Normal Ovulation, Fertilization and Early Development

A normal uterus has a rounded top and a triangular shaped cavity with a single cervix.

The wall of the uterus is comprised of smooth muscle.

The central lining, or cavity, of the uterus is lined by a layer of cells called the endometrium. 

The fallopian tubes rises from each side of the uterus near the top.  

Arcuate uterus can be considered a very mild form of septate uterus.  However, the midline 'septum' is shorter, and wider, making a U shape.  In comparison, a true septate uterus shows a septum longer than it is wide, and with a V shape.   Patients with arcuate uterus are sometimes, and erroneously, told they have a bicornuate uterus.   Arcuate uterus  has not been found to be associated with infertility or miscarriages, but there may be an increased chance of endometriosis. 

 This malformation occurs when the uterine cavity is divided by a septum protruding from the fundus, but keeps the normal outer shape intact. The debate often arises on where to separate the distinction between arcuate and septate uterus. A septate uterus is a common anomaly in women with a history of miscarriages and infertility.  The septum is quite variable in length, but should be at least 1.5 cm.  In some cases, the septum completely divides the uterine cavity and cervix into two halves.  Resection of the septum can improve fertility and reduce the risk of preterm delivery for some patients.  

 Bicornuate uterus appears similar to septated uterus, but the outer fundus no longer has the normal rounded shape.  Instead, the outer shape shows a mid indentation at least 1cm and a wide intercornual (tube) distance that can be appreciated via hysteroscopy, as well as laparoscopy. A bicornuate uterus cannot be treated with simple resection and therefore surgery is not necessarily indicated.  However, there is an increased risk of recurrent pregnancy loss, cervical incompetence, and preterm delivery.  Many patients are told they have a bicornuate uterus when, in fact, they may have an arcuate uterus or septated uterus.  

Uterus didelphys occurs when there is complete lack of fusion, resulting in two uteruses, two cervixes, and in some cases, two vaginas.   It requires special considerations when choosing birth control getting pregnant, and carrying a pregnancy to term Patietnts with uterine didelphys also have an increased chance of renal abnormalities, including an absent kidney.  

 Most women with uterus didelphys experience no symptoms, although some may experience dyspareunia as a result of a vaginal septum. Others have problems with vaginal bleeding.  There is also an association with endometriosis. 

 This form of uterine anomaly occurs when the uterus is predominantly formed by just one of the two paired Müllerian ducts. This abnormality has been shown to have significantly greater chance of infertility,  miscarriage, and preterm delivery.  On coronal 3D images, the uterine cavity no longer shows a normal triangular shape, but rather assume a banana shape.  However, unicornuate uterus is typically missed with standard 2D ultrasound.   In part for this reason, all fertility patients should have 3D coronal images of the uterus.   

 Normal pregnancy depends on a patent (open) fallopian tube for both transport of sperm up the fallopian tube near the ovary, and transport of the fertilized blastocyst down the tube toward the uterus.  

A blocked fallopian tube can fill with fluid (hydrosalpinx), and then is predisposed to developing infection. 

Blockage may be caused by endometriosis, prior infection, scarring, or unknown causes

Hydrosalpinx may be confused for ovarian cysts or other conditions

Endometriosis may produce scarring and blockage of the fallopian tubes

The fallopian tube may become inflamed or infected, interfering with function. 

Scarring with adhesions may block the fallopian tube.  Adhesions may result from prior surgery, infection, or endometriosis.