Medically reviewed by Dr. Bhimi Daimari, MBBS, MS (Obstetrics and Gynaecology) · Review date: 3 November 2026
If you have had a miscarriage, one question often comes first: “Why did this happen?” The honest answer is that most miscarriages happen because of problems no one could control or prevent. In this guide we explain what causes miscarriage, what increases the risk, which foods to avoid, and the common myths many women in Saudi Arabia still believe.
Quick answer: The most common cause of miscarriage in the first trimester is a chromosome problem in the developing pregnancy. It happens by chance and is not caused by anything the mother did. Other causes include problems with the womb or cervix, uncontrolled health conditions, some infections, and lifestyle factors like smoking. In many cases, no exact cause is found.
How Common Is a Miscarriage in the First Trimester?
Miscarriage means losing a pregnancy before 20 to 24 weeks. About 10 to 20 in every 100 known pregnancies end in miscarriage, and around 8 in 10 of these happen in the first trimester (first 12 weeks). Many more happen very early, before a woman knows she is pregnant. To learn the signs, read: what does a miscarriage look like?
What Are the Top 5 Causes of Miscarriage?
- Chromosome problems in the pregnancy (the most common cause)
- A pregnancy that does not develop properly (for example, an empty sac)
- Uncontrolled health conditions such as diabetes or thyroid disease
- Problems with the womb or a weak cervix (mainly later miscarriages)
- Lifestyle factors such as smoking, alcohol and drugs
Things That Can Cause a Miscarriage in the First 8 Weeks
1. Chromosome problems
Chromosomes carry the baby’s genes. Sometimes, by chance, an egg or sperm has the wrong number of chromosomes. The pregnancy then cannot grow normally and stops developing. About half of all early miscarriages happen for this reason (ACOG). Most chromosome-related miscarriages happen before 10 weeks. It is usually random and does not mean the next pregnancy will end the same way.
2. Problems with how the pregnancy forms
Sometimes the pregnancy sac forms but the baby does not develop (a “blighted ovum”). Sometimes the placenta does not develop properly. These problems are usually found on an early ultrasound scan. Rarely, the placenta grows abnormally from the start – this is called a molar pregnancy.
3. Hormone and health problems
Some conditions can affect early pregnancy, especially when they are not well controlled:
- Thyroid disease
- Diabetes
- Polycystic ovary syndrome (PCOS), linked to a higher risk in some studies
4. The mother’s age
Risk increases with age because egg quality changes over time. The NHS gives these rough numbers:
- Under 30: about 1 in 10 pregnancies end in miscarriage
- 30 to 39: about 2 in 10
- Over 45: more than 5 in 10
Video: a doctor answers common questions about miscarriage
In this short video from the Stanford Center for Health Education, a doctor answers 7 common questions about miscarriage, including what causes it and what you can and cannot control.
What Causes Miscarriage After 8 Weeks?
Once a heartbeat is seen on a scan, the chance of miscarriage drops a lot. Miscarriage later in pregnancy (12 to 24 weeks) is less common and often has different causes:
- Weak cervix (cervical insufficiency): the cervix opens too early, often without pain
- Shape of the womb: for example, a septum (wall of tissue) or large fibroids
- Serious infections that reach the womb
- Long-term health conditions: high blood pressure, kidney disease, lupus, or poorly controlled diabetes
- Blood clotting problems such as antiphospholipid syndrome
Risk Factors That Increase the Chance of Miscarriage
These do not mean a miscarriage will happen. They only raise the risk:
- Smoking (and heavy second-hand smoke)
- Drinking alcohol
- Using recreational drugs
- A lot of caffeine (the NHS advises less than 200 mg a day, about 2 mugs of instant coffee)
- Being very overweight or very underweight
- Some medicines (always ask a doctor before taking any medicine in pregnancy)
- Having had 2 or more miscarriages before
Foods to Avoid in Early Pregnancy
No normal food “causes” a miscarriage on its own. But some foods can carry germs or substances that are risky in pregnancy (NHS – foods to avoid):
- Unpasteurised milk and soft cheeses made from it, which can carry Listeria, an infection linked to miscarriage
- Raw or undercooked meat, chicken and eggs
- Raw shellfish and sushi with raw fish
- Fish high in mercury, such as shark, swordfish and king mackerel
- Liver and liver products in large amounts (too much vitamin A)
- Too much caffeine from coffee, tea, energy drinks and cola
- Herbal remedies and supplements not approved by your doctor
Can lemon cause miscarriage?
No. Lemon in normal food and drinks is safe in pregnancy.
Does cinnamon cause miscarriage?
Cinnamon used as a spice in normal food is safe. Avoid cinnamon oil or high-dose cinnamon supplements unless your doctor agrees.
Can a poor diet cause a miscarriage?
An imperfect diet does not cause miscarriage. But severe undernutrition and being very underweight can raise the risk. Eating a balanced diet and taking folic acid (as your doctor advises) supports a healthy pregnancy.
Myths in Saudi Arabia: What Does NOT Cause Miscarriage
A study of Saudi women published in Fertility and Sterility (2017) found that many believed miscarriage is caused by a stressful event (72%) or by long-term stress (64%). Many also thought lifting could cause it. Medical evidence does not support these beliefs. These things do NOT usually cause a miscarriage:
- Normal stress, worry or an argument
- Normal exercise, walking and jumping
- Working, including standing at work
- Sex during a healthy pregnancy
- Lifting light things or doing housework
- Eating spicy food, lemon or normal amounts of spices
- Flying in a plane
- A small fall or bump
- A common cold
If you had a miscarriage, it was not your fault.
Does jumping cause miscarriage in the first months?
No. Normal movement, including jumping, does not cause miscarriage in a healthy pregnancy. Avoid sports with a high risk of falls or hits to the belly.
Can a cold cause a miscarriage?
A common cold does not cause miscarriage. A high fever in early pregnancy should be checked by a doctor, and you should ask before taking any cold medicine.
Is It a Miscarriage or Something Else?
Bleeding and pain in early pregnancy are not always a miscarriage:
- Threatened miscarriage: bleeding, but the pregnancy continues. Read: threatened abortion.
- Ectopic pregnancy: a pregnancy outside the womb. It can cause one-sided pain and is an emergency.
- Implantation bleeding: light spotting around the time of the expected period.
Only a doctor, using a scan and sometimes blood tests, can tell the difference. See also: types of miscarriage explained.
What If I Lose My Pregnancy Symptoms?
Symptoms like nausea and sore breasts often come and go. Losing them can be normal, especially after 10 to 12 weeks. Sometimes, though, symptoms fade because the pregnancy has stopped growing (a missed miscarriage). If your symptoms suddenly stop and you are worried, see a doctor for a scan.
Can Doctors Find the Cause of My Miscarriage?
After one miscarriage, doctors usually do not run many tests, because most are random and the next pregnancy is usually healthy. Tests are often offered after 2 or more miscarriages (recurrent pregnancy loss). These may include:
- Blood tests for thyroid, diabetes and clotting problems
- A scan of the womb to check its shape
- Chromosome tests for both partners
- Testing tissue from the pregnancy, when possible
Can Miscarriage Be Prevented?
Most early miscarriages cannot be prevented. But you can lower some risks:
- Take folic acid before and in early pregnancy (ask your doctor)
- Stop smoking, alcohol and drugs
- Keep caffeine low
- Avoid the risky foods listed above
- Keep a healthy weight
- Control diabetes, thyroid disease and blood pressure before getting pregnant
- Go to your antenatal check-ups
💬 Dr. Bhimi Daimari, Obstetrician & Gynaecologist:
“I want women to understand that a miscarriage is rarely something they caused or could have prevented. Many early miscarriages happen because of chromosomal problems during the development of the pregnancy. Please don’t punish yourself with guilt. Give yourself time to heal emotionally and physically, and seek support when you need it.”
When to See a Doctor
See a doctor quickly if you are pregnant and have bleeding or pain. Go to the emergency department or call 997 in Saudi Arabia if you have:
- Very heavy bleeding (soaking 2 large pads an hour for 2 hours)
- Severe pain, especially on one side
- Fever, chills or bad-smelling discharge
- Feeling faint or dizzy
For advice, you can call the Ministry of Health line 937. If a miscarriage has happened, a doctor will check that it is complete. Read more: incomplete abortion and missed miscarriage.
Want to know how the risk changes each week? Read our guide to miscarriage rates by week.
Frequently Asked Questions
What is the most common cause of miscarriage?
A chromosome problem in the pregnancy. It happens by chance and is not caused by the mother.
What causes miscarriage in the first 8 weeks?
Most are caused by chromosome problems or a pregnancy that does not develop properly. Age, smoking, alcohol and uncontrolled health conditions can raise the risk.
What is the risk of miscarriage at 5 weeks?
The risk is highest in the very early weeks, before a heartbeat can be seen. Once a heartbeat is seen on a scan, the risk becomes much lower.
When do most chromosomal miscarriages happen?
Most happen in the first trimester, usually before 10 weeks.
Why do so many women miscarry their first pregnancy?
A first pregnancy does not have a much higher risk. Miscarriage is simply common in all pregnancies, and many women only learn this after it happens to them.
Can stress cause a miscarriage?
Normal everyday stress does not cause miscarriage. Looking after your mental health is still important.
Can I get pregnant again after a miscarriage?
Yes. Most women have a healthy pregnancy after a miscarriage. Ask your doctor when it is right for you to try again.
Should I get tests after one miscarriage?
Usually not. Tests are normally offered after 2 or more losses, or if there are other health concerns.
Sources
- ACOG – Early Pregnancy Loss
- NHS – Miscarriage: Causes
- NHS – Foods to avoid in pregnancy
- Mayo Clinic – Miscarriage
- Rouzi AA et al. Miscarriage knowledge among Saudi women. Fertility and Sterility, 2017.
- ASRM – Recurrent Pregnancy Loss guidance
Medical disclaimer: This article is for general education only. It does not replace advice, diagnosis or treatment from a qualified doctor.