Monoamniotic Twin Pregnancy and Cord Entanglement: A Clinical Dilemma

EDITORIAL COMMENT: We accepted this case for publication because it makes the point that even accurate antenatal ultrasonographic diagnosis of monochorionic twin pregnancy with cord entanglement still leave dilemmas of management concerning testing for fetal welfare and decisions regarding timing and method of delivery. It may be of anecdotal interest to readers, as it is to the editor, that the 2 most complicated examples of cord entanglement in such pregnancies known to him both resulted in 2 living infants born vaginally. Figure 1 shows braided umbilical cords of the pregnancy published by Golan A, Amit A, Baram A, David MP. Aust NZ J Obstet Gynaecol 1982; 22:165–167. Figure 2, courtesy of Dr Michael Somerville, shows the placenta and knotted cords from a patient delivered at 39 weeks' gestation at the Mercy Hospital for Women, Melbourne, in 1994. In this pregnancy ultrasonography at 19 weeks and 32 weeks' gestation failed to detect either the monochorionic nature of the pregnancy or the knotted cords. Both of these cords were individually knotted and then entangled with additional pseudoknots, fibrotic segments at the points of crossing and with adhesions between the coils. It is extraordinary that both of these rare specimens shows what appears to our consultant pathologist to be chorioangiomas of the placenta that were not mentioned in the pathology reports of either specimen. At the Mercy Maternity Hospital, Melbourne, in the 16 years 1979–1994 there were 82,530 deliveries, 1,138 twin pregnancies and 4 cases of monoamniotic pregnancies with cord entanglement ± knotting, none of which were diagnosed antenatally. The first in 1981 resulted in delivery at 37 weeks of malformed infants, 1 stillborn, 1 neonatal death; the second in 1992 resulted in 2 intrauterine fetal deaths at 27 weeks with true knots in each cord; in the third, Caesarean section was performed at 30 weeks because of premature rupture of the membranes and both infants survived although the cords were knotted together; the fourth case is that shown in figure 2. This case reported by Drs Ritossa and O'Loughlin really is unusual and their discussion of the literature is comprehensive. Summary: Monoamniotic twin pregnancies are rare, but are associated with a high risk of perinatal death. The major complications are due to cord entanglement and twin twin transfusion. We were recently faced with the clinical problem of a monoamniotic twin pregnancy complicated by cord entanglement. Fortunately the outcome was favourable with the survival of both twins after delivery by elective Caesarean section at 32 weeks' gestation. Our case as well as some of the controversies in the management of this unpredictable condition are presented. Most authors seem to prefer abdominal delivery upon reaching fetal lung maturity in the case of known monoamniotic twins although this management is not validated by the available studies. Hospital admission for fetal monitoring upon discovery of a cord entanglement at a viable gestation is also advocated.