Fibroids and Pregnancy
Uterine fibroids are benign tumors that grow in the muscular walls of the uterus. The fact that approximately 20% to 50% of women suffer from the symptoms generated by fibroid tumors at some stage of their lives suggests that they are quite common growths in the reproductive system of a woman.
Fibroids are more common in women who are 35 years of age or older. Women are under the age of 20 rarely have fibroids. These tumors of the uterus tend to shrink after menopause. Studies indicate that black women are nine times more susceptible to fibroids than white women. Furthermore, women who are overweight are more likely to have fibroids because of higher levels of oestrogen.
As fibroids usually develop in women of childbearing age, the most obvious question that confronts any woman is, "What are the impacts of fibroids on pregnancy?" Apart from generating symptoms, such as heavy vaginal bleeding, severe pelvic and back pain, constipation, and bloating, fibroids are known to cause infertility and complications during pregnancy.
How can Uterine Fibroids Cause Infertility?
Generally, uterine fibroids do not have any adverse effect on the fertility of a woman. However, 3% of women find conceiving troublesome due to the presence of large, multiple or pedunculated fibroids. Women with large subserosal fibroids, which develop on the outer covering of the uterus, may developed compressed fallopian tubes. This can cause a blockade to form in the fallopian tube, thereby blocking the passage of sperm and eggs. Subserosal fibroids can also distort the pelvic anatomy to such an extent that it becomes difficult for the fallopian tube to capture an egg at the time of ovulation.
Sperm may also be prevented from reaching its intended destination when intramural fibroids are located in the cervical region, which can prevent the entry of the sperm into the uterus. Submucosal fibroids, which develop just beneath the inner lining of the uterus, may block the fallopian tube. As a result, sperm is not able to enter the fallopian tube in order to fertilize an egg.
Both intramural and submucosal fibroids may increase the size of the uterus cavity, forcing sperm to travel a greater distance. Additionally, both types of fibroid tumors can interfere with the uterus’ ability to contract. As a result, sperm and egg transport may be hindered.
The uterine cavity can also be distorted by multiple and large submucosal as well as intramural fibroid tumors. These fibroids can all impair the blood supply to the endometrium and disturb the structure of the endometrium, thereby altering the uterus’ anatomy and reducing the chances of implantation.
What are the Effects of Uterine Fibroids on Pregnancy?
Fibroids are known to cause some complications during pregnancy, including:
- Some intramural and submucosal fibroids change the shape of the uterine cavity and act like an IUD causing miscarriages to occur
- Depending on the location and size of the uterine fibroids, pregnant women with fibroids may be at a greater risk of experiencing premature labour
- Due to the increase in oestrogen levels during pregnancy, uterine fibroids may enlarge and displace the placenta
- Large fibroids in the uterine cavity can create a shortage of space and impede the growth of the baby, which may either lead to miscarriage or cause congenital deformities in the baby
- Multiple fibroids located in the lower part of the uterus can block the vagina during pregnancy, making it necessary to have a cesarean birth
Does Pregnancy have any Effect on Fibroids?
Between the 12th and 22nd week of pregnancy a complication called ‘Red Degeneration’ can occur. During this process, the blood supply of the fibroids is cut off, which causes them to turn red and die. Red degeneration can cause intense abdominal pains and contractions of the uterus, which could lead to early labour or miscarriage. This process can also occur outside of pregnancy.
Uterine fibroids are never removed during pregnancy due to the increased risk of haemorrhage.