Some pregnancies seem like a short moment in time. You may have just found out you were expecting when a miscarriage occurred. Having a miscarriage is painful, both physically and emotionally. For pregnancies verified by a healthcare provider, 10 to 25 percent end in miscarriage. This is because most miscarriages happen in the first trimester, sometimes before you even have a chance to visit with your doctor.
When you have a miscarriage, it’s easy to blame yourself or wonder what caused it to happen. You may even worry about getting pregnant again. Thankfully, some of your concerns can be eased by knowing more about common causes of miscarriage.
Signs of a miscarriage
If you’re having a miscarriage you may experience:
- Abdominal pain or cramping
- Back pain
- Large clots or tissue discharging from your vagina
- Vaginal spotting or bleeding. However, bleeding may not mean you’re having a miscarriage. Up to 25 percent of women will experience some kind of vaginal bleeding during their first trimester, and the majority have successful pregnancies.
Common miscarriage causes
While it’s often difficult to know the cause of your particular situation, there are several common causes of miscarriage.
Genetic or chromosomal issues
About half of all miscarriages happen because of an extra or missing chromosome. These chromosomal issues arise as the embryo divides (not because of an inherited problem). Abnormalities that result from an abnormal combination of chromosomes might include:
- Molar pregnancy or partial molar pregnancy. A molar pregnancy happens when both sets of chromosomes in the embryo come from the father. A molar or partial molar pregnancy doesn’t survive.
- Intrauterine fetal demise. The embryo's heartbeat stops before symptoms of miscarriage occur.
- Blighted ovum. The embryo fails to form. All that’s ever seen on ultrasound is some fluid inside the uterus where the pregnancy started to take hold.
Health conditions related to miscarriage
- Physical conditions such as uterine abnormalities or an incompetent cervix. Uterine abnormalities account for about 10 percent of miscarriages.
- Thyroid disorders. Both hypo- and hyper-thyroidism can cause infertility and recurrent miscarriages. The hormones you have with a thyroid disorder , either too much or too little, can interfere with your body’s ability to carry a baby.
- Uncontrolled diabetes. If you’ve been diagnosed with diabetes and fail to manage the disease appropriately, it could cause difficulties with carrying a pregnancy.
- Immunologic disorders can cause an embryo to not be accepted by your body. In cases like this, your body’s antibodies attack the developing embryo.
- Polycystic Ovary Syndrome (PCOS) can cause recurrent miscarriages because of high levels of testosterone. PCOS-related insulin resistance can also affect the lining of your uterus.
- Bacterial infections can live in your or your partner’s genital tracts. When this is the case, the bacterial infection can inflame the lining of your uterus and make it impossible for an embryo to develop.
Certain lifestyle factors also make it more likely that you’ll experience a miscarriage. If you smoke, you double your chance of miscarrying. Drinking alcohol, using recreational drugs, and some work environments can also contribute to miscarriage.
The older you are, the more likely you are to conceive a baby with a chromosomal abnormality, which often results in a miscarriage. Your risk of miscarriage also increases with each child you have.
Risk factors for miscarriage
You may be at a higher risk to miscarry a pregnancy if you:
- Have had a miscarriage before.
- Choose to do invasive prenatal testing.
- Are older than 35.
- Have a chronic condition (such as diabetes).
- Smoke, drink alcohol, or use illicit drugs.
- Have uterine or cervical problems.
- Are overweight or underweight.
Can you prevent miscarriage?
You may be able to help reduce your risk of experiencing a miscarriage if you:
- Take a prenatal vitamin. It’s best to start them prior to conceiving.
- Exercise regularly (but not necessarily heavily).
- Avoid smoking and using alcohol or recreational drugs.
- Attend regular prenatal appointments.
- Limit your caffeine intake.
- Eat a healthy diet.
Talk to your doctor if you’ve had a miscarriage in the past, or if you have concerns about not being able to carry a pregnancy to term. Consider scheduling an appointment with your doctor prior to getting pregnant to discuss possible or known risks and how to prevent them. Early prenatal care can help you avoid miscarriage and problems in your pregnancy.