Causes of Miscarriage: The Truth About What You Can Do To Avoid Them
It can be tempting to intensely analyze your recent activity for potential causes of miscarriage: Was it stress? Should you have avoided that intense workout? Could it have been that extra cup of coffee?
All of this wondering really comes down debunking this important miscarriage myth: can you cause a miscarriage?
The answer, for the vast majority of miscarriages, is NO. Still, the early weeks of pregnancy can be anxiety-provoking, watching for miscarriage symptoms, being cautious about what you can do, and even wondering if you should risk announcing your pregnancy early.
To dispel myths surrounding causes of miscarriage, this post will answer whether the following are truly causes of miscarriage:
- genetic conditions?
- uterine and cervical conditions?
- previous contraception?
- history of miscarriage?
- molar pregnancy?
Yes, chromosomal abnormalities are the most common causes of miscarriage
About 20 – 30% of pregnancies end with miscarriage, and while there isn’t a test or a procedure to definitively account for every single cause of miscarriage, we know that most of the time, miscarriages occur during the first trimester, and the most likely reason is chromosomal abnormalities.
A chromosomal abnormality means that when the sperm fertilized the egg, the resulting embryo had the incorrect number of chromosomes, or there were errors in cell division that led to parts of the chromosomes getting lost or incorrectly copied. These abnormalities result in a non-viable embryo and ultimately a pregnancy loss, included miscarriages such as a blighted ovum miscarriage or chemical pregnancy.
The most likely explanation for why this happens is random chance. While researchers are trying to understand whether certain environmental factors, like folic acid intake or radiation, affect chances of chromosomal abnormalities, there is currently no definitive evidence to support these connections.
No, exercise does not cause miscarriages
A common misunderstanding is that exercise or intense workouts are causes of miscarriage. In fact, a recent survey of pregnant women found that about 27% of women deliberately avoided exercise because they were worried about this risk[1.https://www.ncbi.nlm.nih.gov/pubmed/26104611].
There is no scientific evidence to support this claim. In fact, avoiding exercise can increase the likelihood of factors that do increase risk for miscarriage, like obesity[2.https://www.ncbi.nlm.nih.gov/pubmed/15142995]. So, it’s important to regularly exercise and maintain a healthy weight, and healthcare professionals encourage pregnancy workouts .
Maybe extreme stress causes miscarriage, but it’s tricky to pinpoint
A recent survey found that about 75% of women thought that stress caused their miscarriage [3.https://www.ncbi.nlm.nih.gov/pubmed/26000502]. The problem in debunking this claim is that stress is a potent but complex phenomenon. Here’s what you need to know:
- Daily stress, like making work deadlines and annoying traffic, does not cause miscarriage.
- Traumatic psychological stress, like loss of a spouse or family member, may increase risk for miscarriage, but the evidence is inconclusive and requires further research.
- A major caveat to these studies is the subjective bias in self-reporting stress, how closely it happened to the miscarriage, and how recently the miscarriage took place.
- Another major caveat is that stress increases predisposition to excessive alcohol intake and illicit drug use, which are definitely risk factors for miscarriage. This overlap blurs the relationship between whether stress itself causes miscarriage or whether stress increases behavior related to miscarriage.
The bottom line? Managing your stress levels is always a good idea, but in most cases, there are no grounds for blaming a miscarriage on stress. Even if traumatic stress preceded a miscarriage, there still isn’t a definitive way to determine that the two events are connected. Remember, factors outside of your control like chromosomal abnormalities are the mostly likely causes of miscarriage.
Yes, uterine and cervical structure can cause a miscarriage
If you’re struggling with recurrent miscarriages, talk to your doctor about examining your uterus and cervix for structural abnormalities which can prevent pregnancy.
If the uterus is irregularly-shaped or if you have a uterine septum (aka a piece of extra tissue that divides the uterus into two sections), then the embryo implantation cannot properly happen, leading to miscarriage. Depending on the type of uterine abnormality, your doctor could recommend a corrective surgery.
If the cervix is weak or “incompetent”, then it can prematurely dilate, leading to loss of the fetus. To treat this, your doctor can do a cerclage procedure, which means adding a set of stitches to strengthen the cervix.
Yes, alcohol can cause miscarriage, but it depends on how much you drink
Alcohol can increase chances of a miscarriage, but the risk only seems to start above a certain threshold of drinking. While it’s difficult to say exactly where that threshold begins, one study found that women who consumed more than four drinks per week were significantly more likely to have a miscarriage in comparison to women who did not drink at all. Interestingly, the risk was found to be highest among women who drank only liquor rather than only beer or wine.
Drinking fewer than four drinks per week did not significantly increase risk for miscarriage in comparison to not drinking at all. [4.https://www.ncbi.nlm.nih.gov/pubmed/24810392 ].
No, previous contraceptive use does not cause a miscarriage
Women who use hormonal contraception or IUDs often wonder if the contraceptive effects have long-term harmful effects on fertility. According to the American College of Obstetricians and Gynecologists, there is currently no evidence to suggest that history of hormonal or intra-uterine contraceptive methods increases risk for miscarriage after you stop using them.
In the unlikely event that you become pregnant while you have an IUD, then there is a slight increased risk of miscarriage if the IUD is still in place (but not if it’s been removed).
Also, even if you miss a dose or more of the pill and become pregnant, the additional pills you may take do not increase miscarriage risk[5. https://www.ncbi.nlm.nih.gov/pubmed/18578746]
Yes, infections cause miscarriages
Certain bacterial infections, especially with the bacteria mycoplasma hominis and ureaplasma urealyticum, increase infection of the uterine lining, prohibiting implantation and embryo growth, leading to a miscarriage. Your doctor can test for these bacteria, and, if need be, antibiotics can remedy this problem.
No, one miscarriage does not mean more miscarriages
Typically, a miscarriage is a one-time event, and the vast majority of women who experience a miscarriage go on to conceive rainbow baby. If you experience two or more miscarriages in a row, then talk to your doctor to check for any issues like infections or uterine abnormalities, which are treatable causes of miscarriage.
Yes, but only slightly, amniocentesis increases risk for miscarriage
One concern when undergoing an amniocentesis is whether or not this invasive procedure causes miscarriage. This was definitely a concern when amniocentesis was first performed decades ago, but with current advancements in medical technology, the risk is minimal. Nonetheless, the risk of miscarriage after amniocentesis is estimated to affect approximately 1 in 400 pregnancies, with the miscarriage occurring due to infection or premature labor induction. However, it’s important to remember that like with alcohol, exercise, and stress, it’s really challenging to define events like this procedure as definitive causes of miscarriage.
No, a molar pregnancy is not a miscarriage cause
A molar pregnancy is condition when the cells forming the placenta don’t grow normally. While it seems like a miscarriage because it results in heavy bleeding and pregnancy loss, it’s different from one because it’s due to a placenta defect, not because of embryo survival. Also, while getting pregnant after a miscarriage can happen as soon as you’re ready and are cycling, a molar pregnancy can result in a complication where irregular placenta cells keep growing in other places of the body, becoming cancerous. For this reason, if you experience one, it’s important for your doctor to monitor extra cell growth and recommend waiting to try again so that these cancerous cells can be effectively detected