5 Common causes of miscarriages (+ how to prevent a miscarriage)


According to SingHealth estimates, one in four to six pregnancies end in a miscarriage. If you think about it, those are some pretty worrying odds!

In this article, we walk you through 5 most common causes of miscarriage, and explain exactly how miscarriages work. For the mummies-to-be who are pregnant and hoping that they’ll experience a successful, complication-free delivery, check out our tips on how to prevent a miscarriage at the end of the article!

#1: Thyroid disorders

Thyroid disorders include hypo-thyroidism and hyper-thyroidism; both these conditions contribute to infertility and miscarriages.

What’s the science behind this? If your thyroid function is too low, your body will try to make up for it by producing hormones that suppress ovulation, making it more difficult for you to get pregnant. At the other end of the spectrum, if your thyroid is overactive and producing too many hormones, this results in an “unfavourable” uterine condition that makes it challenging for an embryo to survive.

#2: Chromosomal abnormalities

Ob-gyns across the globe agree that one of the most common causes of miscarriage is chromosomal abnormalities. To break it down: this means that your embryo either has an incorrect number of chromosomes, or that the process of cell division didn’t go smoothly, and parts of the embryo’s chromosomes were lost or copied incorrectly.

Generally speaking, miscarriages due to chromosomal abnormalities are more likely to happen for women over the age of 35. Scientists are also studying the possibility that paternal age influences the likelihood of miscarriage due to chromosomal abnormality.


#3: Diabetes

Here’s the common consensus amongst ob-gyns: women who get pregnant without first getting their diabetes under control are at higher risk of experiencing a miscarriage. On top of that, these women also have a higher likelihood of giving birth to children with major birth defects. Diabetes aside, women with other chronic medical disorders such as hypothyroidism and hypertension (high blood pressure) are also at higher risk of experiencing a miscarriage.

#4: Smoking and drug/alcohol use

Plenty of studies have linked smoking and drug/alcohol use to infertility and miscarriages, and women are well aware that smoking, drinking, and using drugs does negatively impact their fertility.

The problem, though, is that with unplanned pregnancies, women only realize they’re pregnant a few weeks after they’ve missed their period. If these women drank alcohol, smoked, or engaged in other “unhealthy” behaviours during their first trimester (when they were unaware they were pregnant!), this increases the chances of miscarriage both in the early and late trimesters.


#5: Uterine abnormalities

Uterine abnormalities and other physical complications are less common, but these also affect the chances of a woman having a miscarriage. Miscarriages caused by these complications typically occur later on, in the second or third trimester.

More specifically, women who have uterine septum (read: a uterine that is shaped abnormally) tend to experience a miscarriage because their embryo is unable to implant. (In certain cases, the embryo does successfully implant, but doesn’t get the nourishment that’s necessary for its survival). Uterine septum aside, an incompetent cervix (that’s too weak to hold the foetus in) may also cause a miscarriage.

How to prevent a miscarriage

Want to do all you can to prevent a miscarriage? Here are a few tips:

  • Eat well and get sufficient sleep.
  • Exercise and keep active. Many women cut back on exercising in the fear that this will result in a miscarriage, but that’s just a myth.
  • Don’t smoke and drink, and stay away from second-hand smoke.
  • Avoid visiting saunas and taking hot baths.
  • Meditate and eliminate sources of stress.
  • For those who have diabetes, make sure your blood sugar level is under control.
  • Keep your doctor informed about any meds you’re on, and make sure these are safe to consume while you’re pregnant.
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