The pill is one of the most popular forms of contraception in the UK - with more than 3.5 million British females currently using it, including a quarter of all those between 16 and 49 years old.
Now, a new study has found that women who take it have higher levels of the “love hormone”.
Scientists at Aarhus University, in Denmark, discovered it raises concentration of oxytocin in their blood, which can increase feelings of attachment - and, of course, love.
The findings, published in journal Scientific Reports, could help researchers understand how and why being on this form of birth control can affect emotions.
Professor Michael Winterdahl, study leader from the university’s Department of Clinical Medicine, said: "Oxytocin is a hormone found naturally in the body and is secreted during social cues and bonding, reinforcing social behaviour.
"A constantly elevated level of oxytocin may mean that it is not secreted in the same dynamic way as under normal conditions. It is precisely these dynamics that are important to our emotional lives.
"This may explain why feelings such as closeness, attachment and love appear to be altered in some women who use birth control pills."
The researchers collected and analysed blood samples from 185 young women in the United States, with participants also answering a variety of questions about their mental wellbeing.
Professor Winterdahl continued: "Many women have used birth control pills at some point in their lives.
"Our study presents, for the first time, evidence for changes in the levels of oxytocin in response to birth control, providing a mechanism by which some women experience altered mood.
"Since oxytocin is important for attachment to a partner, one can imagine that the constantly elevated level is important - not only for the woman herself, but also in the broader sense of the relationship.
"Humans are super social beings, we are able to put ourselves in the place of others, show empathy, fear loneliness and seek community - all driven by the brain's secretion of oxytocin.
"Even very small changes in brain oxytocin levels will affect the way we process emotions and thus how we interact with each other.
"Our study can help explain why some women on birth control pills experience a diminished sense of closeness, for example."
Researchers found that those in relationships who stop taking it, or switch to a different version, experience a change in how they feel about a partner.