Multiple Pregnancy Flashcards
(31 cards)
In how many pregnancies do twins occur?
1 in 80
considerable geographic variation
Why are the incidence of twins increasing?
because of sub fertility treatment and the increasing number of older mothers
What are the two kinds of twins?
Dizygotic twins
Monozygotic twins
What is the cause of dizygotic twins?
fertilisation of different oocytes by different sperm - such foetuses may be of different sex and are no more genetically similar than siblings from different pregnancies
What is the cause of monozygotic twins?
Result from mitotic division of a single zygote into ‘identical twins’
Which type of twins have the best outcome?
the best outcomes are with diamniotic, dichorionic twin pregnancies, as each fetus has their own nutrient supply.
What are the factors that cause twins?
assisted conception
genetic factors
increasing maternal age
parity
IVF conceptions / clomiphene-assisted conceptions
What are the effects of twins In early/late pregnancy?
Vomiting more marked
larger uterus than expected for the dates and palpable <12 weeks
later in pregnancy, there will be three of more foetal poles - but most are diagnosed only at USS
Dichorionic diamniotic - a lambda sign or twin peak sign
Monochorionic diamniotic: T sign
What are the maternal complications of multiple pregnancy?
Anaemia Polyhydramnios Hypertension Malpresentation Spontaneous preterm birth Instrumental delivery or caesarean Postpartum haemorrhage
What are the foetal antenatal complications of multiple pregnancies?
Miscarriage Stillbirth Fetal growth restriction Prematurity Twin-twin transfusion syndrome Twin anaemia polycythaemia sequence Congenital abnormalities
IUGR - more common
Congenital abnormalities - not more common per baby in dichorionic - but they are monochorionic
What are the major risk factors for complications in all multiple pregnancies?
Preterm delivery - main cause of perinatal mortality
IUGR - much more common
Monochrorionicity
Miscarriage - one of a twin pregnancy can ‘vanish’ where there is a 1st trimester death - late miscarriage is also more common, particularly in MC twins
congenital abnormalities - not more common per baby in dichorionic, bu they are in monochorionic pregnancies
What is the cause of monochorionic pregnancy?
shared blood supply in the single placenta
What is the cause of Twin-twin transfusion syndrome?
occurs when the fetuses share a placenta
What are the effects of TTTS?
One fetus (the recipient) may receive the majority of the blood from the placenta, while the other fetus (the donor) is starved of blood. The recipient gets the majority of the blood, and can become fluid overloaded, with heart failure and polyhydramnios. The donor has growth restriction, anaemia and oligohydramnios. There will be a discrepancy between the size of the fetuses.
How is TTTS staged?
Staged according to Quintero in stages 1-5
both twins are at very high risk of in utero death or severely preterm delivery
What is twin anaemia polycythaemia sequence?
Twin anaemia polycythaemia sequence is similar to twin-twin transfusion syndrome, but less acute. One twin becomes anaemic whilst the other develops polycythaemia (raised haemoglobin).
can follow incomplete laser ablation for TTTS
What is twin revered arterial perfusion?
Rare abnormality of MC twins - an abnormal, often cardiac foetus is perfused by a normal ‘pump’ twin - therefore is at risk of cardiac failure
In what kind of twins is IUGR more common?
MC twins in the absence of clear blood volume discordancy
particular problem - umbilical artery waveform of the smaller twin = erratic
which may be the result of the superior artery-artery anastomoses. sudden in utero death occurs in up to 20% and handicap in 8%
What is the result of co twin death?
If one of an MC twin pair dies due to TTTS or any other causes, the drop in its blood pressure allows acute transfusion of blood from the other twin
this rapidly leads to hypovolaemia and in 30% cases, death or neurological damage
What is the common complication of mono amniotic twins?
The cords are always entangled
in utero demise is common, probably because of this and/or sudden acute shunting of blood between the two babies anastomoses between the close cord insertions
What are the common complications of multiple birth intrapartum?
Malpresentation - one of the 1st twins occurs in 20% and this is an indication for C-section
Foetal distress - common in labour. the 2nd twin has an increased risk of death after the first has been delivered because of hypoxia, cord prolapse, tetanic uterine contractions or placental abruption - may present as breech
PPH - more common
Wha is the antepartum management of all multiples?
additional monitoring for anaemia, with a full blood count at:
Booking clinic
20 weeks gestation
28 weeks gestation
Additional USS:
2 weekly scans from 16 weeks for monochorionic twins
4 weekly scans from 20 weeks for dichorionic twins
Planned birth is offered between:
32 and 33 + 6 weeks for uncomplicated monochorionic monoamniotic twins
36 and 36 + 6 weeks for uncomplicated monochorionic diamniotic twins
37 and 37 + 6 weeks for uncomplicated dichorionic diamniotic twins
Before 35 + 6 weeks for triplets
Delivery at 37 weeks for DC and 36 for uncomplicated MC twins
How can women with multiple pregnancy deliver?
Vaginal delivery is possible when the first baby has a cephalic presentation (head first)
Caesarean section may be required for the second baby after successful birth of the first baby
Elective caesarean is advised when the presenting twin is not cephalic presentation
What is the management of monochorionic twins?
USS surveillance for MC twins starts by 12 weeks - USS is advised every 2 weeks until 24 weeks and ever 2-3 weeks after that
