SupervisorSupervisor: : Prof .Salah Prof .Salah

RoshdyRoshdy Presented byPresented by : :

Tasneem Al-Tasneem Al-ajlanajlan

OBJECTIVESOBJECTIVES: :

• Definition.• Incidence and epidemiology.• Classification.• Diagnosis.• Complications.• Abnormalities of the twinning process.• Management.

: :DEFINITIONDEFINITION

• Any pregnancy which two or more embryos or fetuses present in the uterus at same time.

• It is consider as a complication of pregnancy due to ; - The mean gestational age of delivery

of twins is approximately 36 weeks.- The perinatal mortality &morbidity

increase.

Terminology vs. numberTerminology vs. number

Singletons one fetus. Twin two fetuses.

Triplets three fetuses. Quadruplets four

fetuses. Quintuplets five

fetuses. Sextuplets six

fetuses. Septuplets seven fetuses.

Mean gestational age of Mean gestational age of deliverydelivery

Number of babies Weeks of Gestation

1 40 weeks

2 36 weeks

3 33 weeks

4 29 ½ weeks

Incidence & epidemiologyIncidence & epidemiology• The incidence of multiple pregnancy in

US is approximately 3 % (increase annually due to ART ). • Monozygotic twins ( approx.1 in 250

births ).• Triplet pregnancies (approx. 1 in 8000

births ).• Multiple gestation increase morbidity &

mortality for both the mother & the fetuses.

• The perinatal mortality in the developed countries– Twins = 5 – 10 % births.– Triplets = 10 – 20 % births.

Factors are associated with Factors are associated with higher incidence:higher incidence:1. Racial: more in Negro.2. Family history of multiple pregnancies.3. Induction of ovulation: clomifene(8%), gonadotrophins(30%).4. Multiparas than primiparas.5. Maternal age: common in women over 35 years6. Previous multiple pregnancy.

DDx of uterus that is greater DDx of uterus that is greater than expected for gestational than expected for gestational

ageage::

1- Gestational trophoplastic disease

2- Macrosomia. 3- Placental abruption.4- Polyhydramnios.5- Uterine fibroid.6- Ovarian mass.

ClassificationClassification

Monozygotic (<30%)Monozygotic (<30%)Dizygotic (>70%)Dizygotic (>70%)

Monochorionic/Monoamniotic(1%)

Monochorionic/Monoamniotic(1%)

Monochorionic/Diamniotic(20%)

Monochorionic/Diamniotic(20%)

Dichorionic/Diamniotic (8%)

Dichorionic/Diamniotic (8%)

Dichorionic/DiamnioticDichorionic/Diamniotic

Important notesImportant notes::

1- Monozygotic twins having same sex & blood group.

2- Process of formation of chorion is earlier than formation of amnion.

3-Dizygotic twins must be dichorionic/diamniotic.

4- There is no dichorionic/ monoamniotic.

:A- Dizygotic twins A- Dizygotic twins (fraternal)(fraternal)

• Most common represents 2/3 of cases.• Developed from two separate ova which may

or may not come from the same ovary and fertilized by two separate spermatozoa.

• The twins are of the same or different sex.• The similarity between them is not more than

that between members of the same family.• They have : - two placenta, -two chorions, -

two amnions, - two umbilical cords.

ContCont....

The incidence of dizygotic twins is higher in :

1.Certain families .2. Race ;African Americans .3.Increases with maternal age, parity, weight

and height .4.Ovulation induction.

• Constitutes 1/3 of twins• Developed from a single ovum which after

fertilization, by a single sperm, has undergone division to form two embryos.

• The twins are of the same sex.• They have similar physical and mental

characters as well as the blood group but not finger prints.

• The timing of cleavage determines the placentation of the pregnancy.

• Constant incidence .• Not affected by heredity.• Not related to induction of ovulation.

B- Monzygotic (identical ) B- Monzygotic (identical ) twinstwins::

Time of cleavage

Nature of membranes

% Perinatal mortality

0 - 72 hr diamniotic,dichorionic

30 8.9%

4 – 8 days diamniotic,monochorionic

69 25%

9-12days monoamniotic,monochorionic

1 50-60%

>13 days Conjoined twin ---- -----

The timing of cleavage The timing of cleavage determines the placentation of determines the placentation of the pregnancythe pregnancy..

History :-History :-

- Family hx of dizygotic twins.- Use of fertility drugs.- Sensation of excessive fetal movements.- Exaggerated symptoms of pregnancy (hyperemesis gravidarum ).

: :DiagnosisDiagnosis

( weight gain, Pre-eclampsia signs )• Inspection: More enlargement of the abdomen.• Palpation:1. Fungal level: higher than that

corresponds to the period of amenorrhoea.2. Fundal, umbilical and first pelvic grips:

can detect multiple foetal poles. • Auscultation: Foetal heart sounds: are heard with

maximum intensity in 2 separate points .

ExaminationExamination::

• Ultrasonography ( diagnostic ):- demonstrating two separate fetuses

and heart activities .- can be made as early as 6 weeks of

gestation.

• HCG & serum alpha-fetoprotein levels are elevated for gestational age.

investigation :investigation :

::DETERMINATION OF ZYGOSITYDETERMINATION OF ZYGOSITY

• Very important as most of the complications occur in monochorionic monozygotic twins.

By :Ultrasound : genders , number of placentas,Blood groups.HLA.DNA analysis.

• Very accurate in the first trimester, two sacs, presence of thick chorion between amniotic membrane .

• Less accurate in the second trimester the chorion become thin and fuse with the amniotic membrane .

• Different sex indicates dizygotic twins.

• Separate placentas indicates dizygotic twins.

During pregnancy by US :During pregnancy by US :

A: Real-time ultrasound with a thick vertical amnion-chorion septum (membrane) separating one twin on the left side from the second twin on the right. - The arrow points to a "peak or inverted V" suggesting dizygotic twins.

:: DizygoticDizygotic

B: Ultrasound of a thin vertical membrane separating one twin on the left side from the second twin on the right, suggesting a monochorionic gestational sack.

:: MonozygoticMonozygotic

After birth :After birth :

• By examination of the MEMBRANE, PLACENTA,SEX , BLOOD group .

• Examination of the newborn DNA and HLA may be needed in few cases.

USUS

gendergender same different

1Monozygotic

twinsMonozygotic

twins

2

sameBlood group Blood group HLA & DNA

analysis HLA & DNA

analysis

samedifferent

Number of placenta

Number of placenta

different

dizygotic twins

dizygotic twins

Findings Zygosity Freq.

Different genders 30%

Two placentas , same gender

different blood groups

27%

One placentas

23%

Two placentas , same gender

Same blood group

20%

DETERMINATION OF DETERMINATION OF ZYGOSITYZYGOSITY: :

dizygotic

dizygotic

HLA & DNA analysis

monozygotic

Septum Placental type Twin type

1 -None Monochorionic/Monoamniotic

monozygotic

2 -Amnion only

Monochorionic/Diamniotic

monozygotic

3 -Amnion &

chorion

Dichorionic/ diamniotic

Dizygotic or monozygotic

4 -No common septum

Dichorionic/ diamniotic

dizigotic

1 2 3 41 2 3 4

• A - Maternal:– Antepartum:

• Miscarriage • Anemia: (because of the increased foetal

demand for iron and folic acid ).• Hyperemesis gravidarum.• Preeclampsia :( 40% in twins & 60% in

triplets ).• Polyhydramnios : ( 5 – 8% ) • Preterm Delivery :( Twin account for 10%

of all PTL & 25% of all preterm perinatal deaths ).

• Cervical incompetence .

ComplicationsComplications::

ContCont....

- Intrapartum: - CS - Retained second twin - locked twins- Postpartum: - Postpartum hemorrhage due to: a. Atony results from over distended uterus and prolonged labor, b. large placental site, c. placenta praevia or early separation of the placenta after delivery of the first twin. - Postpartum endometritis .

ContCont.. ..

• B - Fetal:• Congenital anomalies(Monozygotic

twins have a risk of 2% to 10% for developmental defects ).

• Fetal Malpresentation .• Placenta previa and Abruptio placenta .• Premature rupture of the membranes

( PROM ).• Prematurity .• Umbilical cord prolapse .• Intrauterine growth restriction ( IUGR ).• Increased perinatal morbidity and

mortality .

Causes of perinatal morbidity Causes of perinatal morbidity and mortality in twinsand mortality in twins: :

• Respiratory distress syndrome . • Birth trauma .• Cerebral hemorrhage . • Birth asphyxia .• Birth anoxia .• Congenital anomalies .• Stillbirths .• Prematurity .

Abnormalities of the twinning Abnormalities of the twinning processprocess: :

• Conjoined Twins .• Locked twins .• Fetal Malformations .• Interplacental Vascular Anastomosis .• Twin-Twin Transfusion Syndrome .• Discordant Twin Growth .• Umbilical Cord Abnormalities .• Single fetal death . • Rupture of membrane in single sac .

Conjoined Twins : “ siameseConjoined Twins : “ siamese“ “

• Etiology : It result from cleavage of the embryo is incomplete because it happen very late ( after 13 days, when the embryonic disc has completely formed ).

• Incidence : once in 70,000 deliveries .

• Classification :- Thoracopagus (antreior) “most common” .- Pygopagus ( posterior ).- Craniopagus ( cephalic ).- Ischiopagus ( caudal ).

• Delivery by C.S.

ThoracopaguThoracopagu

ss CraniopagusCraniopagus

PygopaguPygopagus s

IschiopaguIschiopagus s

Locked twins :Locked twins :

- Rare condition (1 in 817 twin gestations ). - It occurs with breech/vertex twins . - When the body of twin A delivers, but the

chin locked behind the chin of twin B - Risk factors : Hypertonicity, monoamniotic twinning, or

oligohydraminous . - Deliver by CS .

Locked twinsLocked twins

• It occurs almost exclusively in monochorionic twins at a rate of 90% or more.

• Type :- Arterial_artarial(most common).- Arterial_venous.- Venous_venous.

• Complications : - Abortion.- Hydramnios.- Twin-twin transfusion syndrome ( TTTS ).- Fetal malformations .

Interplacental Vascular Interplacental Vascular AnastomosesAnastomoses: :

Twin-Twin Transfusion Twin-Twin Transfusion Syndrome ( TTTS )Syndrome ( TTTS )

• Definition :– The presence of unbalanced anastomosis in

the placenta (typically arterial-venous connections) leads to a syndrome in which one twin’s circulation perfuses the other Twin .

–  In about 10% of monozygotic twins .–  The arterial blood from the "donor twin"

enters the placenta (through the umbilical artery) and is taken up by the umbilical venous system belonging to the "recipient twin," which results in a net transfer of blood from the donor to the recipient twin .

Donor[ Recipient

Hypotensive Hypertensive

Anemic Polycythemic

Oligohydramnios Polyhydramnios

 growth restriction Overgrown Hydrops fetalis

Hypovolemia Hypervolemia

Heart failure 2ry to anemia

Congestive heart failure

TTTS TTTS ( cont.. )( cont.. )

Both: risk of demise & PTL .

Management of TTTsManagement of TTTs: :

• Serial amniocentesis and fluid reduction for the recipient twin. • Intrauterine blood transfusion for the donor twin. • Indomethacin. • Fetoscopic laser ablation of placental anastomoses.

• If not treated death occurs in 80-100% of cases.

Fetal MalformationsFetal Malformations: :

• Incidence:– Twice as common in twins & 4 times

more common in triplets than in singleton infants.

– Monozygotic > Dizygotic.• Etiology:

– Usually result from arterial-arterial anastomosis.

– Common deformations in twins include limb defects, plagiocephaly, facial asymmetry, and torticollis.

– Acardia and twin-reversed arterial perfusion (TRAP) “ rare but unique to multiple pregnancy”.

• Amniocentesis:– If U/S shows abnormality.

Acardiac twinNormal

(pump) twin

Umbilical Cord Umbilical Cord AbnormalitiesAbnormalities: :

• Absence of one umbilical artery occurs in about

3% to 4% of twins (30% of case absence of one artery associated with other congenital anomalies  (e.g. ”renal agenesis” ).

• Cord entanglement ( esp. in monochorionic monoamniotic twins ).

• primarily associated with monochorionic twins .

Discordant Twin GrowthDiscordant Twin Growth: :

• Definition:- Discrepancy of more than 20% in the

estimated fetal weights .• Causes :

- TTTS .- Chromosomal or structural anomalies .- Discordant viral infection .

When weight discordance exceeds 25%, the fetal death rate increases 6.5-fold and the neonatal death rate 2.5-fold .

1-Antepartum :1-Antepartum :

• Frequent antenatal visits .• Adequate nutrition:

Adequacy of maternal diet is assessed due to the increased need

for overall calories, iron, vitamins, and folate .

• Periodic U/S assessment “ every 3 - 4 weeks from

23 weeks’ gestation “ to monitor the growth and detection of

discordant growth or TTTS.• Fetal surveillance:

- Performance of NST is not indicated before 34 wks unless to

confirm IUGR or discordant growth . - ( avoid CST ) might precipitate preterm delivery .

Cont.Cont.

•Adequate rest : to improve placental blood flow and avoid preterm labor.• Prophylactic tocolytics or cerclage .• Amniocentesis : ( If indicated for prenatal diagnosis of a fetal condition, including genetic disorders or isoimmunization ).

In case of death of one fetus is managed based on the gestational age and condition of the surviving fetus .

1- fetal surveillance evidence weekly

measured Until

2- maternal clotting profiles of fetal lung maturity in the

surviving fetus is exhibited

Delivery should be considered if : 1) Fetal lung maturity is demonstrated . 2) If compromise of the remaining fetus

develops . 3) If evidence of disseminated intravascular

coagulation in the mother is present . In the setting of TTTS, the death of one twin

should prompt consideration of delivery, particularly after 28 weeks, given the high rates of embolic complications in the surviving twin.

2- Intrapartum:2- Intrapartum:

• The route of delivery depends on :- Presentation of the twins .- Gestational age .- Presence of maternal or fetal

complications .- Experience of obstetrician .- Availability of anesthesia & neonatal

intensive care .

DeliveryDelivery: :

• Vertex / Vertex ( 43% ):- Vaginal delivery. ( Successful in 70 - 80%

of cases ).

• Vertex / Nonvertex ( 38% ):- Vaginal delivery ( better ) ( in absence of

discordant growth ).- Either external cephalic version or podalic

version with breech extraction of twin B may be attempted.

• Nonvertex Twin A ( 19% ):- CS .

Caesarean section is Caesarean section is indicated inindicated in::1- Conjoined twins.

2- Locked twins. 3- Non vertex presentation of first twin (transverse

lie)4- Fetal distress in the first stage.5- Cord prolapse , TRAP6- Retained second twin when it is : - transverse lie. - membranes are ruptured. - uterus is retracted . - cervix is not fully dilated. 7- Triplets or more are safer delivered by C.S.8- Other indications of C.S as placenta praevia,

contracted pelvis , IUGR .

3-Postpartum :3-Postpartum :• Active management . • By giving oxytocin in the 3nd stage of

labor just after delivery of both fetuses and

placentas.

Any Question?

REFERENCESREFERENCES

• Essentials of Obstetrics and Gynecology .

• Johns Hopkins Manual of Gynecology and Obstetrics, The, 3rd Edition .