Multiple Pregnancy Flashcards
What are the 2 types of twin pregnancy?
Monozygotic 1/3
Dizygotic 2/3
What do monozygotic twin pregnancies arise from?
division of the fertilized oocyte into 2 embryonic layers
What do dizygotic twin pregnancies arise from?
fertilization of 2 oocytes with 2 spermatozoa
What are 4 predisposing factors for dizygotic twins?
Previous multiple pregnancy
Maternal FH
Increasing maternal age >35y
Induced ovulation + IVF
What is the only chorionic cavity and amniotic sac composition for dizygotic pregnancies?
Dichorionic-Diamniotic
separate placentas + separate amniotic sacs
What are the 4 possible compositions of placenta and amniotic sacs for monozygotic pregnancies?
Monochorionic-Diamniotic 70%
Dichorionic-Diamniotic 20-30%
Monochorionic- Monoamniotic 1-5%
Monochorionic-Monoamniotic (conjoined twins) <0.1%
What are Dichorionic-Diamniotic pregnancies? When does the zygote divide?
2 placenta
2 amniotic sacs
Division within first 3 days after conception
What are Monochorionic-Diamniotic pregnancies? When does the zygote divide?
1 placenta
2 amniotic sacs
Division day 4-7 after conception
What are Monochorionic-Monoamniotic pregnancies? When does the zygote divide?
Share 1 placenta + 1 amniotic sac
Division day 8-11 after conception
What are Monochorionic-Monoamniotic (conjoined) pregnancies? When does the zygote divide?
Share 1 placenta + 1 amniotic sac + are conjoined
Division day 12+ after conception
What is found on examination in multiple pregnancies?
Fundal height + abdominal girth are unusually large for the gestational age.
> ,2 fetal HRs can be heard on auscultation
.
What is seen on ultrasound in dichorionic twins?
LAMBDA sign
Chorionic cavities separated
What is seen on ultrasound in monochorionic diamniotic twins?
T-sign
1 chorionic cavity + each twin has individual amniotic sac
What is the most common complication of multiple pregnancy?
Preterm labour
Give 5 antenatal complications of multiple pregnancy
Hyperemesis gravidarum
GDM
Preeclampsia, eclampsia + pregnancy induced HTN
Miscarriage/ loss of 1 fetus
Antepartum haemorrhage
Give 4 intrapartum complications of multiple pregnancy
Prolonged 1st stage of labour
Premature placenta abruption after 1st born
Cord prolapse
PPH
What is twin-to-twin transfusion syndrome?
Blood is continuously shunted from one twin to the other through vascular anastomoses on the shared placenta, posing a risk to both fetuses.
Affects 10-15% monochorionic pregnancies
Give 3 complications of twin-to-twin transfusion syndrome for the recipient twin
Polycythemia
Hypervolemia: More blood –> more cardiac strain –> hydrops fetalis
Polyhydramnios in diamniotic pregnancies
Give 4 complications of twin-to-twin transfusion syndrome for the donor twin
Anemia
Growth retardation
Hypovolemia, dehydration (stuck twin or cocooned appearance)
Oligohydramnios in diamniotic pregnancies
Give 3 symptoms of TTTS
Sudden weight gain
Abdo pain
SOB
What is diagnostic of TTTS?
What is the management of TTTS?
If <26w: foetoscopic laser ablation of vascular anastomoses
If >26w: delivery
Give 4 fetal complications in multiple pregnancy
Spontaneous reduction or vanishing twin syndrome
Twin to Twin transfusion syndrome
Cord entanglement (only in monoamniotic)
Increased mortality + morbidity: IUGR, prematurity, congenital abnormalities
How is gestational age calculated in multiple pregnancies?
Use largest baby to estimate GA at dating scan
Describe the antenatal care in multiple pregnancies
Obstetric led
Increase screening for anaemia: additional FBC at 20w
Serial growth + doppler USS: monitor for IUGR + TTTS: 2-4 weekly depending on chorionicity + amnionicity
Consider need to refer to tertiary level foetal medicine centre
Give 8 indications for referral to a tertiary level foetal medicine centre
Pregnancy with shared amnion
Discordant foetal growth (>25% difference)
Foetal anomaly (structural or chromosomal)
Discordant foetal death
TTTS
Twin anaemia polycythaemia sequence
Twin reverse arterial perfusion sequence
Conjoined twins/ triplets
What delivery is possible in multiple pregnancies?
Dichorionic-Diamniotic + Monochorionic-Diamniotic: vaginal delivery if 1st twin is cephalic
Monochorionic-Monoamniotic + Triplets: elective C section
What is the recommended type of elective birth in dichorionic-diamniotic twins?
37w
What is the recommended type of elective birth in monochorionic-diamniotic twins?
36w (after a course of steroids)
What is the recommended type of elective birth in monochorionic-monoamniotic twins?
32w (after a course of steroids)
What is the risk of preterm birth in twin pregnancies?
60%
