Delivery & Fetal Medicine Flashcards
Alpha-fetoprotein (AFP) is a protein produced by
the developing fetus
Increased AFP
Neural tube defects (meningocele, myelomeningocele and anencephaly)
Abdominal wall defects (omphalocele and gastroschisis)
Multiple pregnancy
Decreased AFP
Down’s syndrome
Trisomy 18
Maternal diabetes mellitus
breech presentation is
the caudal end of the fetus occupies the lower segment.
Most babies who are breech at 28 weeks will not turn
false
around ?% of pregnancies at 28 weeks are breech it only occurs in ?% of babies near term
around 25% of pregnancies at 28 weeks are breech it only occurs in 3% of babies near term
Which type of breech is most common?
frank breech
What is frank breech
is the most common presentation with the hips flexed and knees fully extended.
What is footling breech?
A footling breech, where one or both feet come first with the bottom at a higher position, is rare but carries a higher perinatal morbidity
Risk factors for breech presentation
uterine malformations, fibroids
placenta praevia
polyhydramnios or oligohydramnios
fetal abnormality (e.g. CNS malformation, chromosomal disorders)
prematurity (due to increased incidence earlier in gestation)
What complication is more common in breech presentations
cord prolapse
Management breech
if < 36 weeks: many fetuses will turn spontaneously
if still breech at 36 weeks NICE recommend external cephalic version (ECV)- this has a success rate of around 60%. The RCOG recommend ECV should be offered from 36 weeks in nulliparous women and from 37 weeks in multiparous women
if the baby is still breech then delivery options include planned caesarean section or vaginal delivery
‘Women should be informed that planned caesarean section carries a reduced/increased perinatal mortality and early neonatal morbidity for babies with a breech presentation at term compared with planned vaginal birth.’
reduced
‘Women should be informed that there is no evidence that the long term health of babies with a breech presentation delivered at term is influenced by how the baby is born.’
true
RCOG absolute contraindications to ECV:
where caesarean delivery is required antepartum haemorrhage within the last 7 days abnormal cardiotocography major uterine anomaly ruptured membranes multiple pregnancy
There are two main types of caesarean section:
lower segment caesarean section: now comprises 99% of cases
classic caesarean section: longitudinal incision in the upper segment of the uterus
Which indications for CS are NOT relative (absoulte indication)
absolute cephalopelvic disproportion
placenta praevia grades 3/4
What are relative indications for CS?
pre-eclampsia
post-maturity
IUGR
fetal distress in labour/prolapsed cord
failure of labour to progress
malpresentations: brow
placental abruption: only if fetal distress
vaginal infection e.g. active herpes, cervical cancer (disseminates cancer cells)
If placental abruption and fetus is dead CS is indicated
false
Deliver vaginally
placental abruption is absoulte indication for CS
false
only if fetal distress
The RCOG advise clinicians to make women aware of serious and frequent risks when undergoing CS
true
CS ‘Frequent’ risks maternal
persistent wound and abdominal discomfort in the first few months after surgery
increased risk of repeat caesarean section when vaginal delivery attempted in subsequent pregnancies
readmission to hospital
haemorrhage
infection (wound, endometritis, UTI)
CS ‘Frequent’ risks fetal
lacerations, one to two babies in every 100
CS ‘Serious’ risks maternal
emergency hysterectomy need for further surgery at a later date, including curettage (retained placental tissue) admission to intensive care unit thromboembolic disease bladder injury ureteric injury death (1 in 12,000)
CS ‘Serious’ risks future pregnancies
increased risk of uterine rupture during subsequent pregnancies/deliveries
increased risk of antepartum stillbirth
increased risk in subsequent pregnancies of placenta praevia and placenta accreta)
Other complications which are recognised but not specificially mentioned in the RCOG document include;
(CS)
prolonged ileus
subfertility: due to postoperative adhesions
If a women has had a previous caesarean section due a factor such as fetal distress the majority of obstetricians would not/ would recommend a trial of normal labour
Why?
would
around 70-75% of women in this situation have a successful vaginal delivery
VBAC contraindications include
previous uterine rupture or classical caesarean scar
Indications for a forceps delivery include
fetal distress in the second stage of labour
maternal distress in the second stage of labour
failure to progress in the second stage of labour
control of head in breech deliver
Human chorionic gonadotropin (hCG) is produced by
first produced by the embryo and later by the placental trophoblast
HCG’s role?
Its main role is to prevent the disintegration of the corpus luteum
Measurement of hCG levels form the basis of many pregnancy testing kits
true
hcg levels increase/decrease when
hCG levels double approximately every 48 hours in the first few weeks of pregnancy. Levels peak at around 8-10 weeks gestation
What is oligohydramnios
reduced amniotic fluid. Definitions vary but include less than 500ml at 32-36 weeks and an amniotic fluid index (AFI) < 5th percentile.
Causes oligohydramnios
premature rupture of membranes fetal renal problems e.g. renal agenesis intrauterine growth restriction post-term gestation pre-eclampsia
Risks of prematurity
increased mortality depends on gestation respiratory distress syndrome intraventricular haemorrhage necrotizing enterocolitis chronic lung disease, hypothermia, feeding problems, infection, jaundice retinopathy of newborn, hearing problems
Reduced fetal movements can represent
fetal distress, as a method of fetal compensation to reduce oxygen consumption as a response to chronic hypoxia in utero. This is concerning, as it reflects risk of stillbirth and fetal growth restriction
It is believed that there may also be a link between reduced fetal movements and
placental insufficiency.
What is quickening?
How does it evolve?
The first onset of recognised fetal movements is known as quickening. This usually occurs between 18-20 weeks gestation, and increase until 32 weeks gestation at which point the frequency of movement tends to plateau. Multiparous women will usually experience fetal movements sooner, from 16-18 weeks gestation.
Towards the end of pregnancy, fetal movements should not reduce.
true
There is no established definition for what constitutes reduced fetal movements (RFM), but the RCOG says
less than 10 movements within 2 hours (in pregnancies past 28 weeks gestation) an indication for further assessment.
Fetal movements should be established by
24 wks
Reduced fetal movements is a fairly common presentation
true
Reduced fetal movements is a fairly common presentation, affecting up to ?% of pregnancies. ?% of pregnant women will have recurrent presentations with RFM.
Reduced fetal movements is a fairly common presentation, affecting up to 15% of pregnancies. 3-5% of pregnant women will have recurrent presentations with RFM.
Factors affecting perception of fetal movements
Posture Distraction Placental position Medication Fetal position Amniotic fluid volume Fetal size
Obese patients are less likely to feel prominent fetal movements
true
When are fetal positions more /less prominent
more prominent during lying down and less when sitting and standing
Awareness of fetal movements can be distractable, and if a woman is busy or concentrating on something else, these can be less prominent
true
Patients with which placental position have LESS awareness of fetal movements?
Patient with anterior placentas prior to 28 weeks gestation may have lesser awareness of fetal movements
Which medications can reduce fetal movements?
alcohol and sedative medications like opiates or benzodiazepines can temporarily cause reduced fetal movements
which fetal position means movements are less noticeable
anterior
Both oligohydramnios and polyhydramnios can cause reduction in fetal movements
true
29% of women presenting with RFM have a big/small fetus
SGA
Fetal movements are usually based solely on maternal perception, though it can also be objectively assessed using
handheld Doppler or ultrasonography.
As per RCOG Green-top guidelines, investigations are dependent of gestation at onset of RFM. What are the gestations to consider?
past 28 weeks gestation
between 24 and 28 weeks gestation
below 24 weeks gestation
Ix RFM below 24 weeks gestation
If below 24 weeks gestation, and fetal movements have previously been felt, a handheld Doppler should be used.
If fetal movements have not yet been felt by 24 weeks, onward referral should be made to a maternal fetal medicine unit.
Ix RFM between 24 and 28 weeks gestation
Handheld Doppler should be used to confirm presence of fetal heartbeat.
Ix RFM past 28 weeks gestation
Initially, handheld Doppler should be used to confirm fetal heartbeat.
If no fetal heartbeat detectable, immediate ultrasound should be offered.
If fetal heartbeat present, CTG should be used for at least 20 minutes to monitor fetal heart rate which can assist in excluding fetal compromise.
If concern remains, despite normal CTG, urgent (within 24 hours) ultrasound can be used. Ultrasound assessment should include abdominal circumference or estimated fetal weight (to exclude SGA), and amniotic fluid volume measurement
If RFM are recurrent, further investigations are also required to consider
structural or genetic fetal abnormalities.
Prognosis RFM
Concern regarding absent or reduced fetal movements stems for the potential for this presentation to represent fetal distress or impending demise.
Between 40-55% of women who suffer from stillbirth experience reduced fetal movements prior to diagnosis.
However, in 70% of pregnancies with a single episode of reduced fetal movement, there is no onward complication.
‘Foetal lie’ is the term which refers to
the long axis of the foetus relative to the longitudinal axis of the uterus.
The 3 types of lie are:
longitudinal lie (99.7% of foetuses at term) transverse lie (<0.3% of foetuses at term) oblique (<0.1% of foetuses at term)
The incidence of transverse lie is slightly higher than oblique lie. However, the causes and management options are the same for both
true
Oblique or transverse easier to correct?
Oblique lie is easier to correct because the foetus is closer to longitudinal lie.
What is transverse lie
Transverse lie is an abnormal foetal presentation whereby the foetal longitudinal axis lies perpendicular to the long axis of the uterus. In real terms, this means the foetal head is on the lateral side of the pelvis and the buttocks are opposite. When in transverse lie, the foetus can be either ‘scapulo-anterior’ (most common) where the foetus faces towards the mother’s back or ‘scapulo-posterior’ where the foetus faces towards the mothers front.
Epidemiology of transverse lie
Early in gestation, transverse lie is very common. Most have moved to longitudinal lie by 32 weeks.
At term, one in 300 foetuses are in transverse lie.
Risk factors transverse lie
Most commonly occurs in women who have had previous pregnancies Fibroids and other pelvic tumours Pregnant with twins or triplets Prematurity Polyhydramnios Foetal abnormalities
Diagnosis transverse lie
Abnormal foetal lie will be detected during routine antenatal appointments with a midwife during abdominal examination.
Abdominal examination: the head and buttocks are not palpable at each end of the uterus. The foetus can be felt to be lying directly across the uterus.
Ultrasound scan: allows direct visualisation of the foetal lie. Foetal heart rate is also auscultated to assess for distress.
Complications transverse lie
Pre-term rupture membranes (PROM)
Cord-prolapse (20%)
If allowed to progress to vaginal delivery, compound presentation may occur. This is extremely rare in the UK.
Management transverse lie Before 36 weeks gestation: no management required
true
The patient should be informed that most foetuses will spontaneously move into longitudinal lie during pregnancy.
Management transverse lie after 36 weeks
discuss management options:
Active management: perform external cephalic version (ECV) of the foetus. This can be performed late in pregnancy and even early labour if the membranes have not yet ruptured. ECV should be offered to all women who would like a vaginal delivery.
Elective caesarian section: this is the management for women where the patient opts for caesarian section or ECV has been unsuccessful or is contraindicated.
The decision to perform caesarian section over ECV will be based on the perceived risks to the mother and foetus, the preference of the patient, the patient’s previous pregnancies and co-morbidities and the patient’s ability to access obstetric care rapidly.
Contraindications to ECV in mx Transverse lie
Contraindications include maternal rupture in the last 7 days, multiple pregnancy (except for the second twin) and major uterine abnormality. Success rate is around 50%
The incidence of multiple pregnancies is as follows
twins: 1/105
triplets: 1/10,000
Twins may be dizygotic or monozygotic
dizygotic (non-identical, develop from two separate ova that were fertilized at the same time) or monozygotic (identical, develop from a single ovum which has divided to form two embryos).
?% of twins are dizygotic
80%
Monoamniotic monozygotic twins are associated with:
increased spontaneous miscarriage, perinatal mortality rate
increased malformations, IUGR, prematurity
twin-to-twin transfusions: recipient is larger with polyhydramnios (do laser ablation of interconnecting vessels)
The incidence of dizygotic twins is increasing mainly due to
infertility treatment
Predisposing factors for dizygotic twins include:
previous twins family history increasing maternal age multigravida induced ovulation and in-vitro fertilisation race e.g. Afro-Caribbean
Antenatal complications of twins
polyhydramnios
pregnancy induced hypertension
anaemia
antepartum haemorrhage
Fetal complications - perinatal mortality (twins * 5, triplets * 10)
prematurity (mean twins = 37 weeks, triplets = 33)
light-for date babies
malformation (*3, especially monozygotic)
Labour complications of twins
PPH increased (*2)
malpresentation
cord prolapse, entanglement
Management of twin pregnancies?
rest
ultrasound for diagnosis + monthly checks
additional iron + folate
more antenatal care (e.g. weekly > 30 weeks)
precautions at labour (e.g. 2 obstetricians present)
75% of twins deliver by 38 weeks, if longer most twins are induced at 38-40 wks
