Miscarriage Symptoms, Causes, Types, Diagnosis & Treatment

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Miscarriage, also called spontaneous abortion, is the natural loss of pregnancy before the embryo or fetus can survive independently outside the uterus. Around one in ten women miscarries within the first trimester (1). Vaginal bleeding and cramps are common symptoms of miscarriage. Unfortunately, it is not possible to completely prevent miscarriages since many causes are not modifiable.

Read this post to know about the causes, risk factors, symptoms, types, diagnosis, treatments, and myths and misconceptions about miscarriage.

What Are The Miscarriage Rates By Week?

The miscarriage rate measures the occurrence of miscarriage in specific weeks of pregnancy. According to the American College of Obstetricians and Gynecologists (ACOG), miscarriage is the most common form of pregnancy loss, and 26% of pregnancies end in miscarriages. This includes up to 10% of clinically recognized pregnancies (where ultrasound or pregnancy tissue is identified) and miscarriages before pregnancy is detected (2).

The relative risk of miscarriage in different weeks of pregnancy is (3) (4):

• 50 to 75% before week five
• 3% in week five
• 5% in weeks six to seven
• 2–4% in weeks eight to 13
• 1% in weeks 14 to 20

The miscarriage rate varies in each week of gestation. However, nearly 80% of miscarriages happen in the first trimester, and the miscarriage rate reduces as the pregnancy progresses.

What Are The Different Types Of Miscarriages?

Miscarriages occurring in the first trimester are called early miscarriage or early pregnancy loss. Late miscarriage, also called second trimester or mid-trimester loss, occurs after 12 weeks of pregnancy. Loss of pregnancy beyond 20 weeks of gestation is called a stillbirth.

Miscarriages can be of the following types (1) (5):

• Threatened miscarriage: Mild vaginal bleeding with cramping and a closed cervix. Half of the cases of threatened miscarriages go into inevitable miscarriage and end in pregnancy loss, whereas bleeding stops in others, and the pregnancy continues without any further problem.

• Inevitable miscarriage: Heavy vaginal bleeding, often with strong abdominal cramps and an open cervix. It typically ends in pregnancy loss.

• Incomplete miscarriage: Some products of conception (POC) or pregnancy tissue remain in the uterus after an incomplete miscarriage. The pregnancy can not be continued, and the remaining tissue is removed to avoid complications.

• Complete miscarriage: All the POC are expelled from the uterus in a complete miscarriage. Additional treatments are not required after this type of miscarriage. This is common for miscarriages occuring before 12 weeks.

• Missed miscarriage: Miscarriage without cramps and bleeding may go unnoticed by many women. The ultrasound shows a pregnancy sac without an embryo or an embryo without a heartbeat in missed miscarriages. The remaining tissue may pass by on their own or require medical attention.

• Septic miscarriage: Uterine infection before, during, or shortly after a miscarriage is called a septic miscarriage. Symptoms such as fever, vaginal discharge, and peritonitis are observed. It may cause sepsis and demands immediate care including antibiotic treatment.

• Recurrent miscarriage: The loss of two or more consecutive pregnancies before 20 weeks of gestation is called a recurrent miscarriage. Additional tests to look for the causes are recommended for women experiencing consecutive pregnancy loss. This type of miscarriage only affects about 1% of couples.

Diagnostic tests and treatment may vary depending on the type of miscarriage. However, it is not possible to continue viable pregnancy in any case except for threatened miscarriage.

What Are The Signs And Symptoms Of A Miscarriage?

Vaginal bleeding is a hallmark sign of a miscarriage. It could be light spotting, brownish discharge, or heavy bleeding with bright red blood or blood clots and may last for several days. However, light spotting is common in the first trimester and does not always indicate a miscarriage (6).

Other symptoms of miscarriage may include (6)

• Lower abdominal pain or cramps
• Vaginal discharge
• Expulsion of tissue and clots from the vagina
• Lack of pregnancy symptoms
• Severe back pain

These symptoms are not specific to miscarriage. However, seek medical care if you experience these symptoms during pregnancy.

What Are The Risk Factors And Causes Of Miscarriages?

According to the ACOG, around 60% of miscarriages occur randomly when the embryo gets an abnormal number of chromosomes (extra or missing) during fertilization (7). These genetic abnormalities occur by chance and do not result in a medical condition.

Chromosomal abnormalities can result in the following conditions (8):

• Blighted ovum: The fertilized egg is implanted into the uterine wall without an embryo (anembryonic pregnancy). The pregnancy sac and placenta may grow without the fetus.

• Early embryonic death: The embryo stops developing in the early weeks of pregnancy After the embryo dies, a viable pregnancy cannot continue.

• Molar pregnancy and partial molar pregnancy (hydatidiform mole): It occurs when the egg and sperm are abnormally fertilized. Molar pregnancies are a gestational trophoblastic disease (GTD). These tumor tissues cannot nourish and support the embryolike the placenta, and the pregnancy fails. They can sometimes be associated with cancerous changes of the placenta.

The following maternal health conditions can cause or increase the risk of miscarriages (8):

• Infections
• Chronic health conditions such as uncontrolled diabetes
• Thyroid disease
• Cervix and uterus abnormalities such as incompetent cervix (cervical insufficiency)
• Hormonal issues
• Use of alcohol, tobacco, or illicit drugs
• Being underweight, overweight, or obese
• Invasive prenatal tests such as amniocentesis and chorionic villus sampling (a slight increase of risk)
• Previous miscarriages
• Advanced maternal age of >35 years

Routine exercises such as cycling, jogging, and other high-density activities, working (if not exposed to harmful chemicals or radiation), and sexual intercourse don’t cause miscarriages. Avoid sexual intercourse only if your healthcare provider says so.

How Is A Miscarriage Diagnosed?

A pelvic exam and ultrasound test help confirm a miscarriage. Ultrasound imaging also helps to confirm that the POCare expelled from the uterus after a miscarriage. The following tests are ordered in case of a recurrent miscarriage (9) (10):

• Blood tests to look for a decline in hormone levels after a miscarriage

• Chromosome testing or genetic testing of the tissue of miscarriage to identify chromosomal anomalies in the This can be helpful while planning future pregnancies.

• Hysterosalpingogram, an X-ray of the fallopian tubes and uterus

• Hysteroscopy to visualize the uterus with a thin, telescope-like device

• Laparoscopy to view the pelvic organs with a fiber-optic device with a camera and light

• Endometrial biopsy to analyze tissue collected from the inner wall of the uterus 

How Is A Miscarriage Treated?

Treatment options include expectant management, medcial management and surgical evacuation, which may vary from case to case.

No treatment is required after a complete miscarriage if the uterus is clear. Dilatation and curettage (D&C) or dilation and extraction (D&E) evacuates the POC from the uterus if the miscarriage is incomplete (10).

During this procedure, the cervix is dilated, and the pregnancy tissue are gently scraped from the uterus wall with devices or vacuum aspirators. Some may receive medications to expel the pregnancy tissue. Doctors may also recommend treatment for underlying conditions and Rh immunoglobulin if needed (1).

How To Prevent Miscarriages?

Miscarriages due to random genetic causes or unknown causes cannot be prevented. However, the following measures may help reduce your risk of miscarriage (11):

• Maintain a healthy, balanced diet and exercise regularly.

• Take folic acid /prenatal vitamins 2-3 months prior to trying to conceive daily

• Maintain a healthy weight before planning pregnancy.

• Avoid caffeine, unpasteurized dairy products, and raw or undercooked poultry, meat, and seafood.

• Get the necessary vaccines to prevent infections such as rubella during pregnancy

• Avoid smoking and using tobacco products, alcohol, and illegal drugs in the preconception period and during pregnancy

• Seek preconception care and early prenatal care to review chronic medical conditions and medications

Treating conditions such as antiphospholipid syndrome (APS) or Hughes syndrome with medications such as a combination of aspirin and heparin can reduce the risk of blood clots and recurrent miscarriages. Cervical cerclage (stitches in the cervix) can help prevent recurrent miscarriages in women with a weakened cervix.

What Are The Common Myths And Misconceptions About Miscarriage?

The following are some common myths and misconceptions about miscarriages (12):

• Miscarriage is rare.
• Self-care reduces the risk of miscarriage.
• Miscarriages are completely preventable.
• Traveling by air increases the risk of miscarriage
• The emotional state of the mother, such as stress or depression, can cause miscarriage
• Fright and shock during pregnancy may result in miscarriage
• Exercising during pregnancy can increase the risk of miscarriage.
• Lifting something may result in
• Working, especially if it requires long hours of standing or sitting, increases the risk for miscarriage.
• Eating spicy foods can cause pregnancy loss
• Having sex during pregnancy causes miscarriage

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Reviewer Author

Dr. Uma MishraMD

Dr. Uma Mishra is a postgraduate in Obstetrics & Gynaecology from PMCH, Patna. She did her MBBS (graduation) from the SCB Medical College, Cuttack. With over 12 years of experience, Dr. Mishra has worked with Indraprastha Apollo Hospital & Fortis Hospital, New Delhi.

Read full bio of Dr. Uma Mishra

Dr Bisny T. JosephMedical Doctor

Dr. Bisny T. Joseph is a Georgian Board-certified physician. She has completed her professional graduate degree as a medical doctor from Tbilisi State Medical University, Georgia. She has around 5 years of experience in various sectors of medical affairs as a physician, medical reviewer, medical writer, health coach, and Q&A expert.

Read full bio of Dr Bisny T. Joseph