Transcript Document

Twins & higher multiple
gestations
Is it good NEWS to be told that you
are going to have twins?
Definition
Multiple pregnancies consists of two or more fetuses ,there are
exceptions to this such as twins gestations made of a
singleton viable fetus & a complete mole.
Prevalence
Twins account for approximately 1.5%
Higher multiple occur in 1/2500
Risk factors
1- assisted reproductive techniques (IVF& induction of ovulation )
2-high parity
3- black race
4- maternal family history
5- increasing maternal age.
Hellin`s rule
Twins were expected in 1/80
Triple (1/80)2
Classification
1- according to number of fetuses
2-number of fertilized eggs
3-number of placentas ( chorionicity)
4-number of amniotic cavities (amniocity)
Non identical twins( dizygotic twins)
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*Always have two separate placentas (DC)
*separate amniotic cavities (DA)
*the fetuses either the same or different sex pairing
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Identical twins (monozygotic)
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Arise from fertilization of single egg
Always of same sex
Either MC or DC
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The vast majority of MC are DA
Not all dichorionic are dizygotic
All monochorionic pregnancy are monozygotic
Aetilogy
Dizygotic twins may arise spontaneously from the release of two eggs at
ovulation
Causes
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Familial
Racial
Increasing maternal age
Induction of ovulation
IVF
Monozygotic twins
Arise from a single fertilized ovum that splits into two identical
structures
Types of monozygotic twins
When the split occur within 3 days of conception , two placentas &two
amniotic cavities result (DC,DA)
• When splitting occur between 4-8 days ,monochorionic diamniotic twins
will result (MC,DA)
• Later splitting results in two fetuses in a single amniotic cavity sharing
single placentas (MC.MA)
• If splitting delayed beyond 12 days , conjoined or Siamiese twins will result
The incidence of monozygotic twins 1/250 it is not influence by race ,family
history or parity.
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MONOZYGOTIC TWINS
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70% are diamniotic monochorionic.
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30% are diamniotic dichorionic.
Results from division of fertilized
egg:
0-72 H.
4-8 days
9-12 days
>12 days
Diamniotic dichorionic.
Diamniotic monochor.
Monoamnio.monochor.
Conjoined twins.
Conjoined twins or Siamese twins
 *Anterior (thoracopagus)
 *Posterior (pygopagus)
 *Cephalic (craniopagus)
 *Caudal (ischiopagus)
Maternal Physiological Adaptation
 Increase blood volume and cardiac output.
 Increase demand for iron and folic acid.
 Maternal respiratory difficulty.
 Excess fluid retention and edema.
 Increase attacks of supine hypotension.
Complications of pregnancy
1- preterm labour
2-pregnancy-induced hypertension
3-anaemia
4-polyhydramnia
5-congenital malformation
6- growth restriction
7-miscarriage
8- high perinatal mortality & morbidity
Complication of labour
1-malpresentation
2-postpartum haemorrhage
3-cord prolapse
4- locked twins
In monochorionic twins death of one fetus
may result in immediate complications in
the survivor (brain damage ,death,
neurodevelopment handicap)
Acute hypotensive episodes secondary to
placental vascular anastamosis between
the two fetuses result in haemodynamic
volume shifts from the life to the dead
fetus.
Fetal abnormalities
The risk of fetal abnormalities carry at least twice the risk in
twins pregnancy
• *In each DC twins the risk of structural abnormalities
,such as spina bifida is similar to that for singleton
pregnancy
• *Each MC twins carries the risk 4 X that of singleton
pregnancy
• Multiple gestations with an abnormality in one fetus can be
managed expectantly or by selective fetocide of the
affected fetus
• 1-When the abnormality is not lethal the parents should
outweighs the risk of loss of a normal fetus from fetocide
related complications
When the abnormality is lethal it may better to avoid
such risk to the fetus
• In MC twins selective fetocide is dangerous for the
second twins so they do cord occlusion techniques,
these require significant instrumentation of the
uterus & are therefore associated with higher
complications.
• Chromosomal defects & twining
1-monozygotic twins are affected either both or non of
the twins will be affected ( the risk is based upon
maternal age)
2- in DZ twins the risk will be twice that of singleton
pregnancy ( e.g. the risk of Down syndrome 1/50)
Complications unique to monoamniotic twins is cord
accident
Differential diagnosis of twin pregnancy
1-polyhydramnious
2-big baby
3-ovarian cyst or mass
4-uterine fibroid
5-retntion of urine.
Complications unique to
monochorionic twins
TWIN-TWIN transfusion
 Chronic shunt occurs ,the donor bleeds into
the recipient so one is pale with
oligohydraminose while the other is
polycythemic with hydraminose.
 If not treated death occurs in 80-100% of
cases.
Twin –twin transfusion syndrome
Either mild , moderate or sever depends on the degree of imbalance
the donor fetus suffers from
1- hypovolaemia & hypoxia
2-growth restricted
3- oliguric
4-oligohydramnious
The recipient fetus suffers
1-hyprrvolaemic
2-polyhydraminous
3- myocardial damage
4- high output failure
Sever disease appear at18-24w
Mother complain of
1- sudden increase in abdominal girth.
2- extreme discomfort
3- polyhydramnious (detcted by US)
90% of TTTS end in miscarriage or preterm labour
due to polyhydramnious or death of one fetus.
Treatment
*Amniocentesis every 1-2w
*fetoscopically guided laser coagulation to disrupt
the placental blood vessels that connect the
circulation of the two fetuses
Other Complications in Monochorionic
Twins:
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Congenital malformation. Twice that of singleton.
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Umbilical cord anomalies. In 3 – 4 %.
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Conjoined twins. Rare 1:70000 delivaries. The
majority are thoracopagus.
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PNMR of monochorionic is 5 times that of
dichorionic twins(120 VS 24/ 1000 births)
Diagnosis of Multiple Fetuses
1.
History.
2.
Clinical Examination.
3.
Investigations.
 History ovulation inducing drug
 Family history of twin
 Exaggerated symptoms
 Cardiopulmonary embarrassment
 Excessive fetal movement
 General examination
 Anaemia more than single pregnancy
 Unusual weight gain
 Evidence of PET ( 25% more)
Per abdominal examination
 Height of the uterus more than the period of
gestation
 Too many fetal parts
 Two fetal head
 Two distinct fetal heart sound, at separated
spot, provided the difference at least 10
beats per minute
Lab Investigation
 Ultrasonography
 Two gestational sacs can be detected as
early as 10 weeks of pregnancy
 Radiography
 Should be done after 30 weeks
Management
Antenatal.
2. In Labor.
1.
Antenatal Management
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Early diagnosis (mainly by ultra sound)
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Adequate nutrition:1- Caloric consumption increased by 300 Kcal per day.
2- Iron 60-100 mg per day.
3- Folic acid 1mg per day.
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Frequent prenatal visit:observe maternal and fetal complications
1- Frequent ultra sound  fetal growth, congenital
anomalies, amniotic fluid.
2- Doppler.
3- BPP(Biophysical profile).
Management of twin pregnancy
The patient is seen more often than usual
from mid-pregnancy onwards .
She should be seen every two weeks until 20
weeks & every weeks till 36 weeks
Investigations
1-confirming a diagnosis
2-determining chorionicity
3-detecting fetal anomalies
4-evaluating fetal growth
5-confirming fetal wellbeing
6-assisting in delivery
Antepartum management
1-Preterm labour (40%) in twin pregnancies
&(75%) in triplet pregnancies
*there is no evidence that prophylactic cervical
cerclage or prophylactic tocolytic agent have
been beneficial.
*bed rest at home or in the hospital has not
proved effective in preventing preterm labour or
delivery
2- pre-eclampsia
the risk of gestational hypertension or preeclampsia has been reported to range from 1020% in a twin pregnancy, 25-60% in triplet
pregnancy.
3- other maternal complications
Daily supplementation of at least 60 mg of
elemental iron &1mg of folic acid is
recommended because of the increased risk of
iron &folate deficiency anaemia
multiple pregnancy is a particular risk for the
occurrence of acute fatty liver of pregnancy
Intrapartum management
1- all twin and multiple fetuses should be
delivered by 40 weeks
2-the use of prostaglandins for induction &
oxytocin for induction or augmentation of
labour is an acceptable alternative to the
elective delivery by CS
2- requires adequate obstetric & nursing staff
3-US to confirm fetal presentation & size before a
decision is made on mode of delivery
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Four principal combinations of presentations
 Cephalic/cephalic
60%
 Cephalic/breech
20%
 Breech/cephalic
10%
 Breech/breech
10%
The presentation of the fetuses may be
1- vertex- vertex twins
2- vertex –nonvertex twins
3-higher order multiple gestation
Vertex- vertex twins
In the absence of obstetrical indications for CS
delivery ,vaginal delivery should be planned
regardless of gestational age.
Delay of over half an hour in the delivery of the
second twin increases the ocurrence of fetal
morbidity, thus the CS rate for the second twin
increases with the increase in the delivery time
Vertex –nonvertex presentaton
Vertex –breech or vertex-transerse presentation occurs in
35-40% of all twin pregnancies selection of delivery
depends on the following
*the size of the second twin
*presence of growth discordance
 The availability of an obstetrician skilled in assisted
breech delivery , internal podalic version & total breech
extraction
 If the second twin in a transverse lie or a footling
presentation, the membrane should be left intact until
the feet can be secured in the pelvis, following which
immediate rupture of the membranes & total breech
extraction should be performed
Nonvertex first twins
 Breech-vertex or breech-breech occurs in
15-20% of all twin pregnancies. These cases
are almost always managed by CS
 Higher order multiple gestation
Cesarean delivery is recomended
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C.S. for Multiple Pregnancy:
Indications of C.S. :
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More than 2 viable fetuses, if:
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weight < 2 kg,
discordant growth ( i.e.; IUGR or twin-twin transfusion, or
disproportionate twins, twin B larger than A (BPD > 2 mm),
twin A: is non-vertex.
Conjoined Twins
Single amniotic cavity (as diagnosed by U/S or amniogram).
Previous Uterine scar.
During Labor: if delayed progress, fetal distress, or if twin B
transverse and cervix is thickened (retained second twin).
Associated pregnancy complication i.e.; severe PIH, placenta previa.
Contracted Pelvis
Lack of expertise
Requirements for twin delivery
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Large delivery room
Operating theatre and staff ready
Anaesthetist present
Senior obstetrician present
At least two midwives present
Twin resuscitaires
Ventous/forceps to hand
Blood grouped and saved
Intravenous access
Neonatologists present
Pre-mixed oxytocin infusion ready
Conjoined twins Chang and Eng Bunker (1811-1874), Chinese
brothers born in Siam, now Thailand .They traveled with
Barnum's circus and were billed as the Siamese Twins .They
had fused livers