Vanishing Twin Syndrome can occur even when a mother is expecting triplets- Dr Angela Anzeze, Obstetrician/Gynecologist
By Yvonne Kawira
If it weren’t for early scans, Jane Nungari might never have known about her child who mysteriously ‘vanished’ from her womb before birth.
It all started when Nungari went for her 10-week scan, and the news was nothing short of thrilling. She was carrying twins! With twins running in her family’s paternal side, the discovery felt like destiny unfolding. Bursting with excitement, she couldn’t wait to share the big news with her hubby.
“This was my first pregnancy. I was so excited. I doubled down on my pregnancy supplements not willing to take any chances,” she recalled.
But the joy soon took an unexpected, shocking news during her 20-week scan: only one baby appeared on the screen.
But the sonographer’s expression told a different story. He was the same one who had confirmed the twin pregnancy, yet this time, he said nothing, simply handing her the printed report for the obstetrician.
“Curiosity and fear got the best of me and I opened the envelope. That was when I discovered something had gone terribly wrong. The obstetrician later confirmed my fears—I had only one baby. The other had vanished. This, I learned, was a condition known as Vanishing Twin Syndrome, where twins are detected early in pregnancy, but as it progresses, one fetus ‘disappears’ from the gestational sac. I was surprised” she told Willow Health in an interview.
Nungari, in her desperate search for answers, sought a second opinion at another hospital. She even carried the initial scan results scan indicating she was in deed pregnant with twins. But the results were the same.
The doctor later explained to her that the Vanishing Twin Syndrome was a rare condition, often unnoticed if early scans are missed.
The doctor went on to say that the baby vanishes without bleeding, and the tissues are absorbed into the surviving twin or the mother’s body.
“True to his word, in my next scan, the baby was gone,” Nungari added, “Some things are God’s mystery doctors might not always have the answers.”
Nungari eventually gave birth to a healthy baby girl but often thinks about the mystery of the vanished twin.
According to Dr Angela Anzeze, a consultant obstetrician/Gynecologist, Vanishing Twin Syndrome is the loss or miscarriage of one of the embryos or fetuses, which occurs when they stop developing during pregnancy.
“Once the embryo or fetus stops developing, the tissue gets absorbed by the other twin, maternal tissue or placenta, and the pregnancy continues as usual with the other surviving twin. Subsequent ultrasounds performed after this loss, will only detect the surviving twin. It can also occur in higher order pregnancies such as triplets,” Dr Anzeze explained adding that the cause is unknown.
She explains that abnormalities usually appear during early development of the pregnancy, rather than suddenly. Causes such as genetic and chromosomal abnormalities have commonly been stipulated. Other risk factors include advanced maternal age (more than 35 years), IVF, abnormalities in the placenta and infections such as rubella.
There may be complications associated with the Vanishing Twin Syndrome to both the mother and the surviving twin and Dr Anzeze lists spotting or cramping during early Trimesters and “the pregnancy will be managed as a high risk up to delivery to prevent adverse outcomes as the pregnancy advances.”
She also includes risk of early labour before the due date and risk of reduced Amniotic fluid – provides nutrients and protects the fetus- as the other possible outcomes.
As for the surviving twin, complications may range from poor blood supply, especially if the twins share a placenta – this puts them at risk of growth restriction, low birth weight and other complications as a result of reduced oxygen.
This, she said may cause preterm birth, placing the twin at risk of prematurity and low birth weight such as respiratory distress syndrome (difficulty in breathing due to poor lung development).
Vanishing Twin Syndrome can be identified by an ultrasound scanning during early stages of antenatal clinic and the reason medics recommend that antenatal clinics start at the onset of pregnancy.
Vanishing Twin Syndrome can be detected by observing the educing levels of beta-human chorionic gonadotropin (BHCG), which were initially very high to support multiple pregnancies may also be indicative.
According to Dr Anzeze, if it occurs in the first trimester (first three months) – one is unlikely to get severe complications, and the pregnancy will continue as usual, as high risk and follow up by a specialist.
“But if it occurs in the second or third trimester, one requires high risk follow up by a specialist, with ultrasound scans performed to ensure the fetus is stable. The scan measures the growth rate, weight, blood supply and checks if the organs are well formed. If any abnormality is detected, early delivery of the surviving twin may be advised followed by close monitoring by a pediatrician,” offered Dr Anzeze.
Currently, because the condition is rare, there is no specific mode of prevention but doctors advise mothers to start preconception care if they intend to conceive soon.
It is during pre- conception care, when they’re screened for medical conditions and started on supplements early to prevent abnormal embryo formation. As soon as they test positive for pregnancy, they must ensure they attend antenatal clinics, start supplements and have ultrasound scans done, to identify any abnormalities early.
“I don’t think there are any pros related to this condition, considering it is a miscarriage of one of the embryos of fetuses. Cons are the complications mentioned above, in addition to the negative effects it has on the mother during and after the pregnancy. It may cause anxiety in future pregnancies,” she added.
Conservative estimates reveal that approximately one in four multiple pregnancies—about 25 out of every 100—are affected by this syndrome. It is difficult to have accurate data on the condition because some women do not do scans in the early stages of their pregnancy which may help them to detect the condition. Therefore, if this happened to them they would not know that they had twins or triplets.
