O&G - Normal Labour & Delivery Flashcards
(43 cards)
What is the definition of Preterm?
Baby born < 37-weeks
What is Breech presentation?
Bottom first i.e.
When caudal end (bottom first) occupies the lower uterine segment
How long do we say a normal pregnancy should last?
40-weeks
(from the 1st day of the LMP to estimated delivery date)
Name some risk factors for Breech presentation.
Risk factors for Breech ppresentation:
- uterine malformations
- fibroids
- placenta praevia
- amniotic fluid abnormalities - polyhydramnios or oligohydramnios
- fetal abnormality (e.g. CNS malformation, chromosomal disorders)
- prematurity (~25% of pregnancies are breech at 28-weeks, this drops to ~3% at birth - thus in prematurity breech is more likely)
What serious complication of delivery is more common in Breech births?
Cord Prolapse
How is Breech presentation managed?
- if < 36-weeks –> many fetuses turn spontaneously
- if breech at 36-weeks –> external cephalic version (ECV)
- ECV success rate = 60%
- Offer ECV from 36-weeks in nulliparous women
- Offer ECV from 37-weeks in multiparous women
- if breech after ECV –> plan delivery options include vaginal delivery OR planned C-section
What advise/info should be given to women when they are considering management of breech presentation after ECV?
- Choice of delivery method for breech-baby at term –> No long term impact on health of baby
- Planned C-section for breech has ↓ perinatal mortality & early neonatal morbidity compared with vaginal delivery for breech
What are some contraindications to women being offered External Cephalic Version (ECV) at 36-weeks (or in general)?
- if C-section delivery is required
- antepartum haemorrhage in last 7-days
- abnormal cardiotocography (CTG)
- major uterine anomaly
- ruptured membranes
- multiple pregnancy
What is Cord Prolapse?
When the umbilical cord descends ahead of the fetus during delivery - if not managed can cause cord compression / cord spasm –> fetal hypoxia / irreversible dmg or death
- 1 in 500 deliveries
- Diagnosis:
- fetal HR abnormal + palpable cord vaginally OR visible cord at vaginal entrance
What are some risk factors for Cord Prolapse?
- prematurity
- multiparity
- twin pregnancy
- polyhydramnios
- cephalo-pelvic disproportion
- abnormal presentations e.g. Breech or transverse lie
- placenta praevia
- long umbilical cord
How is Cord prolapse managed?
- Presenting part of fetus is pushed back into uterus
- Uterine relaxants (tocolytics) used
- If cord is past vaginal entrance –> keep warm + moist (do not push inside)
- Pt is put ‘on all fours’ unitil preparations for emergency C-section are made
- Emergency C-section
Beta-hCG:
- Where is it produced?
- When do it peak during pregnancy?
- What is its effect?
- B-hCG is produced by the placenta
- B-hCG peaks at ~ 7-weeks gestation
- B-hCG –> keep corpus luteum alive
Where are Oestrogen and Progesterone released from during pregnancy?
Corpus luteum until 3rd trimester - then is mainly the placenta
What does Oestrogen do to the uterus during pregnancy?
↑ no. of Oxytocin receptors in uterus
What does Progesterone do to the uterus during pregnancy?
Relaxes uterine smooth muscle - preventing pre-term labour
What is the sequence of hormonal events causing labour in pregnancy?
- Fetal stress –> stims Adrenocorticotropic hormone (ACTH) release from anterior pituitary (fetal) –> stims cortisol release from fetal adrenal glands
- Fetal cortisol –> acts on placenta to:
- ↓ Progesterone
- ↓ Oestrogen
- ↑ Prostaglandins –> stim uterine contraction
- Fetus pushes on cervix/uterus –> stims sensory nerve fibres –> stims oxytocin production by hypothalamus (which is then stored in and released from the posterior pituitary)
- Oxytocin –> stims uterine contraction + ↑ prostaglandins –> labour
What is Labour?
Onset of regular and painful contractions associated with cervical dilation and descent of the presenting part of the fetus
What are the signs of labour?
- a ‘show’ i.e. shedding of mucous plug (clear mucoid discharge)
- regular + painful uterine contractions
- rupture of the membranes (not always) - due to uterine contractions causing rupture of amnitoic sac i.e. ‘water-breaking’
- shortening & dilation of the cervix
What are the Stages of Labour?
- Stage 1 - from the onset of true labour to when the cervix is fully dilated
- Stage 2 - from full dilation to delivery of the fetus
- Stage 3 - from delivery of fetus to when the placenta & membranes have been completely delivered
What monitoring is done during labour?
- Fetal HR every 15-min for 1 min (or continuously via CTG)
- Contractions assessed every 30-min
- Maternal HR / pulse assessed every 60-min
- Maternal BP + temp checked every 4-hours
-
Vaginal exam offered every 4-hours to check progression of labour
- Offer hourly in 2nd stage of labour
- Maternal urine checked for ketones & protein every 4-hours
What position does the head normally deliver in a cephalic delivery?
Occipito-anterior position
(fetus face down)
Fetal head enters the pelvis in the left/right occipito-lateral position then turns for delivery normally
Stage 1 of labour is made of 2 phases - what are they?
- latent phase = 0-3 cm dilation (normally takes ~ 6-hours)
- active phase = 3-10 cm dilation (normally 1 cm/hr)
How long does the stage 2 of labour last on avg?
-
Nulliparous - birth in ~ 3-hours from start of active 2nd stage
- Diagnose delay if active 2nd stage > 2-hours
-
Multiparous - birth in ~ 2-hours from start of active 2nd stage
- Diagnose delay if active 2nd stage > 1-hours
If delay is diagnosed –> operative vaginal birth (instrumental)
What causes amniotic fluid during rupture of membranes to be green / smelly?
Presence of Meconium in amniotic fluid
- Danger - fetus can aspirate the meconium as it floats in the amniotic fluid
