upgrading Knowledge

1. Dr. Sourav Chowdhury
Senior Resident
Preterm Labour

2. Definitions
WHO defines PTL as
onset of labour after the
gestation of viability and before
37 completed weeks or 259
days of pregnancy.

3. Working Classifications
PRETERM
LABOUR
Extreme
preterm
Early
Preterm
Late
Preterm
< 28 weeks 28 - < 32 weeks 32 - < 37 weeks
The majority of the preterm infants belong to the late preterm subgroup (Marken et al., 2008).

4. Criteria for PTL
Documented uterine Contr.
(1/10min)
Ruptured fetal membranes
Documented Cx change (<1cm)
Cx dilatation>2cm
James 4th Edition High Risk Pregnancy Chap. 61 pg-1075

5. Associations
 Low socioeconomic status
 Maternal age
 Low pregnancy wt.
 Smoking & substance abuse
 Multiparity
 Previous History
 Infection
 Cervical Intrumentation or surgery
 Uterine Abnormalities
 PROM

6. Screening
 Uterine contraction monitoring
 Colton and Associates
 US preventive service task force
 Cervical screening by TVS(sogc)
 Cervical length (less than 25mm)
 Cervical Funneling
 Fetal Fibronectin ( 50ng/ml )RCOG
23rd edition Williams Obstetrics ACOG Practice Bulletin Vol.120 no.4 N Engl J
Med 1998;338:15–9. (Level I)

7. Preterm Management
Management
Preventive Definitive

8. Prevention
Progesterone
Cervical
Cerclage
There is no clear evidence that tocolytic drugs improve outcome and therefore it is reasonable not to use
them. However, tocolysis should be considered if the few days gained would be put to good use, such as
completing a course of corticosteroids or in utero transfer.

9. Progesterone
 Cervical Length ≤15mm or prior H/O – spont.
Preterm
 Progesterone group 90-200mg P/V or 17a-
Hydroxy P caproate IM
 Spontaneous delivery before 34 weeks in
progesterone group vs placebo significantly less (
19.2% vs 34.4%; RR 0.56; 95% CI 0.36 to 0.86)
 No statistical Significant reduction in neonatal
morbidity
SOGC & ACOG

10. Short Cervix with TVS
Singleton Multiple
Low risk
Group
Vaginal
Progestero
ne offered if
Cx 20mm
or less at or
before 24
weeks
High risk
Group and
receiving
progesterone
since 16-
34wks
Cerclage
should be
considered if
cervical
length is
less than25
mm
before24
weeks of
gestation
No intervention
improves
outcome
ACOG

11. Indications Indicate
d
Formulation, dose and
route
FDA
Approved
Prior spont. preterm birth Yes 17alpha
Hydroxyprogesterone
caproate 250mg weekly IM
from 16-20weeks to
36weeks
Yes
Cervical shortening
≤15mm prior to 24 weeks
Yes Progesterone suppository
90-200mg vaginally each
night from time of diagnosis
to 36weeks
No
Multiple gestations No - No
PPROM No - No
Positive fFN test No - No
Cervical cerclage in place No - No
Undelivered after an
episode
Unclear - No

12. Cervical Circlage
 History Indicated Circlage
 Only if 3 or more previous preterm or 2nd Trimester loss (15% vs 32% p<0.005)
 Not offered if 2 or less previous preterm or 2nd trimester loss (14% vs
17% & 12% vs 14%)
 H/O painless cervical dilatation, rupture of membrane before onset of
contraction and additional risk factors are not helpful for decision to
place History indicated circlage
 Usg Indicated
 If Cx is ≤25mm circlage is not indicated if no H/O spontaneous
preterm or 2nd trimester loss ( 22% vs 26%; RR 0.84; 95% CI 0.54 -
1.3; p=0.44)
 Women with singleton pregnancy without
 Spontaneous Midterm loss or preterm birth should not be offered usg
indicated circlage IF Cx is ≤25mm before 24 weeks gestation
 USG indicated circlage not recommended for funneling of cervix in
absence of cervical shortening≤25mm
 Rescue Cerclage –
 Cx dilated >1-2cm with or without perceived ut. Contractractions ( with
or wihtout membrane bulging)

13. Definitive
 Corticosteroid Administration
 Single dose antenatal corticosteroids to women
between 24-34 weeks with High risk of preterm birth
(level 1++)
 Ante-natal corticosteroid can be considered for
women between 23rd and 23+6 (level 2)
 Ante-natal corticosteroid should be given to all
women whom an elective caesarean section
planned prior to 38weeks. (level 2)
Green-top Guideline no.7 RCOG

14. Tocolysis :
 There is no clear evidence that tocolytic drug
improve outcome therefore it is reasonable not to
use them. (level A)
-Use them only to gain few days would be put to good
use such as corticosteroid course or in-utero
transfer
 Tocolytic drug not associated with clear reduction
in perinatal or neonatal mortality or morbidity
(level A)
 Not recommended in suspected preterm labour
who had otherwise uncomplicated pregnancy
- Only in those who benefit by gaining time to
Hosiptal or NICU transfer or not completed steroid

15. Tocolytic Drugs :
 Nifedepine and Atosiban has comparable
effectiveness (levelA)
 Compared to β agonist nifedepine improves
neonatal outcome (levelA)
 β agonist have higher side-effects (levelA)
 Nifedepine, Atosiban and COX inhibitor lesser side-
effects(levelA) comparing effectiveness is unclear
 There is insufficient evidence for any firm
conclusions about whether or not tocolysis leads to
any benefit in preterm labour in multiple pregnancy
 Maintenace therapy in threatened preterm is not
recommended

16. Antibiotics :
 In PROM
 Routine use reduces maternal and neonatal
morbidity (level 1a)
 Choice of antibiotic any penicillin (except co-
amoxiclav) or erythromycin for 10days
 In Preterm Labour (membrane intact)
 Use of antibiotic is not at all recommended
 Kenyon & colleagues study shows neonatal
exposure to antibiotic more prone to cerebral palsy
at age 7 than non exposed

17. Neuroprotection
Magnesium Sulphate
 Administration of MgSO4 significant reduction
in cerebral palsy in gestation age before
28weeks (rouse et al)
 Administration of MgSO4 before 30weeks of
gestation (University of Adelaide)
 Administration even for multiple gestation
 For expected delivery within 24hour
 Even in PROM
 Can be administer 4hour before delivery
(Australian guidelines)

18. Take Home Message
 TVS preferred modality for Cx length
 Fibronectin level positivity between 24-34 wks-asso with
PTL
 No usefulness of routine uterine monitoring (cost-benefit)
 Vaginal Progesterone recomm. for singleton
pregnancy(lowrisk) with CxL <2cm at 24 weeks or more
 High risk group should given 17alpha Hydroxy
Progesterone Caproate
 Only if 3 or more previous preterm or 2nd Trimester loss -
History indicated cerclage
 There is no clear evidence that tocolytic drug improve
outcome therefore it is reasonable not to use them.
 Administration of MgSO4 before 30weeks of gestation for Fetal
neuroprotection.

19. Thank
You !