A multifetal pregnancy is a pregnancy in which there are two or more fetuses in the uterus at the same time. This can include twin pregnancies, triplet pregnancies, and higher-order multiple pregnancies. The most common type of multifetal pregnancy is twin pregnancy, which can be either fraternal (dizygotic) twins, which are formed from two separate eggs fertilized by two separate sperm, or identical (monozygotic) twins, which are formed when a single fertilized egg splits and develops into two separate embryos. Risk factors for multifetal pregnancy include: Advanced maternal age Assisted reproductive technologies (ART) such as in vitro fertilization (IVF) A family history of twin pregnancies Use of ovulation-inducing drugs The management of multifetal pregnancies can be challenging and requires close monitoring and specialized care. It can include ultrasound monitoring to assess the growth and well-being of each fetus, and to detect any potential complications such as twin-to-twin transfusion syndrome (TTTS) or selective intrauterine growth restriction (sIUGR). Due to the increased risk of complications, multifetal pregnancies are at a higher risk of preterm labor, cesarean delivery, and perinatal morbidity and mortality. It's important to note that multifetal pregnancies should be managed by a team of specialists such as obstetricians, perinatologists, and pediatricians with experience in the care of multifetal pregnancies.

1. Multifetal pregnancy

2. Why to care about ?
• Multifetal pregnancy carries higher risks for both mother
and fetus
• Maternal complications as : hyperemesis gravidarum ,
GDM , PET , PHH , maternal death , more CS and more
hysterectomies
• Fetal wise : more perinatal morbidity and mortality ,
more Preterm labor as 60 % of twins will be delivered
preterm before 37 weeks

3. Incidence
• In general multiple pregnancy occur in 3 %
• Advanced maternal age increases the risk ( 10% above 45 years old )
• IVF increases the risk (20 % of pregnancies after IVF )
• Maternal Family history
• African (Nigeria )

4. Fertilization

5. Stages of fetal development
• First mitotic division occur 30 hrs after fertilization
• Cells multiply every 12 hours after that
• Day 2 = 2 cell stage
• Day 3-4 = morula (16 cell stage )
• Day 5 = blastocyst
• Day 9 = cell differentiation (inner cell mass became epiblast and hypoblast )
• Day 18 (3rd week) = gastrulation (cells divided into ectoderm , mesoderm and
endoderm )

7. Classification
• A. according to the number of fetuses : twins , triplet , quadruplet …..
• B. according to the number of ova fertilized : dizygotic or monozygotic
• C. according to the number of placentae : dichorionic , monochorionic
• D. according to the number of amniotic sacs : monoamniotic , diamniotic

8. Dizygotic twins
•2 ova fertilized separately by 2 sperms
•More common than monozygotic
•2/3 of twins pregnancies (1:80)
•Always diamniotic dichorionic
•Not all diamniotic dichorionic are dizygotic
•If different gender its dizygotic , but if same gender it
can be dizygotic or monozygotic

9. Monozygotic twins
• 1/3 of twins
• Relatively constant (1:300 )
• Gender is same
• One ova fertilized by one sperm then separated

11. Chronicity and amniocity differs according to
the time when the fertilized ovum separated
The most common is monochorionic diamniotic

12. How to determine the chorionicity and
zygosity ?
• Determining chorionicity is important for follow up antenatal care ,
monitoring and timing of delivery
• It can be determined by ultrasound by :
1. Fetal gender : not accurate and it’s a late sign
2. Number of placenta
3. Presence and thickness of membrane
4. T sign and twin peak sign (lambda sign ) on ultrasound

13. Dizygosity
• If fetal sex is different its dizygotic
• If fetal sex is the same it can be monozygotic or dizygotic
• It’s a late sign and not accurate so other signs is more important
• The important thing is to know if its monochorionic or dichorionic to assess
pregnancy risk

14. Chorionicity
• Determinig chorionicity is most accurate in the first trimester scan (dating scan )
• Between 10-13+6 weeks
• Presence of 2 placenta suggests dichorionic pregnancy that can be monozygotic
or dizygotic
• Presence of a thick membrane more than 2 mm between sacs suggest
dichorionic
• Presence ofT sign of the membrane with the placenta suggests monochorionic
• Presence of lambda sign (twin peak sign ) suggest dichorionic twins

15. Twin peak T sign

16. Antenatal care of multiple gestation
• Same advice on diet , supplements and life style
• No need for untargeted corticosteroid for lung maturity
• Multidisciplinary team care (senior obstetrician and midwife and sonographer )
• Ultrasound for dating , fetal growth monitoring (not SFH )
• Pregnancies with monochorionic twins should receive special care
• Mode and time of delivery is according to the type of multiple gestation

17. Antenatal care
• Visits for dichorionic at least 8
• Visits for monochorionic diamniotic at least 9
• Hb checked at booking , 20 weeks and 28 weeks
• Management of pregnancy complications is the same as singleton
• Supplements are the same as singleton

18. Screening in multiple pregnancy
Women with multiple pregnancy should be offered a first trimester scan when the
crown–rump length (CRL) measures 45–84 mm, which equates to approximately
11 weeks 0 days to 13 weeks 6 days.The purpose of this is threefold:
• To accurately estimate gestational age
• To determine chorionicity
• To screen for Down’s syndrome
Screening ofTTTS at 16 weeks by ultrasound findings and DV doppler a wave
Both amniocentesis and chorion villous sampling (CVS) can be performed in twin
pregnancies, but in dichorionic pregnancies, it is essential that both fetuses are sampled

19. Anomaly scan
• More risk of congenital anomalies
• More in monozygotic
• Usually one twin is affected (20 % both fetuses are affected )
• In non lethal condition (expectant or feticide * )
• In lethal conditions (expectant management) unless its harmful for pregnancy, as
anencephaly which will lead to polyhydramnios
• Feticide in monochorionic twins by cord occlusion techniques only

20. Growth assessments
• From 20 weeks
• By estimated fetal growth using ultrasound every 4-6 weeks
• Significant fetal growth restriction = more than 25 % difference in the weight of
twins
• Refer to tertiary care if diagnosed (fetomaternal ) for more follow up and delivery
plan

21. Screening for preterm labor
• Screening for preterm labor by cervical length at 24 weeks or fetal fibronectin at
28 weeks
• Cut off cervical length is 25 mm
• Cerclage and bed rest increases preterm labor
• Progesterone prophylaxis and prophylactic tocolysis are not effective

22. Complications of multiple gestation

23. •Congenital malformation
•More emesis gravidarum
•HTN and PET
•PPH
•Cs and hysterectomy
•Placenta previa

24. Preterm labor
• Of dichorionic twins : 60 % delivered before 37 weeks and 15 % before 32 weeks
• Monochorionic twins has more risk
• Both indicated (more complication )or spontaneous preterm labor
• Increases with increasing the number of fetuses

25. Pregnancy loss
• 7 % loss of pregnancy
• 2 % late loss in dichorionic pregnancies
• Its more with monochorionic
• More congenital anomalies maybe considered as one of the causes
• IVF itself has a higher risk of

26. Perinatal mortality
• Perinatal mortality = number of still birth + early neonatal death (first 7 days ) per
1000TOTAL birth
• Increased 5 times than singleton
• 3.8/1000 in dichorionic and 30/1000 in monochorionic
• Still birth : loss of fetus on 24 weeks and after is 12/1000 in twins
• Vanish twin (death of one twin in the first trimester ) 25 %

27. Fetal growth restriction
• more likely to be low birthweight than singleton pregnancies due to restricted fetal growth
and preterm delivery
• 25 % in dichorionic and double this in monochorionic twins
• Maybe one fetus or both fetuses (sGR)
• The aim is to prevent fetal morbidity and mortality by monitoring growth and doppler
ultrasound of fetal and placental vessels, aiming for delivery before injury occur

28. Twin-to-twin transfusion syndrome
• abnormal unbalanced vascular anastomoses
• Occur in monochorionic twins and more if monochorionic diamniotic
• In monochorionic twins (monochorionic diamniotic 10 % and monoamniotic
monochorionic 5 %)
• Abnormal unidirectional AV malformation
• Bidirectional AV malformation and AA malformation doesn't lead toTTS
(protective)

29. Manifestation ofTTTS
I. Concordant gender.
II. Oligohydramnios with maximum vertical pool (MVP) less than 2 cm in one sac
III. and polyhydramnios in the other sac (MVP >8 cm).
IV. Discordant bladder appearances.
V. Haemodynamic and cardiac compromise.
Ultrasound screening forTTTS between 16 to 24 weeks
In monochorionic twins to detectTTTS

30. Quintero staging ofTTTS

31. Management ofTTTS
• Referral to fetomaternal medicine
• Options include : expectant , selective feticide ,septetomy ,amnioreduction and
Fetoscopic laser ablation
• The treatment of choice before 26 weeks and sever (stage 2 or more ) is
fetoscopic laser ablation (ultrasound guided AV anastomoses ablation by laser
diodie laser )

32. TAPS (twin anemia polycythemia syndrome)
• Difference between the twins Hemoglobin without oligo or polyhydramnios
• Most commonly occur as complication few weeks after fetoscopic laser ablation of
TTS or spontaneously
• Due to very small (less than I mm ) unidirectional AV anastomoses without
accompanying AA anastomoses
• Severe polycythemia can occur, leading to fetal and placental thrombosis and
hydrops fetalis in the anemic twin.
• Diagnosed by MCA doppler difference between the twins
Screening forTAPS is done 5 weeks afterTTTS treatment by laser ablation

33. Twin-Reversed Arterial Perfusion (TRAP)
Sequence
• acardiac twin
• caused by a large artery-to-artery placental shunt, often also accompanied by a
vein-to-vein shunt

34. DISCORDANT GROWTH OFTWIN
FETUSES
• It develops in approximately 15 percent of twin gestations
• Discordancy in monochorionic twins is usually attributed to placental
vascular anastomoses that cause hemodynamic imbalance between the
twins
• Discordancy in dichorionic twins may result from various factors.
• Dizygotic fetuses may have different genetic growth potential
• the placentas are separate and require more implantation space, one placenta might
have a suboptimal implantation site

35. Single FETAL DEMISE
• If one of the fetuses died early in pregnancy (vanishing twin) fetus papyraceus
• No harm

36. Single FETAL DEMISE
 If it occurs later especially in monochorionic pregnancy there is a risk of :
 death of the other twin
 neurological injury of the other twin
 preterm labor
 Maternal DIC
 Follow up by ultrasound and fetal brain MRI and doppler scan
 prolongation of pregnancy if no risk on the mother and fetus

37. Monochorionic monoamniotic twin
pregnancy (MCMA )
Incidence : 1:10.000
1% of monozygotic twins
Rare but carries high complications rate
Perinatal mortality 20 %
Discordant birthweight 20%
cord entanglement (50 %)
more fetal morbidity
More fetal loss
Follow up closely with fetomaternal specialist
Deliver at 32 weeks

38. indications for a tertiary level fetal
medicine opinion
 discordant fetal growth
 fetal anomaly
 discordant fetal death
 TTTs ,TAPSTRAP

39. Delivery …. Intrapartum management
• Antenatal education and a pre-agreed birth plan.
• Continuous fetal heart monitoring.
• Two neonatal resuscitation trolleys, two obstetricians and two paediatricians are
available and that the special care baby unit and anaesthetist are informed well in
advance of the delivery.
• Analgesia, ideally in the form of an early epidural, to allow for internal podalic
version (if needed) for twin 2.
• A standard oxytocin solution for augmentation should be prepared, run through
an intravenous giving-set and clearly labelled ‘for augmentation’, for use for
delivery of the second twin.
• Oxytocin infusion in anticipation of postpartum haemorrhage.
• Portable ultrasound

40. Mode of delivery for dichorionic
diamniotic twins
uncomplicated and the first is vertex : vaginal delivery with risk of cs 4 % for
the second twin
If the first is non cephalic : CS
If the second is breech : vaginal breech delivery of second twin (breech
extraction if distress
If the second is transverse : external or internal podalic version

42. Delivery of monochorionic twins
Uncomplicated monochorionic diamniotic
Cs + corticosteroid at 36 weeks
Uncomplicated monochorionic monoamniotic
Cs+ corticosteroid at 32 weeks

43. Locked twin
• For twin fetuses to become locked together during delivery, the first must present
as breech and the second cephalic
• Cesarean delivery should be considered when the potential for locking is identified