The number of women having difficulty getting pregnant or maintaining a pregnancy is increasing exponentially every year. There can be many reasons for this and they are not always easy to identify. Apart from hormonal or psychological problems, the issue of congenital anatomical abnormalities of the uterus is very important. What is their impact on a woman's fertility and do they really prevent her from having children?
Uterine malformations - causes and breakdown
A normal uterus resembles a pear in shape. It is made up of three parts: the body, the isthmus and the cervix. The body has two horns, each connected to its corresponding fallopian tube, while the cervix is stabilised by the vaginal vault.
Anatomical defects of the uterus occur in approximately 3% of the female population in Poland. They result from abnormalities in the development of the reproductive tract while still at the stage of foetal organogenesis. This is when the paired ducts of Muller*, come together to form the fallopian tubes, the uterus and the upper part of the vagina. If this process is disturbed, a number of defects can develop that affect the woman's life to a greater or lesser extent.
In general, there are seven basic defects of the uterus:
- unicornuate uterus - in this case, only one uterine horn and one fallopian tube connected to it have developed,
- unicornuate uteruswith a vestigial horn - in addition to the unicornuate uterus, a second, abnormally constructed uterine horn with a dysfunctional fallopian tube has developed,
- unicorn uterus with a vestigial hornwith a non-communicating cavity - a vestigially developed second uterine horn has anon-communicating cavity,
- unicornuate uterus with vestigial hornwith communicating cavity - the vestigially developed second horn of the uterus has a cavity connected to the uterus,
- double uterus - the rarest of the congenital malformations of the uterus. Two uteruses with two cervixes (sometimes even two vaginas or a divided vagina!) have developed,
- bicornuate uterus - similar in structure to a double uterus except that there is one cervix behind which two almost complete uterine bodies have developed,
- septate uterus - a defect involving a single uterus whose cavity is divided by an incomplete septum.
photo: panthermedia
Uterine malformations - impact on fertility
The genesis of the development of each of the above-mentioned defects is different, but their impact on a woman's fertility is very similar. Although not all randomised scientific studies** confirm this, it is recognised that congenital malformations of the uterus do not affect the ability to become pregnant. This is because the fertilisation of the ovum itself still takes place in the fallopian tube, and if its structure is normal, this process is smooth. Reproductive failure, however, can already occur at the stage when the embryo is implanted in the endometrium***. Even more problematic is often the woman's inability to maintain the pregnancy.
To better illustrate the problems associated with uterine defects, let us use the example of a patient of childbearing age with a double uterus. In practice, this defect means that the Muller's ducts have not fused and a separate uterus has developed from each of them - usually smaller and less vascularised. A fetus in such an abnormally constructed uterus has limited space for growth, which can eventually lead to its death. Other important factors that worsen the chances of carrying a pregnancy, in this case, may be abnormalities in the blood supply and vascular structure of the uterus, increased excitability and contractility of the uterine muscle or cervicovaginal insufficiency. In cases where the foetus does not abort, there may in turn be the development of congenital abnormalities in the baby, a reduction in the baby's weight or an increased risk of the need for a caesarean section due to an abnormal position of the baby in the uterus.
