Things That May Cause Recurrent Pregnancy Loss

Given that unintended pregnancy is quite common, mothers should understand all the underlying predisposing factors. Moreover, those who have more than two consecutive unplanned abortions should benefit from a complete evaluation to determine possible risks and to find out what treatments are necessary to prevent recurrent loss. In general, recurrent pregnancy loss can be caused by these factors:


Hormonal disorder

Anatomic problems


Autoimmune disorders

Thrombophilic problems

It is natural for women who suffer from recurrent pregnancy loss to feel determined on finding an answer. There are steps that can be taken to deal with this problem, they are standard IVF, IVF with preimplantation genetic diagnosis (PGD), UIU and fertility medications, empiric baby aspirin and empiric progesterone. However, older women and patients with diminished ovarian reserve may require donor-egg IVF.

Genetical factor

Genetical factors are the most common cause of pregnancy loss. Most mothers who lose their babies on first-trimester have genetic problem. Autosomal trisomies are the most common abnormality. In these cases, there is one extra chromosome present during the pregnancy development, causing failure more likely. However, not all trisomies cause pregnancy loss. For example, Down syndrome is an example of autosomal trisomies, which is well known in our society. Most pregnancies with trisomies involve spontaneous miscarriage. Parents who have more than three consecutive losses are advised to undergo blood examination, which involve kryotype analysis to check for genetic abnormalities. Certain chromosal rearrangements may lead to higher rate of fetal abnormalities or pregnancy loss. Balanced translocation is the most common chromosomal rearrangement which is caused by the separation of two different chromosomes. This disorder can happen both in the sperm or the egg, subsequently causing miscarriage. Although those with balanced translocations may still deliver a perfectly healthy baby, fertility treatments are usually needed to reduce the possibility of miscarriage.

Hormonal disorder

There are several hormonal disorders suspected to cause pregnancy loss, including luteal-phase defects, polycystic ovarian syndrome (PCOS), diabetes and untreated thyroid disease. Women who produce low amount of progesterone on the luteal phase have a higher risk of miscarriage. Unfortunately, examinations for luteal-phase defects are often controversial and somewhat problematic. Often doctors routinely supplement patients with progesterone suppositories during the first trimester to obviate the need for endometrial biopsy and other diagnostic tests. Patients who have PCOS are more likely to suffer miscarriage during the first trimester. It is estimated that they have a 25% chance of experiencing miscarriage. Researchers are still uncovering how PCOS can raise the risk of pregnancy loss, but preliminary results suggest that the prescription of Glucophane (metformin) can improve the possibility for a successful pregnancy. Although diabetes can cause pregnancy loss, this condition can be detected far before the pregnancy and women can take necessary steps to improve their chances. Thyroid disease can be detected through checking for thyroid hormone and thyroid-stimulating hormone (TSH) levels. This disorder can be treated easily.

Anatomic problems

Two common anatomical problems that can cause pregnancy loss are:

• Unicornuate uterus. It is a small malformed uterus and usually connected to only one fallopian tube.

• Uterine spetum. It happens when the uterine cavity is divided by a fibrous band into a few smaller cavities.

Prenatal exposure to DES (diethylstilbestrol) can cause uterine malformations, which improve the possibility of poor pregnancy. The presence of fibrous material inside the uterus and around the endometrial cavity has been believed as a risk factor for pregnancy loss. The same also applies to uterine polyps. Major intrauterine adhesions after a D&C (dilatation and curettage) can also lower the chance for a successful reproduction process. Most anatomical abnormalities can be treated with surgical correction, however if you decide to pursue the surgery route, you should discuss with your doctor.


Both viral and bacterial infections have been proposed as the cause for recurrent pregnancy loss, especially, when bacteria such as mycoplasma and ureaplasma are detected inside the uterus and cervix. Although there are no valid evidences to prove the connection, doctors routinely culture their patients for mycoplasma and ureaplasma. Women who eat unpasteurized dairy products and get infected by Listeria, also have higher risk of miscarriage. A virus, the parvovirus B19, while only causing mild illness on children, can cause miscarriage on pregnant women, even on the third trimester. Once infected, people become immune to this virus and it won’t cause recurrent pregnancy loss. Unfortunately, no vaccine exists for this virus.

Autoimmune disorder

There are already some researches on the effects of autoimmune disorder on pregnancy, for example on patients with a history of lupus or rheumatic. Lupus is clearly a risk factor for recurrent pregnancy loss, and among lupus sufferers, women with anticardiolipin antibodies have the worst risk. Women with lupus are often treated with injectable blood thinners, such as Lovenox or heparin, low dose of aspirin (80 mg/day) or both. It is currently still unwarranted for women with recurrent pregnancy loss to be tested for antiphospholipid antibodies.

Thrombophilic problems

Recently, there have been some interests on testing women with recurrent pregnancy loss for the possibility of thrombophilia. Thrombosis means “blood clot” and thrombophilia means “thrombosis loving”. A healthy human has good balance between blood clotting and bleeding. People with hemophilia can suffer complications due to excessive bleeding, while people with high rate of clotting may suffer problems like deep vein thrombosis and pulmonary embolus, and certain pregnancy problems like intrauterine growth retardation and intrauterine fetal demise. Tests for thrombophilia may include assessment of methyltetrahydrofolate reductase enzyme, antithrombin III, proteins C and S, and Factor V Leiden. Except for MTHFR, these are genetic deficiencies that cause a person to have tendencies toward excessive blood clotting. These conditions are often treatable with Lovenox and low dose of aspirin. Women with MTHFR enzyme disorder have an even higher chance for pregnancy loss if they have an abnormal homocystine level, a by-product of folic acid metabolism. People who have MTFHR enzyme mutation can be treated effectively with vitamin supplementation consisting of vitamin B12, vitamin B6 and folic acid. Folgard is a specially formulated vitamin supplement for women with this condition.

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