This document discusses multifetal pregnancies, including twins, triplets, and higher order multiples. It defines key terms, describes the types and incidence of twins. Complications are more common in multifetal pregnancies and include preterm birth, preeclampsia, and increased risk of stillbirth. Specific complications discussed include twin-twin transfusion syndrome and conjoined twins. The management of multifetal pregnancies during antenatal, intrapartum, and postpartum periods is also summarized.
2. Introduction
Definition:
Simultaneous development of more than
one fetus in the uterus
Two- twins, commonest
Three- Triplet
Four-Quadruplet
Five- Quintuplet, etc
Number & rate of multi-fetal gestation have
increased
Infertility therapy
Higher diagnostic rate
Elderly Primigravidae
3. Introduction
Types of twins:
Dizygotic twins (70 %) : the result of two
ova and two sperms
By definition they are dichorionic and
diamniotic
When the blastocyst implantation site is
proximal one to another single fused
placental disc results
4. Type of twins...
When implantation site is not proximal
two separated placentae result
Same or different fetal sex
Variable incidence, affected by risk
factors
No anastomoses between fetal vessels
5. Monozygotic twins
Monozygotic twins (30%): a single
fertilized ovum splits into two distinct
individuals
Incidence: 1:250 deliveries, almost
constant
Almost always same sex
Placenta: one fused or two separate
Risk factors: not influenced except
ART
6. Type of twins...
Timing of egg division determines
placentation in monozygotic twins
Dichorionic Diamniotic placentation (24%)
occurs with division prior to the morula
stage (within 3 days post fertilization)
Monochorionic Diamniotic placentation (75%)
occur with division b/n days 4 and 8 post
fertilization
7. Type of twins...
Monochorionic Monoamniotic
Placentation (1%) occurs with division
b/n days 8 and 13 post fertilization
Division at or after day 13 results in
conjoined twins (1/60,000)
9. Incidence
Twin rose by 77%, high order-459%, and
singletons by 11%
More than 3 % of deliveries in USA are product
of multiple gestation
Increased rate of higher order multiple births is
a concern because of preterm delivery and low
birth weight.
Increased rate of maternal and perinatal
morbidity and mortality.
Incidence: according to Hellins hypothesis, it is
1: 80n-1
10. Incidence
Twins : 1: 80 or 90
Triplets : 1:80 square
Quadruplet : 1:80 cube or 1: 512 000
Highest in Nigeria
Lowest in Japan or east Asia
Spontaneous ovulation twins 1%
Clomiphene induced ovulation 10 %
HMG (gonadotrophins) induced 30%
11. Incidence...
Monozygotic twins is relatively stable worldwide:-
◦ 3 to 5 per 1000 births
There is a significant ethnic variation in the
incidence of dizygotic twinning:-
◦ 1.3 per 1000 births in Japan
◦ 49 per 1000 births in Nigeria
12. Incidence...
The incidence of dizygotic twins is affected by a
number of factors:-
1. Use of fertility stimulating drugs
2. Race/geographic area
- Africa (1/30 births),
- Asians (fewer than 1.3/100 births),
- Caucasians (1/80 births).
3. Maternal age (higher 30-40yrs, peak at 37years)
4. Parity
5. Family history (maternal history)
6. Maternal weight and height (higher in tall and
obese)
7. Prolonged use of OCP
13. Determination of zygosity, chorionicity,
amniocity
Objective: aid in obstetrical risk assessment &
guide management of multifetal gestation
Monochorionic gestations are at increased
risk
Zygosity determination needs
sophisticated genetic tests
1. Ultrasound evaluation: thickness of
separating membrane, number of
placenta, sex of fetuses, twin peak sign &
T- sign
17. Diagnosis
History, examination & investigations:
- Risk factors
- Exaggerated minor ailments
- Anemia
- Preeclampsia
- Unusual weight gain
- Barrel- shaped abdomen
- Positive discrepancy
- Palpation of multifetal parts
- Two distinct FHB of at least d/ce of 10BPM
18. Diagnosis...
- Palpation of more than two fetal poles
- Ultrasound: diagnosis, chorionicity, GA,
viability, fetal anomalies, presentation,
etc
- Radiography: rarely done these days
- Biochemical: serum hCG, aFP &
unconjugated estriol. They are almost
doubled.
19. Diagnosis...
Chorionicity can be determined several
ways:-
If separate placentas = DC/DA
“Twin peak" or "lambda" = DC/DA
Discordant genders = DC/DA
Intertwin membrane thickness
24. Fetal complications
Miscarriage
Prematurity
Growth problems- discordant-25%
Intrauterine fetal death of one fetus
Fetal anomalies
Asphyxia & stillbirth
NB: complications are more common in
monochorionic twin pregnancy
25. Prognosis
Maternal mortality is increased in
twins than singletons due to
hemorrhage, preeclampsia & anemia
Perinatal mortality is increased mainly
due to prematurity though others
contribute
One-third is stillbirth & two-third is
neonatal death.
26. Prognosis...
Published perinatal mortality rate for twins in
developed countries range b/n 47 and 120 per
1000 twins birth this represent 5 fold increased
compared to singleton
The mortality risk is greater for second twins
compared to the first twins
Greater for monozygotic compared with dizygotic
Greater for triplet and other high order
pregnancy
27. Prognosis...
Contributors to the increased risk of
perinatal mortality Include:
Increased frequency of congenital
anomaly
Placental abruption
Cord accident
Preeclampsia
Malpresentations
Birth trauma and
IUGR
28. Prognosis...
Although twins represent only 2% of live birth they
account for more than :
15% of all very low birth infant
11 % of neonatal death
3.4 % post neonatal death
8.4 %of infant death
Twins represent more than 10% of all admissions to
newborn intensive care unit
5% to10% of all cases of cerebral palsy in the USA
29. Complications specific to twinning
Twin-twin transfusion syndrome
(TTTS)
Dead fetus syndrome
Twin reversed arterial perfusion
(TRAP) acardiac twin
Conjoined twins (Simians twin)
Growth discordance
30. Peculiar Complications
A. PRETERM BIRTH
The most serious risk of multiple gestations,
associated with increased perinatal mortality and
short-term and long-term morbidity
The relative risk of preterm birth compared to
singletons = 5.4 for twins and 9.4 for triplets
Rate of preterm delivery of twins = 42 to 54 percent,
The overall rate of preterm delivery 9-11%
10 to 14 percent of preterm births were attributable
to twin deliveries
31. Peculiar Complications...
The gestational age at delivery decreases as fetal
number increases.
The average gestational age is:-
◦ 35 weeks for twins ,
◦ 32 weeks triplets ,
◦ 30 weeks quadruplets , and
◦ 29 weeks for quintuplets and higher order
multiples
Preterm twins are at risk for developing
complications that result from anatomic or
functional immaturity
32. TWIN-TWIN TRANSFUSION
SYNDROME
Occur in Monochorionic placentae
Artery-to-artery, vein-to-vein, and artery-to-
vein
Results from unbalanced blood flow through
vascular anastomoses
One twin becomes the donor and the other is
the recipient
Discordance in fetal growth and amniotic fluid
volumes
TTTS complicates 10 to 15 percent of
Monochorionic twin pregnancies
33. TTTS...
Responsible for 16 percent of perinatal
deaths
Ultrasonography:-
◦ AFV, Growth disparity, Sex, chorionicity
The recipient twin
The larger fetus in the amniotic sac with
Polyhydramnios
The donor twin is
The smaller fetus and is in the
oligohydramniotic sac
34. TTTS...
Donor twin:-
◦ Have severe IUGR with anemia, hypovolemia,
and renal insufficiency.
◦ Severe Oligohydramnios ("stuck twin"),
pulmonary hypoplasia and deformations.
Recipient twin:-
◦ Excessive volume can lead to CVS
decompensation with cardiomegaly, and hydrops
fetalis.
◦ Polycythemia, thrombosis or jaundice after birth
* Diagnostic criteria?
35. Conjoined twins
Occurs when MZ twins fail to separate into two
individuals
Ranges from simple joining of ectodermal tissues to the
extreme case when one twin is contained within the
other.
Incidence 1 in 60,000
The ratio of females to males is 3:1.
Classified by the site of their most prominent union,
which is ventral (87%) or dorsal (13%)
The abnormality is named with the suffix pagus, which
means fixed
37. Conjoined twins...
Diagnosis
A fixed position of the fetal heads,
Inability to detect separate bodies or
skin contours
The lack of separating membranes
38. Management
Antenatal management:
Diet: additional 300kcal /day
Rest
Supplementary iron & folate
Frequent antenatal visits
Fetal surveillance every 3-4 weeks
Admission not mandatory
Tocolytics & steroids are not
indicated
39. Management...
Management during labor:
Place of delivery in a hospital
First stage same as singletons
Experts: obstetrician/ anesthesiologist
Avoid general anesthesia
Avoid uterotonics after 1st baby
Mode of delivery depends on obstetric
factors, presentation of 1st baby, chorionicity
& amniocity
40. Mode of delivery
Cesarean delivery:
Obstetric: Placenta previa, previous C/D, cord
prolapse of 1st baby, contracted pelvis, abnormal
uterine contraction
Twins:
1st nonvertex
Twins with complications: IUGR, conjoined
Monoamniotic twins
TTTS
Collision of both heads preventing engagement
41. Delivery of second twins
Depends on presentation, lie, FHB, fetal
weight, cord prolapse
Vaginal: longitudinal lie
Indications of urgent delivery of second
twin:
Severe intrapartum vaginal bleeding
Cord prolapse of second baby
1st delivery under GA
Occurrence of fetal distress
Inadvertent use of ergometrine after 1st
baby
42. Intrapartum management
Epidural anesthesia is recommended
The capacity for immediate cesarean is important
Both twins should be monitored continuously
during labor (CTG for all)
After delivery of the first twin,
◦ the heart rate and position ultrasound and
ECM.
Oxytocin if labor does not resume.
Amniotomy can be performed when the
presenting part is engaged.
Umbilical cords should be marked with
progressive numbers of clamps