4. INTRODUCTION
Many myths are linked to the birth of twins.
Twin pregnancy has been a fascinating subject and
has generated a lot of interest in obstetrics, many
religions, communities and cultures.
There have always been some naturally, or
spontaneously, occurring multiple pregnancies -with
twins, most common & the most frequent, then
triplets and the much rarer quadruplets.
But the frequency has increased enormously since
assisted procreation has become available.
5. DEFINITION OF MULTIPLE PREGNANCY
• DEFINITION: When more than one fetus
develops simultaneously in the uterus, it is
called multiple pregnancy (D.C.Dutta).
• Many placental species give birth to multiples.
7. TYPES
• Monozygotic – multiple (usually two) fetuses
produced by the splitting of a single zygote.
• Dizygotic – multiple (typically two) fetuses
produced by two zygotes.
• Polyzygotic – multiple fetuses produced by two
or more zygotes & may contain all fraternal or
combination of identical & fraternal siblings.
7
8. Terminology
• Two offspring - twins
• Three offspring - triplets
• Four offspring - quadruplets
• Five offspring - quintuplets
• Six offspring - sextuplets
• Seven offspring - septuplets
• Eight offspring - octuplets
• Nine offspring - nonuplets
• Ten offspring - decaplets
• Eleven offspring - undecaplets
• Twelve offspring - duodecaplets
8
10. INCIDENCE
• Global being 1 in 250.
• Varies from 5.6-46 per 1,000 births
• Highest rate of twins in Nigeria being 1 in 20
• Lowest in far eastern countries(Japan 1 in 200)
• In India,1 in 80 pregnancies.
According to Hellin’s rule,
• Twins 1 in 80 pregnancies,
• Triplets 1 in 802,
• Quadruplets 1 in 803 and so on.
11. Etiology of Multiple Pregnancy
A woman's chances of having identical –MZ twins are
not related to age, race or family history & the
frequency remains constant throughout the globe.
Prevalence of dizygotic twins is related to,
Advancing age of the mother
• Increased incidence of twinning is observed with the
advancing age of the mother, the maximum b/w 30-
35 years & the incidence is markedly reduced
thereafter.
Influence of parity
• The incidence is increased specially from 5th gravida.
12. Cont..
Race:
• The frequency is highest amongst Africans, lowest
amongst Mongols and intermediate amongst
Caucasians.
Hereditary:
• There is hereditary predisposition likely to be more
transmitted through the female (maternal side).
Iatrogenic- ART
• Drugs used for induction of ovulation (clomiphene
citrate or gonadotrophins ) may produce multiple
foetuses to the extent of 20-40%.
• Revised ART policies have reduced incidence,
currently.
13. Iatrogenic Twinning
• Ovulation induction should be carried out when
possible with specific treatments - bromocriptine and
pulsatile GnRH to induce single ovulations.
• With normo gonadotrophic anovulation, the first line of
tt for ovulation induction is, clomiphene which is
associated with twin rates (10%) and triplet rates to 1%.
• Tt with FSH causes upto 40%. Hence, Gonadotrophin tt
should be reserved for clomiphene-resistant women &
low dose regimens should be encouraged. 13
14. TYPES OF TWINS
• Dizygotic/ Binovular / Fraternal Twins
• Monozygotic/ Uniovular /Identical Twins
• Zygosity - refers to the genetic makeup of twin
pregnancy.
• Chorionicity - indicates the pregnancy’s
membrane status.
15.
16. Genesis & Varieties of Twining
Dizygotic/ Fraternal /Binovular Twins (80%)
• Dizygotic twinning is the commonest.
• Results from the fertilization of two ova either from
same or both the ovaries most likely ruptured from
two distinct graffian follicles usually of the same or one
from each ovary during a single ovarian cycle each
fertilized by a separate sperm.
• All dizygotic twins have two placentae which are
dichorionic and diamniotic.
16
17. Binovular Twins - Cont’d…
• Fraternal twins (like siblings) share about 50 %
of their genes, hence can be of different sexes.
• They look like brothers or sisters born from
different pregnancies.
• Triplets & other higher-order multiples can
result from three/more eggs being fertilized,
one egg splitting twice (or more), or a
combination of both.
17
18. Monozygotic Twins (Identical
Twins/Uniovular - 20%)
• Arises from a single fertilized oocyte by a single sperm
that subsequently divides true or identical twins (or
occasionally more).
• Monozygotic twins (Identical, uniovular):
Twinning occurs at different periods after fertilization and
this markedly influence the process of implantation &
formation of fetuses & membranes.
• The fetuses usually share one placenta. Identical twins
have the same genes, so they look alike and are of the
same sex. 18
19.
20. Timing of division & the results
• If the division takes place within 72 hours after
fertilization (prior to morula 8 cell stage) the
resulting embryos will have two separate
placentaes, chorions and amnions (diamniotic-
dichorionic or DID).
On rare occasions, the following possibilities occur.
• If the division takes place between the 4th and 8th
day after the formation of inner cell mass when
chorion has already developed – diamniotic
monochorionic twins develop (DIM).
21. Timing of division & the results- Cont’d…
• If the division occur after 8 day of fertilization, when
the amniotic cavity has already formed, a
monoamniotic –monochorionic twin develops (MIM).
• On extremely rare occasions, When splitting occurs
after the 13th day of fertilization (during the
development of embryonic disc) it results in the
formation of conjoined twins called Siamese twins*.
* Until the late 1800s conjoined twins were called “monsters.” The term Siamese twins comes from the twin conjoined brothers
Chang and Eng Bunker who were born in Siam, now Thailand. When they first arrived in England to become circus
exhibits, they were called “The Siamese Twins.”
22. Five type of fusions
• Thoracopagus (commonest)
• Omphalopagus (umbilical fusion)
• Pyopagus (posterior fusion)
• Craniopagus (cephalic)
• Ischiopagus (caudal)
22
23. The other possibilities…
• Superfecundation
• Superfetation
• Fetus papyraceous or compressus
• Fetus acardiacus
• Hydatidiform mole
• Vanishing twin
• Dicordant twins
23
24. Cont’d…
• Superfecundation:
It is the fertilization of two different ova released in
the same cycle, by separate acts of coitus within a
short period of time.
• Superfetation:
It is the fertilization of two ova released in different
menstrual cycles. The nidation and development
of one fetus over another fetus is theoretically
possible until the decidua space is obliterated - by
12 weeks of pregnancy.
25. Cont’d…
FETUS PAPYRACEOUS or COMPRESSUS
• It is a state which occurs if one of the foetuses
dies early. The dead fetus is flattened and
compressed between the membranes of the
living fetus and the uterine wall.
• It may occur in both varieties of twins, but is
more common in monozygotic twins and its
discovered at delivery or earlier by sonar.
26. Cont..
• Fetus Acardiacus:
It occurs only in monozygotic twins. Part of one
fetus remains amorphous and becomes
parasitic without a heart.
• Hydatidiform Mole:
A normal fetus and placenta(from the other
conceptus) has been observed by
ultrasonography.
27. Cont’d…
• Vanshing Twins:
Serial ultrasound imaging in multiple pregnancy since
early gestation has revealed occasional death of one fetus
& continuation of pregnancy with the surviving one.
The dead fetus (if within 14 weeks) simply ‘vanishes’ by
resorption. The rate of disappearance could be to the
extent of 40%.
• Dicordant Twins (sGR Twins):
Birth weight discordance was defined as a difference of
20% or more of the weight of the heavier twin, associated
with an intra-uterine growth restriction (10(th) percentile)
of at least one twin. Ultrasound discordance was defined
as a difference of estimated fetal weight>20%.
28. DETERMINATION OF ZYGOCITY
With the advent of organ transplantation, the
identification of the zygosity of the multiple
fetuses has assumed much importance.
28
29. Examination of placenta and membranes
DIZYGOTIC TWINS:
• There are two placenta, either completely
separated/more commonly fused at the margin
(appearing to be one).
• There is no anastomosis between the two fetal
vessels.
• Each fetus is surrounded by a separate amnion and
chorion. And as such, the intervening membranes
consist of 4 layers- amnion, chorion, chorion and
amnion.
• In early pregnancy, the decidua capsularis of each
sac may be identified under the microscope in b/w
chorionic layers. 29
30. Examination of placenta and membranes
Monozygotic Twins:
• The placenta is single. There is varying degree of
free anastomosis between the two fetal vessels.
AtoA orVtoV anastomosis is ok, but…
• Each fetus is surrounded by a separate amniotic sac
(at times single), chorionic layer be common to
both (diamniotic-monochorionic) and the
intervening membranes consist two layers of
amnion only.
30
31. DETERMINATION OF ZYGOCITY
• Sex: While twins having opposite sex are almost always
binovular (also of the same sex) and uniovular twins
are always of the same sex.
• Genetic features: If the fetuses are of the same sex and
have the same genetic features (dominant blood
group), monozygotic is likely.
• DNA microprobe technique is most definitive.
• Follow up study: between 2-4 years, showed almost
similar physical and behavioural features suggestive of
monozygosity.
• Skin grafting: Matches fully in MZ, less likely in DZs.
31
37. MULTIPLE GESTATION PROCESS
• If the division takes place within 72 hours after
fertilization (prior to morula stage) resulting
embryos have two separate placenta, chorions &
amnions -diamniotic-dichorionic or D/D (30%).
• If the division takes place b/w 4th to 8th day after
formation of inner cell mass when chorion has
already developed- monochorionic, diamniotic
twins develop D/M (66%).
37
38. 38
• History
• symptoms
• General examination
• Abdominal examination
• Internal examination
• Sonography
• Radiography
• Biochemical tests
Diagnosis of Multiple Pregnancy
40. SYMPTOMS
Some of the symptoms are related to the undue &
unusual rate of enlargement of the uterus:
• Increase nausea and vomiting in early months.
• Cardio-respiratory embarrassment in the later
months—such as palpitations, shortness of breath.
• Greater tendency of swelling of the legs, varicose
veins & haemorrhoids
• Excessive fetal movements(&FHR) noticed by an
experienced parous mother.
41. General examination
• Prevalence of anaemia is more than in singleton
pregnancy.
• Unusual weight gain, not explained by
preeclampsia or obesity, is an important feature.
• Evidence of preeclampsia 25% is a common
association.
41
42. 42
Abdominal examination
Inspection
• The elongated shape of a normal pregnant uterus is
changed to a more “barrel shape’ and the abdomen is
unduly enlarged.
Palpation
• Increased height & girth of abdomen: The height of the
uterus is more than the period of amenorrhoea. This
discrepancy is evident from mid pregnancy.
• Palpation of too many fetal parts
• Finding of two fetal heads or fetal poles makes diagnosis
certain.
43. Internal examination:
• In some cases, one head is felt deep in the pelvis,
while the other one is located by abdominal
examination.
• Presentation and lie of the fetuses sd be checked.
• Vertex & vertex - 50%
• 1st breech 2 nd Vertex- 30%
• 1 st Vertex 2nd breech- 10%
• Both breech - 10%
• 1 st Vertex 2nd transverse & so on…..
44. Auscultation
• Simultaneous hearing of two distinct fetal heart
sounds located at separate spots with silent area in
between gives a certain clue in the diagnosis of twins,
provided the difference in heart rates is at least 10
beats per minutes.
• More than one heartbeat heard by a provider using a
hand-held ultrasound device (Doppler).
44
46. Sonography
Sonography
• Confirmation of diagnosis as early as 10th weeks of
pregnancy
• Viability of foetuses, vanishing twin in the second trimester.
• Chorionicity of the placenta.
• Pregnancy dating,
• Fetal anomalies
• Fetal growth monitoring at every 3-4 weeks interval.
• Presentation and lie of the fetuses.
• Amniotic fluid volume.
• Twin peak sign/Lamda sign
• Fetal surveillance is maintained by serial sonography, every 3-
4 weeks interval. 46
47. Radiography
• Two fetal heads and spine- Presentation and
lie of the fetuses could be seen.
• Triplets or conjoined twins could be diagnosed
accidentally.
48. Biochemical tests
Abnormal results on prenatal screening
tests around 16 weeks of pregnancy for certain
birth defects.
• Maternal serum Human chorionic
gonadotrophin,
• Maternal serum alpha feto protein,
• Unconjugated oestriol
48
51. Prenatal screening
GUIDELINES FOR COUPLES & CARERS
• To couples considering treatment for infertility.
• Give detailed information on the chances of a
multiple pregnancy, on the consequent risks
and implications for the children and the family
and about fetal reduction.
51
52. Prenatal screening
• Prenatal screening: Ensure that parents
understand the options available if an anomaly is
present in only one fetus, (selective feticide).
• Provide special prenatal classes, in collaboration
with local parents of twins group, for parents and
grandparents, including guidance on feeding,
equipment, sources of information and practical
help, promotion of individuality and language,
and the needs of older siblings.
52
53. Management
Antenatal management
Advice
• Diet : Increased dietary supplement is needed for increased
energy supply to the extent of 300 K cal per day.
• Increased rest at home & early cessation of work to prevent
preterm labour. Even if a woman with multiples has no signs of
preterm labor, it is recommended that she cut her activities
from 20th to 24th weeks, even sooner and to rest several
times a day if she is expecting more than two babies.
• Supplementary therapy: i) Iron therapy to be increased to the
extent of 60-100 mg per day. ii) additional vitamins, calcium
and folic acid (1 mg) are to be given.
54. Antenatal management
Interval of antenatal visits
• Women with multiples need to visit their health care
providers more frequently.
• These extra visits can help prevent, detect and treat the
complications that develop more often in a multiple
pregnancy.
• Health care providers may recommend twice-monthly visits
during the second trimester and weekly or more visits
during third trimester.
Hospitalisation:
• Hospital admission only for bed rest is not essential.
• Improves utero-placental circulation.
55. Assessment of fetal growth
• Starting around the 20th week of pregnancy, a health
care provider monitors for signs of preterm labor.
• The provider may do an internal exam or recommend a
vaginal ultrasound to see if the woman's cervix is
shortening (a possible sign that labor).
• The biophysical profile, which combines the non-stress
test with an ultrasound, is done.
• As a multiple gestation progresses, regular check on
blood pressure, & regular ultrasounds starting around
20 weeks of pregnancy,, etc, to check that all babies
are growing at about the same rate.
55
56. DURING PREGNANCY
• Provide written information including contacts
of local & national organizations, for families
with multiple births.
• In monochorionic pregnancies, ensure that
parents understand the implications and need
for close monitoring.
56
57. INDICATIONS FOR CAESAREAN SECTION
Obstetric causes:
• Placenta praevia
• Severe preeclampsia
• Previous caesarean
section
• Cord prolapse of the first
baby
• Abnormal uterine
contractions
• Contracted pelvis
Fetal causes:
• Both fetuses or the first in
non cephalic presentation,
• Complication of IUGR,
• Conjoined twins
• Monoamniotic twins
• Monochorionic twins
• Collision of both the heads
at brim preventing
engagement of either.
57
58. MANAGEMENT DURING LABOUR
• Skilled obstetrician should be available
• Presence of ultrasound in labour ward
• The patient should be in bed
• Use of analgesic drugs
• Careful fetal monitoring
• Internal examination should be done
• An intravenous line with RL solution
58
59. Birth & the Neonatal period
• Ensure that each umbilical cord and infant is labelled
immediately. All placentae should be examined by an
experienced midwife or obstetrician for chorionicity, sites
of cord implantation and vascular anastomosis.
• Determine zygosity by sex, chorionicity or (in like-sex
dichorionic twins) DNA analysis (of blood or placenta) or
blood - genetic markers.
• Ensure that babies' clothes are readily identifiable so that
parents (and staff) can recognize babies from distance.
59
60. Birth and the Neonatal period
• Ensure that staff label and refer to the babies by their
names.
• Consider co-bedding the twins.
• Take photographs of the babies together (particularly
if one is likely to die). Offer practical help to the
mother throughout all feedings.
• Whenever practicable, nurse babies in the same ward
& discharge from hospital at the same time.
• Ensure that the neonatal unit has a special protocol if
a multiple birth baby dies, as well as literature to give
and contact with a bereaved parent of twins who can
offer immediate support.
60
61. THE PRE-SCHOOL YEARS
Encourage parents,
• To promote the individuality of their children
(and encourage grandparents and friends to
do the same) by,
• avoiding similar names,
• making them readily distinguishable
• giving them times apart from an early age;
• promote language development by providing
one-to-one communication from infancy.
61
62. PROGNOSIS
• Maternal morbidity is increased in twins than in a
singleton pregnancy due to the prevalence of
complications and increased operative interference.
• There is a higher perinatal mortalityesp. In MZTs, due
to sharing of a single gestational sac.
• Death is mostly due to haemorrhage, PIH and anemia.
• Because of increased risk to both mother and baby,
compared to that of a singleton pregnancy, twin
pregnancy is considered high risk and as such should
be delivered in a hospital.
62
63. Complications
• Women who are expecting more than one baby
are at increased risk, the more the babies, the
greater her risk for complications.
• There is an exaggerated adaptation of all body
systems of the mother specially of the
cardiovascular system.
• Cardiac output is higher & Plasma volume during
pregnancy is much greater with lower Plasma
proteins.
63
64. Complications
MATERNAL – DURING PREGNANCY
• Increased severity of nausea and vomiting
• Urinary infection is more common
• Gestational hypertension & Pre-eclampsia( low Plasma
proteins)
• Gestational diabetes
• Haematocrit and haemoglobin is lower than in singleton
pregnancy causing anaemia.
• Hydramnios
• Antepartum haemorrhage-Placenta previa, Abruption
• Malpresentation
• Preterm labour
• Mechanical distress
65. Complications
DURING LABOUR
• Early rupture of membranes
• Cord prolapse
• Prolonged, difficult labour
• Increased operative interference
• Intrapartum haemorrhage
69. Preeclampsia (25%)
• Women expecting twins are more than twice
as likely as women with a singleton pregnancy
to develop this complication.
• Severe cases can be dangerous for mother and
baby, the babies may have to be delivered
early to prevent serious complications.
69
70. Pregnancy Related Diabetes
• Women carrying multiples are at 2 to 3 fold,
increased risk of this pregnancy related diabetes.
• This causes the baby to grow large, increasing risk
of injuries to mother and baby during vaginal birth.
• Babies born to GDM women also have breathing &
other problems during the newborn period.
• Early diagnosis and management of the
complications protect mother and babies.
70
71. Common complications
Prematurity
• About 80 percent of twins, more than 90 percent
of triplets, and virtually all quadruplets and
higher-order multiples are premature.
• The length of pregnancy decreases with each
additional baby. On an average, most singleton
pregnancies last 39 weeks; for twins, 35 weeks;
for triplets, 32 weeks; for quadruplets, 29 weeks.
71
72. Common complications
Low Birth Weight (LBW)
• More than half of twins and almost all higher-
order multiples are born with LBW (less than
2,500 grams) .
• LBW can result from premature birth and/or
poor fetal growth.
• Both are common in multiple pregnancies.
72
73. Common complications-LBW
• LBW babies, especially those born before 32
weeks and/or weighing less than 500 grams, are at
increased risk of health problems in the newborn
period, as well as disabilities - intellectual
disabilities, cerebral palsy, vision and hearing loss.
• While advances in caring for very small infants has
brightened the outlook for these tiny babies,
chances remain slim, that all infants in a set of
sextuplets will survive.
73
74. TAPS
• Doppler shows blood flow differences in mid
cerebral artery,
• Difference of Hb as 11gm for donar twin vs
20gm for reciepient twin.
• This occurs due to smaller anastamosis.
74
77. Common complications
TWIN-TWIN TRANSFUSION SYNDROME (TTTS)
• About 10 percent of identical twins –MCDA
who share a placenta develop this
complication.
• Here, a connection between the two babies'
blood vessels in the placenta causes one baby
to get too much blood & the other too little.
• Severe cases often resulted in loss of both
babies.
77
78. In Poli-oli syndrome,
the donar twin has,
• Anemia,
• Oliguria,
• Oligohydramnios,
• Hypotension
the reciepient twin has,……
78
79. Quintero staging in TTTS
In Poli-oli syndrome,
hydramnios, visible bladder, abn. doppler in
umbilical artery, hydrops & fetal demise are
measured.
79
80. Comparison of laser surgery&
amniocentesis
.
• TTTS now can be treated with laser surgery to seal
off the connection between the babies' blood
vessels.
• It also can be treated with serial (repeated)
amniocentesis to drain off excess fluid. Removing
the excess fluid appears to improve blood flow in
the placenta and reduces the risk of preterm labor.
• Both procedures improve the outlook for babies.
• A septotomy improves the outlook for babies
80
81. Laser Surgery versus Amniocentesis
• However, recent studies suggest that laser surgery
may save more babies and cause fewer neurological
problems (such as cerebral palsy) in survivors than
amniocentesis.
• For example, an European study found a 76 %
survival rate for at least one fetus after laser surgery
compared to 56 % for serial amniocentesis.
• Another advantage of laser surgery is that only one
treatment is needed, while amniocentesis generally
must be repeated more than once.
81
82. SELECTIVE FETOCIDE
Embryo reduction
• Embryo reduction techniques were developed
initially to carry out selective fetocides in
cases of fetuses affected by some
malformation or genetic disorder.
• Later the technique was applied to the
reduction of one or more fetuses in cases of
high-order multiple pregnancies.
82
83. Multi Fetal Pregnancy Reduction
(MFPR)
• The procedure is variably named: selective
abortion, selective reduction, but the preferred
term is Multi Fetal Pregnancy Reduction (MFPR).
• It is now recognized as a safe and effective
method to improve outcome in multiple
pregnancies, esp. in quadruplets and higher order
pregnancies, arguably in triplets.
• The procedure is performed under ultrasonic
control at 11 or 12 weeks gestation by injecting
into the chest of each fetus 1–2 ml of KCl, 2 N.
83
84. MFPR
• The embryos selected for reduction are those
which are in the upper part of the uterus, those
which have increased nuchal translucency or
other ultrasonographic markers of risk.
• Some authors advocate karyotyping by chorionic
villous sampling prior to MFPR, but this requires
an additional procedure and, when karyotype
results are available, it is not always easy to be
certain which embryo has the given karyotype.
84
85. MFPR
• In addition, if two viable embryos are left, the
risk of chromosomal abnormality per
pregnancy is only twice that of the age of the
woman and subsequent amniocentesis could
be performed at a later stage, if the woman
wishes to do so.
85
87. 87
Fetal anomalies*……
The most common types of congenital anomalies were as
per journal findings,
• Cardiovascular anomalies (51, 28.0%),
• Anomalies of the central nervous system (24, 13.2%),
• Genito-urinary system (25, 13.7%),
• Chromosomal anomalies (21, 11.5%),
• Musculoskeletal (19, 10.4%) and
• Others (31, 17.0%) including facial clefting, oesophageal
atresia, other anomalies of the digestive system, syndromes
(2.7%) and multiple anomalies (2.2%)
Congenital anomalies in twins: a register-based study, S.V. Glinianaia, J. Rankin, C. Wright.
Human Reproduction, Volume 23, Issue 6, June 2008
