Thirty years ago, oxytocin was seldom administered to assist in giving births. Now, it happens in half of American pregnancies, yet little research has been done on whether or not there are any long-term consequences. An intriguing study has observed changes to the brains and behavior of voles whose mothers were administered oxytocin shortly before giving birth. We're a long way from knowing if the same is true for humans, but if the vole results do translate, society might reap some unexpected benefits.
Oxytocin is often called the "love drug" because romantic activities stimulate its release. However, like other hormones, it performs several apparently unrelated biological functions, including stimulating labor. More than a quarter of American pregnancies end with artificial oxytocin being given because the baby is overdue. In almost as many cases, labor starts naturally, but oxytocin is given to expedites the birth.
There is inconclusive evidence that children born to mothers given oxytocin are more likely to be autistic than those from other births. Even if this is true, Dr Will Kenkel of the Kinsey Institute told IFLScience we don't know if it reflects an effect of the drug or if autism is actually linked to difficult births, where oxytocin is more likely to be required.
It's obviously hard to study this directly as few mothers would volunteer to be part of a random trial of a drug with both important benefits and risks. Therefore, Kenkel experimented on prairie voles.
In Science Advances, Kenkel reports that the administration of doses of 0.125-0.5 milligrams/kilogram oxytocin to vole mothers on the anticipated day of birth resulted in changes in the brains of the offspring, even in adulthood. Voles whose mothers were given the drug were more gregarious and likely to care for the offspring of other voles than those from mothers given saline solution as a control.
Kenkel stressed to IFLScience that voles and humans have very different brains and the doses given were larger relative to body weight than are administered during human pregnancies. Nevertheless, the possibility exists that the widespread use of oxytocin could be producing a more extroverted, caring, and empathetic generation, quite without intent.
Extroversion might generally be seen as neutral and empathy highly desirable, so this may not cause alarm. On the other hand, if any human changes are detected that are considered to be harmful, it may be challenging to scale back. The paper notes that oxytocin administration has contributed to making childbirth less dangerous, reducing the risk of death for both mother and child – so no one is keen to abandon it.
Voles' association with oxytocin is longstanding. Prairie and meadow voles are closely related species, but one is monogamous and the other plays around. The differences have been shown to be strongly associated with oxytocin receptors, which can be altered with genetic engineering.