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Draion BurchObstetrician-gynecologist |
Content:
- Birth of a "Pregnant" Infant
- Medical Enigma
- Obstetrician's Perspective
- Theory of Triplet Absorption
- "Vanishing Twin" Syndrome
- Medical Literature and Rare Cases
Birth of a "Pregnant" Infant
A baby girl born in Hong Kong was found to be 'pregnant' with two brothers. This condition, known as fetus in fetu ("fetus within a fetus"), is extremely rare, occurring in about one in 500,000 births. The exact cause remains unknown.
Medical Enigma
"The abnormalities happen very early on, in very early pregnancy," says obstetrician Dr. Deryan Birch. "It's one of the mysteries of medical science." The World Health Organization suggests that the tiny fetus found inside the infant is likely a teratoma, or tumor, rather than a fully formed embryo. However, the doctors who treated the newborn reported finding actual fragments of her twin brothers, who had begun developing normally before being absorbed into her body.
Obstetrician's Perspective
Dr. Yu Kai-man, an obstetrician at Hong Kong's Queen Elizabeth Hospital, initially diagnosed the infant with a tumor. Prenatal ultrasound revealed an unidentified mass inside the fetus. The infant was placed under observation. During surgery performed around the third week of life, surgeons found two fetuses between the baby's liver and kidney. One weighed 9.3 grams, the other 14.2 grams, corresponding to eight and ten weeks of gestation. Each fetus had an umbilical cord connected to a placenta-like mass in the infant's abdomen.
Theory of Triplet Absorption
Researchers speculate that the infant was originally part of a triplet. For unknown reasons, the other two embryos, which were smaller, were absorbed into the infant's body. Genetic or placental abnormalities may have played a role.
"Vanishing Twin" Syndrome
The tragedy of this case is that the brothers were likely alive when they were absorbed into their sister's body. Their development could not continue, however. "They need placental blood flow and all the other things that go with being a viable pregnancy," explains Dr. Birch. He notes that fetus in fetu is surprisingly similar to the more common "vanishing twin" syndrome. In twin pregnancies, one twin is often absorbed into the other and "disappears" within the surviving twin's body. "When you deliver a baby, and you see an extra placenta and cord," says Birch, "you think, 'Oh, maybe this was a twin.'"
Medical Literature and Rare Cases
Elizabeth Noble, in her book "Having Twins," states that in 80% of multiple pregnancies, there is a loss of one or both babies. Other studies estimate that vanishing twin syndrome occurs in 21-30% of multiple pregnancies. Only about 200 cases of fetus in fetu have been reported in medical literature. In 2006, doctors in Pakistan removed two fetuses from a two-month-old girl named Nazia. In 2011, fragments of twin fetuses were surgically removed from an 18-year-old boy. In rare cases, fetuses that die in utero can become calcified, forming a stone. In August 2014, doctors in India removed a lithopedion, a petrified fetus, from a 60-year-old woman who had carried it in her body for 36 years. She sought medical attention for abdominal pain and a protrusion in her lower abdomen.
