Most twin pregnancies are considered high-risk and to ensure a safe and healthy delivery, it is important that the pregnancy is closely monitored by expert doctors. Monochorionic- monoamniotic twins is a rare and dangerous pregnancy condition that can lead to the loss of both fetuses. It is essential that couples who want to start a family learn more about this condition beforehand.
MCMA or monochorionic-monoamniotic twins is a condition in which twin babies live in one sac and share one placenta. MCMA is a rare condition, affecting only one percent of all twin pregnancies. During a normal twin pregnancy, division will occur during the first four days of life and the twins will have separate placentas and sacs. But for MCMA twins, the division will occur during the first eight days of life. This will result in the twins sharing the same sac and placenta. MCMA happens naturally and has no defined causes.
MCMA carries the same complications as normal twins; including diabetes, hypertension and a 50 percent chance of preterm labor. However, the most serious and unique complication is umbilical cord entanglement. Sharing the same placenta means that both cords are very close to the placenta, with a distance of only about six inches, making it easier for the cords to get tangled. The entanglement prevents blood from going to both babies and will eventually lead to the loss of both infants, if left untreated. There are no warning signs for MCMA; once the cords are tied together, the lives of both babies are immediately at risk.
Fetuses move all the time and we cannot know when their movement will cause entanglement. Therefore, early detection of MCMA is key to a safe and healthy delivery of both babies. Detection is done through ultrasound and it is easier to spot the entanglement of the umbilical cords during the early stages of pregnancy, when it is clear from the scans that the twins are sharing the same sac.
Once the condition is detected, the patient must be monitored as often as possible. When the pregnancy reaches 24 to 26 weeks, it is recommended that the mother comes in for fetal monitoring once or twice a day, depending on her specific condition. The doctor will also do a scan to monitor the blood flow within the umbilical cords, as well as to observe how stable the fetal heart rates are. The mother must come to the hospital right away if she feels that the twins’ movements are slowing.
If there is a significant drop in the fetal heart rate, an emergency delivery might have to be carried out in order to save the lives of both babies. This is a decision that will be made together between the parents and the doctor.
Diploma Thai Board of Obstetrics and Gynecology Faculty of Medicine Vajira Hospital, Navamindradhiraj University , 1995