Labour and delivery/premature labour Flashcards
When do labour and delivery normally occur?
-between 37 and 42 weeks gestation
What are the three stages of labour?
- first stage
- second stage
- third stage
When does the first stage begin and end?
-form onset of labour(true contractions) until 10 cm cervical dilatation
When does the second stage begin and end?
-from 10cm cervical dilatation until delivery of the baby
When does the third stage begin?
-from delivery of the baby until delivery of the placenta
What are the three phases of the first stage?
- latent phase
- active phase
- transition phase
What is the latent phase of the first stage of labour?
- from 0 to 3cm dilation of the cervix
- this progresses around 0.5cm per hour (>1cm every 2 hours)
- there are irregular contractions
What are some causes of prolonged 1st stage of labour?
- dysfunctional uterine activity
- cephalopelvic disproportion
- malpresentation
What is the active phase of the first stage of labour?
- from 3cm to 7cm dilation of the cervix
- progresses around 1cm per hour
- regular contractions
What is the transition phase of the first stage of labour?
- from 7cm to 10cm dilation of the cervix
- progresses at around 1cm per hour
- strong and regular contractions
What is prolonged 2nd stage of labour for nulliparous and multiparous women
-nulliparous women >3 hours with epidural or >2 hours without
- multiparous women >2 hours with epidural or >1 hour without.
what are some causes of prolonged 2nd stage of labour?
-dysfunctional uterine contractions
-android pelvis
-resistant perineum
when is 3rd stage of labour considered prolonged?
> 30mins active management
60 mins passive management
what are some causes of prolonged 3rd stage labour
- uterine atony
- placental problems eg placenta accreta
What are braxton-hicks contractions?
- braxton-hicks contractions are occasional irregular contractions of the uterus
- usually felt during the second or third trimester
- these are not true indications and do not indicate the onset of labour
- staying hydrated and relaxed can reduced these
What are the signs to look for when diagnosing the onset of labour?
- Show (mucus plug from cervix)
- rupture of membranes
- regular, painful contractions
- dilating cervix on examination
What does rupture of membranes (ROM) refer to?
-amniotic sac has ruptured
What does rupture of prelabour membranes (PROM) refer to?
-amniotic sac has ruptured before the onset of labour
What does preterm prelabour rupture of membranes refer to (P-PROM)?
amniotic sac has ruptured before the onset of labour and before 37 weeks gestation
Management of preterm prelabour rupture of membranes (P-PROM):
- Prophylactic antibiotics should be given to prevent the development of chorioamnionitis. The NICE guidelines (2019) recommend erythromycin 250mg four times daily for ten days, or until labour is established if within ten days.
- Induction of labour may be offered from 34 weeks to initiate the onset of labour.
What does preterm Prolonged rupture of membranes (also PROM)refer to?
amniotic sac ruptured more than 18 hours before delivery
What is classed as a premature birth?
-birth before 37 weeks gestation
What babies are considered non-viable?
- those below 23 weeks gestation
- resuscitation is not considered in these babies that do not show signs of life
- they have a 10% chance of survival
- from 24 weeks onwards there is increased chance of survival and resusciation is offered
What gestation is classified as extreme preterm?
-under 28 weeks
What gestation is classified as very preterm?
28-32 weeks
What gestation is classified as moderate to late preterm?
32-37 weeks
What options are there for prophylaxis of preterm labour?
- vaginal progesterone
-Cervical Cerclage (including “rescue” cerclage)
- cervical cerclage
when is “rescue” cerclage carried out?
between 16 -27 + 6 weeks gestation when there is cervical dilatation without rupture of membranes, to prevent progression and premature delivery.
How does vaginal progesterone work as prophylaxis for preterm labour?
- maintains pregnancy and prevents labour by decreasing myometrium activity and preventing cervix remodelling
- offered to women with cervical length <25mm on US between 16 and 24 weeks gestation
How does cervical cerclage work as prophylaxis for preterm labour?
- involves putting stitch in cervix to add support and keep it closed
- stitch is removed when women goes into labour or reaches term
- offered to women with cervical length <25mm on US between 16 and 24 weeks gestation, who have had previous preterm birth or cervical trauma (eg colposcopy or cone biopsy)
How can rupture of membranes be diagnosed?
- by speculum exam which reveals pooling of amniotic fluid in the vagina
- if doubt about diagnosis, can test for IGFBP-1(Insulin-like growth factor-binding protein-1) and PAMG-1 (Placental alpha-microglobin-1)
A 37-year-old woman is 38 weeks pregnant. She underwent in vitro fertilisation (IVF) treatment to become pregnant, and so far, her pregnancy has been uncomplicated. At her 36-week appointment with her midwife, her baby was palpated to be a breech presentation which was subsequently confirmed on an ultrasound scan. She is considering external cephalic version (ECV).
Which of the following is a risk factor for breech presentation?
A. Polyhydramnios
B. Maternal age >35 years
C. Nulliparity
D. Assisted conception treatment
E. Singleton pregnancy
A. Polyhydramnios (excess fluid provides more room for the foetus to move around
-multiparity and multiple pregnancy are risk factors for breech presentation
How is preterm labour with intact membranes diagnosed?
<30 weeks gestation, clinical assessment alone is enough to offer management of preterm labour.
> 30 weeks gestation, a transvaginal ultrasound can be used to assess the cervical length. When the cervical length on ultrasound is<15mm, management of preterm labour can be offered. A cervical length of more >15mm indicates preterm labour is unlikely.
-Fetal fibronectin is an alternative test to vaginal ultrasound. Fetal fibronectin is the “glue” between the chorion and the uterus, and is found in the vagina during labour. A result of <50 ng/ml is considered negative, and indicates that preterm labour is unlikely.
What are management options for improving outcomes with preterm labour?
- Tocolytics (1st line nifedipine:CCB, 2nd line atosiban: oxytocin receptor antagonist)
- Corticosteroids <35 weeks (eg.2 doses of IM betamethasone 2 days apart, reduce respiratory distress syndrome)
- MgSO4 <34 weeks (neuroprotective: it reduces the risk and severity of cerebral palsy: given within 24 hours of delivery of preterm babies of less than 34 weeks gestation. It is given as a bolus, followed by an infusion for up to 24 hours or until birth)
- Continuous foetal (CTG or intermittent auscultation) and maternal monitoring
- delayed cord clamping/cord milking
Monitoring for magnesium toxicity & treatment:
Mothers need close monitoring for magnesium toxicity at least four hourly. This involves close monitoring of observations, as well as tendon reflexes (usually patella reflex). Key signs of toxicity are:
- Reduced respiratory rate
- Reduced blood pressure
- Absent reflexes
Antidote: calcium gluconate treatment ( 1 g IV over 3 minutes.)
A 40-year-old pregnant woman is seen for her 41 week check. Her blood pressure has consistently been 140/90 mmHg for the last 2 weeks. Her booking blood pressure was 110/70 mmHg. You administer labetalol to treat the high blood pressure. What should be the next step in the management?
A. Give magnesium sulphate
B. Give nifedipine
C. Emergency caesarian section
D. Watchful waiting
E. Offer induction of labour
E. Offer induction of labour
The pregnancy is now post term. A woman who has reached 41 weeks gestation can be offered induction of labour, or alternatively she can choose expectant management. At this gestation the risks to the foetus are increased, and women with either pregnancy-induced hypertension or pre-eclampsia are usually delivered. Medical induction of labour would be the preferred choice. Caesarean section would usually only be indicated if there was foetal compromise. This level of blood pressure does not require treatment.
when is foetal blood sampling usually done?
assessing for foetal hypoxia in the presence of an abnormal CTG.
what are late decelerations a sign of?
foetal hypoxia
what are variable decelerations a sign of?
cord compression
what are early decelerations a sign of?
foetal head being compressed.
What is CTG used to measure?
- fetal heart rate
- contractions of uterus
- useful way of monitoring the condition of fetus and activity of labour
What does a CTG involve?
2 transducers are placed on the abdomen to get the CTG readout:
- one above the fetal heart to monitor the fetal heartbeat
- one near the fundus of the uterus to monitor the uterine contractions
Transducer above fetal heart monitors heartbeat using doppler US
Transducer near fundus uses US to assess tension in uterine wall, indicating uterine contraction
What are the indications for continuous CTG monitoring in labour?
- sepsis
- maternal tachycardia (>120)
- significant meconium
- pre-eclampsia (esp BP > 160/110)
- fresh antepartum hemorrhage
- delay in labour
- use of oxytocin
- disproportionate maternal pain
Management of shoulder dystocia (mnemonic) :
Immediately call for help - further midwifery assistance, senior obstetrician, paediatrician and anaesthetist may be required
Do not apply fundal pressure as this may lead to uterine rupture and discourage maternal pushing as this may exacerbate shoulder impaction
- McRoberts manoeuvre (if performed correctly, 90% success rate in delivering baby vaginally)
Hyperflexion and abduction of the mother’s legs tightly to the abdomen
This may be accompanied with applied suprapubic pressure
Routine traction (as applied during normal delivery) in an axial direction should be applied to assess whether the shoulders have been released. - All fours position
- Internal rotational manoeuvres:
Woods’ screw manoeuvre: anterior shoulder is pushed towards the foetal chest and the posterior shoulder is pushed towards the foetal back.
Rubin manoeuvre II: rotation of the anterior shoulder towards the foetal chest
Note that episiotomy will not relieve shoulder dystocia as it is a bony obstruction, but may be indicated to allow space for internal rotational manoeuvres.
- Cleidotomy or symphysiotomy (division of the foetal clavicle or maternal symphysial ligament)
- Zavanelli manoeuvre: replacement of the head into the canal (pushing baby back into uterus) and then subsequent delivery by caesarean section
Following the delivery of a baby after shoulder dystocia:
- The mother should be examined and monitored for postpartum haemorrhage, severe perineal tears and other genital tract trauma.
2.The baby should be examined by a neonatologist for injury including brachial plexus injury, hypoxic brain damage, humeral or clavicular fractures
HELPER
o call for Help
o Episiotomy
o Legs up (McRoberts maneuver)
o Pressure suprapubically
o Enter vagina for shoulder rotation
o Reach for posterior shoulder/ Return head into vagina (Zavanelli maneuver)/ Rupture clavicle or pubic symphysis
why/when is FBS (foetal blood sampling) done?
Foetal blood sampling (FBS) is indicated when there is a suspicious cardiotocograph. It is used during labour to confirm whether there is foetal hypoxia.
Indications for elective C-section (mnemonic) and analgesia:
- Previous caesarean
- Symptomatic after previous perineal tear
- Placenta praevia/placenta accreta
- Vasa praevia
- Multiple pregnancy
Uncontrolled HIV - Cervical Cancer
Elective caesarean section involves a planned date on which a woman will come in for delivery.
It is usually performed under a spinal anaesthetic, and is considered generally a very safe and routine procedure. Usually these are performed after 39 weeks gestation.
Caesarian section procedure (ie during surgery: mnemonic)
The most commonly used skin incision is a transverse lower uterine segment incision. There are two possible incisions:
Pfannenstiel incision is a curved incision two fingers width above the pubic symphysis
Joel-cohen incision is a straight incision that is slightly higher (this is the recommended incision)
A vertical incision down the middle of the abdomen is also possible, but this is rarely used. It may be used in certain circumstances, such as very premature deliveries and anterior placenta praevia.
Blunt dissection is used, after the initial incision with a scalpel, to separate the remaining layers of the abdominal wall and uterus. Blunt dissection involves using fingers, blunt instruments and traction to tear the tissues apart, rather than to cut them with sharp tools such as a scalpel. This results in less bleeding, shorter operating times and less risk of injury to the baby.
The layers of the abdomen that need to be dissected during a caesarean are:
SSS EXIT
Skin
Subcutaneous tissue
Fascia / rectus sheath (the aponeurosis of the transversus abdominis and external and internal oblique muscles)
-Rectus abdominis muscles (separated vertically)
-Peritoneum
-Vesicouterine peritoneum (and bladder) – the bladder is separated from the uterus with a bladder flap
-Uterus (perimetrium, myometrium and endometrium)
-Amniotic sac
The baby is delivered by hand with the assistance of pressure on the fundus. Forceps may be used if necessary.
The uterus is closed inside the abdomen using two layers of sutures. Exteriorisation (taking the uterus out of the abdomen) is avoided if possible. The abdomen and skin are then closed.
key counselling points (PACES) C-section:
- A caesarean section is the delivery of a baby through a surgical incision in the abdominal wall and the uterine wall and accounts for 25-30% of births in the United Kingdom.
- The main indications are a previous C-section, fetal compromise, failure to progress in labour and breech presentation.
- Caesarean sections are commonly performed through a Pfannenstiel incision with access to the uterine cavity through a transverse lower uterine incision.
- Caesarean sections are associated with a reduced risk of perineal pain and trauma.
- Caesarean sections are associated with an increased risk of abdominal pain, venous thromboembolism, and bladder or ureteric injury. There is an increased risk associated with stillbirth and placental insertion disorders in subsequent pregnancies.
- VBAC is an option for women in future pregnancies but should be performed after careful consideration due to the risk associated with uterine rupture.
flatten the bed (vs episiotomy)
Caesarian (C-section) summary:
