Pregnancy Flashcards
What happens in the first stage of labour?
Latent stage (onset of labour to 4cm dilation) • Effacement: thinning of the cervix, internal os incorporated into uterus. • duration <20hrs primagrav, <14hrs multigrav
Active stage (4 cm dilation to full dilation (about 10cm)) • should dilate minimum of 1.2cm/hr primagrav, 1.5cm/hr multigrav.
What happens during the second stage of labour?
Stage 2 lasts from full dilation to delivery
• lasts <2hrs, or <3hrs if regional anaesthesia used
Propulsive: baby propelled by uterine contractions (from full dilation until head hits pelvic floor)
Expulsive: baby expelled by pelvic floor muscles (from irresistible urge to push caused by floor stretching to delivery)
What happens in the third stage of labour?
Afterbirth: expulsion of placenta and membranes (<30 minutes)
What happens in the latent phase of the first stage of labour (and how long does it last)?
Latent stage (onset of labour to 4cm dilation) • Effacement: thinning of the cervix, internal os incorporated into uterus. • duration <20hrs primagrav, <14hrs multigrav
What happens during the active phase of the first stage of labour?
Active stage (4 cm dilation to full dilation (about 10cm)) • should dilate minimum of 1.2cm/hr primagrav, 1.5cm/hr multigrav
What happens during the propulsive phase of the second stage of labour?
Baby propelled by uterine contractions (from full dilation until head hits pelvic floor)
What happens during the expulsive phase of the second stage of labour?
Baby expelled by pelvic floor muscles (from irresistible urge to push caused by floor stretching to delivery)
What are the CARDINAL signs of labour?
- Effacement (incorporation of internal os and cervical canal into lower uterine segment)
- Dilation (increased diameter of cervical os)
What are ALL the signs of labour?
- Effacement (incorporation of internal os and cervical canal into lower uterine segment)
- Dilation
- Contractions
- Descent of head
- Operculum (“show” - blood stained mucus discharge, occurs in 2/3rds of pregnancy in early labour)
- Rupture of membranes (ROM - “waters breaking”. 75% occur after cervix is >9cm dilated)
What is caput succedaneum?
Odema of neonate’s scalp, due to pressure against dilating cervix. (Fluid between scalp and skull).
Management: observation only. Usually resolves itself
What is moulding (in neonates)?
Pressure on the head (from the birth canal) may cause the fontanelles to close, and skull bones may even overlap (more common in cephalic position)
The baby will be born with an oblong head, but will usually resolve by itself.
How do you define engagement of the foetus?
Descent of biparietal diameter (diameter from left to right parietal bones) through pelvic brim (pelvic inlet, superior)
Clinically: less than 2/5ths of baby’s head palpable in abdomen
What is the lie of the foetus? What types are there?
Lie: relation of long axis of foetus to mother.
Types: Longitudinal, transverse, or oblique.
What is the presentation of the foetus? What types are there?
Presentation: part of foetus in lower pole of uterus
Types: cephalic, vertex (transverse lie), or breech
What is the position of the foetus?
Position: relationship of presenting part of baby to pelvis
Examples:
• DOA: direct occipito anterior (normal)
• LOL: left occipito lateral
(In breech presentation, sacrum is used to describe position)
What is the attitude of the foetus?
Attitude: degree of flexion/extension of foetal head
What does the “station” of the foetus describe?
Station: relation of head to ischial spines
E.g.:
-3 = foetal head is 3cm superior to spines
+4 = 4cm inferior to spines
0 = level with spines
What is the mechanism of normal birth? (LOL, ED FIRER)
LOL, ED FIRER:
Engagement and Descent
• Head engages in LOL position and descends past pelvic brim
Flexion
• Chin tucks against chest so smallest diameter is presenting - “sub-occipito bregmatic”
Internal Rotation
• Head turns to DOA (head rotates more than body)
Extension
• Head and neck extend, delivering the head
Restitution (or External Rotation)
• Head and shoulders rotate back to LOL for easier passage
Which drugs might you give in the event of post partum haemorrhage? Why?
Oxytocin (Syntocinon)
• Stimulates uterine contraction; induces strong contractions, aiding clotting. Short acting
Ergometrine
• Induces “tetanic contraction” - prolonged spasm lasting up to 30 mins; “clamps down” uterus, aiding clotting. Long acting (older drug - oxytocin preferred)
Syntometrine
• Combination of oxytocin and ergometrine - short and long acting
CONTRAINDICATIONS:
• Previous caesarean: risk of uterine rupture
• High BP (further elevates BP)
Which drug might you give for inefficient uterine action? Why?
(Inefficient uterine action almost exclusively occurs in primagravidae.)
Oxytocin (Syntocinon)
• Stimulates uterine contraction; short acting.
CONTRAINDICATIONS:
• Previous caesarean: risk of uterine rupture
• High BP (further elevates BP)
Which drugs might you use to induce labour? Why?
Oxytocin (Syntocinon)
• Important in effacement of cervix, stimulates uterine contraction.
Prostaglandin E2 analogues (e.g. Dinoprostone)
• Ripens (softens) and effaces cervix.
