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

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

Total no. of deliveries (women), twins and triplets St Total no. of deliveries (women), twins and triplets St. Olavs University Hospital 1980-2008

Spontaneous multiples rate Twins 1/80 Triplets 1/802 1:6 400 Quadruplets 1/803 1:512 000 Quintuplets 1/804 1:40 000 000 USA 2002: 70% of twins and 99% of triplets/quads/quints is caused by infertility treatment

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

Twins Chorionicity rather than Zygosity determines the outcome

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

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

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

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

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

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

T 

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

Twins MZ DZ MC DC

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

Delivery of multiples DC twins VD* at 39 weeks MC twins VD* at 37 weeks MCMA twins CS at 32 weeks Triplets CS at 34-35 weeks VD* = vaginal delivery with CS on obstetrical indications

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

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?

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

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: 1004-6

BMJ 2002; 325: 1004-6

Term twins, n = 2 436 Birth related death (- elective CS) Cause of death Twin 1 Twin 2 Both p-value All causes 0 9 0 0,004 Intrapartum anoxia 0 7 0 0,02 Pulmonary causes 0 0 0 Pediatric causes 0 2 0 0,05 Gordon CS et al. BMJ 2002; 325: 1004-6

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: 1004-6