Multiple Gestation
Authored by:
Susan Bishop, RNC-OB, MN
Perinatal Outreach Coordinator
MultiCare Regional Perinatal Outreach Program
susan.bishop@multicare.org
Incidence of
Multiples
Currently 3% of all births (95% twins)
Naturally occurring twins 1 in 80
pregnancies
Naturally occurring triplets 1 in 8000
pregnancies
 incidence in African descent
 incidence in Asian descent
(7 – Mandy & Weisman)
Between 1980-2004 Incidence of
Twins Increased by 70%
(8 – Simpson & Creehan)
HOM* increased by 500%
*HOM=Higher Order Multiples
(8 – Simpson & Creehan)
Factors Associated with Multiple
Gestation
Delayed childbearing: AMA


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75% increase
Higher levels of Follicle
Stimulating Hormone
Greater use of fertility
services
ART (assisted reproductive
technology)
OI (ovulation induction)
400% triplets/HOM
(1 – ACOG, 7 – Mandy & Weisman, 8 – Simpson & Creehan)
Physiology of Twinning
Monozygotic (MZ) – fertilization of a single
ovum that subsequently divides into 2 or more
zygotes (31% incidence)

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Cell splits between day 4-day 12
Genetically the same: physical characteristics, sex,
blood type hair & eye color
Dizygotic (DZ) – fertilization of multiple ova
(67% incidence)

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Two separate eggs/two separate sperm
No more alike than other siblings born to the same
parents
(8 – Simpson & Creehan)
Monozygotic Twins
(8 – Simpson & Creehan)
Dizygotic Twins
(8 – Simpson & Creehan)
Triplets
(8 – Simpson & Creehan)
Diagnosis of Multiple Gestation
1st trimester ultrasound
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>5weeks chorionicity
>6weeks fetal number
>8weeks amnionicity
Highly accurate at 10-14 weeks
Clinical Exam

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Fundal height 2-4 cm > estimated GA
Leopolds/FHR
Subjective symptoms

Fatigue, hyperemesis, increased appetite/wt gain,
FM, exaggerated pregnancy discomforts, “feel
different”
(8 – Simpson & Creehan)
Maternal Changes
GI

Hyperemesis/N&V; reflux
Hematologic

Plasma volume  by 50-100%=dilutional anemia/iron deficiency
anemia
Cardiovascular

HR/stroke volume;  risk pulmonary edema; supine aortocaval
compression
Respiratory

>tidal volume and oxygen consumption; more alkalotic arterial pH; >
dyspnea and SOB
Musculoskeletal

Symptoms earlier in pregnancy; back/ligament pain
Dermatologic

PUPPP (Pruritic urticarial papules and plaques of pregnancy) 3%
twins/14% triplets
(8 – Simpson & Creehan)
Maternal Complications
Preterm Labor – 50% twins, 76% triplets, 90%
quads

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Education important!
Serial U/S with assessment of cervical length
Fetal fibronectin testing
Tocolytics, corticosteriod therapy, bedrest
Hypertension

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Preeclampsia develops earlier and is more severe
HELLP may present with atypical signs/symptoms
ART multiple pregnancies at higher risk
(1 – ACOG, 6 – Jones, 7 – Mandy & Weisman, 8 – Simpson & Creehan)
Maternal Complications (continued)
PPROM – increased rate; shorter latency
to birth time
Gestational Diabetes
Intrahepatic Cholestasis – 2-5 x greater
Abruptio Placenta
Pulmonary Embolism
Acute Fatty Liver
(1 – ACOG, 6 – Jones, 7 – Mandy & Weisman, 8 – Simpson & Creehan)
Fetal Risks/Complications
Mortality increased with plurality and late GA
(Jones, 7 – Mandy & Weisman, 8 – Simpson & Creehan)
Fetal Risks/Complications (continued)
MZ twin mortality 3-10x than DZ twins

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Intrauterine demise is usually cord
entanglement
Greater incidence of congenital anomolies
such as:
Neural tube defects
Urinary tract malformations
Discordant birth weight (20%)
Twin to Twin Transfusion Syndrome
(7 – Mandy & Weisman)
Discordant Growth
Weight of one multiple differs
significantly from that of the other(s) by
 25%
More common in Mono chorionic twins
Twin to Twin Transfusion Syndrome
Also effected by maternal age, parity,
sex discordance and gestational age.
Discordance ranging from 15-40% has
been considered predictive of an
adverse outcome
(7 – Mandy & Weisman)
Twin-to-Twin Transfusion
Syndrome
Almost exclusively occurs in monochorionic (1
placenta) diamniotic (2 amniotic sacs) pregnancies
Unequal balance of blood flow between the two
fetuses due to placental vascular anastomoses
within the placenta allowing one twin to transfuse
the other
20% growth discordance, poly/oligo, discrepancy
in cord size, cardiac dysfunction &/or abnormal
cord Doppler studies
Staging: I-V
(5 – Jackson & Mele, 7 – Mandy & Weisman)
TTTS
TTTS Management
Treatment options:
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Amnioreduction
Septostomy
Photocoagulation
Umbilical cord occlusion
Maternal dietary management
Patient education, support
(5 – Jackson & Mele, 7 – Mandy & Weisman)
Reduction Amniocentesis
Selective Vessel Laser Ablation
Septostomy
Umbilical Cord Occlusion/Ablation
Fetal Risks/Complications (continued)
Intrauterine Growth Restriction (IUGR)


Due to placental insufficiency and competition
for nutrients
Fetal growth rates  at:
30-32 weeks (twins)
29 weeks (triplets)
(7 – Mandy & Weisman)
Fetal Loss
Spontaneous loss early in multiple
pregnancy associated with bleeding
“Vanishing Twin”
Fetal death  20 weeks gestation

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Surviving twin at  risk of fetal death,
neonatal death and severe long-term
morbidity.
Survival is inversely related to time death
occurred and survivors of opposite-sex twin
pairs more likely to survive than same-sex
twin pairs.
(7 – Mandy & Weisman)
( Fuller & Fuller)
Fetal Surveillance
Fetal Activity
Assessment
Serial NSTs – BPP
if nonreactive
Doppler
velocimetry
Close assessment
for possible
complications
(8 – Simpson & Creehan)
Laboring with Multiples
Must occur in facility capable of emergent
C/S and neonatal resuscitation
Capability of monitoring all fetuses
simultaneously and continuously
Qualified personnel in numbers required to
care for all neonates
Ultrasound at bedside
VBAC possible
(1 – ACOG, 6 – Jones, 7 – Mandy & Weisman, 8 – Simpson & Creehan)
Management of Multiple Birth
Route: Vaginal or C/S
Dependant on presentation and number!
 Twin: VV/ VB/ BB
 HOM=C/S
(2 – Chasen & Chervenak)
Management of Multiple Birth
(continued)
Timing of delivery
is controversial.
Lowest fetal
death rates of
twins 36-37
weeks
Lowest fetal
death rates for
triplets 34-35
weeks
FLM testing may
be required
Dependant on
pregnancy
course and
type of twin
pairings
(6 – Jones, 7 – Mandy & Weisman, 8 – Simpson & Creehan)
Management of Multiple Birth
IV access, Type & Screen
Prepare for PP Hemorrhage BEFORE
delivery!
Continuous monitoring of all
Bedside U/S on admission to
determine/confirm fetal lie
Delivery in OR for all twins and HOMs

6-25% C/S for B after vaginal delivery of A
(1 – ACOG, 2 – Chasen & Chervenak, 8 – Simpson & Creehan)
Delivery of Multiples
Each must have own bed, own team, own
identifier (bracelets)

Double check bands before, during and after delivery!
Prepare to differentiate cords and send placentas
to pathology
Vag Del: After delivery of Twin A be prepared with
U/S to confirm lie and stabilize Twin B.
Twin B at higher risk of perinatal mortality when
delivered vaginally
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When > 36 weeks gestation and most likely due to
mechanical problems (compound presentation, cord
prolapse, abruption)
Continue to monitor Twin B!
May need pitocin, C/S if problems develop
(2 – Chasen & Chervenak, 8 – Simpson & Creehan)
Delivery of Multiples (continued)
Nonreassuring FHR Twin B
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VE – assess dilatation and check for
presence of cord!
Bedside U/S
Prepare for forceps or vacuum assist
External version/internal rotation/extraction for
transverse or footling breech
Interval >30 minutes associated with poorer
outcomes
C/S via general anesthesia for deterioration
(2 – Chasen & Chervenak, 8 – Simpson & Creehan)
Postpartum
Hemorrhage – count on it!
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Twin EBL avg 1000 mL
Twice as likely to need
transfusion
Fundal checks!
Uterine Atony -> act quickly
Physical & Emotional
Stress
Muscle Atrophy/Endurance
Breastfeeding
(8 – Simpson & Creehan)
Triplets and HOM
Increased Gestational Diabetes, preeclampsia, PTL, Pregnancy Associated
HTN
Common discordant growth
Increased risk of velamentous insertion of
cord
BPPs weekly from 30 weeks on
Increased risk of PP Hemorrhage (1035%)
(2 – Chasen & Chervenak 6 – Jones, 7 – Mandy & Weisman)
Resources &
References
1.
American College of Obstetricians & Gynecologists (2004) Multiple Gestation: Complicated
Twin, Triplet, and High-Order Multifetal Pregnancy, ACOG Practice Bulletin Number 56.
2.
Chasen, ST & Chervenak, FA (2009) Delivery of twin gestations, UpToDate online
www.uptodate.com
3.
Creasy, RK & Resnick, R (2004) Maternal-Fetal Medicine: Principles and Practice (5th ed.)
Philadelphia: Saunders.
4.
Gilbert, ES (2007) Manual of High Risk Pregnancy & Delivery (4th ed.) St. Louis: Mosby.
5.
Jackson, KM & Mele, NL (2009) Nursing for Women’s Health, Twin-to-twin transfusion
syndrome: what nurses need to know, 13 (3), p224-233.
6.
Jones, D (2008) Triplet pregnancy: Mid and late pregnancy complications and management,
UpToDate online www.uptodate.com
7.
Mandy, GT & Weisman, LE (2009) Multiple Births, UpToDate online www.uptodate.com
8.
Simpson, KR & Creehan, PA (2008). AWHONN Perinatal Nursing (3rd ed). Philadelphia:
Wolters Kluwer/Lippincott Williams & Wilkins.