A hydrosalpinx is a blocked, dilated, fluid-filled fallopian tube usually caused by a previous tubal infection, for example sexually transmitted diseases such as chlamydia trachomatis and gonorrhea. The build-up of fluid is usually at the end of the tube nearest the ovary. Diagnosis of hydrosalpinx is usually made by a hysterosalpingogram (HSG), an x-ray procedure in which contrast dye is injected through the cervix into the uterine cavity to demonstrate the shape of the uterus and the patency (degree of openness) of the fallopian tubes. If the tubes are open, the liquid will spill out the ends of the tubes (Figure A). If the tubes are blocked, the liquid is trapped. Hydrosalpinx may also be diagnosed by laparoscopy, which is the insertion of a thin, telescope-like instrument called a laparoscope into the abdomen through an incision to visually inspect the tubes. They may also be visualized by ultrasound. Many patients with a hydrosalpinx have chronic or recurrent pelvic pain, while others are asymptomatic. Patients with a hydrosalpinx may experience repeated acute tubal infections, which cause fever and pain. If the fallopian tubes are completely blocked, pregnancy will not occur without the use of Assisted Reproductive Techniques. In milder cases, fertility may be restored by opening the tubes surgically. However, if the lining of the tubes is badly damaged, in vitro fertilization (IVF), which bypasses the tubes, is the treatment of choice. IVF is a form of assisted reproduction that involves stimulating the ovaries with hormones and surgically retrieving the eggs. The eggs are then combined with sperm in a laboratory dish. If the eggs fertilize and continue to divide, the resulting embryos are then transferred to the uterus where they hopefully implant in the endometrium (uterine lining) and develop into a viable pregnancy. Although IVF is considered to be the best fertility treatment for hydrosalpinx, the presence of a hydrosalpinx appears to reduce the success rates of IVF. Fluid within the hydrosalpinx appears to reduce embryo implantation rates and increase the risk of miscarriage. For these reasons, some physicians advise removing the tube (salpingectomy) or separating it from the uterus prior to undergoing IVF. article re-cited from: fertilityjourney.com