obstetrics & gynecology,

3. Multiple Gestations
Nizam-ud-Din
09-147

4. Definition:
Presence of more than one fetus in the gravid uterus
-Twins (two babies)
-Monozygotic(Division of 1 ova fertilized by the same sperm)
-Dizygotic(Fertilization of 2 ova by 2 sperm)
-Triplets (three babies)
-Quadruplets (four babies)

5. Incidence
• Twins - 1 in 85 births
• Chile : 1 in 51
• African : 1 in 70
• Japanese : 1 in 150
• Chinese : 1 in 300
• Triplets are about 1 in 7,629 births
• Quadruplets are about 1 in 670,734 births

6. • Twins : 1 in 80
• Triplets : 1 in 80 × 80
• Quadruplets : 1 in 80 × 80 × 80….
• Gemellology : Study of twins
Hellin’s Rule

8. Types of Twins:

9. DIZYGOTIC or FRATERNAL TWINS
Always Dichorionic & Diamnionic
Amnion Amnion
2 Chorions

10. Dizygotic Twins
Fertilizations of 2 ova by different spermatozoa.
Each twin has its own placenta, chorions , amnion.
Hence always dichorionic, diamnionic.

11. Factors Affecting Dizygotic Twinning
Ethnic group
Increasing maternal age

12. Increasing parity.
Family history of twinning.
Ovulation induction

13. MONOZYGOTIC or IDENTICAL Twins

14. MONOZYGOTIC
or
IDENTICAL Twins

15. Monozygotic Twins
Result from splitting of a single fertilized ovum
Always same sex and look alike. [ IDENTICAL ]
Rate of monozygotic twinning is relatively constant , not
affected by any factors.
True etiology unknown.
Type of placentation is determined by the time of splitting

16. ULTRASOUND DETERMINATION OF CHORIONICITY
Number of sacs
Placenta
Sex
Intertwin membrane
Lambda sign & T sign
Ideal time for assessing of chorionicity is
before 14 weeks

17. DIZYGOTIC
LAMBDA SIGN

18. MONOCHORIONIC & DIAMNIONIC
T SIGN

19. Maternal Complications
Hyperemesis – increased β- hCG
Hydramnios – monoamniotic pregnancies, Twin
transfusion syndrome, major cause of prematurity
Pre- Eclampsia – 3 times commoner compared
to singleton
Pressure symptoms
Anaemia – increased plasma volume expansion
, fetoplacental demand for iron increased.
ANTEPARTUM HEMORRHAGE – Placenta
praevia , Abruptio placenta.

20. Fetal Complications
Antepartum Intrapartum
1. Prematurity
1. Premature Rupture of the
Membranes
2. Intrauterine Growth Restriction 2.Cord Prolapse
3. Single Fetal Demise 3.Abruption in second twin
4. Twin To Twin Transfusion
Syndrome
4.Interlocking (rare)
5. Vanishing Twin/Abortion
6. Cong. Anomalies
7. Conjoined Twins

21. I. Prematurity
Single most important cause of
perinatal mortality and morbidity.
Fetal Complications

22. Can affect one or both fetuses.
Monochorionic > Dichorionic.
UPTO 30-32 Weeks twins grow with same velocity ,
after that reduction in abdominal circumference.
Poor growth – poor placentation , unequal
placental sharing, fetal anomalies.
II. IUGR

23. III. Single Fetal Demise
Monochorionic
Death of one
twin
Shift of blood
Normal
twin
25% risk of co-twin death /25% risk of neurological
damage in surviving twin

24. IV. TWIN-TWIN TRANSFUSION SYNDROME
Occurs in monochorionic placentation
due to AV anastomoses with resultant
flow in one direction.

25. Arterio venous anastomoses with
net flow in one direction..
Donor(arterial side)
Recipient
•Severe IUGR
•poor renal perfusion
•Anuria
•Severe Oligohydramnios
•Hypervolemia
•Polyuria with polyhydramnios
•Hydrops…death

27. V. Vanishing Twin & Abortion
Incidence of abortion more in multiple pregnancy
Spontaneous cessation of cardiac activity in a
previously viable fetus of a multiple gestation. –
VANISHING TWIN
When fetal death occur after the first trimester, results in a
thin parchment – like body called FETUS PAPYRACEOUS
Diagnosis made after delivery
No effect on mother or the viable fetus.

28. VI. Congenital anomalies
• Unique to twins – conjoined twins , Acardiac fetus
• Non specific but common in twins – CHD , Anencephaly
• Postural deformities – Talipes & Congenital dislocation of
Hip
STRUCTURAL MALFORMATIONS
• Dizygotic – independent risk, but both will not be
involved
• Monozygotic – same risk as that of singleton, both
affected
• Down’s syndrome
CHROMOSOMAL ANOMALIES

29. VII. Conjoined Twins
Always monozygotic
Incomplete division occurring after 13 days.
Very rare
Prenatal diagnosis important – for termination , for planning operation
Severe cases detected early – Termination
Surgical separation only in some cases – sharing of brain and heart – unsuccessful
operation
Caesarean preferred

30. THORACOPAGUS ISCHIOPAGUSCRANIOPAGUS
RACHYPAGUSPYOPAGUSOMPHALOPAGUS

39. DELIVERY OF THE SECOND BABY
Following the birth of the first baby, the lie, presentation, size and FHS of
second baby should be noted by abdominal examination.
Vaginal examination is done to confirm the presentation.