High Risk Pregnancy Flashcards
Multiple pregnancy, antenatal causes of maternal mortality and morbidity, breech presentations, preterm labour, small for dates, large for dates, antepartum haemorrhage
What are the risk factors for multiple pregnancy?
Assisted conception (IVF, ovulation induction),
Increased maternal age,
Ethnic origin (West africa),
Family History
What do the following terms mean:
Zygosity,
Chorionicity,
Amnionicity
Zygosity - number of fertilized eggs.
Chorionicity - number of placentas
Amnionicity - number of sacs
What are Dizygotic twins?
Most common type.
Two eggs and two sperm so no more identical than siblings.
They are always DCDA (dichorionic and diamniotic), meaning always have two placenta and two sacs
What are monozygotic twins?
When one egg is fertilized so they are identical.
If splits before day 4 (before chorion development) then they are dichorionic and diamniotic.
Splits from day 4-8 (prior to amnion development) then they are monochorionic and diamniotic.
Split after day 9 (after amnion development) then monochorionic and monoamniotic. Increased risk of conjoined twins.
Dichorionic - Two placentas
Diamniotic - Two amniotic sacs
What ultrasound signs indicate Monochorionic vs dichorionic
Mono - Lambda sign.
Di - T sign
What are the maternal antenatal complications of multiple pregnancy?
Hyperemesis gravidarum,
Pre-eclampsia,
Gestational diabetes,
Placenta praevia,
Minor complications
What are the fetal complications of multiple pregnancy?
Miscarriage,
Congenital anomaly,
Growth restriction,
Pre-term delivery
If monochorionic then increased risk of twin to twin transfusion syndrome (recipient is larger with polyhydramnios), acute transfusion and twin reversed perfusion sequence.
How do you diagnose multiple pregnancies?
Ultrasound - Essential to determine chorionicity. Screen with nuchal translucency for aneuploidy.
Invasive proceedures - Amniocentesis and chorionic villus sampling.
How can you monitor foetal growth in multiple pregnancies?
Regular ultrasounds!
Dichorionic twins 4 weekly from 24 weeks.
Monochorionic twins 2 weekly from 16 weeks.
When are twins delivered?
37 weeks for DCDA twins
36 weeks for MCDA twins
Explain features of delivery for twins
Analgesia for mum - often epidural.
Monitoring during labor: Maternal - BP IV access, fluids and ranititdine,
Faetal: Continuous CTG, abdominal and fetal scalp electrodes
What are the postnatal complications of twins/multiple pregnancies?
Increased risk of PPH,
Increased risk of post natal depression, anxiety, relationship issues and bereavement
What specific complications affect monochorionic twins?
Acute transfusion,
Twin to twin transfusion syndrome,
Twin reversed arterial perfusion sequence
Describe features of an acute transfusion
Death of one twin in utero leads to increased risk of hypoxic-ischaemic injury in survivor due to acute transfusion from health to dying twin. Risk of exsanguination of healthy twin into dying twin.
Delivery expedited if compromise detected.
Describe features of twin to twin transfusion syndrome
Connection between bloody supplies of the two fetus. Recipient fetus receives more blood and gets heart failure and polyhydramnios. Donor receives less blood and gets growth restriction, anaemia and oligohydramnios.
Explain the diagnosis, staging and management of twin to twin transfusion syndrome?
Diagnosis is via ultrasound.
Quintero staging
Management - Fetoscopic laser ablation of anastomosis or cord occlusion.
What is twin reversed arterial perfusion syndrome?
Where two cords linked by big aterio-arterial anastamosis and retrograde perfusion. it is a severe form of TTTS.
There is a pump twin and a perfused twin.
Managed with ablation of anastamosis.
Describe features of monoamniotic twins
Almost all develop cord entanglement and there is high mortality. Elective C-section required at 32-33 weeks
what is a breech presentation and what are the different types?
When baby comes feet first. It can either be flexed, footling or extended.
What are the associations with breech presentations?
Multiple pregnancies,
Bicornate uterus,
Fibroids,
Placental praevia,
Polyhydramnios,
Oligohydramnios
Fetal anomaly
What is the management of breech presentation?
External cephalic version - 50% success rate. Must do CTG during and after procedure. May need anti-D.
Done at 36 weeks if nulliparous and 37 for multiparous women. Before this, they are likely to turn on their own.
What are the contraindications to external cephalic version?
Absolute - Antepartum haemorrhage within last 7 days, abnormal CTG, major uterine anomaly, ruptured membranes, multiple pregnancies and absence of maternal consent.
Relative - Nuchal cord, FGR, proteinuric pre-eclampsia, oligohydramnios, major fetal anomalies, hyperextended fetal head, maternal morbid obesity.
What are the risks of vaginal vs C-sections in breech presentations?
Vaginal is mainly risks to fetus - Intracranial injust, widespread bruising, damage to internal organs, spinal cord transection, umbilical cord prolapse and hypoxia.
C-section is mainly maternal risks - surgical morbidity and mortality
What are the definitions of the following:
Pre-term
Very pre-term,
Extremely pre-term,
Pre-term labour,
Pre-term Pre-labour rupture of the membranes
Pre-term - Less than 37 weeks
Very pre-term - 28 to 32 weeks
Extremely pre-term - <28 weeks
Pre-term labour - Regular uterine contractions acompanied by effacement and dilation of cervix between 20-37 weeks.
Pre-term Pre-labour rupture of the membranes - Rupture of fetal membranes before 37 weeks and before onset of labout.
What are the definitions of the following:
Low birth weight
Very low birth weight
Extremely low birth weight
Low birth weight < 2501g
Very low birth weight < 1501g
Extremely low birth weight < 1000g
What are the complications of preterm labour?
Perinatal morbidity and mortality.
Immature fetal organs
Long term disability eg lung disease, cerebral palsy.
Explain the role of maternal corticosteroids
IM Betamethasone/dexamethasone is given in divided doses over 24 hours. Used in preterm labour/rupture of membranes.
Crosses placenta and increases amount of fetal pulmonary surfactant which reduces respiratory distress syndrome, intraventricular cerebral haemorrhage, neonatal death, necrotizing enterocolitis.
What is the classification of antepartum haemorrhage?
Minor < 50ml
Moderate - 50-1000ml but no hypovolaemic shock.
Major > 1000ml +/- hypovolaemic shock
What are the local causes of antepartum haemorrhage
Vulva,
Vagina,
Cervix: cervical ectropion or polyps.
Cervical carcinoma
Explain the classification of placenta praevia
I - placenta encroaches lower uterine segment.
2 - Reaches internal os of cervix.
3 - Covers part of internal os.
4 - completely covers internal os.
What are the risks of placenta praevia?
A sudden unpredictable major/massive haemorrhage.
Abnormally invasive placenta or placenta accreta
What is the management of placenta praevia
May be admitted from 30-32 weks till delivery. Elective delivery at 36-37 weks. Emergency delivery may be required
What is placenta accreta?
When the placenta implants deeper through the endometrium and invades the myometrium. Diagnosed via ultrasound
This markedly increases risk of PPH and women may require a hysterectomy following an elective C-section around 35 weeks.
RFs are previous C-section or previous placenta accreta.
What is placental abruption and its risk factors?
Bleeding between the placenta and uterus, often with a degree of placental separation. May cause fetal hypoxia and acidosis.
RFs: Previous abruption, HTN, thrombophilia, PROM, multiple pregnancy, folic acid def, cocaine smoking, social deprivation.
What is the management of placental abruption?
Fetus alive and < 36 weeks: No distress then observe closely and steroids. If distressed then immediate caeserean.
If > 36w and alive: C-section if distressed, vaginal delivery if no ditress.
Fetal death - induce vaginal delivery.
How can you determine the difference between placenta praevia and placental abruption?
Abruption - Shock is out keeping with visible loss and there is constant pain. There is a tense, woody uterus.
Praevia: Shock in keeping with visible loss, no pain and soft uterus.
