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A miscarriage is defined as the fetus dying in the womb before the 20th week of pregnancy, according to WebMD. A miscarriage is also known as a spontaneous abortion. A spontaneous abortion is different from an induced abortion. This is very important to know, as some women become concerned when medical providers discuss their miscarriage as an abortion.

Many miscarriages occur before the woman even realizes she’s pregnant, and the majority of miscarriages occur within the first trimester, which comprises the first 12 weeks of pregnancy.

About 10 percent to 15 percent of known pregnancies end in a miscarriage. However, many miscarriages happen so early that women don’t even realize they are pregnant. They simply believe that their period was late that month.

WebMD estimates that as many as 50 percent of pregnancies end in miscarriage when counting those that occur with women who don’t realize they are pregnant.

Most women who miscarry will go on to have healthy future pregnancies and deliveries. Repeat miscarriages, also known as recurrent pregnancy loss, are defined as two or more miscarriages in a row. Even for those with recurrent pregnancy loss, 50 percent to 60 percent still go on to have a successful pregnancy with the birth of a healthy baby.

Signs and Symptoms of a Miscarriage

According to WebMD, the signs and symptoms of a miscarriage include:

  • Contractions
  • Vaginal bleeding or spotting or tissue that looks like blood clots passing through the vagina
  • Severe cramps, similar to menstrual period cramps
  • Abdominal pain
  • Severe back pain or back pain that worsens
  • White-pink mucus
  • Weight loss
  • Fever

Women who experience these symptoms should call their health-care provider right away.

Some miscarriages, called missed miscarriages, have no symptoms; providers detect them only through ultrasounds. In the case of a missed miscarriage, the fetus has died or was never formed, but the tissue has not passed from the mother’s body. Her body generally still feels like she’s pregnant. Doctors will use medications or a procedure to get the fetal tissue out of the uterus.

Causes and Risk Factors

Although doctors cannot determine the cause of every miscarriage, known causes include chromosomal abnormalities, problems with the uterus or cervix, and infections. Factors that increase the risk of miscarriages include maternal medical conditions, the use of drugs, tobacco, or alcohol, and maternal age.

Chromosome Abnormalities

About half of miscarriages occur when the fetus has the wrong number of chromosomes. Chromosomes contain genes, and each person typically has 23 pairs. Occasionally, an embryo will have the wrong number of chromosomes. In most cases, this is incompatible with life, meaning the embryo cannot survive and develop into a baby.

This may result in a condition known as a blighted ovum, in which a fertilized egg implants in the uterus but fails to develop.

Translocation, another major genetic abnormality, occurs when one part of a chromosome moves to another chromosome. This may also be incompatible with life.

The third type of chromosomal abnormality is known as a molar pregnancy, or hydatidiform mole. This occurs when two sperm fertilize the same egg or when one or two sperm fertilize an empty egg (which doesn’t contain the mother’s genetic material).

Although the abnormal embryo will start dividing, it cannot develop into a baby. Instead, tissue containing multiple abnormal cysts will form inside the mother’s uterus. This tissue will need to be removed.

Uterine or Cervical Problems

Uterine or cervical problems also cause some miscarriages. In a condition known as cervical insufficiency or incompetent cervix, the cervix tissue is too weak to remain closed against the growing pressure of the baby. This can lead to a miscarriage that typically occurs in the second trimester.

A health care provider can prevent miscarriages from cervical insufficiency by putting a stitch, called a cerclage, in the cervix to help it remain closed against pressure.

A septate uterus can also cause a miscarriage. A septate uterus occurs when a piece of tissue partially divides the uterus into two compartments, which may not leave enough room for a baby to grow. If a health care provider detects a septate uterus, the provider will usually recommend surgery to repair the uterus before you become pregnant.

Fibroids, abnormal growths in the uterus, can also cause a miscarriage because they can interfere with blood flow to the baby or limit space for the baby to grow. A procedure called myomectomy can remove these fibroids.


Infections, including sexually transmitted infections and listeriosis, can cause miscarriage. Sexually transmitted infections, such as syphilis or genital herpes, are contracted from having sex with an infected partner. These infections don’t always cause obvious symptoms in the mother, especially in their early stages, but they can have serious effects on the baby.

Listeriosis is food poisoning contracted from a type of bacteria known as Listeria. It can cause severe problems for the baby, even if the mother doesn’t feel sick. That is why pregnant women are advised to avoid foods like raw or undercooked meat or seafood and unpasteurized cheese.

Rubella, also known as German measles, also puts a mother and baby at greater risk of miscarriage. Women of childbearing age can receive rubella vaccinations before they become pregnant to lower their risk of contracting the infection.

If you suspect you have an infection, contact a provider right away to protect the baby.

Maternal Medical Conditions

Certain other maternal medical conditions may not necessarily be a direct cause of miscarriages but can still increase the risks. These conditions include:

  • Autoimmune disorders
  • Obesity
  • Hormonal issues
  • Thyroid problems such as hypothyroidism and hyperthyroidism
  • Preexisting type 1 or type 2 diabetes
  • Gestational diabetes

Other Risk Factors

Several other factors increase the risk of a miscarriage, including smoking, drinking alcohol, and using street drugs. The mother or father’s exposure to certain chemicals can pose a risk.

Women older than 35 are at a greater risk of miscarrying than younger mothers. Women who have had previous miscarriages are also at an increased risk of having another one.

How long does a miscarriage last?

The duration of a miscarriage can vary from woman to woman and will also differ depending on how far along the pregnancy was. Some women have labor-like pain, while others don’t feel much pain at all.

Blood and fetal tissue may pass from the mother’s body for up to two weeks. In some cases, a health care provider will prescribe misoprostol, which induces uterine contractions, to help the fetal tissue pass more quickly.

Sometimes a miscarriage doesn’t complete on its own, and some of the fetal or placental tissue remains in the body. This is known as an incomplete miscarriage. A doctor may suggest a dilation and curettage (D&C) to remove the remaining tissue. A D&C is done under general or regional anesthesia and is considered a safe procedure with a low risk of long-term complications.

Pregnancy After a Miscarriage

After a miscarriage, most women can have a successful future pregnancy and deliver a healthy baby. Women seeking to become pregnant after a miscarriage should speak with their health care provider.

Some experts believe you should wait three months or more after your first post-pregnancy menstrual cycle before trying to conceive, according to WebMD. You should be fully healed physically and emotionally. Your provider may want to schedule a pelvic exam and checkup before you try to become pregnant again.

How do I know if I’m having a miscarriage?

Miscarriages look different for everyone, but the most common symptoms are vaginal bleeding and cramping. The bleeding may be light at first.

Note that light bleeding in early pregnancy is actually common and does not necessarily signify a miscarriage. However, notifying your health care provider right away is important.

In most cases, you can’t stop a miscarriage once it has begun, although treatment can help the miscarriage complete more quickly.

In some cases, the symptoms may indicate a threatened miscarriage. In a threatened miscarriage, a fetal heartbeat is still present, and the pregnancy may be able to continue. Treatment for a threatened miscarriage can include bed rest, avoiding intercourse, a progesterone injection, and treating any underlying conditions.

When does a miscarriage usually happen?

Although some miscarriages occur after the third month of pregnancy, most occur within the first trimester (before the 13th week of gestation).

What should I do to avoid miscarriage?

Many miscarriages occur because of factors the pregnant woman cannot control, such as chromosomal abnormalities in the embryo. However, you can control some of the risk factors for miscarriage and other types of pregnancy complications.

Miscarriage vs. Stillbirth (IUFD)

Although intrauterine fetal demise (stillbirth) is similar to a miscarriage, it is different. Stillbirth “is a fetal death that occurs at or greater than 20 weeks gestation or at a birth weight greater than or equal to 350 grams,” according to researchers from William Sparrow Hospital in Michigan. In other words, miscarriage occurs in the first half of pregnancy, while stillbirth occurs in the second half.

Intrauterine fetal demise is the fifth leading cause of death worldwide. Symptoms also include bleeding and cramping. Lack of fetal movement and an undetectable heartbeat during an ultrasound or Doppler are other symptoms of intrauterine fetal demise.

The Loss of a Pregnancy Is Difficult

The loss of a pregnancy is challenging physically and often extremely difficult emotionally. Grief, disappointment, shock, and despair often occur and, for many women, continue for some time. These are normal emotions.

If you have experienced a miscarriage, surround yourself with loving friends and family. Be patient with yourself. Healing will come at a different pace for everyone.

If you believe that your miscarriage was the result of medical malpractice, contact the Birth Injury Center. Our compassionate team can ensure you receive the resources you need to heal and look forward to a brighter future.

Written by:
Birth Injury Center Team

The Birth Injury Center aims to create informational web content and guides to help women and their families seeking support and guidance for birth injuries caused by medical negligence. All of the content published across The Birth Injury Center website has been thoroughly investigated and approved by medical expert Natalie Speer, RNC-OB, Attorney Ryan Mahoney, and Attorney Rick Meadows.