OF A FETUS
- This concept was based on
the findings that the incidence of early twin gestations was significantly
higher than that noted later in pregnancy (about 5% versus 1 in 90
- Can occur at any time
during the gestation but is most common in the first trimester.
- True loss rate is
approximately 20% (1).
- Loss prior to 15 weeks
gestation may result in no sonographic evidence of a twin pregnancy at a
later date (pathologic examination at delivery may show no evidence that
the twin ever existed) (2). This has been termed the "vanishing twin
Demise of one embryo in a dichorionic twin pregnancy
Demise of one embryo in a trichorionic
- Loss of one twin in the
second trimester may result in compression and mummification of that fetus.
This has been called fetus papyraceus. The compressed fetus is a thin
structure of residual bone and tissue stuck against the uterine wall.
- Loss of a twin in the late
second and third trimester leads to fetal maceration.
- Risk to surviving twin.
- Minimal in
- In monochorionic
twins, vascular injuries as a result of thrombotic emboli or disseminated
intravascular coagulation pose a small additional risk to the surviving
VANISHING TRIPLET SYNDROME
Outcome of Multiple Pregnancies
- Landy HJ, Weiner S, Corson
SL et.al. Ultrasonographic assessment of fetal disappearance in the first
trimester. Am J Obstet Gynecol 1986;155:14.
- Levi S. Ultrasonic
assessment of the high rate of human multiple pregnancy in the first
trimester. J Clin Ultrasound 1976;4:3.
- Janiaux E, Elkazen N, Leroy
F et.al. Clinical and morphological aspects of the vanishing twin
phenomenon. Obstet Gynecol 1988;72:577.
- Johnson SF, Driscoll SG.
Twin placentation and its complications. Semin Perinatol 1986;10:9.