1. Multifetal gestation

2. Introduction

4. etiology Dizygotic (Fraternal) twins: not strict sense true twins
Monozygotic (identical) twins: not identical d/t not equal sharing of protoplasmic materials

5. Genesis of Monozygotic & Dizygotic Twins

6. Placenta &Membranes in Twin pregnancy

8. Superfetation : interval mense cycle between 2 fertilization but not improved in human
Superfecundation: 2 ovum in same mense cycle but not at same coitus

9. Frequency
monozygote: constant (1/250)
but increase d/t zygote splitting by ART (assisted reproductive technology)
<<race, heredity, age, parity>>
Dizygote: especially fertility treatment

10. Vanishing Twin:
20-60 % in twin conceptions
Special increase in MC twins but singleton del
36% in twins, 53% in triple, 65% quadruplet before 12wks preg
DDX d/t maternal serum AFP ↑
Amniocentesis >> CVS

11. Factors that influencing twinnig
Race : nigeria
Heredity : dizygosity(mother>father)
Maternal age & parity : 37age
Nutritional factor: higher folate intake
Pituitary gonadotropin : within 1Mo stop OC
Infertility Therapy: clomiphene citrate
ART: 1% in birth but 17% in twins
Reducing multifetal gestation but increase survival rate

12. Sex ratio with mutiple fetus
Male decrease in multiple gestation
51.6% in singleton
50.9% in twins
49.5% in triplets
46.5% in quadruplets
MCMA twin 70% female, conjoined twins 75% female→ female mortality & dividing tendency

13. Determine Chorionicity

14. Sonographic evaluation
Twin-peak sign (lamda sign)

15. Sonographic evaluation
T-sign

16. Sonographic evaluation
Easiest & most accurate procedure by evaluation of dividing membrane
More than 96% accuracy
More sensitvity & specificity in 1st trimester >> 2nd trimester

17. Placenta Exam & infant sex
Careful visual exam in delivery
zygosity & chorionicity promptly in 2/3
ABO blood typing in Cord blood if same gender
DNA finger printing : definite method
Twins of opposite sex: always dizygosity but rarely monozygotic twins

18. Unique complications in Twins
Monoamnionic twins
: 1% in monozygotic twin
: High fetal death rate d/t PTL, TTP, cord entanglement, congenital anormaly
: 10% fetal demise if live until 20wks
: Diamnionic twins→monoamnionic twins
d/t dividing memb rupture

19. Mx: After Diagnosis, not promptly del
→ daily 1hr FHR monitoring in 26-28wks
→ betamethasone d/t lung maturation
→ C/S rec at 34wks

20. Abnormal twinning
Conjoined twins

21. Classification: parapagus (m/c)

22. Dx: sono in Mid pregnancy
Determine to continue preg
If organ not share, surgical separation
Termination by C/S rec

23. Vascular anastomoses between fetuses

24. Acardiac twins Twin reversed arterial perfusion(TRAP) sequence
Rare(1/35,000) but serious complication in MC twins
Donor: heart failure
Recipient: lack of structure (acardiac)
Arcardiac acephalus, arcardiac myelacephalus, arcardiac amorphus

25. Acardiac twins

26. Prognosis : donor(pump) twin : 50-75% death d/t cardiomegaly & high output heart failure
Tx: RF ablation: 90% survival rate
closed observation: 90%

27. Twin-Twin Transfusion syndrome(TTTS)
Incidence : ¼ more in MC twin
Donor : pale, anemic, growth restriction
Recipient: plethoric, polycythemic →servere hyperbilirubinemia, hydrop with heart failure d/t circulatory overload

28. Pathophysiology
With AV anasotomosis, uncompensated unidirectional blood flow in 2nd trimester → imbalance in blood volumes
Donor: Oligo, pul hypoplasia
Recipient: severe hydroamnios, PROM, heart failure
 poly-oli syndrome, stuck twin

29. Fetal brain damage
Cerebral palsy, microencephaly, proencephaly, muticystic encephalo-malasia  severe complications
Neurologic damage: ischemic necrosis
Donor: hypotension,anemia→ ischemia
Recipient: BP unstable, severe hypotension episode → ischemia

30. Dx: monochorionicity
Same genser sex
hydroamnios(LP>8cm)Oligo(LP<2cm)
umbilical cord size discordant
hydro in recipient c cardiac dysfuction
abnormal doppler in umbilicus,ductus venosus
Significant growth discordant

31. Staging system
Stage Ⅰ: discordant AF vol ,
but urine(+) in donor bladder
Stage Ⅱ: urine(-) in donor bladder
Stage Ⅲ: abnormal doppler study
Stage Ⅳ:ascites hydrops in either twin
Stage Ⅴ: fetal demise

32. Tx: poor prognosis
amnioreduction
septostomy
laser ablation
selective feticide

33. 감사합니다.