Third stage of labour

Anatomy and applied physiology

1. Third stage of labour

2. Definitions and Principles
Third stage –From birth of the baby, until complete
expulsion of placenta and membranes, and control of
haemorrhage.
Physiological v Active management

3. Definitions and Principles
Physiological management
•Leave cord intact
•Placenta expelled by normal physiological processes
aided by gravity/maternal effort
Active management
•administration of prophylactic uterotonic,
•clamping and cutting of umbilical cord
•delivery of the placenta by Controlled Cord Traction
(CCT) / modified Brandt Andrews.

4. Definitions and Principles
Delayed cord clamping –Recent interest in delaying
cord clamping to enable neonate to obtain extra
blood and prevent anaemia.
Lotus birth –cord is kept attached to placenta until it
separates from umbilicus
http://sarahbuckley.com/lotus-birth-a-ritual-for-our-times

5. Separation and descent of the placenta
Mechanical factors
•Retraction during second
stage results in reduction in
size of placental bed by 75%
•Placenta becomes
compressed
•Blood in intervillousspaces
forced back into decidua
•Oblique muscle fibres clamp
down on blood vessels
•Vessels become tense,
congested

6. •With next contraction
vessels burst, blood seeps
between spongy layer of
decidua and the placenta
•Placenta separates and
falls into LUS
•Uterus contracts strongly
and placenta expelled

7. Schultze method of separation (A)
•Placenta separates usually
centrally first forming
retroplacentalclot
•Increased weight continues
separation process and
peeling of membranes off
uterine wall.
•Clot enclosed in
membranous bag and
expelled fetalsurface first
•Associated with less blood
loss and complete
membranes

8. Matthews Duncan method of separation (B)
•Placenta separates from a
lateral border
•Blood escapes, no clot to aid
process
•Placenta descends by
slipping down uterine wall
•Placenta expelled maternal
surface first
Associated with ragged,
incomplete membranes and
increased blood loss

9. Haemostasis
Potential blood loss through
placental site 500-800mls per
minute!
Haemostasis achieved by
•Ligature action of oblique
muscle fibres (living ligatures)
•Direct pressure from uterine
walls with contraction
•Activation of coagulation
cascade –rapid clot formation
•Oxytocin –neonate nuzzling,
breastfeeding

10. Physiological/expectant management
Normal physiological processes expel placenta.
Takes 10 –60 mins, occasionally longer
Calm, quiet environment
Put baby to the breast
Upright position -gravity aids process
Watch and wait
Contraction with pressure felt by mother
Maternal effort will deliver placenta/ may need
gentle assistance/twist to remove membranes

11. Signs of separation
Contracted uterus –
fundus rises, narrows,
becomes mobile
Small fresh blood loss
Cord lengthens

12. Active management
Oxytocic drug given with
anterior shoulder or soon after
birth
Early cord clamping?
Observe for signs of separation
Counter traction above
symphysis pubis
Deliver by Controlled Cord
Traction (CCT) / modified Brandt
Andrews.
Takes 5-15 mins
Mother plays passive role

13. Uterotonic drug choices
Syntocinon –IV/IM 5iu –drug of choice
Ergometrine –IV 0.25 –0.5mg, not used routinely
Syntometrine –IM 1ml contains syntocinon 5iu plus
0.5mg ergometrine
Misoprostol (prostaglandin analogue) –
Oral/vaginally/rectally 400-600 microgrammes.
Useful where no refridgeration facilities
NB Use of ergometrine in any combination not
recommended if raised BP

14. Action of syntometrine

15. Midwife’s role
Be aware!
Maintain asepsis -laceration/bruising/open
placental site
Observation of mother and baby
After expulsion of placenta and membranes
•Cord blood if required
•Check fundus well contracted
•Examine birth canal for lacerations (?PR)
•Estimate and continue to observe blood loss
•Examination of placenta and membranes

16. Cord Blood Sampling
Required
•When mother’s blood group is Rhesus Negative
•When atypical maternal antibodies are present
•Where haemoglobinopathyis suspected
•When there has been concern about the neonate
during labour or immediately after birth (NICE
2014)
Taken from fetalsurface of placenta or cord

17. Paired cord sampling
‘Paired samples’ -both arterial and venous samples
taken from the cord.
Carried out routinely in some units
Selectively for circumstances such as
•Babies having had fetalblood sampling in labour
•Instrumental/Caesarean/Vaginal breech births
•Babies with Apgar under 5 at 1min
•Babies with severe growth restriction
•Babies >24 wks<37 wks

19. Examination of the Placenta
and Membranes

20. The placenta at term
Flat, round/oval
Approximately 20cm diameter, 2.5 cm deep
Weighs approx. 1/6
th
weight of fetus
Usually situated in Upper Uterine Segment.
Two surfaces –maternal, fetal

22. Maternal surface
Embedded into decidua
Deep –red appearance
Surface composed of 16-20
cotyledons, divided by sulci

23. Fetal surface
Lies adjacent to the fetus
White, glistening
appearance
Umbilical cord joins,
usually centrally
Cord vessels radiate out
across surface
Cord and fetal surface
covered by amnion.

24. Umbilical cord
Approximately 50cm long, 2cm thick, spiral twist
Contains two umbilical arteries, one vein
Vessels enclosed in Wharton's jelly
Covered by amniotic membrane continuous with that covering
fetal surface

25. Fetal membranes
Chorion
•Formed from the
trophoblast of the embryo
•Opaque in appearance,
thick, friable
•Continuous with edge of
placenta
Amnion
•Secretes amniotic fluid
•Smooth, transparent
•Covers fetalsurface of
placenta

26. Amniotic fluid
Also known as liquor amnii
•Produced continuously by the amnion
•Clear straw coloured fluid
•99% water and 1% solid matter
•Made up of proteins, carbohydrates, lipids, and
phospholipids, electrolytes, urea, uric acid, and
creatinine, enzymes and placenta hormones.
•Contains fetalepithelial cells, vernix caseosaand
laguno-makes liquid milky

27. Amniotic fluid
•Fetus recycles it –swallowing/urinating
•Approximately 1000ml at term
•Maintains a constant temperature
•Cushions fetus
•From uterine walls
•From the noises of body systems
•From the pressure of the cervix during labour

28. Why examine the placenta and membranes?
To rule out any abnormalities which may indicate
fetalanomalies
To ensure placenta and membranes expelled
complete
•Retained placenta/membranes lead to
haemorrhage or infection

29. Process
Maintain universal
precautions
Hold by cord –may
indicate where
membranes ruptured
and whether membranes
are complete

30. Lay on flat surface and examine both surfaces
•Maternal surface –missing cotyledons, infarctions,
position of blood vessels
•Fetalsurface –insertion of cord,
•Presence of two membranes
Check umbilical cord for three vessels, 2 arteries, 1
vein
Dispose appropriately

31. Placental anomalies
Succenturiatelobe
•Extra segment may be
retained leading to
infection/haemorrhage
•Cord in membranes –
vasa praevia

32. Velamentous
insertion of cord
•Vasa praevia
•Cord separates from
placenta during
third stage
Mamabirth.com

33. Battledore placenta
•Cord attached to
edge of placenta
•May separate during
third stage
Mamabirth.com

34. Circumvallate placenta
•Membranes doubled
back at the edge
•No clinical significance
Fetalultrasound.com

35. Bi/Tripartite placentae
•Two or three separate
lobes
•?Vasa praevia
Minnesotaplacenta.com

36. Cord anomalies
Vasa praevia
•Blood vessels from the placenta lie over the cervical
os
•Risk of rupture and haemorrhage if artificial rupture
of membranes
•Spontaneous rupture usually follows more friable
membrane route
Absence of blood vessels

37. Knots in the cord
True False

38. Immediate care
Skin to skin –maintain infant temperature
Dispose of all equipment appropriately including
placenta (mother may wish to keep this)
Carry out postnatal observations including blood loss
Carry out neonatal examination
Make mother comfortable
Encourage breastfeeding
Documentation
Observe mother and baby for one hour

39. Sources
National Institute for Health and Care Excellence 2014 Guideline CG
190 Intrapartum care for healthy women and babies. NICE, London
Marshall J, Raynor M (eds) 2014 Myles’ Textbook for Midwives 16
th
ed
Elsevier, Edinburgh
MacDonald S, Maguill –Cuerden J (eds) 2011 Mayes’ Midwifery 14
th
ed. Elsevier, Edinburgh
Wylie L 2005 Essential Anatomy and Physiology in Maternity Care 2
nd
ed. Elsevier, Edinburgh