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MS WordPerinatologist Corner - C.E.U/C.M.E. Modules
Twins: Antepartum assessment and Intrapartum management
Sponsored by The Indian Health Service Clinical Support Center
8 Twin Pregnancy: Double Trouble?
Step 8. Fetal complications: Vanishing twin
How should the difficult situation of demise of one twin be managed?
Three quarters of such cases occur in monochorionic twins. In the first trimester this is manifest as “the vanishing twin” phenomena, which usually has a benign outcome. In the third trimester, the management goal is to safeguard the well-being of the viable twin and accomplish delivery as close to term as is feasible. Close monitoring with non-stress tests and biophysical profiles is appropriate, with delivery for non-reassuring fetal surveillance. In monochorionic twins there is always the possibility of passage of thromboplastic material from the dead twin to its co-twin.
This may occur in up to 15-20% of co-twins, resulting in cerebral thrombosis with subsequent neurological damage in the survivor. Grief counseling of the mother, and preparations for postnatal disposition of the remains of the twin that has been lost, are important aspects of care. If the death has occurred some time prior to delivery, the parents should be prepared for the fact that the dead twin may be a “fetus papyraceous” which will be attached to the placenta and may not be recognizable as a normal baby.
Assisted reproductive technology
Preclinical spontaneous pregnancy loss (eg, "vanishing twin") is common in pregnancies conceived naturally and with assisted reproductive technology. The rate of very early fetal loss after IVF is illustrated in the following representative examples:
- One study performed transvaginal ultrasonography four to five weeks after ovum retrieval and again in the second trimester in patients with a biochemical diagnosis of pregnancy. Embryonic loss was defined as loss of previously identified fetal cardiac activity. At least one spontaneous loss occurred in 26 percent of singleton, 35 percent of twin, 59 percent of triplet, and 47 percent of quadruplet pregnancies.
- A second study reported similar findings; spontaneous reduction of one or more gestational sacs and/or embryos before the 12th week of gestation was observed in 36 percent of twin, 53 percent of triplet, and 65 percent of quadruplet pregnancies.
