The majority of miscarriages occur within the first 20 weeks of pregnancy. A miscarriage (also known as a spontaneous abortion) occurs when a woman loses a baby while it’s still within her womb. Almost all miscarriages occur before a woman reaches the 20-week point in her pregnancy, with only 1% of miscarriages occurring after that time (these are known as late miscarriages). Miscarriage is relatively common—approximately one-third to one-half of all pregnancies end in miscarriage before the woman even realizes that she’s pregnant, and another 10% to 20% of women who are aware that they’re pregnant also miscarry. 

Causes of Miscarriage 

Approximately half of the miscarriages that occur during the first trimester of pregnancy are caused by chromosomal abnormalities in the woman’s egg or the man’s sperm. Because the risk of chromosomal abnormalities increases with age, the chances of miscarriage are also higher in older women. 

Other potential causes of miscarriages include: 

  • Faulty implantation of the fertilized egg in the woman’s uterus
  • Hormonal irregularities 
  • Uterine abnormalities 
  • Incompetent cervix (characterized by the premature opening of the cervix during pregnancy) 
  • Certain health conditions, such as congenital heart disease, uncontrolled diabetes, infections, kidney disease, lupus and thyroid disease 
  • Certain medications, including Accutane 
  • Exposure to high levels of radiation or toxins 
  • Severe malnutrition 
  • Smoking 
  • Drinking alcohol 
  • Abusing drugs 

It’s important to remember that having a miscarriage doesn’t mean that you’ll never be able to carry a pregnancy to term—the large majority of women who miscarry subsequently have normal pregnancies and births. 

Symptoms of Miscarriage 

The following can be signs of a miscarriage: 

  • Vaginal bleeding or heavy spotting 
  • Abnormal vaginal discharge 
  • Severe abdominal pain or cramping 
  • Back pain 

If you’re pregnant and you experience any of these symptoms, you should immediately contact your healthcare provider, who will be able to offer you further instructions on what to do next. 

Diagnosing Miscarriage 

If a physician suspects that a woman has miscarried, he or she will likely perform a pelvic examination and order an ultrasound to confirm the diagnosis. And in the event that a woman repeatedly miscarries, a physician may order one or more of the following diagnostic tests to determine what’s causing the miscarriages: 

  • Endometrial biopsy 
  • Hysterosalpingogram
  • Hysteroscopy 

Treatment for Miscarriage 

Treatment will generally depend on whether a woman’s uterus needs to be cleared following a miscarriage. If not, she likely won’t need any further treatment. But if her uterus does need to be emptied, a physician may need to perform a dilation and curettage (D&C) or a dilation and extraction (D&E) procedure, both of which involve dilating the cervix and either scraping or suctioning out any leftover fetal or placental tissue.