Fertility Chronicles is proud to present a special blog series, “From the Fertility Experts,” where leading fertility experts answer commonly asked questions for patients about their fertility health and treatment options.We hope this series can help patients navigate their personal fertility journeys.—Catherine T. Yang, Editor, Fertility Chronicles
Dr. Antonio R. Gargiulo, our guest blogger, shares his advice on the impact of uterine fibroids on fertility:
Uterine fibroids are benign, smooth muscle cell tumors that affect 25% to 45% of reproductive-age women and are particularly prevalent among African-American women. If you have them, you want to know if they can affect your ability to get pregnant. The medical name for fibroids is “leiomyomas.” These tumors quickly undergo degeneration that can fall into any one of four categories: Fibroid, calcific, hemorrhagic, adipous, or (exceedingly rarely) neoplastic. By far, the most frequent type is fibroid; hence, the common name “fibroids”.
Each woman’s situation is different, and having uterine fibroids doesn’t necessarily mean that you’ll have trouble conceiving. There is no consensus on how fibroids may interfere with conception, but recent studies have begun to shed light on this controversial topic.
One should start by saying that not all fibroids are biologically identical: Depending on their genetic make-up and their degree of natural degeneration, fibroids may secrete different local hormone-like substances that interfere with the ability of the uterine muscle to contract, as well as with critical messages traveling between the uterine lining and the embryo. If such molecular communications are altered, the embryo may not implant successfully or stop developing, leading to miscarriage. That is why some women with fibroids do not have difficulty conceiving but experience recurrent pregnancy loss.
Even if we know that different fibroids may have different potential to do damage, we have no way to clinically assess that. Therefore, we currently work on the assumption that all fibroids have the potential to disrupt the reproductive process, and we counsel patients based on the size and location of fibroids instead, as assessed by radiologic imaging.
If a fibroid is almost completely on the outside of the uterus (called a subserosal fibroid, as “serosa” is the name for the outer layer of the uterus), experts believe that it has little chance to impact embryo growth. Clearly, size is an important variable in such cases, as very large subserosal fibroids may bring about a degree of pelvic anatomy distortion that can have later obstetrical and medical ramifications.
When fibroids are located mostly within the uterine wall (called intramural fibroid, from Latin “intra murum,” inside the wall), it’s another story. A fibroid there may distort the shape of the uterine cavity itself and leave less room for an implanting embryo to develop. The fibroid’s demand for blood supply may also interfere with blood supply to the embryo. Finally, as discussed above, the fibroid may cause irritability of the uterine muscle.
The same may hold true if the fibroid is located under the endometrium, or lining of the uterus, in which case it is called a submucosal fibroid (from “mucosa,” the term referring to the innermost layer of the uterus, a.k.a. the endometrium). In addition to crowding the small endometrial space, the fibroid can chemically interfere with implantation and embryo growth, as discussed above.
If a fibroid (either intramural or subserosal) is located near the place where the fallopian tubes open into the womb, it may also interfere with the passage of sperm into the tube or a fertilized egg or embryo from reaching the womb.
With so much uncertainty, uterine fibroids can be a red herring if you’re having trouble getting pregnant. They can be blamed for infertility when there may be another cause. On the other hand, reproductive surgeons often resolve difficult infertility or recurrent pregnancy loss cases with a focused surgical intervention to remove clinically significant fibroids.
In his next blog, Dr. Gargiulo will explain surgical options for uterine fibroid removal..
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