AS has a reported incidence of 25% of D&Cs performed 1–4 weeks post-partum, up to 30.9% of D&Cs performed for missed miscarriages and 6.4% of D&Cs performed for incomplete miscarriages. In another study, 40% of patients who underwent repeated D&C for retained products of conception after missed miscarriage or retained placenta developed AS.

In the case of missed miscarriages, the time period between fetal demise and curettage may increase the likelihood of adhesion formation due to fibroblastic activity of the remaining tissue.

The risk of AS also increases with the number of procedures: one study estimated the risk to be 16% after one D&C and 32% after 3 or more D&Cs. However, a single curettage often underlies the condition.

In an attempts to estimate the prevalence of AS in the general population, it was found in 1.5% of women undergoing hysterosalpingography HSG, and between 5 and 39% of women with recurrent miscarriage.

After miscarriage, a review estimated the prevalence of AS to be approximately 20% (95% confidence interval: 13% to 28%).

The major cause for distal tubal occlusion is pelvic inflammatory disease (PID), usually as a consequence of an ascending infection by chlamydia or gonorrhea. However, not all pelvic infections will cause distal tubal occlusion. Tubal tuberculosis is an uncommon cause of hydrosalpinx formation.

While the ciliae of the inner lining (endosalpinx) of the fallopian tube beat towards the uterus, tubal fluid is normally discharged via the fimbriated end into the peritoneal cavity from where it is cleared. If the fimbriated end of the tube becomes agglutinated, the resulting obstruction does not allow the tubal fluid to pass; it accumulates and reverts its flow downstream, into the uterus, or production is curtailed by damage to the endosalpinx. This tube then is unable to participate in the reproductive process: sperm cannot pass, the egg is not picked up, and fertilization does not take place.

Other causes of distal tubal occlusion include adhesion formation from surgery, endometriosis, and cancer of the tube, ovary or other surrounding organs.

A hematosalpinx is most commonly associated with an ectopic pregnancy. A pyosalpinx is typically seen in a more acute stage of PID and may be part of a tuboovarian abscess (TOA).

Tubal phimosis refers to a situation where the tubal end is partially occluded, in this case fertility is impeded, and the risk of an ectopic pregnancy is increased.

Over one million cases of acute salpingitis are reported every year in the US, but the number of incidents is probably larger, due to incomplete and untimely reporting methods and that many cases are reported first when the illness has gone so far that it has developed chronic complications. For women age 16–25, salpingitis is the most common serious infection. It affects approximately 11% of females of reproductive age.

Salpingitis has a higher incidence among members of lower socioeconomic classes. However, this is thought of being an effect of earlier sex debut, multiple partners, and decreased ability to receive proper health care rather than any independent risk factor for salpingitis.

As an effect of an increased risk due to multiple partners, the prevalence of salpingitis is highest for people age 15–24 years. Decreased awareness of symptoms and less will to use contraceptives are also common in this group, raising the occurrence of salpingitis.

The extent of adhesion formation is critical. Mild to moderate adhesions can usually be treated with success. Extensive obliteration of the uterine cavity or fallopian tube openings (ostia) and deep endometrial or myometrial trauma may require several surgical interventions and/or hormone therapy or even be uncorrectable. If the uterine cavity is adhesion free but the ostia remain obliterated, IVF remains an option. If the uterus has been irreparably damaged, surrogacy or adoption may be the only options.

Depending on the degree of severity, AS may result in infertility, repeated miscarriages, pain from trapped blood, and future obstetric complications If left untreated, the obstruction of menstrual flow resulting from adhesions can lead to endometriosis in some cases.

Patients who carry a pregnancy even after treatment of IUA may have an increased risk of having abnormal placentation including placenta accreta where the placenta invades the uterus more deeply, leading to complications in placental separation after delivery. Premature delivery, second-trimester pregnancy loss, and uterine rupture are other reported complications. They may also develop incompetent cervix where the cervix can no longer support the growing weight of the fetus, the pressure causes the placenta to rupture and the mother goes into premature labour. Cerclage is a surgical stitch which helps support the cervix if needed.

Pregnancy and live birth rate has been reported to be related to the initial severity of the adhesions with 93, 78, and 57% pregnancies achieved after treatment of mild, moderate and severe adhesions, respectively and resulting in 81, 66, and 32% live birth rates, respectively. The overall pregnancy rate after adhesiolysis was 60% and the live birth rate was 38.9% according to one study.

Age is another factor contributing to fertility outcomes after treatment of AS. For women under 35 years of age treated for severe adhesions, pregnancy rates were 66.6% compared to 23.5% in women older than 35.

For the affected, 20% need hospitalization.

Regarding patients age 15–44 years, 0.29 per 100,000 dies from salpingitis.

However, salpingitis can also lead to infertility because the eggs released in ovulation can't get contact with the sperm. Approximately 75,000-225,000 cases of infertility in the US are caused by salpingitis. The more times one has the infection, the greater the risk of infertility. With one episode of salpingitis, the risk of infertility is 8-17%. With 3 episodes of salpingitis, the risk is 40-60%, although the exact risk depends on the severity of each episode.

In addition, damaged oviducts increase the risk of ectopic pregnancy. Thus, if one has had salpingitis, the risk of a pregnancy to become ectopic is 7 to 10-fold as large. Half of ectopic pregnancies are due to a salpingitis infection.

Other complications are:

- Infection of ovaries and uterus

- Infection of sex partners

- An abscess on the ovary

A number of causes may account for a hematosalpinx, by far the most common being a tubal pregnancy. Blood may also escape into the peritoneal cavity leading to a hemoperitoneum.

A hematosalpinx can also be associated with endometriosis or tubal carcinoma. Further, if menstrual blood flow is obstructed (cryptomenorrhea), caused for instance by a transverse vaginal septum, and gets backed up it may lead to a hematosalpinx.

Endometrial polyps usually occur in women in their 40s and 50s. Endometrial polyps occur in up to 10% of women. It is estimated that they are present in 25% of women with abnormal vaginal bleeding.

As pelvic inflammatory disease is the major cause of hydrosalpinx formation, steps to reduce sexually transmitted disease will reduce incidence of hydrosalpinx. Also, as hydrosalpinx is a sequel to a pelvic infection, adequate and early antibiotic treatment of a pelvic infection is called for.

Endometrial polyps are usually benign although some may be precancerous or cancerous. About 0.5% of endometrial polyps contain adenocarcinoma cells. Polyps can increase the risk of miscarriage in women undergoing IVF treatment. If they develop near the fallopian tubes, they may lead to difficulty in becoming pregnant. Although treatments such as hysteroscopy usually cure the polyp concerned, recurrence of endometrial polyps is frequent. Untreated, small polyps may regress on their own.

Ovarian pregnancies are rare: the vast majority of ectopic pregnancies occur in the fallopian tube; only about 0.15-3% of ectopics occur in the ovary. The incidence has been reported to be about 1:3,000 to 1:7,000 deliveries.

In the United States, uterus didelphys is reported to occur in 0.1–0.5% of women. It is difficult to know the exact occurrence of this anomaly, as it may go undetected in the absence of medical and reproductive complications.

Interstitial pregnancies account for 2–4% of all tubal pregnancies, or for 1 in 2,500 to 5,000 live births. About one in fifty women with an interstitial pregnancy dies. Patients with an interstitial pregnancies have a 7-times higher mortality than those with ectopics in general. With the growing use of assisted reproductive technologies, the incidence of interstitial pregnancy is rising.

Ovarian torsion accounts for about 3% of gynecologic emergencies. The incidence of ovarian torsion among women of all ages is 5.9 per 100,000 women, and the incidence among women of reproductive age (15–45 years) is 9.9 per 100,000 women. In 70% of cases, it is diagnosed in women between 20 and 39 years of age. The risk is greater during pregnancy and in menopause. Risk factors include increased length of the ovarian ligaments, pathologically enlarged ovaries (more than 6 cm), ovarian masses or cysts, and enlarged corpus luteum in pregnancy.

Most women of reproductive age develop small cysts each month, and large cysts that cause problems occur in about 8% of women before menopause. Ovarian cysts are present in about 16% of women after menopause and if present are more likely to be cancer.

Benign ovarian cysts are common in asymptomatic premenarchal girls and found in approximately 68% of ovaries of girls 2–12 years old and in 84% of ovaries of girls 0–2 years old. Most of them are smaller than 9 mm while about 10-20% are larger macrocysts. While the smaller cysts mostly disappear within 6 months the larger ones appear to be more persistent.

A hematosalpinx from a tubal pregnancy may be associated with pelvic pain and uterine bleeding. A gynecologic ultrasound will show the hematosalpinx. A hematosalpinx from other conditions may be painless but could lead to uterine bleeding.

Tubal cancer is thought to be a relatively rare primary cancer among women accounting for 1 to 2 percent of all gynecologic cancers, In the USA tubal cancer had an incidence of 0.41 per 100,000 women from 1998 to 2003. Demographic distribution is similar to ovarian cancer, and the highest incidence was found in white, non-Hispanic women and women aged 60–79. However, recent evidence suggests tubal cancer to be much more frequent .

Evidence is accumulating that individuals with mutations of BRCA1 and BRCA2 are at higher risks for the development of PFTC.

PTCs have been reported in all female age groups and seem to be most common in the third to fifth decades of life. A study in Italy estimated their incidence to be about 3%, while an autopsy study of postmenopausal women detected them in about 4% of cases.

These cysts constitute about 10% of adnexal masses.

A number of twin gestations have occurred where each uterus carried its pregnancy separately. A recent example occurred on February 26, 2009, when Sarah Reinfelder of Sault Ste. Marie, Michigan delivered two healthy, although seven weeks premature, infants by cesarean section at Marquette General Hospital. It is possible that the deliveries occur at different times, thus the delivery interval could be days or even weeks.

Most commonly a tube may be obstructed due to infection such as pelvic inflammatory disease (PID). The rate of tubal infertility has been reported to be 12% after one, 23% after two, and 53% after three episodes of PID. The Fallopian tubes may also be occluded or disabled by endometritis, infections after childbirth and intraabdominal infections including appendicitis and peritonitis. The formation of adhesions may not necessarily block a fallopian tube, but render it dysfunctional by distorting or separating it from the ovary. It has been reported that women with distal tubal occlusion have a higher rate of HIV infection.

Fallopian tubes may be blocked as a method of contraception. In these situations tubes tend to be healthy and typically patients requesting the procedure had children. Tubal ligation is considered a permanent procedure.

There are a number of risk factors for ectopic pregnancies. However, in as many as one third to one half no risk factors can be identified. Risk factors include: pelvic inflammatory disease, infertility, use of an intrauterine device (IUD), previous exposure to DES, tubal surgery, intrauterine surgery (e.g. D&C), smoking, previous ectopic pregnancy, endometriosis, and tubal ligation. A previous induced abortion does not appear to increase the risk.

Approximately 20% of female infertility can be attributed to tubal causes. Distal tubal occlusion (affecting the end towards the ovary) is typically associated with hydrosalpinx formation and often caused by "Chlamydia trachomatis". Pelvic adhesions may be associated with such an infection. In less severe forms, the fimbriae may be aggluntinated and damaged, but some patency may still be preserved. Midsegment tubal obstruction can be due to tubal ligation procedures as that part of the tube is a common target of sterilization interventions. Proximal tubal occlusion can occur after infection such as a septic abortion. Also, some tubal sterilization procedures such as the Essure procedure target the part of the tube that is near the uterus..

Women with the condition may be asymptomatic and unaware of having a uniconuate uterus; normal pregnancy may occur. In a review of the literature Reichman et al. analyzed the data on pregnancy outcome of 290 women with a unicornuate uterus. 175 women had conceived for a total of 468 pregnancies. They found that about 50% of patients delivered a live baby. The rates for ectopic pregnancy was 2.7%, for miscarriage 34%, and for preterm delivery 20%, while the intrauterine demise rate was 10%. Thus patients with a unicornuate uterus are at a higher risk for pregnancy loss and obstetrical complications.

In gynecology, endosalpingiosis is a condition in which fallopian tube-like epithelium is found outside the fallopian tube. It is unknown what causes this condition. It is generally accepted that the condition develops from transformation of coelomic tissue. It is often an incidental finding and is not usually associated with any pathology.

PTCs originate from the mesothelium and are presumed to be remnants of the Müllerian duct and Wolffian duct.

Although most cases of ovarian cysts involve monitoring, some cases require surgery. This may involve removing the cyst, or one or both ovaries. Technique is typically laparoscopic, unless the cyst is particularly large, or if pre-operative imaging suggests malignancy or complex anatomy. In certain situations, the cyst is entirely removed, while with cysts with low recurrence risk, younger patients, or which are in anatomically eloquent areas of the pelvis, they can be drained. Features that may indicate the need for surgery include:

- Persistent complex ovarian cysts

- Persistent cysts that are causing symptoms

- Complex ovarian cysts larger than 5 cm

- Simple ovarian cysts larger 10 cm or larger than 5 cm in postmenopausal patients

- Women who are menopausal or perimenopausal