Multifetal gestation

1. MULTIFETAL GESTATION

2. INTRODUCTION
Simultaneous development of more than one
fetuses in the uterus.
Twins, triplets, quadruplets, quintuplets,
sextuplets.
Twins
Simultaneous development of two fetuses
Most common variety of multifetal gestation (94%)

3. MECHANISM OF MULTIFETAL
GESTATION
Results from:
– Two or more fertilization events
– Single fertilization followed by splitting of zygote
– Combination of both
Fertilization of two separate ova : Dizygotic or fraternal or
biovular twins
Single fertilized ovum which further divides: Monozygotic
or identical or uniovular twins
Either or both process involved in higher order
pregnancies.

4. MECHANISM OF MULTIFETAL
GESTATION

5. MONOZYGOTIC TWINS

6. RELATIVE FREQUENCY OF
TWINNING
Type of twinning
Dizygotic Twin 80%
Monozygotic twin
Dichorionic diamiotic
Monochorionic diamniotic
Minochorionic monoamniotic
20%
6-7% (30% Monozygotic)
13-14% (70-75% Monozygotic)
< 1% (1-2% Monozygotic)
Conjoined Twin 0.002- 0.008%

7. MECHANISM CONTD…
Superfetation:
ovulation and fertilization
during the course of an
established pregnancy
Superfecundation:
fertilization of two ova
within the same menstrual
cycle but not at the same
coitus.

8. INCIDENCE
Hellin’s Rule (1895):
Mathematical frequency of multiple birth:
Twins in 1 in 80, triplets in 1 in 802 , quadruplets in 1 in
803 and so on.
Monozygotic twins:
Incidence is relatively constant: 1 per 250 births.
Independent of demographic factors, except ART
Dizygotic twins:
Incidence is influenced by race, heredity, maternal age,
parity

9. FACTORS AFFECTING TWINNING
Demographics:
Race
– Highest among Blacks, lowest in Mongols.
Geographical area:
– Highest in Nigeria (1 in 20)
– Lowest in far eastern countries (Japan 1 in 200)
– India ( 1 in 80)
Due to variability in baseline FSH

10. FACTORS AFFECTING TWINNING
Maternal age:
– Twinning ↑ by almost 4 fold from age of 15 to 37
years.
– Declining fertility but increasing twinning rate
with advancing maternal age
Parity:
– Increased rate of twinning with increasing parity.
Heredity:
– Family history of mother more important
• Mother was a twin: 1 in 58
• Father was a twin : 1 in 116

11. FACTORS AFFECTING TWINNING
Nutrition:
– Greater nutritional status and maternal weight are risk
factors
– Increased prevalence among women taking
supplementary folic acid ( Not proven by systematic
reviews)
Pituitary Gonadotropins:
– Higher level of gonadotropins a/w twinning
– Supported by increased incidence of twinning in
Obese, blacks, advancing age, on first month of
stopping OCP

12. FACTORS AFFECTING TWINNING
Infertility therapy
– Ovulation induction with clomiphene, FSH
– Reported rate twins 28.6%, higher order
pregnancies 9.3%.
– IVF : Greater the number of embroys transferred,
greater the chance of multifetal gestation.

13. DETERMINING ZYGOSITY
Zygosity: Type of conception
Chorionicity: Type of placentation
Sex:
Twins of opposite sex almost always dizygotic
Twins of same sex: Maybe Mono or dizygotic
Placenta:
Dizygotic twins : Dichorionic placenta
Monozygotic Twins: Mono or Dichorionic placenta
Genetic analysis

14. DETERMINING CHORIONICITY
Accurate determination of chorionicity is important
as it is the major determinant of pregnancy outcome
Sonographic determination
– Accuracy is greatest in 1st trimester (up to 98%) & ↓
with increasing gestational age ( 90% in 2nd trimester).
Early first trimester : two separate gestational sac
(dichorionic).

15. DETERMINING CHORIONICITY
After 10-14 weeks:
• Number of placental mass:
– 2 separate placenta → dichorionic
• Thickness of intervening membrane dividing sacs:
– ≥ 2mm in dichorionic
• Presence of intervening membrane:
– in dichorionic pregnancy, composed of 2 amnion and 2
chorion
• Fetal Gender:
– different gender indicates dichorionic

16. DETERMINING CHORIONICITY
Twin peak sign, Delta sign or
Lambda sign :triangular
projection of placental tissue
extending short distance b/w the
layers of dividing membrane.
T or inverted T sign: the
relationship of membranes
with placenta without
intervening tissue.

17. DETERMINING CHORIONICITY
Examination of placenta

18. MATERNAL PHYSIOLOGICAL
ADAPTATION
Physiological burdens and maternal complications
are more with multifetal gestation
First trimester
– Increased β hCG levels: more nausea and vomiting
Blood volume expansion:
– 50-60% Vs 40-50% in singleton
– Proportionately low expansion of RBC- increased
requirements of iron and folate, more chances of
anemia

19. MATERNAL PHYSIOLOGICAL
ADAPTATION
BP change:
– at 8 weeks DBP lower than in singleton, rises by greater
degree at term
Cardiac output:
– increases by 20% more than that in singleton
– Due to increased stroke volume (+15%) & HR (+3.5%)
Peripheral vascular resistance:
– decreases more than in singleton.
Uterine growth:
– Greater than in singleton
– Uterus and non fetal contents may reach volume of 10L

20. DIAGNOSIS OF MULTIFETAL
GESTATION
History
– Assessment of risk factors ( age, parity, family history,
infertility treatment)
– Increased Nausea, vomiting
– Unusual weight gain
– Increased cardiorespiratory discomfort (Palpitation, SOB)
– Overdistension of abdomen
– Excessive fetal movements
– Swelling of limbs
– Presence of hemorrhoids, varicose veins

21. DIAGNOSIS OF MULTIFETAL
GESTATION
Clinical Examination
General examination:
– Anemia, Edema
Abdominal examination:
– Uterine size larger than expected
– Palpation of two fetal head especially in two different
quadrants, or more than two fetal poles palpable
– Two distinct fetal heart rates on separate spots with
difference of 10 bpm.

22. DIAGNOSIS OF MULTIFETAL
GESTATION
Lie and presentation
42%
27%
18%
5%
8%
cephalic-cephalic
cephalic-breech
cephalic-
transverse
breech-breech
others
Williams Obstretics

23. Diagnosis
Sonography
Should detect all sets of twins practically
1st trimester: separate gestational sacs
Higher order pregnancies difficult to diagnose.
Used to determine
Fetal number, Estimated gestational age, Chrionicity
and Amnionicity, Fetal weight, Amniotic fluid volume

24. PREGNANCY COMPLICATIONS
MATERNAL COMPLICATIONS:
• Hyperemesis: More severe
• Anemia
• Minor problems of pregnancy (edema, SOB with increasing
POG) and pressure symptoms : More pronounced
• Hypertension:
– increased risk, risk increases with increase in number of fetuses (
greater placental mass)
– 14% in twins, 21% in triplets, 40% in quadruplets
– Develops earlier, more severe
• Gestational Diabetes Mellitus
• Placenta previa
• Abruptio Placenta

25. PREGNANCY COMPLICATIONS
Maternal complications contd..
• Polyhydramnios
– more common in monochorionic
• Preterm birth:
– The duration of gestation shorten with number of
fetuses.
– More than 50% of twins and 90% of triplets deliver
preterm.
• Preterm prelabor rupture of membrane (PPROM)
• Malpresentation

26. PREGNANCY COMPLICATIONS
Maternal complications contd…
During labor
• Increased operative delivery
• Cord prolapse of second twin
• Third stage hemorrhage ( premature separation of
placenta), PPH
Postpartum:
• Subinvolution of uterus
• Lactation failure

27. PREGNANCY COMPLICATIONS
Fetal Complications
Spontaneous abortion:
– increased risk as compared to singleton
Vanishing twin:
– 10-40% of all twin pregnancies one twin may get
spontaneously lost
– sonographic study in first trimester have shown
that one twin is reduced or vanished before
reaching second trimester.

28. PREGNANCY COMPLICATIONS
Fetal Complications:
Congenital malformations:
– Incidence is higher in multiple gestation than in
singleton
– More in monochorionic/ monozygotic twins
Structural defects can be divided into three groups:
1) Anomalies unique to twin like conjoined twin,
acardiac twins
2) Defects as consequence of mechanical or vascular
factors
3) Anomalies not specific to twins

29. PREGNANCY COMPLICATIONS
Fetal complications contd..
Low birth weight:
– more likely to be low birth weight
– Restricted fetal growth and preterm delivery
Birth weight of twin parallel to that of singleton until 28-
30 weeks. Thereafter the weight progressively lag.

30. PREGNANCY COMPLICATIONS
Fetal Complications contd…
Long term infant development:
– Similar cognitive development as in singletons
– Cerebral palsy risk is higher in twins

31. COMPLICATIONS SPECIFIC TO
TWIN
Discordant twin
– Difference between inter-twin birth
weight > 20%
– Difference in abdominal
circumference > 20mm
– Difference in BPD >8 mm
Due to
– IUGR of one fetus
– unequal distribution of placental mass
– Abnormal umbilical cord
morphology
– TTTS

32. COMPLICATIONS SPECIFIC TO
TWIN
Single Fetal Demise
– 5% of twins, 17% of triplets
Prognosis depends on
Gestational age, interval b/w
the death and delivery.
If remote from term: first and
early second trimester
– Pregnancy continues as
singleton
Manifests as :
– Vanishing twin
– Fetus compressus
– Fetus Papyraceus
In late 2nd trimester or later
– ↑ed risk of preterm delivery
– In dichorionic twin:
Negligible risk to other fetus
– In monochorionic twins: risk
of death & neurological
damage to other twin
(Multicystic
encephalomalacia)
– Death of fetus may trigger
coagulation defect in mother

33. COMPLICATIONS SPECIFIC TO TWIN
Aberrant twinning pattern

34. COMPLICATIONS SPECIFIC TO
MONOCHORIONIC TWIN
Eng and Chang Bunker born in
Siam (Thailand) in 1811

35. COMPLICATIONS SPECIFIC TO
MCMA TWIN
Cord entanglement.

36. COMPLICATIONS SPECIFIC TO
MONOCHORIONIC TWINS
Abnormal Vascular
anastomosis
• Twin to Twin Transfusion
Syndrome (TTTS)
• Twin Anemia
Polycythemia Sequence
(TAPS)
• Twin Reverse Arterial
Perfusion Sequence
(TRAP), Acardiac twin

37. MANAGEMENT : PRENATAL CARE
Aim: To prevent or detect and manage
complications at early
• Prevention of preterm labor
• Evaluation of fetal growth
• Assessment of fetal well being
• Determination of best mode of delivery

38. MANAGEMENT: PRENATAL CARE
Antenatal visit:
• Every two weeks or more frequently if complications
develop
– Evaluation of fetal movements, fundal height growth,
blood pressure and proteinuria
Diet:
– Daily requirement 40-45KCal/Kg/Day ( 20% protein, 40%
CHO, 40% fat divided in three meals and three snacks)
– 300Kcal/day more than singleton pregnancies
– Folic acid supplementation (1mg/day)
– Iron and Calcium supplementation (60-100 mg & 1500-
2500mg)

39. MANAGEMENT: PRENATAL CARE
Ultrasuond examination
1st trimister USG
- Diagnosis, chorionicity and amniocity accurately
- Early detection of missed abortions
2nd trimister:
– At 18 -20wks for congenital anomaly
Serial USG every 3-4 weeks to monitor fetal growth and to
assess amniotic fluid volume
– Starting from 16 weeks in monochorionic
– Starting from 18-20 weeks in dichorionic
Infections to be recognized and treated

40. MANAGEMENT: PRENATAL CARE
Prevention of preterm Labor
• Bed rest
– In lateral recumbent position
– Begin at 24 week till 34 week
– Minimum 2 hours in morning and afternoon and 10
hours in night
• Prophylactic tocolytics
• Infection surveillance
• Progesterone
• Cervical circlage

41. MANAGEMENT: PRENATAL CARE
Evaluation of fetal growth:
Serial Ultrasonography every 3-4 weeks to
monitor fetal growth and to assess amniotic fluid
volume
Antepartum Fetal surveillance :
– NST twice weekly
– BPP

42. MANAGEMENT: LABOR AND
DELIVERY
TIMING OF DELIVERY
Affected by:
Type of twin pregnancy
Fetal growth
Presence of Maternal complications
Twin pregnancy at 40 weeks should be considered postterm.
(Bennet and Dunn, 1969)
ACOG, 2016
Uncomplicated dichorionic : 38 weeks
Monochorionic diamniotic: 34-376/7 weeks
Monochorionic monoamniotic: 32-34 weeks

43. MANAGEMENT: LABOR AND
DELIVERY
Route of delivery
Depends on
– Fetal lie and presentation
– Type of twinning
( Monoamniotic,
Diamniotic)
– Fetal weight
– Other obstetric
complications
Vaginal delivery:
– Diamniotic
– Cephalic presentation of
first fetus
– Fetal weight > 1500 gm
Labor Induction ??

44. MANAGEMENT: LABOR AND
DELIVERY
Route of delivery contd…
Cesarean section
– Noncephalic first twin
– Monochorionic monoamniotic twin
– Conjoined twin
– Discordant twin
Cesarean section of second twin
– Large second twin- transverse/breech
– Fetal distress
– Interlocking twin

45. MANAGEMENT: LABOR AND
DELIVERY
1. Skilled obstetrician (skilled in intrauterine identification of
fetal parts and in intrauterine manipulation)
2. Continuous external electronic monitoring preferable.
3. IV infusion of RL or dextrose at a rate of 60 to 125 mL/hr.
4. Blood readily available if needed
5. A sonography machine to evaluate the presentation and
FHR of the remaining fetus(es) after delivery first twin

46. MANAGEMENT: LABOR AND
DELIVERY
6. An anesthesia team is immediately available (emg
cesarean delivery or intrauterine manipulation).
6. Oxytocics should be available
7. Two skilled attendants for resuscitation and care of
newborns.
8. Equipment must be on site to provide emergent
anesthesia, operative intervention, and maternal and
neonatal resuscitation

47. MANAGEMENT: LABOR AND
DELIVERY
Delivery of first twin:
• Uterine distension
– tendency towards uterine inertia and prolong active phase
– Oxytocin can be used
• Controlled ARM (Cord Prolapse- 5 times more )
• Liberal Episiotomy
• Oxytocin is not given with the delivery first baby
• Cord clamped at 2 places and cut inbetween
• At least 8-10 cm cord is left behind for administration of
any drug or transfusions

48. MANAGEMENT: LABOR AND
DELIVERY
Vaginal Delivery of second twin
Following delivery of first twin,
– Abdominal and vaginal examination should be
done to assess presenting part, FHR
– Safe interval between delivery < 30 minutes
– Newer evidences: with continuous fetal monitoring
, good outcome is achieved even with longer
interval

49. MANAGEMENT: LABOR AND
DELIVERY
Vaginal Delivery of second twin contd..
Longitudinal lie
If fetal head or breech is fixed, membranes should be ruptured
Vaginal examination should be repeated to rule out cord
prolapse
Labor is allowed to resume
If contractions do not begin in 10 min, start oxytocin
If cephalic : Vaginal delivery or forceps delivery
If breech: Assisted breech delivery or breech extraction
After delivery apply two clamps on the cord to distinguish
from 1st twin
Transverse lie: Internal podalic version and breech extraction

50. MANAGEMENT: LABOR AND
DELIVERY
Third Stage of Labor:
– Active management of third stage of
labor
– 10-20 units of oxytocin added to
infusion- continued 3-4 hrs
Increased risk of PPH: larger placenta,
uterine inertia due to overdistension
Examine placenta for any abnormalities,
to determine chorioniciy

51. MANAGEMENT: POSTPARTUM
Vigilant as there are increase chances of
– PPH
– Subinvolution
– Infection
– Lactation failure
Encourage breast feeding
Adequate nutrition
Contraceptive counselling