Preventing Miscarriage

The hard truth is that there’s a 15-25% chance any given pregnancy, in the first trimester, will end in miscarriage. That’s a scary statistic. The most important thing to note is that you DO NOT have to wait to have a miscarriage to make sure you don’t have risk factors for miscarriage, and you DO NOT have to wait for multiple miscarriages before you get assessed for future losses.

The most common cause of miscarriage is fetal chromosome abnormality, which is about 60% of the time. Egg and sperm cells are very fragile, and sometimes don’t have the right number of chromosomes after fertilization to create a viable embryo. This doesn’t mean there aren’t things that can be done to prevent this from happening.

Factors to consider in miscarriage:

1. Did you have an early loss in the first trimester, or a late loss in the second or even third? Different diagnoses are more likely in late pregnancy versus early pregnancy.

2. Do you already have a child, and in trying to conceive again have a miscarriage? Having a baby already can rule out some causes of miscarriage.

3. Do you have a family history of autoimmune, hormonal, or blood disorders? That makes some of the diagnoses more likely.

Factors NOT to consider in miscarriage:

1. You haven’t “stressed” yourself to the point of miscarriage. I promise!

2. Exercise is always healthy! You don’t need to avoid physical activity

The following conditions are the most common causes of miscarriage that I see in practice:

1. Anti-phospholipid syndrome (and other causes of poor placental perfusion) This is a syndrome where antibodies attack components of your blood vessels. Anti-phospholipid antibodies include: lupus anticoagulant, anticardiolipin antibody, and anti-B2 glycoprotein. These antibodies interfere with uterine blood flow, more specifically the development of the trophoblast, which are the cells that form the placenta.


The foundation of PCOS is insulin resistance, which interferes with ovulation, follicle maturation, and maintaining a pregnancy. Insulin resistance, and the corresponding hormonal imbalances, cause poor egg quality, pelvic inflammation, and progesterone deficiency – all which contribute to miscarriage.

3. Chromosome translocation(it’s not all about the woman!) This genetic condition can occur in men or women. If you have a chromosome translocation you won’t have any signs or symptoms, but some of the gametes you produce (i.e. egg or sperm) will also have the translocation. Unfortunately, if you’re conceiving naturally it’s a game of chance as to whether or not you will produce a viable embryo. IVF with PGS (pre-implantation genetic screening) can determine whether your embryo has a viable number of chromosomes.

4. Hypothyroidism & thyroid antibodies

TSH greater than 4.0 and anti-thyroid antibodies during pregnancy are associated with miscarriage, preterm birth, premature rupture of membranes, and placental detachment.

5. Anatomical causes: fibroids, polyps, uterine malformations, cervix incompetence Anatomical issues are more commonly at play during second trimester losses, and the outcome depends greatly on the location of the finding.

6. Poor quality sperm(it’s not all about the woman!) The best test for measuring sperm quality is called sperm DNA fragmentation. Greater than 25% fragmented DNA indicates poor quality.

7. Poor quality egg

If only we had a test for egg quality like we do sperm quality! Age is the number one predictor for egg quality, steadily declining after age 35 – lucky us! But don’t worry, there is lots that can be done!

8. Vitamin D deficiency

One prospective cohort study identified vitamin D deficiency as a risk factor for miscarriage, preterm birth, and low birth weight. Adequate vitamin D levels, hard to come by in gloomy Canada, are extremely important when it comes to reproductive health. 1 nmol increase in serum vitamin D levels decreases miscarriage rate by 1%. Testing is clearly imperative!

9. Inflammation & oxidative stress

Conditions like PCOS, listed above, and endometriosis cause increased uterine inflammation and oxidative stress. Inflammation can also be elevated in the presence of other autoimmune diseases during pregnancy. However, there is significant research on specific anti-inflammatories and antioxidants increasing live birth rate and preventing miscarriage in these scenarios!

10. Progesterone deficiency &hyperprolactinemia

Progesterone supplementation is helpful when there is a progesterone deficiency. Elevated prolactin levels can suppress progesterone production and lead to deficiency.

11. MTHFR deficiency & elevated homocysteine

MTHFR deficiency refers to a mutation in the gene “MTHFR”, responsible for metabolizing folate (a vitamin found in your prenatal supplement to prevent spina bifida). When folate is not metabolized properly, a build up of an amino acid called homocysteine results. Elevated homocysteine can cause blood clotting and inhibit uterine and placental blood flow.

12. Immunological causes

I’m going to throw out some pretty fancy terms here: HLA incompatibility, anti-paternal antibodies, and natural killer cells. They’re all terms for potential immunological conditions that cause miscarriage, meaning the woman’s immune system is attacking the embryo. Currently there’s insignificant research to suggest any of the above cause miscarriage, and the treatment is theoretical as well.

13. Vaginal infection

You may wish to be assessed for the following vaginal infections, which may interfere with embryonic growth: ureaplasma, mycoplasma, bacterial vaginosis. As part of your prenatal screening you will have already been assessed for STIs like chlamydia and gonorrhoea. The treatment for these infections is antibiotics for both partners.

If you’re looking for support to learn more about, and prevent, miscarriage, book an appointment HERE.