1. Twins in Norway Twins per year 1:95 births in 1967-69 1:50 children

2. Twins in Norway 2006 Total births 55 509 Twins 968 Triplets + 11
Twin rate 1:57 births :29 children

3. Total no. of deliveries (women), twins and triplets St
Total no. of deliveries (women), twins and triplets St. Olavs University Hospital

4. Spontaneous multiples rate
Twins 1/80
Triplets 1/802 1:6 400
Quadruplets 1/803 1:
Quintuplets 1/804 1:
USA 2002:
70% of twins and 99% of triplets/quads/quints is caused by infertility treatment

5. Multiple pregnancies Antenatal care provided by specialist
Complications are more frequent:
Fetal anomalies
Preterm delivery
IUGR/FGR
Preeclampsia

6. Twins
Chorionicity
rather than
Zygosity
determines the outcome

7. DZ
Dizygotic DC DA twins
2 Plac/chor 2 Amn 2 Yolk

8. Monozygotic DC DA twins
2 weeks
3 days
3 weeks
2 Plac/chor 2 Amn 2 Yolk

9. MC DA twins
2 weeks
4 days
6 days
3 weeks
1 Plac/chor 2 Amn 2 Yolk

10. MC MA twins
3 weeks
5 days
4 weeks
1 Plac/chor 1 Amn 1 Yolk

11. Conjoined twins 3 weeks 4 weeks 1 Plac/chor 1 Amn 1 Yolk

12. Conjoined twins Sludge Incidence: 1 : 75 000 1 : 200 MZ twins
MBR Norway
1981 – one
1983 – two
1984 – one
1985 – one

13. T 

14. Twins MC DC % % Fetal loss < 24 weeks 13 3 Delivery 24-32 weeks 9 6
% %
Fetal loss < 24 weeks 13 3
Delivery weeks 9 6
IUGR (< 5th centile) 34 23
TTTS 15 0

15. Twins MZ DZ MC DC

16. Multiples in Norway Total births 60 000 Twins 1 000 Triplets 10
DC twins 900
MC twins 100
MCMA twins 5
Triplets 10

17. Delivery of multiples DC twins VD* at 39 weeks
MC twins VD* at 37 weeks
MCMA twins CS at 32 weeks
Triplets CS at weeks
VD* = vaginal delivery with CS on obstetrical indications

18. Vaginal delivery of twins
Must be cleared
for breech delivery
Must be cleared
for breech delivery

19. Vaginal twin delivery Epidural is recommended
Pediatrician / anaesthesiologist present
CTG monitoring of both twins
Following delivery of twin I:
Immediately correct and secure longitudinal position of twin II
Check lie/presentation with ultrasound
Amniotomy and oxytocin if necessary
Reasonable interval between twin I and twin II
20-30 minutes?

20. Second twin
The prognosis is slightly less favourable, independent of mode of delivery
4 x risk for CP
Placental abruption
Umbilical cord complications

21. CS for all twins? Scotland 1992-97, N = 4 545 twin deliveries
Retrospective cohort study
671 (15%) elective CS
3 874 vaginal deliveries
Stratified analysis at birth (> 36 weeks)
IUFD > 24 wks + neonatal deaths < 4 wks (no malformations, hydrops or TTTS)
Gordon CS et al. BMJ 2002; 325:

22. BMJ 2002; 325:

23. Term twins, n = 2 436 Birth related death (- elective CS)
Cause of death Twin 1 Twin 2 Both p-value
All causes ,004
Intrapartum anoxia ,02
Pulmonary causes 0 0 0
Pediatric causes ,05
Gordon CS et al. BMJ 2002; 325:

24. Twins at term Absolute risk of perinatal death
Cause of death Twin 2 Singleton
All causes 1:270 1:1 000
Intrapartum anoxia 1:350 1:2 000
Anoxia due to 1:500 1:20 000
”mechanical cause”
Gordon CS et al. BMJ 2002; 325: