Relative contribution of male and female age to the frequency of marital intercourse

Predictors of Sexual Intercourse Frequency Among Couples Trying to Conceive

BACKGROUND

Little is known about the predictors of sexual intercourse frequency (SIF) among couples trying to conceive despite the well-established link between SIF and fecundity.

AIM

To evaluate men's and women's demographic, occupational, and lifestyle predictors of SIF among couples.

METHODS

469 Couples without a history of infertility participating in the Longitudinal Investigation of Fertility and the Environment Study (2005-2009) were followed up for ≤1 year while trying to conceive. At enrollment, both partners were interviewed about demographic, occupational, lifestyle, and psychological characteristics using standardized questionnaires. Multivariable generalized linear mixed models with Poisson distribution were used to estimate the adjusted percent difference in SIF across exposure categories.

OUTCOMES

SIF was recorded in daily journals and summarized as average SIF/mo.

RESULTS

The median (interquartile range) SIF during follow-up was 6 (4-9) acts/mo. For every year increase in age for women and men, SIF decreased by -0.8% (95% CI -2.5 to 1.0%) and -1.7% (95% CI -3.1 to -0.3%). Women with high school education or less and those of non-white race had 34.4% and 16.0% higher SIF, respectively. A similar trend was seen for men's education and race. Only couples where both partners (but not just 1 partner) worked rotating shifts had -39.1% (95% CI -61.0 to -5.0%) lower SIF compared to couples where neither partner worked rotating shifts. Men's (but not women's) exercise was associated with 13.2% (95% CI 1.7-26.0%) higher SIF. Diagnosis of a mood or anxiety disorder in men (but not women) was associated with a 26.0% (95% CI -42.7 to -4.4%) lower SIF. Household income, smoking status, body mass index, night work, alcohol intake, and psychosocial stress were not associated with SIF.

CLINICAL TRANSLATION

Even among couples trying to conceive, there was substantial variation in SIF. Both partners' age, education, race, and rotating shift work as well as men's exercise and mental health play an important role in determining SIF.

CONCLUSIONS

As this was a secondary analysis of an existing study, we lacked information on many pertinent psychological and relationship quality variables and the hormonal status of participants, which could have affected SIF. The unique population-based couple design, however, captured both partners' demographics, occupational characteristics, and lifestyle behaviors in advance of their daily, prospective reporting of SIF, which was a major strength. Important predictors of SIF among couples attempting to conceive include men's exercise and mental health and both partners' age, education, race, and rotating shift work. Gaskins AJ, Sundaram R, Buck Louis GM, et al. Predictors of Sexual Intercourse Frequency Among Couples Trying to Conceive. J Sex Med 2018;15:519-528.

Coital frequency among married and cohabiting couples in the United States

Coital frequency is studied among couples as a function of marital or cohabiting status, relationship duration, number of children, religious affiliation, income, education, fertility intentions, age, race, self-assessed health, time spent in work, and perceived relationship quality. Data are from the 1987-88 National Survey of Families and Households. Predictors of coital frequency that were stable across several analyses were male's and female's ages, the duration of the relationship, and the male partner's self-assessed health. When the discrepancy in partners' reports was adjusted, cohabitation status, number of children, future fertility intentions, religious affiliation, and relationship quality as assessed by the female partner were significant. The results suggest a substantial idiosyncratic component to the determination of coital frequency in relationships.

Implications of hormonal influences on sexual behavior for demographic models of reproduction

In exploring the implications of hormonal influences on sexual behavior for reproduction, we have focused on androgens because of the convincing evidence for androgenic effects on female sexual motivation. We have been guided by the simple idea, based on clinical findings among hyperandrogenic women, that higher testosterone levels will increase female sexual motivation which in turn will result in increased coital frequency. However, careful consideration of the evidence fails to confirm such a role for testosterone in sexual behavior among normal women at any point in the reproductive span. While some amount of testosterone appears to be important in maintaining female sexual motivation, there is little evidence that variation in testosterone within the normal range is associated with variation in sexual motivation. Reported associations between testosterone and sexual behavior among married women cannot be interpreted as resulting from androgenic effects on sexual motivation. Thus we are left with the task of explaining why testosterone does not appear to play the same role in libido among hyperandrogenic and normal women. As mentioned earlier, some of the difference may attributable to the much higher levels of testosterone among hyperandrogenic women. Sherwin points out that the levels of sexual motivation decline with declining testosterone levels even while testosterone is well above normally occurring levels. It is possible that the brain is simply not sensitive to the variation in testosterone levels found in normal women. Other evidence suggests that the presence of intact ovaries may be equally important. A recent study of androgen replacement in naturally post-menopausal women failed to find a dramatic effect of testosterone on sexual motivation and behavior, despite levels similar to those in studies on surgically menopausal women, pointing to the importance of other factors associated with the presence of ovaries. A similar point can be made with regard to hyperandrogenism related to endogenous sources of testosterone, as in the case of PCOS. High levels of testosterone effectively disrupt ovarian function and interfere with other ovarian processes. Among hyperandrogenic women sexual behavior appears to be related to the direct effects of androgens on motivation, while the indirect effects of estrogen and progesterone are essentially eliminated. Among normal women, on the other hand, there is little evidence for such a dominating role of a direct androgenic effect on sexual behavior. Instead, other ovarian hormones, including estrogen and progesterone may also play a demonstrable role, despite the lack of strong evidence at this point.(ABSTRACT TRUNCATED AT 400 WORDS)

Sexual activity of women in Taiwan

In this paper, we calculate a base line of statistical data on the frequency of sexual activity at various ages of Taiwanese women. A cross-sectional study using questionnaires administered during personal interviews was conducted on more than seventeen thousand women who attended family planning clinics in the Taipei metropolitan area in 1991 and 1992. Of the women surveyed, 2.8 per cent were sexually inactive in the previous month, 83.67 per cent had intercourse one to nine times in the previous month, and 13.56 per cent had intercourse ten times or more. The mean frequency of sexual activity was 6.8 times a month. Age-specific mean coital frequencies for the age groups of less than 25 years, of 25-34 years, and of 35-44 years were 10.3, 7.3, and 6.6 times per month, respectively. Increased sexual frequency was associated with the following factors: young age, unmarried, lower educational level, fewer years of marriage and being on the pill. When logistic regression was used to control for confounding variables, we found that a woman's age is the most significant factor in predicting her sexual frequency.

How does variation in fetal loss affect the distribution of waiting times to conception?

Unmeasured variation has long been a concern in analyses of the waiting time to conception. Recent work by Heckman and Walker (1991) and Trussell and Rodriguez (1990) has underscored the fact that statistical considerations alone cannot discriminate among likely models describing the distribution. Here, we specify a single theoretically important source of heterogeneity, namely variability in intrauterine mortality, and assess its effects on the waiting times to a conception which results in a live birth. We find that the effects on the waiting times to a conception which results in a live birth. We find that the effects of variation in fetal loss are confined to the tail of the distribution. Unless variation in fetal loss is extremely large or a substantial proportion of observed waiting times are initiated at late ages, variation in fetal loss does not appear to explain much variation in conception waits. We conclude that heterogeneity in fetal loss does not explain the variation in fecundability that has been observed for first birth intervals. This conclusion supports the hypothesis that at early ages (below age 35) variation in the waiting time to a fertile conception may largely reflect the proportion of nonsusceptible couples in the population. The analyses suggest that for the purposes of testing theoretically motivated models, future efforts should be directed toward examining reproductive experience after age 35 and toward incorporating information on characteristics of the fertile period as it becomes known.

Decline in coital rates with spouses' ages and duration of marriage

Cross-sectional and longitudinal study of a large sample confirms that mean marital coital rates decline very rapidly over the first year of marriage. They seem to halve over the first year of marriage, and then they take perhaps another 20 years to halve again. This pattern of decline is interpreted as evidence against the suggestion that coital rates are closely related to female hormone levels.

The higher correlation of marital coital rates with wife's age than with husband's age, it is argued here, is because wife's age is more closely associated than husband's age with duration of marriage (here seen as the most important of these three variables in the determination of coital rates). This is because of the substantially smaller variance of wife's age at marriage than husband's age at marriage.

A cross-national comparison of the relative influence of male and female age on the frequency of marital intercourse

Parallel analyses of recent data from the United States, Thailand, Belgium, and Japan all confirm the finding that female age and not male age is the more important contributor to the decline in frequency of marital intercourse during the childbearing ages. The most probable explanation is the decline in female (but not male) androgen levels during the age span examined.

Changes in the frequency of marital intercourse from panel data

Three waves of panel data from a sample of urban U.S. couples in which the wife was under 30 years of age at the first interview show that frequency of intercourse declined about 25% in a 4-year period. Declines were greatest among those with the shortest length of marriage.