The recognition that sexual desire is associated with relationship quality and other important interpersonal experiences has led to a corresponding interest in identifying the correlates and causes of this aspect of human sexual response. Most researchers have focused on intraindividual factors, including hormonal processes. The present review explores the relationship between one hormonally mediated female life event - pregnancy - and sexual desire. Sexual desire is defined, and distinguished from other sexual experiences (e.g., arousal, activity), and its common operationalizations are disscussed. Next, the hormonal changes that characterize each trimester of pregnancy are considered. Empirical research conducted then to determine whether these hormonal changes correspond to alterations in the experience of desire is then reviewed. It is concluded that the hormonal fluctuations that occur during pregnancy are reliably associated with progressive decreases in feelings of sexual desire in the majority of women.
Key words; sexual desire, hormones, pregnancy, maternal sexuality.
A growing body of evidence indicates that sexual desire - the motivational component of sexual response - is related to several significant human life events. For example, feelings of sexual attraction prompt men and women to enter liaisons with both casual sex partners and romantic partners; desire therefore has implications for reproduction and species survival. Sexual desire is also closely associated with relationship quality. Most adults associate feelings of desire with passionate love, and research reveals that dating partners who experience higher levels of desire for each other are more satisfied with the relationship, less likely to consider leaving the current partner, and less likely to engage in infidelity than are partners who feel lesser amounts of desire (Regan, 2000). The recognition that sexual desire has implications for a variety of important individual life events as well as for the emotional tenor and the adjustment of romantic relationships has led to an increased interest in delineating the causes and correlates of this particular sexual experience. Some researchers have examined external causes (e.g., erotic media), whereas others have explored interpersonal causes (e.g., conflict; for a review, see Regan & Berscheid, 1999). However, most have focused on causes located within or under the control of the individual. Of the myriad intraindividual causes that have been targeted as possible precursors to sexual desire, hormones and hormonal processes have received the lion's share of empirical attention.
Four major classes of hormone - the sex hormones - have been implicated in the experience of sexual desire. The sex hormones are produced by several of the various glands that comprise the endocrine system, including the adrenal glands, the pituitary gland, the ovaries in women, and the testes in men. Androgens, or masculinizing hormones, are primarily synthesized in the testes and the adrenal cortex and to a lesser extent in the ovaries. The primary naturally occurring androgens are testosterone, androstenedione, and dehydroepiandrosterone. Estrogens, or feminizing hormones, are secreted by the ovaries, with lesser amounts manufactured in the testes, adrenal cortex, and peripheral tissues. During pregnancy, the placenta is a major source of estrogens. The primary naturally occurring estrogenic hormones are estradiol, estrone, and estriol. Progesterone, like the estrogens, is primarily produced by the ovaries (and, during pregnancy, the placenta), with lesser amounts manufactured in the adrenal cortex and testes. And finally, prolactin is produced by the pituitary gland in both sexes.
Researchers interested in examining the association between hormones and hormonal processes and sexual desire have followed one of two methodological approaches. The first method involves measuring the serum or plasma level of free (unbound or bioavailable) hormone and then correlating that level with subjective reports of sexual response (for a review of this literature, see Regan, 1999). …