Miscarriage – Symptoms and Causes

Overview

Miscarriage refers to the loss of a pregnancy before the 20th week. This affects approximately 10% to 20% of known pregnancies. However, the true number is likely higher since many occur before a person knows they are pregnant.

Despite what the name might suggest, miscarriages rarely happen because of something the pregnant person did wrong. Most often, they occur because the embryo isn’t developing as it should.

While miscarriage is common, experiencing one can be emotionally difficult. If you’ve experienced a pregnancy loss, learning about the causes, risk factors, and medical care options can aid in your healing process.

Understanding miscarriage can help dispel misconceptions and provide clarity during a challenging time. Understanding this topic helps people realize that pregnancy loss is not their fault and that support resources are available.

Signs of Miscarriage

Most miscarriages occur in the first 13 weeks of pregnancy (first trimester). Watch for these warning signs:

• Vaginal bleeding – this can range from light spotting to heavier bleeding.
• Pelvic or lower back pain – often feels like cramping.
• Passing tissue or fluid from the vagina.
• Rapid heartbeat – may occur due to blood loss.

If you pass any tissue, collect it in a clean container and bring it to your healthcare provider for examination. This can help determine if a miscarriage has occurred.

Many pregnant people who experience spotting or light bleeding early in pregnancy go on to have healthy babies. Contact your healthcare team right away if you have heavy bleeding or bleeding that includes cramping pain.

Causes of Pregnancy Loss

Atypical Genetic Material

Most early pregnancy losses happen because the developing baby has problems forming correctly. About 50–66% of first-trimester losses are connected to chromosomal issues—either too many or too few chromosomes.

Chromosomes carry genes that tell our bodies how to grow and work. When egg and sperm join, they combine chromosomes from both parents. If this combination isn’t right, it often leads to pregnancy loss.

These genetic problems might cause:

• Empty Pregnancy Sac: This occurs when no embryo develops, or it forms but is reabsorbed.

• Early Fetal Death: The embryo begins growing but stops developing and dies before any signs of loss appear.

• Complete or Partial Molar Pregnancies: In complete molar pregnancies, a baby does not develop because the chromosomes come solely from the father, leading to abnormal placental growth.
  • In partial molar pregnancies, a baby may start to develop, but cannot survive. This happens when there are three sets of chromosomes instead of two.

These pregnancies should be terminated due to the risk of serious health complications, including rare instances where placental tissue changes can result in cancer.

Health Conditions in the Mother

Sometimes specific health issues can increase the risk of pregnancy loss.

Health Condition	How It Affects Pregnancy
Poorly managed diabetes	Affects blood supply and development
Infections	Can impact the developing baby
Hormone imbalances	May prevent proper growth
Uterine or cervical abnormalities	Can affect implantation and growth
Thyroid problems	Influences hormonal balance
Obesity	Creates various physiological challenges

Common Misconceptions About Causes

Many everyday activities do not cause pregnancy loss:

• Physical activity is generally safe if you are healthy. Just check with your doctor first and avoid high-impact or contact sports.

• Sexual intercourse during pregnancy is typically safe.

• Emotional stress or arguments don’t directly cause miscarriage.

• Birth control pill use doesn’t increase your risk.

• Most jobs are safe during pregnancy unless they involve high levels of harmful chemicals or radiation.

Many people blame themselves after a pregnancy loss. They might think it happened because they fell, were frightened, or did something wrong.

The truth is that most losses occur because of random events that nobody could prevent. These events are no one’s fault.

Risk Factors

Several factors can increase the chance of having a miscarriage:

• Age plays a significant role. People over 35 face higher risks:
  • At age 35: about a 20% risk
  • At age 40: 33–40% risk
  • At age 45: 57–80% risk
• Previous miscarriages increase the likelihood of experiencing another one.
• Health conditions that aren’t well-managed, like uncontrolled diabetes, raise miscarriage risk.
• Structural issues with the uterus or a weak cervix (sometimes called an incompetent cervix) can lead to pregnancy loss.
• Lifestyle factors have a strong impact:
  • Smoking
  • Heavy alcohol consumption
  • Excessive caffeine intake
  • Illegal drug use (particularly cocaine)
• Weight issues at both ends of the spectrum can significantly impact pregnancy. Both being underweight and overweight are linked to higher miscarriage rates.
• Genetic factors sometimes play a role even when both partners appear healthy.
  • Chromosome translocations in either parent can be inherited by the baby, increasing the risk of miscarriage.

Many people experience miscarriages without any identifiable risk factors. However, understanding these potential risks can help with healthcare planning and making informed decisions during pregnancy.

Complications

After a miscarriage, some health issues may develop that need immediate medical attention. If pregnancy tissue remains in the uterus, it can cause an infection called septic miscarriage. This typically appears 1–2 days after the miscarriage.

Signs of septic miscarriage include:

• Fever over 100.4°F (occurring multiple times)
• Chills
• Lower abdominal pain
• Foul-smelling vaginal discharge
• Bleeding from the vagina

This condition can rapidly worsen and become dangerous without proper treatment. Contact a healthcare provider, OB triage, or emergency department promptly if these symptoms appear.

Another serious complication is hemorrhage, which means heavy vaginal bleeding.

Hemorrhage often comes with:

• Rapid heartbeat
• Dizziness caused by low blood pressure
• Fatigue or weakness from anemia (low red blood cell count)

Hemorrhage requires immediate medical care. Some patients may need blood transfusions or surgical intervention to address this complication.

Prevention

Reducing the risk of miscarriage starts with proper self-care during pregnancy. Not all miscarriages can be prevented, but several protective measures can help maintain a healthy pregnancy.

Healthy Pregnancy Practices:

• Attend all scheduled prenatal appointments
• Take a daily prenatal multivitamin
• Avoid all tobacco products
• Eliminate alcohol consumption
• Stay away from illegal drugs

Caffeine Management:

Limit caffeine intake to no more than 200 milligrams daily. This is equivalent to one 12-ounce cup of brewed coffee. Check food labels for hidden caffeine content, as excessive amounts might increase risks during pregnancy.

Special Considerations:

If you’ve experienced previous miscarriages, discuss with your healthcare provider whether low-dose aspirin might be beneficial for your situation.

Managing Existing Conditions:

For those with chronic health conditions, work closely with your healthcare team to maintain proper control throughout pregnancy.