1. Multiple Gestations Cynthia S. Shellhaas, MD, MPH
Associate Professor – Clinical
Obstetrics & Gynecology

2. Objectives To understand the epidemiology of multiple gestations
To be able to list and describe the most common maternal complications of multiple gestations
To be able to list and describe the most common fetal complications of multiple gestations
To describe an ante-partum plan for specialized care for multiple gestations
To describe a delivery plan for multiple gestations

3. Objective
To understand the epidemiology of multiple gestations

4. Twin Birth Rate—United States: 1980-2006

5. Twin Birth Rate: Maternal Age and Ethnicity

6. Objective
To be able to list and describe the most common maternal complications of multiple gestations

7. Physiologic Changes in Multiple Gestation
Increase in plasma volume related to fetal number (96% in triplets/48% in singletons)
Increased TV, O2 consumption, respiratory alkalosis
Increased placental massincreases in HPL, HCG, AFP, progesterone, estradiol
Increased energy demands

8. Maternal Complications: Hypertension
2-3 X increase (Twins:Singletons)
Presents earlier in gestation
Presents w/greater severity (BP elevations, eclampsia)
Increase in HELLP variant
Twins more likely than singletons with same condition to have PTD, LBW, or C/S
Incidence does not vary with zygosity
Higher order gestations: atypical presentations more likely

9. Maternal Complications: GDM
Increased incidence in multiples/Increased HPL
3-6% twins
22-29% triplets
Each fetus increases the risk by a factor of 1.8
Decreased incidence after pregnancy reduction
Unknown: Ideal calories, optimal weight gain, oral hypoglycemic agents in PCO patients, best fetal surveillance, or ideal delivery time

10. Maternal Complications: Other
Acute fatty liver
1 in 10,000 singleton deliveries; 14% of cases occur in twins; 7% of triplet pregnancies
Placental abruption
8.2 X increase (twins:singletons)
Pruritic Urticarial Papules & Pustules of Pregnancy
0.2% singletons, 3% twins, 14% triplets
Pulmonary Embolism
Increased C/S, bedrest, AMA
Post-partum hemorrhage (atony)

11. Physiologic Change - Quiz

12. Antepartum Management: Diet
Increase caloric consumption by 300 kcal/day/fetus over singleton; 600 kcal/day over non-pregnant woman
Anemia
Iron deficiency anemia 2.4-4X higher
Folate deficiency anemia 8X higher
Nutritional supplements
Iron ( mg/day)
Folic acid (1 mg/day)

13. Weight Gain BMI < 18.5 kg/m2: Insufficient data
BMI kg/m2: lbs
BMI kg/m2: lbs
BMI > 30.0 kg/m2: lbs
First trimester weights gains of 4-6 lbs may be beneficial
Weekly weight gain after 20 weeks’
Underweight women: lbs
Normal weight women: 1.5 lbs

14. Recommedations for Supplemental Folic Acid

15. Objective
To be able to list and describe the most common fetal complications of multiple gestations

16. Relationship between Zygosity & Chorionicity

17. Gross specimen: Dichorionic/diamniotic placenta

18. Ultrasound Assessment of Chorionicity

19. Twin Zygosity and Corresponding Complications
Type
Incidence
IUGR
PTD
Placental Vascular Anasomosis
Perinatal Mortality
Dizygotic 80 25 40
10-12
Monozygotic 20 50
----
15-18
Di/Di
6-7 30
18-20
Di/Mono
13-14 60
100
30-40
Mono/Mono
< 1
60-70
80-90
58-60
Conjoined
70-80
70-90

20. Twin-Twin Transfusion Syndrome
Incidence: % of monochorionic/diamniotic twins
Etiology: Artery-to-vein anastomoses
Median GA at dx: 21 weeks
Underlying cause of 16% of twin mortality

21. Twin-Twin Transfusion Syndrome
Williams’ Obstetrics, 22nd edition

22. Quintero Stages 1—Abnormal AFV levels; Donor has identifiable bladder
2—Collapsed bladder in oliguric donor
3—Abnormal doppler studies
4—Hydrops
5--Death

23. Monoamniotic Twins Incidence: 1 in 10,000 pregnancies
Twin-twin transfusion syndrome: 1%
Monozygotic twins: 1-5%
Increased fetal loss: 23%
Cord entanglement: 67%
Congenital anomalies: 26%
NTD, abdominal wall, urinary malformations

24. Monochorionic/Monoamniotic Twins

25. Conjoined Twins Ventral (87%) Dorsal (13%)
Parapagus (28%)
Thoracopagus (19%)
Omphalopagus (18%)
Ischiopagus (11%)
Cephalopagus (11%)
Dorsal (13%)
Pygopagus (6%); craniopagus (5%); rachiopagus (2%)

26. Ultrasound image: Conjoined Twins

27. Conjoined Twins

28. Conjoined Twins

29. Twin Reversed Arterial Perfusion (TRAP) Sequence
Incidence: 1 in 35,000 deliveries
1% monochorionic gestations
Abnormal zygote division at time of twinning
Arterial-arterial anastamoses
Donor (“pump”) twin perfuses recipient (“acardiac”) twin
“Pump” twin: Heart failure, PTD
Weekly surveillance

30. Gross specimen: TRAP Sequence

31. B. Diamnionic, dichorionic C. Diamnionic, monochorionic
Division of a monozygote between the 4th & 8th day after fertilization creates which of the following?
A. Conjoined twins
B. Diamnionic, dichorionic
C. Diamnionic, monochorionic
D. Monoamnionic, monochorionic
C. Diamnionionic, monochorionic

32. Monozygote Division

33. Morbidity/Mortality in Multiple Gestation
Twins
Triplets
Quadruplets
Avg BW
2,347 grams
1,687 grams
1,309 grams
Avg GA
35.3 wks
32.2 wks
29.9 wks
% IUGR
14-25
50-60
% NICU 25 75
100
Avg LOS
18 days
30 days
58 days
% HCP
----- 20 50
CP Risk 4X
17X
IM Risk 7X
20X

34. Objective
To describe an ante-partum plan for specialized care for multiple gestations

35. Antepartum Management: Fetal Growth
Similar rate of growth compared to singletons in 1st & 2nd trimesters; start to lag around weeks’
Sub-optimal placentation
Abnormal umbilical cord morphology/insertion
Structural/genetic anomalies
Monochorionicity

36. 2006 Preterm Birth Rates: Twins vs. Singletons

37. Congenital Anomalies
MZ twins have a 2-3X increase compared to singletons/DZ twins
Anencephaly
Holoprosencephaly
VATER association
Extrophy of cloaca
Sacrococcygeal teratoma
Sirenomelia
Twins concordant for malformation only 5-20% of cases

38. Antepartum Management: Prenatal Diagnosis
Dizygotic twins: independent & additive aneuploidy risk
The risk of having at least one affected fetus is doubled
Twin pregnancy in 33 year old has risk=35 year old with singleton
Monozygotic twins: same risk as singletons

39. Prenatal Diagnosis Ultrascreen MS-AFP Amniocentesis
Chorionic villus sampling

40. Antepartum Management: Ultrasound
Assessment of chorionicity
Level II Ultrasound
Growth
Every 4-6 weeks if normal
Evaluate interval growth every days if compromise
Cervical length
Not before 16 weeks

41. What are these images?
Ultrasound images:  Cervical Length

42. Antepartum Management: Fetal Surveillance
Increased risk for IUFD compared to singletons
Both NST & BPP effective in identification of compromised twins/triplets
Questions
Higher order gestations
GA to initiate testing
Frequency: Once or twice weekly
? Normally growing dichorionic twins

43. Twins Questions

44. Objective
To describe a delivery plan for multiple gestations

45. Timing of Delivery Most twins deliver between 35-36 weeks’ gestation
Lung maturity
Growth velocity
Perinatal mortality & morbidity
Best delivery time: weeks’ gestation

46. Twins: Intra-Partum Management
Twin A Vertex
Twin B Non-Vertex
Twin A Vertex
Twin B Vertex
Twin A Non-Vertex
Breech
Extraction
Cesarean
Delivery
External
Cephalic Version
Successful
Unsuccessful
Cesarean Delivery
Cesarean Delivery
Vaginal Delivery
Vaginal Delivery

47. External Cephalic Version

48. Survey
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