Twins Reach Out to Each Other in Womb

By Dave Andrusko

Editor’s note. My family is on vacation. While we are gone I’ll be running articles from the past 12 months that you’ve indicated you particularly enjoyed. Dave

Unborn babies have the ability to make directed contact with other human beings in the womb, according to a study in the online journal PLoS ONE. Researchers in Italy measured the movements made by twins toward each other, and found that these actions differed from incidental contact made with the uterine wall.

“We conclude that performance of movements towards the co-twin is not accidental: already starting from the 14th week of gestation twin foetuses execute movements specifically aimed at the co-twin,” wrote the researchers, led by Umberto Castiello of the University of Padova, Italy.

Castiello and his colleagues made videos of five pairs of twins at age 14 and 18 weeks using four-dimensional ultrasound, according to At 14 weeks, the twins touched each other head to head, arm to head, and head to arm. By 18 weeks, they made even more contact, “spending up to 30 percent of their time reaching out and stroking their co-twin,” reported.

These movements are often characterized as simple reflexes, occurring with no actual direction by the babies. However, the Italian researchers’ measurements of contact between the twins found that they are actually planned movements. By 18 weeks, the twins’ movements towards each others’ eye and mouth regions showed marked differences from other motions, showing that they take a measure of care when touching delicate parts of their siblings’ bodies.

“The results showed that the spatial and temporal characteristics of foetal movements were by no means uncoordinated, but depended on the goal of the different motor acts, suggesting a surprisingly advanced level of motor planning,” the researchers wrote.

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