Researchers have discovered a strong correlation between positive sexual communication and baseline levels of oxytocin, a product of the endocrine system commonly known as the "love hormone." 

A study published May 14 in Psychoneuroendocrinology suggests that oxytocin levels may underlie certain behaviors that promote relationship health, potentially opening up new avenues of research that deal more directly with sexual communication. Understanding the hormonal basis of sexual communication could promote awareness of behaviors that could help couples navigate challenges and potentially grow closer.

"If they realize there is something specific about sexual communication that uniquely relates to a hormonal and behavioral level, then maybe this will create more awareness that sexual communication is not something that should be disregarded, and maybe should be actively pursued in a positive way," said lead author Rick Roels, a psychiatrist who is pursuing his Ph.D. in sexology at KU Leuven in Belgium.

In his psychiatry practice as well as prior research, Roels has noticed a reluctance to talk about sex openly and directly. 

The new study is part of a larger longitudinal study investigating how various aspects of a sexual relationship, including expressions of sexuality, influence relationship outcomes. Other research on relationship health has shown, for example, a connection to negative outcomes when self-worth is centered around finances. 

Roels and his colleagues recruited 126 heterosexual couples who had been participating in the larger study to observe how oxytocin levels may relate to communication, especially sexual communication, between couples.

"There's something special about sexual communication," Roels said in an interview with The Academic Times. "There's some kind of neurohormonal involvement stating that sexual communication comes close to behavioral changes as well as, maybe, neurohormonal changes."

To assess the potential correlation between oxytocin and communication, Roels and his colleagues first took blood samples from the study participants and sent them to the Kinsey Institute at Indiana University Bloomington for analysis. 

The researchers then arranged conversations between each of the couples, drawing on their answers to questionnaires that asked about the types of changes a person might like to see in their partner. These included non-sexual criteria, such as expressing emotions or meeting up with friends and family, as well as sexual topics. These could have involved, for example, discussions in which one partner wanted to see in the other a greater interest to have sex, more willingness to experiment or improved attention to their sexual needs.

During each of these conversations, Roels and his colleagues observed and judged various behaviors, as well as their intensity, based on a system of observational guidelines to "code" the various behaviors witnessed. These included negative dimensions such as annoyance, frustration and irritability, and positive ones such as validation.

The researchers considered participants to validate one another when they said phrases such as "I understand," showed interest, asked questions or uttered occasional "mhmms," indicating active, empathetic listening.   

The team found that individuals who expressed more — and more intense — validating behaviors during sexual communication tended to have higher blood-plasma levels of oxytocin. Non-sexual communication, however, showed no increase in validation cues based on oxytocin levels.

Another study on couples' communication recently described how partners tend to text more like one another as their relationship forms. Because this study is only the second to combine sexual communication with observational techniques, from here Roels wants to see more of these studies done, both to confirm his results and better investigate the link between oxytocin and sexual communication.

For his future studies, Roels would like to include other variables, such as heart rate variability, to investigate how they, too, may relate to sexual communication. Perhaps most important, he wants to conduct a similar study to this one with multiple oxytocin measurements, either from blood or saliva, before and after observation, to try to form a causal relationship between oxytocin and sexual communication. 

Without more oxytocin measurements, according to Roels, any future studies on the hormone and sexual communication can only describe correlation. Still, he said the research is an important step in promoting sexual communication, not just in research but in relationships, too. 

"I hope this way we can get it out of the shadows of not only research in general, but also out of the shadows in relationships where sexual topics tend to be avoided, or treated with more unease and anxiety," Roels said. 

The study, "The link between oxytocin plasma levels and observed communication behaviors during sexual and nonsexual couple discussions: An exploratory study," published May 14 in Psychoneuroendocrinology, was authored by Rick Roels, KU Leuven; Uzma S. Rehman, University of Waterloo; C. Sue Carter and Hossein P. Nazarloo, Indiana University Bloomington; and Erick Janssen, KU Leuven and Indiana University Bloomington.