What is a hydrosalpinx?
The fallopian tube extends from the upper corner of the uterus and is the conduit which allows the sperm and egg to meet, fertilization to occur, the first 5 to 7 days of embryonic development, followed by, propagating the embryo back into the uterus for implantation.
Hydrosalpinx, derived from Greek, literally means “water tube”. Within the fallopian tube, the presence of fluid is considered normal and a part of healthy function. If fluid is not allowed to freely move throughout the tube, then it collects and causes distention and damage to the fallopian tube. The presence of hydrosalpinges (both fallopian tubes filled with fluid) is the most commonly identified fallopian tube abnormality which causes infertility.
What causes a hydrosalpinx?
A hydrosalpinx is almost always a result of a past pelvic infection, but can also be caused by inflammation. The most common bacteria at fault are gonorrhea, chlamydia, staphylococcus, streptococcus and pelvic tuberculosis. Bacteria infect the upper reproductive tract causing destruction of the tubal wall, adhesions and abscesses. The end result after the infection has cleared is a dilated fallopian tube often shrouded with surrounding adhesions in the pelvis. The lateral end, or fimbria of the tube is usually agglutinated together essentially blocking the opening between the ovary and the tubal conduit which leads to the uterus. Because of the distal obstruction and poor tubal wall motion, it is thought that the uterotubal derived fluid, which normally drains out the end, becomes trapped and distends the tube.
How is one diagnosed?
The upper reproductive tract is best assessed by either radiographic imaging or surgery. The usual first line approach to assess the fallopian tubes is with a hysterosalpingogram (HSG). HSG is a procedure that uses x-ray to assess the uterus and fallopian tubes. X-ray contrast is instilled through the cervix with a small catheter into the uterus which then outlines the contour of the inner cavity and flows down and out of the fallopian tubes. This establishes the length, caliber and patency of the fallopian tubes. It also identifies the presence of a hydrosalpinx.
The test often causes cramps when the uterus contracts due the presence of the catheter or pressure caused by the contrast. A hydrosalpinx is evident when the tube appears dilated and will not allow the dye to spill out into the peritoneal cavity.
Occasionally, an HSG may incorrectly determine the presence or absence of a hydrosalpinx. For example, if the tube is blocked at the junction of the uterus and tube, then the contrast will not enter the hydrosalpinx and it will not be seen.
If a hydrosalpinx is identified or if the study is inconclusive, then laparoscopic surgery is typically the next step. Laparoscopy allows direct visualization of the fallopian tubes and pelvic anatomy. It also allows surgical removal of the affected tube(s).
What impact does it have on fertility?
Hydrosalpinges are blocked or severely compromised tubes which greatly impair fertility. The sperm cannot reach the egg for fertilization, the egg cannot be picked up by the tube and an embryo cannot travel back to the uterus for implantation. The only way for couples to get pregnant is to repair the tube or bypass it.
How is it treated?
Historically, Hydrosalpinges were repaired surgically. While surgical repairs can offer some hope, most patients continue to have very disappointing results. Following surgical repair, the obstruction can return and re-create the hydrosalpinx. Additionally, the presence of a hydrosalpinx is the result of tubal damage that is not repaired by reestablishing patency. Although the tube can be opened, it is still damaged and does not function with nearly the same efficiency as normal fallopian tubes. A damaged tube is unable to pick-up the egg or move the embryo into the uterus. If fertilization does occur, the patient has a high risk of ectopic or tubal pregnancy.
If a hydrosalpinx is the obstacle to conception, then the most efficient and cost-effective way to conceive is to bypass the obstruction through in vitro fertilization (IVF). IVF consists of removing eggs from the ovary and fertilizing them outside the body with the partners sperm. After approximately 5 days, the embryo is gently transferred into the uterus. IVF effectively allows sperm and egg to fertilize, replacing the functions of the fallopian tube. It is the most effective way for a patient with a hydrosalpinx to achieve pregnancy.
Hydrosalpinges and IVF
IVF allows sperm and egg to reach each other and fertilization to be achieved outside the fallopian tubes. However, if a hydrosalpinx is present, the IVF implantation rates are markedly reduced (about 30%), and the miscarriage rates are increased. These effects substantially reduced the pregnancy and take-home baby rates and diminish the effectiveness of IVF.
Several studies have found that the fluid retained in the tube is embryotoxic and may impair the endometrium’s receptivity to allow the embryo to implant. Some suspect that the enlarged tube may compromise the blood flow to the ovary causing a poorer response to gonadotropins.
Currently, the standard of care is to recommend that hydrosalpinges be removed prior to IVF to improve implantation and pregnancy rates. As discussed above, hydrosalpinges are typically removed by laparoscopic surgery. Once, the fallopian tubes are removed, the only route a patient couple can use to achieve pregnancy is through IVF. However, pregnancy rates achieved with IVF following the removal hydrosalpinges are typically very high.