A team of Canadian and Russian researchers investigating an early Neolithic cemetery in Siberia have identified the world's oldest set of human twins, buried with their young mother.
The skeleton of the woman was exhumed in 1997 from a hunter-gatherer cemetery in south-eastern Siberia. Found with 15 marmot teeth - decorative accessories which were probably attached to clothing - the remains were photographed and labelled, but were not investigated by anthropologists.
Now Angela Lieverse, a bioarchaeologist at the University of Saskatchewan, Canada, and colleagues Andrzej Weber from the University of Alberta, Canada, and Vladimir Bazaliiskii from Irkutsk University, Russia, have examined the skeleton and found remains of twin fetuses nestled between the pelvis and upper legs.
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The twins, about 36 to 40 weeks old, probably suffocated during their mother's troubled labor nearly 8,000 years ago.
"This is not only one of the oldest archaeologically documented cases of death during childbirth, but also the earliest confirmed set of human twins in the world," Lieverse said.
Radiocarbon dating on small samples of the mother's and twins' bones confirmed the skeletal remains are about 7,700 years old.
Death from childbirth was quite common in prehistoric and pre-modern societies, but it has rarely been documented.
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This could be because women and their children were rarely buried together or simply because the delicate remains of the unborn didn't survive.
Evidence of twins is exceptionally rare.
"They are basically invisible from the archaeological record," Lieverse told Discovery News.
She noted that only one other case of confirmed human twins has been reported in the archaeological literature. The case involved 400-year-old twin remains, aged about 24 week gestation, which were excavated from a burial in South Dakota. However, death for the twins and their mother did not appear to have resulted from complications related to premature childbirth.
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According to Lieverse, the skeleton of the Siberian woman, who lived with her Neolithic community near the shore of Lake Baikal, the world's deepest, tells "a compelling story and very personal window into life-and death-almost 8,000 years ago."
The researcher estimates the woman was in her early twenties when she went into labor. She likely didn't know she was having twins.
The location of the fetal remains suggests the first baby was breech - coming out feet first - a dangerous condition complicated by the presence of the twin.
While the first baby was partially delivered, at some point labor was obstructed, either by interlocked twins, head entrapment or some other condition such as the infant's arms beside or behind its head.
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There was nothing her community could do for her.
"Without the skills, experience and technology of modern medical practictioners, this case of dystocia [obstructed labor] would have been a virtual death sentence for all three individuals," Lieverse and colleagues wrote in the current issue of the journal Antiquity.
Obstructed labor accounted for as many as 70 percent of maternal deaths worldwide even in the late 20th century.
In the end, the mother would have succumbed to infection, bleeding or exhaustion, taking her suffocated twins with her to the grave.
Image: The skeleton of the mother in her grave pit. The small bones in her pelvic-abdominal area and between her thighs are the remains of the infants. Credit: Angela Lieverse.