Monozygotic One Present 2
Same Acceptance Usually
Dizygotic Two Absent 4 : 2
Differ Rejection Not
The Cause of twinning is not known.
Dizygotic twin pregnancies are slightly more likely when the following factors are
present in the woman:
•She is between the age of 30 and 40 years
•She is greater than average height and weight
•She has had several previous pregnancies.
•Women undergoing certain fertility treatments may have a greater chance of
dizygotic multiple births.
•The risk of twin birth can vary depending on what types of fertility treatments are
used. With in vitro fertilisation (IVF), this is primarily due to the insertion of multiple
embryos into the uterus.
•Ovarian hyperstimulation without IVF has a very high risk of multiple birth.
•Reversal of anovulation with clomifene has a relatively less but yet significant risk of
Maternal Physiological Changes
1. There is increase in weight gain and
2. Plasma volume is increased by an addition
3. There is no corresponding increase in red
cell volume resulting in exaggerated
haemodilution and anaemia.
4. There is increased alpha fetoprotein level,
tidal volume and glomerular filtration rate.
LIE AND PRESENTATION
Commonest lie is
History of ovulation
Family history of
More “barrel shaped” inspection
Abdominal girth more than 100cm.
Too many fetal parts on palpation.
Two distinct fetal heart sounds on
Not easy due
Confirmation of pregnancy as
early as 10th week of
Presentation and Lie of
Viability of fetus
Fetal growth monitoring for
Fetal AnomaliesAmniotic fluid
Lambda or twin peak
The sign describes the triangular appearance
to chorion insinuating between the layers of the inter
twin membrane and strongly suggests a dichorionic
twin pregnancy. It is best seen in the first trimester
(between 10-14 weeks).
In contrast the T sign refers to the appearance of the
intertwin membrane in a monochorionic twin
pregnancy. The sign should not be confused with
the lambda sign of sarcoidosis.
A potential space exists
in the intertwin
membrane, which is
filled by proliferating
placental villi giving
rise to the twin peak
Fibroid or ovarian
Early Rupture of
Increased risk of miscarriage
Premature rate (80%)
Intrauterine death of one
Asphyxia and stillbirth
Management during Labour
What happens during a twin birth?
Most twins are born before 38 weeks. If you haven't gone into labour by then,
you may be recommended to have your labour induced.
During labour, regular monitoring of your twins with electronic fetal monitors
(EFM) is standard practice. This is used to listen to your babies' heartbeats and
the intensity and frequency of your contractions. Your doctor may place a
needle in a vein in your arm (a drip) in case it is needed later.
Discuss your pain relief preferences with your midwife during pregnancy and
write them in your birth plan. But keep in mind that labour and birth
are unpredictable. Your midwife may need to recommend a course of action at
any time which is not what you had originally hoped for, but which will always
be in the best interests of you and your baby.
Once your first baby is born, your midwife or
doctor will check the position of your second
twin by feeling your tummy and doing a
vaginal examination, or an ultrasound scan.
If your second baby is in a good position to
be born, the waters surrounding him will be
broken. Your second baby should be born
very soon after the first, because your cervix
is already fully dilated. If your contractions
stop after your first twin is born, hormones
are added to the drip to restart them.
You'll usually be recommended to have
a managed third stage. This is when the
placenta is delivered with the help of a
hormone injection, instead of a natural
delivery. This is because there is an increased
risk of bleeding when the placenta is larger,
and the uterus (womb) will have been
stretched by two babies.
Female usually outnumber the number of male one. Perinatal loss is markedly
increased due to prematurity.
Average time for delivery in quadruplets is 30-31 weeks.
Selective reduction: If there are 4 or more fetuses, selective reduction of the
fetuses leaving behind only two is done to improve the outcome. This can be
done by intracardiac injection of potassium chloride between 11-13 weeks.
Selective termination of a fetus with structural or genetic abnormalities may be
done in a chorionic multiple pregnancy in the second trimester.