Revision - Obs 5 Flashcards
Frequency of breech presentation?
<5% pregnancies after 37 weeks gestation
What are the 4 types of breech?
1) Complete
2) Incomplete
3) Extended
4) Footling
What is a complete breech?
Where the legs are fully flexed at the hips and knees (like a squat)
What is an incomplete breech?
With one leg flexed at the hip and extended at the knee
What is an extended breech?
(AKA frank breech)
Both legs flexed at hip and extended at knee (like a pike)
What is a footling breech?
A foot is presenting through the cervix with the leg extended.
Management options of babies that are breech at term (37 weeks)?
1) ECV can be offered at 37w
If ECV fails:
2) Choice of vaginal delivery or elective caesarian section.
What is the % chance of an emergency c-section if vaginal birth is attempted in breech babies?
40%
What are women given prior to ECV?
Tocolysis –> relaxes the uterus (i.e. suppresses contractions)
What medication is used for tocolysis in ECV?
Terbutaline
What class of medication is terbutaline?
Beta agonist
Do rhesus D negative women require anti-D prophylaxis prior to tocolysis?
Yes
What type of breech position is most common?
Frank breech (hips and knees fully extended)
What complication is more common in breech presentation?
Cord prolapse
What are some absolute contraindications to ECV?
1) C-section is required
2) Antepartum haemorrhage within last 7 days
3) Abnormal CTG
4) Major uterine anomaly
5) Ruptured membranes
6) Multiple pregnancy
Management of cord prolapse?
Obstetric emergency.
1) the presenting part of the fetus may be pushed back into the uterus to avoid compression
2) if the cord is past the level of the introitus, there should be minimal handling and it should be kept warm and moist to avoid vasospasm
3) the patient is asked to go on ‘all fours’ until preparations for an immediate caesarian section have been carried out
4) tocolytics may be used to reduce uterine contractions
5) retrofilling the bladder with 500-700ml of saline may be helpful as it gently elevates the presenting part
Define stillbirth
The birth of a dead fetus after 24 weeks gestation.
What is used in the induction of labour in stillbirth?
Combination of:
1) oral mifepristone (anti-progesterone)
2) vaginal or oral misoprostol (prostaglandin analogue)
What can be used to suppress lactation after stillbirth?
Dopamine agonists e.g. cabergoline
What are the 3 major causes of cardiac arrest in pregnancy?
1) Obstetric haemorrhage: major cause of severe hypovolaemia and cardiac arrest.
2) PE
3) Sepsis leading to metabolic acidosis and septic shock
What are 5 major causes of massive obstetric haemorrhage?
1) Ectopic pregnancy
2) Placenta praevia
3) Placental abruption
4) Uterine rupture
5) Placenta accreta
How can a pregnant woman lying on her back lead to hypotension (sometimes enough to lead to the loss of cardiac output and cardiac arrest)?
Aortocaval compression:
1) When a pregnant woman lies on her back (supine), the mass of the uterus can compress the inferior vena cava and aorta.
2) The compression on the vena cava is most significant, as it reduces the blood returning to the heart (venous return)
3) This reduces the cardiac output, leading to hypotension.
4) In some instances, this can be enough to lead to the loss of cardiac output and cardiac arrest.
Solution to aortocaval compression?
The vena cava is slightly to the right side of the body –> place the woman in the left lateral position, lying on her left side, with the pregnant uterus positioned away from the inferior vena cava.
In cardiac arrest in pregnancy, how soon after starting CPR should baby and placenta be delivered?
Aim is to deliver the baby within 5 minutes of CPR starting.
CPR should be continued for more than 4 minutes.
The operation is performed at the site of the arrest, for example, in A&E resus or on the ward.
What are the 3 stages of labour?
1st –> from onset of labour until 10cm dilation
2nd –> from 10cm dilation until delivery of baby
3rd –> from delivery of baby until delivery of placenta
How often should foetal heart rate be monitored in labour?
Every 15 mins (or continuously via CTG)
How often should contractions be assessed in labour?
Every 30 mins
How often should vaginal exam be offered in labour to check progression?
Every 4 hours
How often should maternal urine be checked in labour?
4 hours (for ketones & protein)
How long does stage 1 of labour typically last in a primigravida?
10-16 hours
What is cervical effacement?
Cervix gets thinner
What happens in 1st stage of labour?
1) Cervical dilation
2) Cervical effacement
3) Mucus plug in cervix falls out and creates space for baby to pass through
Role of mucus plug in cervix during pregnancy?
Prevents bacteria from entering the uterus during pregnancy.
What are the 3 phases of stage 1 of labour?
1) Latent
2) Active
3) Transition
Describe the latent phase of stage 1 of labour
1) From 0cm to 3cm dilation (progresses at 0.5cm/hour)
2) Irregular contractions
Describe rate of progression of dilation of cervix in latent phase of stage 1 of labour
0.5cm/hour
Describe the active phase of stage 1 of labour
1) 3cm to 7cm (1cm/hour)
2) Regular contractions
Describe rate of progression of dilation of cervix in active phase of stage 1 of labour
1cm/hour
Describe rate of progression of dilation of cervix in active phase of stage 1 of labour
1) 7cm - 10cm dilation
2) Strong & regular contractions
Describe typical location of baby’s head in delivery?
Normally –> OA (i.e. face is facing mother’s spine)
Can sometimes be OP
What is a vertex presentation in delivery?
Ideal position for delivery
It means the fetus is head down, headfirst and facing your spine with its chin tucked to its chest.
What % of babies are vertex at delivery?
90%
When do braxton hicks contractions usually occur?
2nd and 3rd trimester
What can help reduce braxton-hicks contractions?
Staying hydrated & relaxing
Define preterm prelabour rupture of membranes (P‑PROM)
The amniotic sac has ruptured before the onset of labour AND before 37 weeks gestation (preterm).
Define prolonged rupture of membranes (also PROM)
Membranes have ruptured more than 18 hours before delivery
Survival chance of babies born at 23 weeks?
10%
At how many weeks gestation is there an increased chance of survival and full resuscitation is offered in premature babies?
24 weeks onwards
Via what 2 mechanisms can be used for prophylaxis of preterm labour?
1) Vaginal progesterone
2) Cervical cerclage
Role of progesterone in prophylaxis of preterm labour?
Progesterone has a role in maintaining pregnancy and preventing labour by decreasing activity of the myometrium and preventing the cervix remodelling in preparation for delivery.
Who is vaginal progesterone offered to for the prophylaxis of preterm labour?
Women who have a cervical length <25mm on US who are <24 weeks gestation
Who is cervical cerclage offered to for the prophylaxis of preterm labour?
Women with cervical length of <25mm on vaginal US between 16 and 24 weeks gestation who have had previous premature birth or cervical trauma (e.g. colposcopy and cone biopsy).
Investigation for assessing cervical length in pregnancy?
Vaginal US
What length is a ‘short’ cervix?
<25mm
Define prelabour rupture of membranes (PROM)
Rupture of membranes at least 1 hour prior to the onset of labour, at >/=37 weeks gestation.
Define pre-term prelabour rupture of membranes (P-PROM)
the rupture of fetal membranes occurring at <37 weeks gestation.
What do the fetal membranes consist of?
Chorion & amnion
How can a rupture of membranes be diagnosed?
Sterile speculum examination:
1) Look for pooling of amniotic fluid in posterior vaginal fornix (after draining from cervix).
2) Asking the woman to cough during the examination can cause amniotic fluid to be expelled.
3) A lack of normal vaginal discharge (‘washed clean’) can be suggestive of rupture of membranes
Why is digital exam contraindication in PROM/PPROM (until the woman is in active labour)?
Risk of infection