Definition and Overview

Miscarriage occurs when a pregnancy ends by itself before 20 weeks of gestation or before the foetus is viable. Miscarriages are very common, accounting for up to 25% of known (the mother is aware of the pregnancy) pregnancies. Many cases are not recorded because some women are not even aware of their condition and mistaken miscarriage for a normal period.

Often, when miscarriage takes place, the woman’s body is able to completely expel the pregnancy on its own. An incomplete miscarriage occurs when some products of conception remain in the womb, causing heavy bleeding and severe cramping. If foetal tissue is not expelled following a period of watchful waiting, doctors may prescribe medications or perform a surgical procedure to empty the uterus.

Miscarriages can be either:

  • Early miscarriage - Occurs before 13 weeks of gestation and is commonly caused by certain gene abnormalities or chromosomal problems that occur as the embryo grows. The risk of defective genes is higher in women older than 35 years old.

  • Late miscarriage - Occurs between 14 and 24 weeks of gestation and is often related to medical conditions that affect the mother, including infections, diseases, and abnormalities of the reproductive system.

The lost of pregnancy after 24 weeks of gestation is called a stillbirth.

Causes of Condition

A miscarriage can occur due to the following:

  • Acute infections, such as German measles and mycoplasma

  • Uncontrolled diabetes

  • Cervix and uterus problems

  • Thyroid disease

  • Severe high blood pressure

  • Kidney disease

  • Lupus and other autoimmune diseases

  • Fibroids

  • Poor muscle tone in the womb

Contrary to popular beliefs, high-intensity exercises, sexual intercourse, and working while pregnant do not cause miscarriage.

A woman’s risk of losing her pregnancy can be increased by the following factors:

  • Advanced age - At age 35, a woman’s risk of miscarriage is 20%. This increases to 80% at age 40.

  • Lifestyle factors, such as alcohol abuse and smoking

  • Being obese or underweight

  • Trauma to the abdomen

  • Exposure to certain medications or chemicals

  • History of ectopic pregnancy

Key Symptoms

The most common symptoms of miscarriage are bleeding or vaginal spotting, passing of clot-like material and white-pink mucous through the vagina, and cramping.

  • Bleeding or vaginal spotting - After the loss of pregnancy, the uterus will contract in an attempt to expel its content. In the process, it may be able to pass large clot-like material through the vagina. In some cases, miscarriage is completed by this process without complications. Thus, some women are not even aware that they had miscarried.

  • Cramping - As the uterus contract to empty its content, the patient usually experiences cramping and pain in the lower abdomen, which can radiate to the buttocks and genitals.

Some women also report weakness or dizziness, nausea, vomiting, fever, and urinary symptoms.

Diagnosis and treatment

Women who are of childbearing age and experiencing symptoms mentioned above are usually given pregnancy test to measure their hCG levels. Human chorionic gonadotropin is a type of hormone produced by the placenta after implantation. Blood tests will also be performed to check for anaemia and the patient’s blood type. The results of these tests can help the doctor confirm if the patient is pregnant and whether the pregnancy is normal or abnormal. An ultrasound is also performed to look for evidence of pregnancy within and outside the uterus (ectopic pregnancy).

Possible diagnoses include:

  • Threatened miscarriage - This means that there are vaginal bleeding and abdominal pain but pregnancy continues. Many women who have had this diagnosis go on to have healthy births.

  • Inevitable miscarriage - As the term suggests, miscarriage is expected to occur. The patient shows symptoms of pregnancy loss, including bleeding, cramping, cervical dilation, and abdominal pain but fetal matter and tissues are still intact in the uterus.

  • Incomplete miscarriage - The pregnancy is lost but some foetal or placental materials are not shed from the uterus.

  • Missed miscarriage - The embryo has either died or failed to form but embryonic and placental tissues remain in the uterus.

  • Complete miscarriage - The body has successfully expelled all pregnancy tissues.

In the event of an incomplete miscarriage, patients have three treatment options for their condition. If there are no signs of infection, doctors may recommend watchful waiting to allow miscarriage to progress naturally. Often, the body takes up to four weeks to expel all embryonic and placental tissues. For some patients, waiting for such a long time is extremely emotionally difficult that they elect to undergo medical or surgical therapy.

  • Medical treatment - An ideal option for patients who do not want to undergo surgical procedures or are unwilling to wait for up to four weeks for the miscarriage to complete. Medications, such as misoprostol, are used to soften the cervix and trigger uterine contractions. About 90% of women are able to expel all pregnancy tissue and the placenta 24 hours after taking the medicine.

  • Surgical treatment - Patients who have an active infection during treatment often undergo a surgical procedure called dilation and curettage (D&C). For this procedure, the doctor will clear the uterine lining using a surgical instrument (curette) or suction either under general or local anaesthesia.

Recovering from the treatment of incomplete miscarriage is usually quick and uneventful. Many women are able to physically handle miscarriage very well and take only a few hours up to a couple of days to achieve complete recovery. Many of them also get their regular period after four to six weeks.


  • Ectopic pregnancy and miscarriage. National Institute for Health and Care Excellence (NICE).!/content/nice_guidelines/65-s2.0-QS69.

  • What is recurrent pregnancy loss (RPL)? American Society for Reproductive Medicine.

  • Risk factors for miscarriage from a prevention perspective: A nationwide follow-up study. BJOG: An international journal of obstetrics and gynaecology. 2014;121:1375.!/content/medline/2-s2.0-24548778.

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