Miscarriage Causes: Types & What to Expect in Canada
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Understanding miscarriage causes can help parents process one of the most painful experiences they may ever face. Miscarriage and other forms of pregnancy loss are far more common than many Canadians realize — yet they are rarely discussed openly. This silence can leave families, especially mothers, feeling isolated and unsupported during an incredibly difficult time.
Common Miscarriage Causes Every Canadian Should Know
In Canada, early miscarriage symptoms affect roughly 15 to 20 percent of known pregnancies, with most occurring in the first trimester. The actual number of pregnancy losses may be even higher, as some end before a woman knows she is pregnant. In this guide, we explain the most common types of miscarriage, what causes them, the warning signs to watch for, and where Canadian parents can turn for medical care and emotional support.
What Is a Miscarriage?
| Type of Miscarriage | Characteristics | Common Causes | Management Approach |
|---|---|---|---|
| Threatened Miscarriage | Vaginal bleeding with closed cervix; pregnancy may continue | Chromosomal abnormalities, hormonal imbalances, uterine irregularities | Rest, monitoring via ultrasound, hCG blood tests; no proven intervention to prevent loss |
| Inevitable Miscarriage | Heavy bleeding, cramping, and open cervix; loss cannot be prevented | Genetic errors in fetal development, structural uterine issues | Expectant, medical (misoprostol), or surgical management (dilation and curettage) |
| Missed Miscarriage | Embryo stops developing with no obvious symptoms; detected on ultrasound | Chromosomal abnormalities account for up to 50–60% of early losses | Expectant management, medication, or surgical removal; emotional counselling recommended |
| Incomplete Miscarriage | Some pregnancy tissue remains in the uterus after partial loss | Follows any miscarriage type; not caused by a distinct factor | Medication or surgical evacuation (D&C) to prevent infection and heavy bleeding |
| Recurrent Miscarriage | Three or more consecutive pregnancy losses before 20 weeks | Antiphospholipid syndrome, chromosomal issues in parents, uterine abnormalities, thyroid disorders | Referral to reproductive specialist; testing for underlying conditions; possible low-dose aspirin or heparin therapy |
A miscarriage happens when a pregnancy ends before the baby can survive outside the womb. In medical terms, this means the pregnancy ends before 28 weeks of gestation, with the baby weighing less than 500 grams. However, most miscarriages happen much earlier than that.
Miscarriage affects roughly 15 to 20 percent of known pregnancies. Most occur before 13 weeks. In reality, the number may be even higher. Some pregnancies end so early that a woman never knows she was pregnant in the first place.
Doctors often divide miscarriages into two groups. An early miscarriage happens in the first 12 to 13 weeks. A late miscarriage occurs between weeks 13 and 27. Understanding which type occurred can help guide follow-up care and future planning.
According to Health Canada, pregnancy loss of any kind deserves proper medical attention and emotional support.
Common Causes of Miscarriage
In more than 30 percent of cases, doctors cannot find a clear cause. However, several factors are known to raise the risk. These include chromosomal problems, hormonal imbalances, immune system issues, and infections.
Chromosomal Abnormalities
Chromosomal problems are the most common cause of miscarriage. They account for more than 50 percent of all cases. These problems happen when an embryo develops with too many or too few chromosomes, or when the chromosomes are structured incorrectly.
An embryo with serious genetic defects usually cannot develop normally. In most cases, the pregnancy ends on its own. Experts believe this is actually a protective process. It greatly reduces the number of babies born with severe birth defects — from an estimated 12 percent down to just 2 to 3 percent.
The good news is that chromosomal miscarriages tend to happen randomly. They are less likely to repeat in a future pregnancy compared to other causes. However, certain factors can raise the risk. These include very young or older maternal age, exposure to toxic substances, infections, and accidental radiation exposure.
Important note for Rh-negative mothers: If your blood type is Rh-negative and your partner is Rh-positive, talk to your doctor after a miscarriage. You may need an injection to prevent your body from developing antibodies that could harm a future pregnancy.
Hormonal and Endocrine Causes
Hormonal imbalances are another common trigger. Low levels of progesterone or estrogen, or an excess of androgens, can interfere with a healthy pregnancy. The thyroid gland also plays an important role. An overactive or underactive thyroid can increase the risk of miscarriage.
These imbalances can be primary (meaning the gland itself is not working well) or secondary (caused by another condition). A simple blood test can check hormone levels. If you are planning a pregnancy, ask your family doctor to review your hormone health.
Maternal Health Conditions
Certain ongoing health conditions can also raise the risk of pregnancy loss. These include:
- Autoimmune diseases such as lupus
- Congenital heart conditions
- Serious kidney disease
- Poorly controlled diabetes
- Thyroid disorders
- Intrauterine infections
Managing these conditions before and during pregnancy is very important. Therefore, if you have a chronic health condition and are planning to become pregnant, speak with your family doctor or a specialist first. Getting your health stable before conception can make a real difference.
Immune System Factors
The immune system can sometimes work against a pregnancy. For example, high levels of antiphospholipid antibodies can increase blood clotting. This may cause tiny clots to form in the placenta’s blood vessels. As a result, parts of the placenta can lose blood flow, which can lead to fetal loss.
In addition, some women’s bodies may produce antibodies that react to their partner’s white blood cells. Research suggests this can also raise the risk of miscarriage. These immune-related causes can be identified through specific blood tests, so speak with your doctor if you have had repeated pregnancy losses.
Anatomical Causes of Pregnancy Loss
Sometimes the shape or structure of the uterus contributes to miscarriage. These problems can be present from birth or develop later due to injury or surgery. Structural issues in the uterus can make it harder for an embryo to implant or grow properly.
Common anatomical factors include a uterine septum (a wall of tissue dividing the uterus), fibroids, scarring from previous surgery, or a weakened cervix. Many of these conditions can be diagnosed with imaging tests and, in some cases, treated before or between pregnancies.
If you have had more than one miscarriage, your doctor may recommend a pelvic ultrasound or other tests to check the structure of your uterus. This is a normal and important part of follow-up care in Canada’s health system.
Other Types of Pregnancy Loss
Ectopic Pregnancy
An ectopic pregnancy happens when a fertilized egg implants outside the uterus — most often in a fallopian tube. The embryo cannot develop normally in this location. An ectopic pregnancy is a medical emergency. If left untreated, it can cause the fallopian tube to rupture, which is life-threatening.
Symptoms include sharp one-sided pelvic pain, vaginal bleeding, and dizziness. If you experience these signs, go to an emergency room or call 911 right away. Early treatment greatly improves outcomes. According to the Mayo Clinic’s guide on ectopic pregnancy, risk factors include previous pelvic inflammatory disease, prior tubal surgery, and smoking.
Molar Pregnancy
A molar pregnancy is a rare condition where abnormal tissue grows inside the uterus instead of a healthy baby. It happens when a fertilized egg develops incorrectly. The tissue that forms looks like a cluster of fluid-filled sacs. In most cases, there is no viable embryo.
A molar pregnancy requires medical treatment to remove the abnormal tissue. Follow-up monitoring is important because, in rare cases, some tissue can become cancerous. Your doctor will track your hormone levels after treatment to make sure everything returns to normal.
Stillbirth and Neonatal Death
A stillbirth is the death of a baby at 20 weeks of pregnancy or later, before or during birth. Neonatal death refers to the death of a newborn within the first 28 days of life. Both are devastating losses that deserve compassionate medical care and emotional support.
Causes of stillbirth can include placental problems, infections, umbilical cord accidents, or chromosomal issues. In some cases, the cause is never found. The World Health Organization’s stillbirth fact sheet notes that most stillbirths in high-income countries like Canada happen before labour begins.
Neonatal death can result from premature birth, birth defects, infections, or complications during delivery. Canada has strong neonatal intensive care (NICU) programmes in place to give premature and ill newborns the best possible chance of survival.
The Emotional Impact of Pregnancy Loss
Grief after a miscarriage or pregnancy loss is real and valid, no matter how early the loss occurred. Many parents feel shock, sadness, guilt, and isolation. Unfortunately, there is still a culture of silence around this topic, which can make parents feel as though they are suffering alone.
It is important to know that you are not alone. Pregnancy loss is common, and your feelings are completely normal. Counselling, peer support groups, and open conversations with your healthcare provider can all help. Many hospitals and community health centres across Canada offer pregnancy loss support programmes.
Partners and other family members also grieve. Everyone processes loss differently, and that is okay. Give yourself and your loved ones time and space to heal.
When to See a Doctor
You should contact your family doctor or visit a walk-in clinic as soon as possible if you notice any of the following during pregnancy:
- Vaginal bleeding or spotting
- Severe cramping or abdominal pain
- Passing of tissue or clots
- A sudden stop in pregnancy symptoms
- Fever or chills alongside any of the above
If the pain is severe or you feel faint, go to your nearest emergency room or call 911 immediately. Do not wait to see if symptoms improve on their own. Early assessment is always the right choice.
After a miscarriage or pregnancy loss, your doctor will likely schedule follow-up appointments. These visits help confirm that the pregnancy has fully ended, check for any complications, and discuss next steps if you plan to try again. Most provincial health plans in Canada cover this follow-up care.
If you have experienced repeated miscarriages (two or more in a row), ask for a referral to a reproductive specialist. There are tests and treatments that may help identify and address underlying causes.
This article is for informational purposes only. Always consult your family doctor, midwife, or a qualified healthcare provider for personal medical advice.
Frequently Asked Questions About Miscarriage
How common is miscarriage in Canada?
Miscarriage affects approximately 15 to 20 percent of known pregnancies in Canada. Because some losses happen before a woman even knows she is pregnant, the actual rate may be higher. If you have experienced a miscarriage, know that you are far from alone.
What are the most common signs of a miscarriage?
The most common signs of miscarriage include vaginal bleeding, cramping or pain in the lower abdomen, and passing of tissue or clots. Some women also notice that pregnancy symptoms such as nausea or breast tenderness suddenly disappear. If you experience any of these signs, contact your family doctor or visit a walk-in clinic right away.
Can I get pregnant again after a miscarriage?
Yes, most women who experience a miscarriage go on to have healthy pregnancies afterward. A single miscarriage does not mean you will have another one. However, if you have had two or more miscarriages in a row, ask your doctor for a referral to a reproductive specialist to explore possible causes.
What causes repeated miscarriages?
Repeated miscarriage can be caused by chromosomal problems, uterine abnormalities, hormonal imbalances, immune system disorders, or certain chronic health conditions. In some cases, no clear cause is found even after testing. A specialist can run targeted tests to help identify treatable causes and improve your chances in a future pregnancy.
Is miscarriage covered under provincial health plans in Canada?
Yes, in most Canadian provinces, medical care related to miscarriage — including emergency treatment, follow-up appointments, and testing — is covered under provincial health insurance plans. Coverage details vary by province, so it is a good idea to check with your local health authority or speak with your family doctor about what is included.
How long does it take to recover from a miscarriage?
According to Mayo Clinic’s overview of miscarriage symptoms and causes, this information is supported by current medical research.
For more information, read our guide on breast mastitis causes and treatment in Canada.
Physical recovery from a miscarriage usually takes a few weeks, depending on how far along the pregnancy was. Emotionally, recovery can take much longer and looks different for everyone. Many people find it helpful to speak with a counsellor or join a pregnancy loss support group, which are available through many community health centres across Canada.
Key Takeaways
- Miscarriage is common — it affects 15 to 20 percent of known pregnancies, often before 13 weeks.
- Chromosomal problems are the leading cause, accounting for more than half of all miscarriages.
- Hormonal imbalances, immune issues, and chronic conditions can also play a role — many are manageable with proper medical care.
- Ectopic pregnancy is a medical emergency — seek immediate care if you have one-sided pelvic pain and bleeding.
- Emotional support matters — grief after any pregnancy loss is valid, and help is available across Canada.
- Most women go on to have healthy pregnancies after a miscarriage — talk to your doctor about next steps.
- Always consult your family doctor or visit a walk-in clinic if you have concerns about your pregnancy.
Frequently Asked Questions
What are the most common miscarriage causes?
The most common miscarriage causes are chromosomal abnormalities in the embryo, accounting for up to 50% of early pregnancy losses. Other causes include hormonal imbalances, uterine abnormalities, thyroid disorders, uncontrolled diabetes, and infections. Most miscarriages are not caused by anything the mother did or could have prevented.
What are the signs and symptoms of a miscarriage?
Common miscarriage symptoms include vaginal bleeding or spotting, cramping or pain in the lower abdomen or back, passing tissue or fluid from the vagina, and a sudden disappearance of pregnancy symptoms like nausea or breast tenderness. Light spotting alone doesn’t always indicate miscarriage, but any bleeding should be evaluated by a doctor.
What are the different types of miscarriage?
The main types of miscarriage include threatened, inevitable, incomplete, complete, missed, and recurrent miscarriage. Each type is defined by whether the pregnancy loss is in progress, has completed, or if fetal tissue remains in the uterus. A healthcare provider uses ultrasound and blood tests to determine the specific type.
Can miscarriage causes be prevented?
Many miscarriage causes, such as chromosomal abnormalities, cannot be prevented. However, reducing certain risks is possible by managing chronic conditions like diabetes and thyroid disease, avoiding smoking, alcohol, and drugs, maintaining a healthy weight, taking prenatal vitamins with folic acid, and attending regular prenatal appointments throughout pregnancy.
When should you go to the emergency room for a miscarriage in Canada?
Go to a Canadian emergency room immediately if you experience heavy vaginal bleeding soaking more than one pad per hour, severe abdominal or shoulder pain, fever above 38°C, dizziness, or fainting. These symptoms may indicate a serious complication such as an ectopic pregnancy or septic miscarriage requiring urgent medical treatment.
About the Author
Dr. Sarah Mitchell, MDDr. Sarah Mitchell is a board-certified family physician with over 15 years of clinical experience. She completed her MD at the University of Toronto and her residency at Toronto General Hospital. Dr. Mitchell specializes in preventive medicine and chronic disease management. She is a member of the College of Family Physicians of Canada (CFPC) and has published over 30 peer-reviewed articles on preventive health care.
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