MULTIPLE PREGNANCY Supervisor : Prof .Salah Roshdy Presented by : Tasneem Al-ajlan

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

: DEFINITION 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. 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 delivery Number of babies Weeks of Gestation 1 40 weeks 2 36 weeks 3 33 weeks 4 29 ½ weeks

Incidence & 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 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 years 6. Previous multiple pregnancy.

DDx of uterus that is greater than expected for gestational age: 1- Gestational trophoplastic disease 2- Macrosomia. 3- Placental abruption. 4- Polyhydramnios. 5- Uterine fibroid. 6- Ovarian mass.

Classification Dizygotic (>70%) Monozygotic (<30%) Dichorionic/Diamniotic Dichorionic/Diamniotic (8%) Monochorionic/Monoamniotic (1%) Monochorionic/Diamniotic (20%)

Important 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 (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.

Cont.. The incidence of dizygotic twins is higher in : Certain families . Race ;African Americans . Increases with maternal age, parity, weight and height . Ovulation induction.

B- Monzygotic (identical ) twins: 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.

The timing of cleavage determines the placentation of the pregnancy. Perinatal mortality % Nature of membranes Time of cleavage 8.9% 30 diamniotic,dichorionic 0 - 72 hr 25% 69 diamniotic,monochorionic 4 – 8 days 50-60% 1 monoamniotic,monochorionic 9-12days ----- ---- Conjoined twin >13 days

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

Examination: ( 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 .

Ultrasonography ( diagnostic ): investigation : 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.

:DETERMINATION 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.

During pregnancy by US : 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.

: Dizygotic 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.

: Monozygotic 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.

After birth : By examination of the MEMBRANE, PLACENTA,SEX , BLOOD group . Examination of the newborn DNA and HLA may be needed in few cases.

US gender same different dizygotic twins Monozygotic twins Number of placenta 1 2 different same same Blood group HLA & DNA analysis different

DETERMINATION OF ZYGOSITY : Freq. Zygosity Findings 30% Different genders 27% Two placentas , same gender different blood groups 23% One placentas 20% Two placentas , same gender Same blood group dizygotic dizygotic monozygotic HLA & DNA analysis

1 2 3 4 Twin type Placental type Septum monozygotic Monochorionic/Monoamniotic 1- None Monochorionic/Diamniotic 2- Amnion only Dizygotic or monozygotic Dichorionic/ diamniotic 3- Amnion & chorion dizigotic 4- No common septum 1 2 3 4

Complications: 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 .

Cont.. - Intrapartum: - Postpartum: - 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 .

Cont .. 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 and mortality in twins : Respiratory distress syndrome . Birth trauma . Cerebral hemorrhage . Birth asphyxia . Birth anoxia . Congenital anomalies . Stillbirths . Prematurity .

Abnormalities of the twinning process : 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 : “ 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.

Thoracopagus Craniopagus

Pygopagus Ischiopagus

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 twins

Interplacental Vascular Anastomoses : 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 .

Twin-Twin Transfusion 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 .

Heart failure 2ry to anemia Congestive heart failure TTTS ( cont.. ) Donor[ Recipient Hypotensive Hypertensive Anemic Polycythemic Oligohydramnios Polyhydramnios  growth restriction Overgrown Hydrops fetalis Hypovolemia Hypervolemia Heart failure 2ry to anemia Congestive heart failure Both: risk of demise & PTL .

Management of TTTs : If not treated death occurs in 80-100% of cases. 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 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 twin Normal (pump) twin

Umbilical Cord Abnormalities : 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 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 .

Management :

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. 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: 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 .

Delivery : 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 indicated 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 , TRAP 6- 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 : Active management . By giving oxytocin in the 3nd stage of labor just after delivery of both fetuses and placentas.

Any Question?

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