Missed Miscarriage and Miscarriage: What’s the Difference?

Early pregnancy loss or miscarriage happens in nearly 10 out of every 100 known pregnancies, according to the American College of Obstetricians and Gynecologists (ACOG). 

While most miscarriages include obvious symptoms, such as unexplained bleeding and cramping, some do not. These are known as missed miscarriages. If the term “missed miscarriage” is new to you, read on for more info on the prevalence of this type of pregnancy loss, signs to look for and more.

What is a Miscarriage? 

According to the Mayo Clinic, a miscarriage is a spontaneous and sudden pregnancy loss before week 20 of pregnancy.

For many women, a miscarriage includes heavy bleeding and cramping in the pelvic area or lower back. The cervix opens and the body begins to naturally expel the pregnancy and surrounding tissue. 

This can be an incredibly traumatic experience for any woman. It’s important to recognize that a miscarriage is not the woman’s fault and that it’s normal and healthy to grieve your loss. 

Chromosomal abnormalities are the likely culprit behind many miscarriages. Extra or missing chromosomes can cause a blighted ovum (where no embryo forms), stop the embryo from developing as expected or cause a molar pregnancy (abnormal placental growth and no fetal growth). 

A molar pregnancy is the result of two sets of paternal chromosomes and no maternal chromosomes. A pregnancy with one set of the mother’s chromosomes and two sets of the father’s chromosomes is known as a partial molar pregnancy. Neither of these are a viable pregnancy. 

Some miscarriages may also result from serious injury or illness. Certain chronic health conditions such as thyroid disease, uncontrolled diabetes or uterine or cervix problems may also lead to miscarriage. Others have no known cause.

Risk factors for miscarriage may include being older than 35, a history of past miscarriages, uterine or cervical problems, genetic conditions, smoking, alcohol and illegal drugs.

Most times there is nothing you can do to prevent a miscarriage. However, make sure that you are getting regular prenatal care, taking prenatal vitamins, limiting caffeine, smoking, drinking and controlling long-term health conditions. Speak to your doctor about any risk factors that you may have and how to best care for yourself.

What is a Missed Miscarriage?

A missed (or silent) miscarriage is when the fetus hasn’t fully developed or has died, but the body hasn’t physically miscarried. While a missed miscarriage may have similar causes as a miscarriage, it won’t have the same signs. Even though the fetus is no longer growing and there is no heartbeat, the woman’s body hasn’t started to expel it yet. Instead of first-trimester bleeding or cramping, there is usually no evidence of a miscarriage. This means a woman may still notice pregnancy symptoms and the news often comes as a shock.

What are the Signs of Missed Miscarriage? 

The silent nature of this early pregnancy loss means there are no signs, typical miscarriage symptoms or red flags to look for. 

A missed miscarriage doesn’t typically start with spotting, vaginal bleeding, vaginal discharge, a gush of fluid or abdominal pain and cramping. It’s possible some of your first-trimester pregnancy symptoms, such as morning sickness or breast tenderness, may begin to fade or disappear. 

How Do You Know You're Having a Silent Miscarriage? 

Without noticeable warning signs, it's not likely you will know you're having a miscarriage. You may go through several days or weeks before your next appointment, making it challenging to know when the miscarriage happened. Routine prenatal care is a valuable resource. Even though you aren't likely to notice the miscarriage, your doctor, midwife or obstetrics provider should not miss it.

Failure to detect a fetal heartbeat alone typically isn't enough to diagnose a missed miscarriage-- especially if it's still early in your first trimester of pregnancy. Incorrect or even slightly off gestational dating can change the timing of when the healthcare provider would expect to hear a fetal heartbeat. 

According to the ACOG, the majority of pregnancy losses (80%) happen in the first trimester However, you may not have an ultrasound scheduled during this time. The ACOG notes expectant mothers typically have a standard ultrasound between 18 and 22 weeks of pregnancy. Some OBGYNs will perform an ultrasound at 12 weeks, however, if you have a seemingly healthy pregnancy and don't have other issues, such as a high risk of miscarriage or problems with the placenta, an early ultrasound may not be performed. 

Low or no cardiac activity via fetal Doppler is a red flag that a healthcare provider won't ignore. An ultrasound will be ordered to confirm a suspected miscarriage.

Your medical provider may also order a blood test to check your hCG levels. An hCG (or human chorionic gonadotropin) test measures the amount of “pregnancy hormone” in your body. 

According to Mount Sinai Hospital, non-pregnant women have an hCG level of 5 mIU/mL or less. Pregnant women should have an hCG level of 31,366 and 149,094 mIU/mL by 8 weeks. This number should increase during your first trimester, with a level between 27,107 and 201,165 mIU/mL at 12 weeks. HCG levels significantly below normal or continuing to fall could indicate a silent miscarriage.

What Happens After a Silent Miscarriage?

Silent miscarriage has physical, emotional and mental health implications. Retained products of conception (also known as RPOC) are placental or fetal tissue that the woman’s body retains. Left untreated, RPOC can put the mother at risk for uterine infection or severe bleeding. 

If an ultrasound shows that your pregnancy has ended, but the miscarriage process hasn’t started or completed, you will be offered treatment options including:

 Expectant Management 

This is a watch-and-wait approach and allows nature to take its course.  Expectant management is typically limited to the first trimester, there is a presumed increased risk of bleeding complications beyond that. 

Medical Management 

The medications mifepristone and misoprostol induce miscarriage. Some women will only need to take misoprostol. However, a 2020 study published in The Lancet did find the combination of medications was more effective than misoprostol alone. A medical approach is usually faster than expectant management and may lower the likelihood of an incomplete miscarriage. The woman will typically experience complete expulsion within 3 days. 

Surgical Management

Surgical removal of the missed miscarriage pregnancy through a procedure such as dilation and curettage can remove remaining fetal tissue from the uterus. This option is often necessary if the wait-and-see or medical approaches don’t work completely. It is preferred in women who present with hemorrhage or signs of infection because those conditions require immediate treatment.

Unless you require emergency treatment, you should be able to choose which treatment you are most comfortable with. 

Although miscarriages are common, it doesn’t make it any easier. Women experiencing pregnancy-related trauma may want to seek mental health treatment from a licensed therapist or a counselor-led support group. 

A mental health provider or peer support group can help you work through the pain of a pregnancy loss and the powerful emotions that come with a silent and often sudden, miscarriage.