The existence of twins may sound fascinating, but it is not without the added risks. Twins look cute and adorable when lying together in a cot or a stroller but when in the womb together, they have some additional risks that the single fetus doesn’t have.
The twin pregnancies, when compared with singletons, are more at risk of preterm delivery, poorer obstetric outcomes, and pregnancy complications.
One such example is the knotting of the umbilical cords.
A 36-year-old woman pregnant with twins was admitted to the hospital at 32 weeks gestation for elective cesarean section. The twins were a monochorionic, monoamniotic, i.e., shared a single placenta and were within the same amniotic sac. The patient had no complications in the antenatal period.
Before performing the cesarean section, a routine cardiotocography was performed, which showed the heart rate of one twin had severe variable decelerations, whereas the other twin had normal heart tracings.
The twin girls were delivered via the elective cesarean section. After delivery, the umbilical cords were seen twined in a complex knot. Such a complex knot of umbilical cords of monochorionic twins is rarely seen. Overall the incidence of true knots in umbilical cords is from 0.3% to 2%.
The Apgar scores at 1 minute and 5 minutes for both twins were 7 and 8, respectively. The blood gas analysis of the cord blood revealed normal results.
The twins were shifted to the neonatal intensive care unit, where they recovered fully and were discharged after 40 days of hospital stay.
Generally, it is believed that the knots are formed early in the course of pregnancy, usually during the 9th to 12th week of gestation, but can also be formed near or during the labor. Despite the generous use of prenatal ultrasound, the umbilical knots remain undiagnosed.
Umbilical cords are usually loosely entwined without obstructing the blood flow. But, if the knots tighten, the blood circulation might be blocked, which subsequently would lead to fetal complications, including hypoxia, distress, or even death.
The difference between false and true knots is that the former is just the excessive covering of the Wharton’s jelly which appears to be like a true knot but doesn’t endanger the fetus. In contrast, true knots in the umbilical cord are associated with intrapartum complications and fetal distress.
References
Francesca Arezzo, M. a. (2020, August 13). Umbilical Cord Knot. Retrieved from The New England Journal of Medicine: https://www.nejm.org/doi/full/10.1056/NEJMicm1916811
