Uterine malformations are the result of an abnormal development of the Müllerian ducts during a woman’s prenatal development, which may affect her fertility.
Approximately 1 percent of women have uterine malformations. However, only 25 percent of these patients present reproductive problems. Meanwhile, between 25 and 30 percent of recurrent pregnancy loss cases are related to the existence of uterine malformations.
According to classification by the American Society for Reproductive Medicine (ASRM) some of the most common uterine malformations are:
- Müllerian agenesis or uterine absence. This condition is uncommon and is characterized by a Müllerian ducts absence, which form the uterus during prenatal development. Müllerian agenesis is the most severe uterine malformation and is often accompanied by cervical and vaginal developmental problems.
- Unicornuate uterus. In this condition, only one of the Müllerian ducts develops, causing the uterus to be half its normal size and the woman having only one fallopian tube.
- Uterus didelphis. Both Müllerian ducts develop but fail to merge. Thus, the patient has two uterine cavities, each with its own its own cervix and vagina. The woman may have two or more simultaneous pregnancies in both uteri, which have no communication with each other.
- Bicornuate uterus. Due to an incomplete fusion of the Müllerian ducts, the uterus has a depression at the top. Therefore, instead of the usual pear-shape, the uterus has the shape of a heart.
- Uterine septum. This is the most common uterine malformation, with a higher than 50 percent prevalence. In this disorder, the uterus is divided by a wall or septum that begins at the top of the uterine cavity and may extend to the cervix.
- Arcuate uterus. A variant of the uterine septum, in which the septum is much less pronounced. In general, women with arcuate uterus have no fertility problems.
- T-shaped uterus. This malformation is less frequent and occurs in daughters of women who took diethylstilbestrol during pregnancy. This synthetic estrogen was withdrawn from the market in 1975. However, it was widely used for about a decade to help reduce the risk of abortion in the first trimester of pregnancy.
Main uterine malformations symptoms
The most frequent symptoms of uterine malformations are:
- Chronic pelvic pain
- Painful intercourse
- Dysmenorrhea or painful menstrual periods
- Amenorrhea or menstrual period absence
- Menorrhagia or excessively abundant menstrual periods
- Abdominal inflammation, especially during menstrual periods
- Recurrent pregnancy loss
- Premature birth
- Labor complications
- Low newborn weight
Uterine malformation causes
Up to the sixth week of gestational development there are no anatomical differences between the male and female embryonic reproductive systems. It is until the start of this week that the differentiation process begins.
Müllerian ducts are responsible for the formation of the female reproductive system. They fuse laterally and the wall that divides them dissolves to form the fallopian tubes, uterus, cervix and vagina.
Alterations that happen during the process of development and fusion of the Müllerian ducts originate uterine or Müllerian malformations.
Most of these malformations are congenital and in some cases, hereditary. However, they can also be acquired as a result of fetal exposure to radiation, infection or medications such as diethylstilbestrol and thalidomide.
How are uterine malformations diagnosed?
The most reliable study for uterine malformation diagnosis is a gynecological transvaginal ultrasound, in which the specialist carefully introduces an ultrasound probe into the patient’s vagina to examine her reproductive organs (uterus and ovaries). The transvaginal ultrasound is a simple, non-invasive, painless study that generally facilitates a clear diagnosis and identification of the type of uterine malformation present.
It is important to point out that each of the uterine malformation types requires a different therapeutic approach. Therefore, this ultrasound should be performed by an experienced specialist, who will get the most information from this study.
In some cases additional tests may be required, such as a hysterosalpingography, an X-ray of the uterus and Fallopian tubes by means of which the physician can determine if there is a malformation or other issue hindering conception. As it requires the injection of a contrast medium through the cervix, this test may cause slight discomfort, but nothing you should worry about.
Patients with severe uterine malformations may also have renal abnormalities; therefore, in these cases, it is advisable to also evaluate the patient’s kidneys by means of an excretory urography or magnetic resonance (MRI).
Treatments to achieve pregnancy in patients suffering from uterine malformations
Each of the uterine malformations requires a specific treatment. While in some cases such as uterus didelphis they do not normally hinder fertility or a normal pregnancy development, in other in others it may be necessary to carry out assisted reproduction treatments.
In-Vitro Fertilization (IVF) is a particularly effective treatment to achieve pregnancy. While uterine malformations usually alter sperm transport and embryo implantation, IVF allows our specialists to obtain the eggs directly from the patient’s ovaries. These eggs are fertilized under controlled laboratory conditions to generate embryos with a higher implantation potential which are then transferred back into the patient’s uterus.
By placing the embryos directly into the woman’s uterus, In-Vitro Fertilization (IVF) considerably reduces the risk of these implanting outside the uterine cavity, which could cause a rupture of the woman’s uterus, putting her life at risk.
In places where this alternative treatment is permitted, even women with Müllerian agenesis (uterine absence) may have an opportunity to be mothers through In-Vitro Fertilization, by transferring their embryos into the uterus of a surrogate mother.
Before In-Vitro Fertilization (IVF) can be performed, though, a simple test must be conducted during which the physician inserts a thin plastic tube (cannula) through the cervix to simulate an embryo transfer. This painless procedure lasts only a few minutes, and its purpose is to determine if the cervix has any obstruction that could impede embryo transfer and that must be corrected before commencing an IVF treatment. In addition, it allows measuring the uterine cavity to know if there is enough space for the pregnancy to develop normally, and in the cases where there are two cavities, to identify the larger one to transfer the IVF embryos in the future.
Whereas with the other uterine malformations a good assessment is enough, a uterine septum requires corrective surgery known as corrective hysteroscopy which allows the specialist to dry or cut the septum dividing the uterine cavity. Hysteroscopy is a non-invasive ambulatory procedure that consists of introducing a small optical system equipped with surgical instruments through the cervix.
If you have any uterine malformation, your future pregnancies must be carefully planned and closely monitored by a maternal-fetal medicine specialist, who will evaluate your particular condition and will let you know if it is necessary to perform a cesarean section to avoid labor complications.