Labour: Normal and Abnormal Delivery Flashcards
What is foetal lie?
The relationship between the long axis of the foetus and the long axis of the mother
What can foetal lies be?
Longitudinal: parallel
Oblique
Transverse
What is presentation of the foetus?
The part of the foetus that will present first (lying over the inlet)
What can foetal presentations be?
Cephalic (vertex, face, brow)
Breech (footling, frank)
Shoulder
What is engagement of the foetus?
Descent of the foetal head into the pelvis
Described as <=2/5 of the head palpable abdominally, above the pubic symphisis
What is Attitude of the foetus?
Relationship of the foetal head to other body parts (flexed/extended)
What is the denominator’
The arbitrary chosen point of the presenting part of the foetus used to describe the position of the foetus
What is the denominator for a vertex cephalic foetus?
occiput
What is the denominator for a brow cephalic foetus?
frontal
What are the diameters of the pelvic inlet?
Transverse 13.5
AP 11
What are the borders of the pelvic inlet?
Anterior - pubic symphysis
Lateral - ilium
POsterior - sacrum
What are the diameters of the pelvic outlet?
Transverse 11
AP 13.5
What are the borders of the pelvic outlet?
Anterior - inferior border of pubic symphiosis
Lateral - inferior ramus of pubis, ischial tuberosity, ligaments,
Posterior - coccyx
What do the measurements of pelvic inlet and outlet mean for the baby head?
At the pelvic inlet - head should be transversals
At pelvic outlet - head should be OA
Where does the head rotate from transverse to OA?
In the mid pelvis
As diameters in the mid pelvis are quite similar (around 12 cm
How many types of pelvis are there, and which is the most common and best for childbirth?
FOUR types of pelvis
Gynaecoid is the best for labour
Where is the occiput on the baby’s head?
Over the posterior fontanelle
Where is the vertex on the foetal head?
The area between the parietal bones and the anterior and posterior fontanelle
What is caput and how is it graded?
Caput = swelling on the foetal scalp due to pressure against the cervix
Graded subjectively from 1 to 3
What is moulding ?
Overlapping of skull parietal vibes of the foetus as thee baby’s head is squeezed through the maternal pelvis
What it severe moulding an indication of ?
Obstructed labour
What is the best cephalic position for spontaneous vaginal birth? and which positions should you avoid?
OA is the best
OT (occipito-transverse) or OP (occipito-posterior) are bad
What is the cervix like before labour?
Long, firm, closed
Covered internally by a protective mucous plug
What happens to the cervix for labour to progress?
Softens, shortens, thins out (EFFACES), dilates
What is the cellular action of prostaglandins and oxytocin?
They increase cellular calcium
Thereby they stimulates contraction
What is retraction of the uterus?
Progressive shortening of the uterus due to actin-myosin interactions along the whole length of the filament
What happens to the uterus because of retraction?
Upper segment becomes thicker and actively contracting
Lower segment becomes thinner and stretched out
This results in the cervix being taken up (effaced) into the lower segment of thee uterus
What is the function of progesterone during late gestation
Progesterone maintains uterine relaxation (suppresses prostaglandin and oxytocin release)
What hormone opposes the action of progesterone?
oestrogen
What hormonal changes occur prior to labour?=
Decrease in progesterone receptors
Increase in oestrogen
Synthesis of Prostaglandin by chorion and decidua
Synthesis of CRH by placenta
What is the function of CRH?
Potentiates prostaglandins and oxytocin
What is the function of prostaglandins and oxytocin
to cause myometrial contractions
What is the Ferguson reflex?
pressure of the foetal presenting part against the crvix causes increased oxytocin release from the maternal putuitary
This stimulates uterine contractions
This in turn increases pressure on the cervix
What is labour?
The presence of strong regular painful contractions resulting in cervical changes (dilatation, effacementI) and aiming to expel the foetus