to test)
• vaginal infections, neisseria gonorrhoea & chlamydia trachomatis
• previous mid trimester loss
• previous preterm
• cervical surgery
• uterine abnormality
• previous full dilation at c-section

Question 5

what investigation done for preterm?

Answer 5

transvaginal scan on mid trimester anomaly scan (done at 18-20+6 wks) where measure cervix length, < 25 mm risk of preterm birth

Question 6

if find cervix length of less than 25 mm what is next step?

Answer 6

do fortnightly scans from 16-24 wks to check length

Question 7

when are times you would do regular scans to check length of cervix?

Answer 7

• spontaneous labour before 34 wks
• spontaneous miscarraige

Question 8

what is management of <25 mm cervix before 35 wks?

Answer 8

1. cervical cerclage = put stitch into cervix to try maintain integrity to reduce risk birth
2. progesterone pessary = inserted vaginally, pessary into vagina & sits at cervix
3. arabin silicon pessary

Question 9

what management done if cervix already open?

Answer 9

→women should be admitted & screen for infection, called rescue stitch -urgent cerclage placement

Question 10

what are the different types of cerclage/stitches done to try manage risk of preterm labour?

Answer 10

• transabdominal = sits very high - needs C-section for birth if do this
• high transvaginal, shirodkar
• transvaginal = called McDonald stitch →most common

Question 11

what are contraindications to stitch for reducing risk preterm labour?

Answer 11

• active preterm labour
• infection - chorioamnionitis
• vaginal bleeding
• ruptured membranes (risk placental rupture)
• evidence foetal compromise
• lethal fetal abnormality

Question 12

what are complications of cervical cerclage?

Answer 12

*rare, higher if rescue cerclage

• UTI
• membrane rupture
• bleeding
• cervical trauma (tearing through cervix in labour)
• erosion

Question 13

how to predict preterm labour? what examinations done?

Answer 13

• do full history - Obs & Gyn qs
• examination →palpable contractions, foetal lie (confirm w ultrasound), vaginal exam - assess length & dilation cervix

use app as predictive tool, >5% risk need to make plan for potential preterm birth

Question 14

when might plan for preterm birth?

Answer 14

• foetal growth restriction
• preeclampsia (to prevent maternal morbidity & mortality)
• maternal comorbidities
• placenta accreta (placenta grows into uterus wall & fails to detach in childbirth, leaving potentially damaged uterus)

Question 15

what are 4 important antenatal optimisation?

Answer 15

• steroids
• magnesium sulfate
• antibiotics
• place of birth (neonate ward close)

Question 16

why & when give steroids for antenatal optimisation?

Answer 16

= give baby steroids within 7 days of birth, if <34 weeks

• help preterm babies do well after birth, give 2 doses of dexamethasone (needs to be able to cross placenta), help baby produce surfactant that helps long function, reduces mortality etc

Question 17

why & when give magnesium sulfate as antenatal optimisation?

Answer 17

reduces cerebral palsy & death- within 24hrs if birth <32 weeks

Question 18

why & when give antibiotics as antenatal optimisation?

Answer 18

prevent early onset group B strep infection - if before 37 weeks - usually benzyl penicillin (if not vancomycin)

Question 19

what is tocolysis?

Answer 19

slows labour, only use it to allow steroids to take effect, give it 24hrs before steroid doses & so don’t deliver on route to hospital