Coitus

During coitus, female orgasm is accompanied by muscular contractions of the vaginal walls (see Chapter 8), and these contractions create a pressure in the vagina that is higher than that in the uterus.

From: Human Reproductive Biology (Fourth Edition) , 2014

The Human Sexual Response

Richard E. Jones PhD , Kristin H. Lopez PhD , in Human Reproductive Biology (Fourth Edition), 2014

Coitus (Sexual Intercourse)

Coitus (Latin coitio, meaning "a coming together") is, for many of us, a vehicle for the expression of emotion and intimacy. Strictly speaking, coitus (or sexual intercourse) is the penetration of the vagina by the penis, which can be called vaginal coitus (Figure 8.4). However, the term coitus is also used for other forms of sexual contact, including oral coitus (oral–genital contact), femoral coitus (when the penis is inserted between the thighs), mammary coitus (when the penis is inserted between the breasts), and anal coitus (insertion of the penis into the rectum). There are many common slang phrases for coitus, such as "making love," "going to bed," and other more descriptive phrases. Legally, fornication is the voluntary coitus between an adult man and woman who are unmarried. Adultery is voluntary coitus between two people, at least one of whom is married to someone else. Sodomy means different things in different states; it usually refers to anal or oral coitus, but also can mean "acts against nature" such as coitus with an animal. Finally, masturbation, which is not a form of coitus, is the act of deriving sexual pleasure from self-stimulation of the genitals.

FIGURE 8.4. Representation of the erect penis inserted into the vagina during vaginal coitus.

In anal coitus, the penis penetrates the anus and is moved within the rectum. This method of coitus is common in male homosexuals and in some heterosexual couples. A heterosexual couple should use a condom and never switch from anal to vaginal coitus before washing the penis, as the rectum contains microorganisms that could infect the female reproductive tract (see Chapter 17). The walls of the rectum are not as well lubricated as are those of the vagina, and the anal sphincter is constricted. Therefore, lubrication of the anus and penis with saliva or a sterile lubricant is common.

Oral coitus is contact of the mouth with the genital organs. When the mouth of the partner touches the genitals of a female, it is called cunnilingus (Latin cunnus, meaning "vulva"; lingere, meaning "to lick"). Cunnilingus is practiced in several cultures. One danger of this form of oral coitus is the possibility of air being blown into the vagina, as air bubbles could enter the bloodstream and could be dangerous. Therefore, air should not be blown into the vagina.

Fellatio (Latin fellare, meaning "to suck") is the oral manipulation of the penis or scrotum by a sexual partner. Some worry about the adverse effects of swallowing the semen, as it can contain microorganisms such as HIV (see Chapter 18). Obviously, a woman cannot get pregnant from this form of coitus.

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URINARY TRACT INFECTIONS IN WOMEN

Amanda M. Macejko , Anthony J. Schaeffer , in Female Urology (Third Edition), 2008

Sexual Activity

Vaginal and oral intercourse help to propagate potential pathogens into the vagina and urinary tract. Additionally, vaginal intercourse may cause trauma of the vaginal epithelium, rendering it more susceptible to bacterial adherence and vaginal colonization. 14 Several studies have linked sexual activity with vaginal colonization and UTI. Foxman and colleagues found that vaginal colonization with E. coli was inversely associated with the number of days since sexual activity. 15 Hooton and coworkers reported that urine cultures in the immediate postcoital period show a transient bacteriuria. 16 It has been proposed that voiding immediately after intercourse is protective, although there are no current data that support this conjecture. 1

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Sperm Activation, Fertilization, Morula, Blastocyst Formation, and Twinning

Laurence A. Cole , in Biology of Life, 2016

Sperm Activation

Vaginal intercourse leads to the release of semen into the vagina and uterus. That the sperm enters the vagina and uterus does not mean that it will propel its way to an ovum and fertilize it. If mature spermatozoa are incubated with oocytes in a test tube, fertilization either does not occur at all, or it takes many hours to complete. In contrast, if spermatozoa are removed from the vagina, uterus, or fallopian tubes 2 h after coitus, they are completely different and are capable, in a test tube, of immediate fertilization. These sperm have clearly been activated in some way in the uterus or fallopian tubes.

What we understand occurs to sperm on entering an estrogen-primed uterus is called sperm capacitation, which enhances sperm propulsion. Furthermore, the sperm cannot penetrate the zona pellucida or shell of an ovum without going through the acrosome reaction, a second form of activation needed for penetrating the ovum. Here we describe these two activation procedures.

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Repartnering and Stepchildren

F.K. Goldscheider , in International Encyclopedia of the Social & Behavioral Sciences, 2001

1 Introduction

Sexual unions create children and hence, parenthood. Union dissolution creates single parents and absent parents. When these parents enter a new partnership, they may have a new kind of children—stepchildren—children who are not the joint concern of the couple at the start of the union, as at least one member enters the union as a step-parent. This asymmetry in parenthood is likely to shape the partner dynamics that lead to union formation and hence to affect the calculations of those with children (whether coresident or not) and any partners who might join them in a new union. This asymmetry affects their lives as a couple, particularly whether they have additional, joint children, and also affects whether their union survives. This article on children and new partnerships examines three issues: (a) the role of children in the likelihood that their parents repartner (considering different effects for men and women); (b) the role of such children on the fertility of the unions formed, and (c) the effect of stepchildren on union dissolution.

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Women's Health Issues

Helen Bruce , in Immigrant Medicine, 2007

Birth control

Resumption of coitus on completion of the postpartum period is dependent on cessation of bleeding. If present, the woman is not yet fully cleansed and cannot participate in coitus. Discussion regarding contraception and when initiation of a method will begin is made prenatally by most American-born women. This is not so in immigrant women, many of whom will only discuss the topic after the birth is completed. Words are powerful, particularly if heard in a second language with which you are only just becoming fluent. Family planning, family spacing, birth control are all terms used to define a range of options available to prevent pregnancy. To a foreign-born woman and husband the suspicion created by the words 'birth control' can stop a discussion at its very inception. To use or not to use a contraceptive method is commonly not the woman's choice, but resides with the husband or older women (if in an extended family) making the decision. Since pregnancy is often seen as a gift from a higher power, or if a family distrusts Western medicine or the family has seen many of its members die in their country of origin, no interference in the natural process of procreation will be chosen. If a choice is made, clear instruction on any changes in menstrual flow and frequency should be discussed. Many immigrant women believe they must bleed monthly to be healthy and will quickly stop any method that disturbs their menstrual pattern. Fully breast-feeding for up to 2 years prior to coming to the US may have assisted women in spacing their pregnancies. Two factors should be considered when anovulation is used as contraception in the US. Many mothers supplement their breast-feeding with artificial milk (Box 43.1), thus nullifying the anovulatory process. Large numbers of women stop breast-feeding by 6 months (Fig. 43.9) and are therefore no longer safe from pregnancy. Many women have insurance coverage for pregnancy and birth only and can not afford access to contraception when breast-feeding stops. This then perpetuates the cycle of unplanned pregnancies in low income families.

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Risky Sexual Behavior

D. Kirby , in Encyclopedia of Adolescence, 2011

Abstaining from Sex

Abstaining from vaginal sexual intercourse greatly reduces the chances of contracting an STI. However, avoiding vaginal sex does not eliminate the chances of STI transmission. An STI can easily be transmitted through anal sex. It can also be transmitted through oral sex, although it is considerably less likely to be transmitted through oral sex than through vaginal or anal sex. And finally, some STIs, such as HPV and herpes simplex virus (HSV) can be transmitted through genital skin to skin contact. This is true for both heterosexual sex and same-sex sex. (While the focus of this article is on heterosexual behavior, many of the principles regarding STI also apply to same-sex sex.)

Teens who wait until they are older to have sex are less likely to acquire an STI, for at least three reasons. First, they will not contract any STI while abstaining from all sexual activity. Second, girls are more susceptible to contracting an STI from sexual intercourse with an infected person when they are younger because the cervix is more susceptible. Third, if teens delay having sexual intercourse until they are older, they are more likely to use condoms during sex.

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Sexuality

L.M. Diamond , R.C. Savin-Williams , in Encyclopedia of Adolescence, 2011

Prevention of Pregnancy and Sexually Transmitted Infections

Adolescent participation in coitus, oral sex, and anal penetration pose inevitable risks regarding sexually transmitted infections (STIs), and coitus obviously involves the additional risk of pregnancy. Approximately half of all STIs occur among youths between the ages of 15 and 24, and adolescents face particular risks for HIV, chlamydia, and gonorrhea. Each year, nearly 750  000 teen girls aged 15–19 become pregnant and nearly 80% of these pregnancies are unplanned. Notably, the United States has a disproportionately high rate of adolescent pregnancy in comparison to other Western industrialized nations, despite the fact that US teens engage in coitus at approximately the same rates and ages as do youth in other Western industrialized countries: US rates of adolescent pregnancy are twice as high as those in the United Kingdom, four times as high as those in Canada, and 12 times as high as those in the Netherlands. Nonetheless, it bears noting that there has been a significant decline in the US teen birth rate within all 50 states in the last decade, and research suggests that this decline can be most attributed to improved use of condoms and other forms of contraception. Condoms remain the most popular method, preferred by approximately 60% of sexually active young couples, followed by the birth control pill, preferred by approximately 20%. Yet, rates of inconsistent use and nonuse remain high, with many adolescents reporting that they do not use condoms or other forms of contraception during the first time they have intercourse, or during their most recent act of intercourse. Dual-usage, in which condoms are used in conjunction with the birth-control pill (since birth control pills cannot protect against STIs and HIV) also remains an elusive goal. Studies of adolescent girls have found that even the most consistent and reliable contraceptive users use condoms in conjunction with birth control pills less than half the time.

Adolescents' inconsistent use of contraception and condoms appears largely attributable to lack of availability. Studies consistently demonstrate that one of the key predictors of adolescent contraceptive behavior is whether youths have access to a free, confidential family-planning facility. The ability to obtain such services without the knowledge and consent of one's parents also play an important role. Another barrier to reliable contraceptive use is low levels of knowledge about the basic biological facts of fertility and contraception. Without understanding exactly how or why birth control pills work, youths cannot be expected to realistically appraise the risks of missing an occasional pill. It is also critical to consider adolescents' underdeveloped cognitive skills, particularly regarding long-range planning, evaluation of hypothetical probabilities, and future oriented thinking. Such factors contribute to youths' poor estimation (or lack of estimation altogether) of their own risks for pregnancy and STIs, providing them with little motive for consistent contraceptive and condom use. Similarly, adolescents who do find themselves pregnant, or contract STIs, do not report more consistent subsequent contraceptive and condom use. Clearly, adolescents do not appear to be drawing on rational calculations of cause and effect when making real-time decisions about contraceptive and condom use. Nor do they appear to be carefully evaluating the risks of their own behavior; rather, one study showed that adolescents are actually more motivated by the potential benefits of contraceptive/condom nonuse (such as immediate pleasure, feelings of physical and emotional connection to the partner) than by the attendant risks. Another obstacle is youths' ability and willingness to realistically and honestly assess their own sexual behavior. Taking proactive steps to plan for sexual activity and use appropriate protection requires admitting that one is sexually active, an admission that may be particularly difficult for girls or those raised in conservative environments. Youths who report feelings of guilt and shame about sex are less likely to use effective contraception, as are youths from extremely conservative religions, and those who find themselves breaking previous virginity pledges.

Factors that promote effective and consistent condom and contraceptive use include youths' motivations for doing so, their commitment to avoiding pregnancy, their knowledge about condoms and contraception, their feelings of efficacy regarding condom/contraceptive use, and their ability and willingness to communicate openly about these issues with their partners. Some youth advocates have argued that given the multiple risks associated with adolescent sexual activity, it is more appropriate and effective to promote 100% abstinence among adolescents than to provide them with comprehensive contraceptive information and access. In the past decade, numerous abstinence only programs have been developed and implemented across the country, as well as programs encouraging adolescents to take virginity pledges until marriage. Several comprehensive reviews of the effectiveness of these programs have been conducted, and conclusively demonstrate that such programs have no significant effects on adolescents' age of sexual initiation, their rates of participation in unprotected vaginal sex, their number of sexual partners, or their condom and contraceptive use. In the small number of studies that have demonstrated positive effects, the effects typically disappear at follow-up assessments. In contrast, programs offering comprehensive sexual education have been reliably found to be associated with reduced risks of pregnancy and STIs, and survey data suggest that the majority of parents support teaching comprehensive sex education in concert with encouragement for abstinence.

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Male Reproduction

Pierre Clément , in Encyclopedia of Reproduction (Second Edition), 2018

Sensory afferents

Sensory receptors stimulated during coitus or masturbation are essentially located in the penile skin, prepuce, and glans. Sensory inputs are conveyed to the upper sacral and lower lumbar segments of the spinal cord via the dorsal nerve of the penis, a sensory branch of the pudendal nerve ( Fig. 2). A relatively sparse sensory innervation of ductus deferens, prostate, and urethra has also been described which reaches the lumbosacral spinal cord via the pudendal nerve. A second afferent pathway is constituted by fibers traveling along the hypogastric nerve and, after passing through the paravertebral lumbosacral sympathetic chain, enters the thoracolumbar segments of spinal cord (Fig. 2). Sensory afferents terminate in the medial dorsal horn and the dorsal gray commissure of the spinal cord.

Fig. 2.

Fig. 2. Schematic view of the autonomic and somatic innervation of genitalia. Neural pathways involved in ejaculation are indicated. DNP, dorsal nerve of the penis; DRG, dorsal root ganglia; HN, hypogastric nerve; PN, pelvic nerve; PP, pelvic plexus; PudN, pudendal nerve; SGE, spinal generator of ejaculation.

 Reprinted from Handbook of Clinical Neurology, vol.130, P. Clement and F. Giuliano, Anatomy and physiology of genital organs – men, pp. 19–37, 2015, with permission from Elsevier.

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Evaluation of the Patient for Uterine Fibroid Embolization

Linda D. Bradley , in Hysteroscopy, 2009

Postprocedure Follow-up

Patients with persistent symptoms of bleeding, pain, and fever should be evaluated immediately (Fig. 12-15A).

The patient must avoid vaginal intercourse for 2 weeks or until the vaginal discharge resolves. When leukorrhea is persistent or serosanguineous discharge noted, office hysteroscopy is helpful in identifying discontinuity within the endometrium or necrotic prolapsing fibroids (Fig. 12-15C).

The gynecologist sees patients who have no complications within 1 month of the procedure. Subsequent office visits are scheduled the first year at 6 months. One year after the procedure, annual visits are scheduled unless new symptoms occur. At each visit, a pelvic examination, including fundal height measurement, should be performed. Patients are asked about resolution of symptoms and their level of satisfaction with the procedure.

Most fibroid-related symptoms improve within 4 to 6 months after the procedure. Maximum fibroid shrinkage is obtained by mouth 4 to 6. In 10% of patients, additional fibroid shrinkage occurs up to 12 months after the procedure. Repeat MRI of the pelvis if uterine fibroids continue to grow or if unusual pain occurs. Hysterectomy is recommended for UFE failures (Fig. 12-15B).

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Herpesvirales

In Fenner's Veterinary Virology (Fifth Edition), 2017

Pathogenesis and Pathology

Genital disease may result from coitus or artificial insemination with infective semen, although some outbreaks, particularly in dairy cows, may occur in the absence of coitus. Respiratory disease and conjunctivitis primarily result from droplet or smear transmission. Within the animal, dissemination of the virus from the initial focus of infection occurs via a cell-associated viremia.

In both the genital and the respiratory forms of the disease, the lesions are focal areas of epithelial cell necrosis in which there is ballooning of epithelial cells; typical herpesvirus inclusions may be present in nuclei at the periphery of necrotic foci. There is an intense inflammatory response within the necrotic mucosa, frequently with formation of an overlying accumulation of fibrin and cellular debris (pseudomembrane). Gross lesions are frequently not observed in aborted fetuses, but microscopic foci of necrosis are present in most tissues and the liver and adrenal glands are affected most consistently.

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