The prevalence of Müllerian anomalies is 2–3% [1]. Although the genitalia of the developing embryo may be affected at any time during development, the gonads do not acquire their male or female phenotype until the seventh week of development [2]. Most anomalies result from the arrest of development of the uterovaginal primordium during the eighth week; usually there is a failure of the Müllerian ducts to fuse properly, resulting in structural abnormalities of the uterus, fallopian tubes, and upper vagina [3].

It is beyond the scope of this book to discuss in detail human female genital embryology, but a few key concepts should be noted. In the absence of Müllerian-inhibiting substance, the Müllerian (paramesonephric) ducts develop into the uterus, fallopian tubes, and upper third of the vagina. The Wolffian (mesonephric) ducts regress and differentiate into the labia majora, labia minora, and clitoris. The caudal tip of the Müllerian duct fuses with the urogenital sinus to form the vaginal plate and by the fifth month, the vagina is entirely canalized [3]. Interestingly, the vulva is unique in that it is the only place in the human body where all three embryologic layers (ectoderm, mesoderm, and endoderm) may be visualized together. The vulvar vestibule itself is mesodermal in origin, whereas the tissues distal to it are derived from ectoderm, and those proximal to it are from the endoderm.

Lastly, anomalies of the urinary tract appear in approximately 23% of patients with malformations of the genital tract. Therefore, when a congenital anomaly is found in the lower genital tract, the upper genital and tract and urologic system should be evaluated.

Given that female sexual pain has only recently become a topic of scientific study and given that congenital anomalies of the female genital tract are uncommon, it is not surprising that there is a paucity of data on the subject of dyspareunia in women with congenital malformations. Nevertheless, congenital anomalies may be associated with female sexual dysfunction and sexual pain. Therefore, they should be considered when evaluating a patient with dyspareunia. Congenital anomalies of the vulva and vagina may be classified as (1) developmental abnormalities of external genitalia; (2) genetic and chromosomal abnormalities; and (3) anomalies associated with uterovaginal and vulvovaginal abnormalities. Although many conditions may be associated with anomalies of the lower female genital tract, this chapter will discuss the more commonly described conditions.

The Clitoris

Clitoral hypertrophy is most commonly seen in association with congenital adrenal hyperplasia (discussed below). While it is quite possible that adult women with clitoral hypertrophy might have discomfort with intercourse, the vast majority of females with this condition are diagnosed and managed in early childhood. The treatment for clitoral hypertrophy is surgical correction by means of a reduction clitoroplasty, and more recently, a nerve-sparing clitoroplasty has been described [4].

Periclitoral abscesses, a rare cause of dyspareunia, are uncommon in women who have not undergone female genital cutting (see Chapter 36). However, noncircumcised females who develop a periclitoral abscess caused by a pilonidal sinus tract have been reported [5]. This condition may be diagnosed with history and physical examination and treated with marsupialization and antibiotic therapy if needed.

The Vulva

Congenital labia fusion is typically seen in female infants with female pseudohermaphroditism (an individual who is genetically XX, and phenotypically male or has ambiguous genitalia; see below). Acquired labial agglutination, as its name implies, is not a congenital disorder, yet it may be misdiagnosed as labioscrotal fusion (implying a genetic or chromosomal etiology) in young children. Labial agglutination has also been observed in postmenopausal women [6]. Although it is uncommon, it is likely that this condition would be associated with dyspareunia.

Approximately 43% of women with hypertrophic (enlarged) labia minora complain of discomfort with intercourse [7]. This condition may be congenital or acquired, and it is managed with a surgical repair called a “labiaplasty.” There has recently been increasing public awareness of this procedure with some associated controversy, as some women are requesting it for cosmetic purposes.

Prolapsed urethral mucosa typically presents in premenarchal girls and postmenopausal women. The commonality among these two populations is estrogen deficiency, and treatment involves estrogen replacement. Typically, these patients are asymptomatic and the prolapsed urethral mucosa is commonly seen on physical examination especially in a postmenopausal woman. When symptomatic, the most common associated symptom is spotting. Although the association between prolapsed urethral mucosa and dyspareunia has not been rigorously studied, it is possible that this condition may be associated with coital discomfort.

It is becoming increasingly clear that a subset of patients with provoked vestibulodynia (PVD) actually suffer from a congenital defect. It has been shown that women with primary PVD (they have always had dyspareunia) have a markedly increased number of C-afferent nociceptive nerve fibers in the vulvar vestibule [8]. Subsequent studies have demonstrated that these women also have umbilical hypersensitivity [9]. As both the vulvar vestibule and the umbilicus are of the same embryologic origin (the urogenital sinus), this association implies that this subset of PVD patients actually have a congenital disorder. It is the author’s opinion that women who suffer from primary congenital PVD are best managed with a vestibulectomy.

The Vagina

Imperforate hymen is the most common obstructive lesion of the female reproductive tract, but it is still a rare anomaly with an incidence of less than 1% [10, 11].This anomaly is typically diagnosed at birth or in infancy with a bulging introitus due to mucocolpos from vaginal secretions. Sometimes the individual is not symptomatic until menarche, at which time she usually presents with a bulging hymen and hematocolpos.