Single intrauterine fetal death rate in multiple pregnancies is significantly higher than that in singleton. The risk increases with the number of fetuses. Loss of a twin during the first trimester is not an uncommon event. Single twin demise occurs in up to 6% of twin pregnancies and may occur at any trimester with potentially profound consequences. One of the key influential factors of twin morbidity and mortality is zygosity.
- Twin – twin transfusion syndrome
- Congenital anomalies
- Placental insufficiency
- Abnormal cord insertion
- Intrauterine infection
- Maternal and medical condition
- Intrauterine growth restriction
- Twin reversed arterial perfusion
- Foetal reduction
- Umbilical vein thrombosis
Complications following death of a co-twin
- Gestational age
- Timing: In the second and third trimester theoretically puts the co-twin at substantial risk.
- Coagulopathy: an initial maternal clotting profile with reassessment in 2-3 weeks is recommended.
Monochorionic Twin pregnancy
Chorionicity should be determined at the time the twin pregnancy is detected by ultrasound based upon the number of placental masses, the appearance of the membrane attachment to the placenta and the membrane thickness. This scan is best performed before 14 weeks of gestation.
Fetal ultrasound assessment should take place every 2 weeks in uncomplicated Monochorionic pregnancies from 16+0 weeks onwards until delivery.
- Dichorionic diamniotic twins
Delivery should be delayed until at least 34 weeks gestation, provided there is no obvious continuing pathology that may cause demise of surviving co-twin. Regular NST should be undertaken
If the live twin is leading and is in a cephalic presentation, vaginal delivery may be considered.
If the live twin is malpresenting or is growth restricted, or if dead twin is leading, caesarean section is preferred.