In November 2010, a baby girl was born “pregnant” with twins growing inside her in Hong Kong. The deceased unborn babies were between eight and ten weeks gestation, had legs, arms, a spine, rib cage, primitive brain tissue and intestines. According to the Mirror Online, both were covered in skin; and one weighed half an ounce and the other a third of an ounce – and each had an umbilical cord.
The doctors first discovered the rare phenomenon in the baby girl during an ultrasound of the mother. Then, after the girl was born, tests determined the infant had the rare condition fetus-in-fetu. The condition has been reported fewer than 200 times in the world and occurs in an estimated one in 500,000 births.
The infant underwent surgery three weeks after her birth to remove the fetuses.
The latest issue of the Hong Kong Medical Journal details the rare medical occurrence and Dr. Yu Kai-man, a specialist in obstetrics and gyneacology, said he believes it is the first documented case in the city. He said, “It was almost impossible to detect during the prenatal check-up, as the embryo inside the baby was too small. Since it is impossible for the little girl to have conceived the pregnancy on her own, the fertilization of the twin fetuses, of course, belongs to her parents, which has gone to the wrong place.”
The reason behind the abnormality is largely unknown but the World Health Organization classifies it as a type of cancer called mature teratoma. However, the Hong Kong Medical Journal also suggested that it could be linked to the mother having multiple abortions. Researchers wrote “the theory of demised multiple pregnancy has gained much support recently. More evidence is needed to confirm either theory. The widespread use of antenatal ultrasound in early gestation may provide more concrete evidence … and shed light on this intriguing condition.”
“In conventional embryological assessment of aborted products of gestation, size of the fetus can sometimes be smaller than the normal size for embryological age, since the fetuses often undergo a certain period of growth restriction before the actual death.
On the other hand, direct measurement of the specimen size may be slightly larger than the ultrasound assessment due to flattening of the tissue after its passage through the cervix. Interestingly, in the reported literature, a poor correlation has been observed between the level of organogenesis and size of the parasitic fetus. In a review of 87 cases by Hoeffel et al, there were 10 reported parasitic fetuses weighing over 500 g.
The level of organogenesis in these fetuses, however, was immature compared to that of a normal 500 g fetus or newborn. If these parasitic fetuses were once products of multiple pregnancies, an interesting conclusion would be that these ‘fetuses’ continued to grow in size after their arrest in development or, theoretically, the ‘death’ of fetuses, although the ‘death’ of such fetuses is always difficult to define in view of their ‘acardiac’ nature.”