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 amd 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 Missed Miscarriage?
To fully understand what a missed miscarriage is, you need to separate this type of pregnancy loss from the term ‘miscarriage.’ According to the Mayo Clinic, a miscarriage is a spontaneous pregnancy loss that happens before the 20th week.
Chromosomal abnormalities are the likely culprit behind many miscarriages. Extra or missing chromosomes can cause 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 is a viable pregnancy.
Some miscarriages may also result from a serious injury, illness, or chronic condition. Others have no known cause. Whatever the reason, a miscarriage is the result of fetal death.
For many women, a miscarriage includes heavy bleeding and cramping. 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 is normal and healthy to grieve this loss.
While a missed miscarriage may have the same 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, one wouldn’t feel anything. This means a woman may still notice pregnancy symptoms, and nothing more.
How Many Mothers Experience a Silent or Missed Miscarriage?
The symptoms of a missed miscarriage aren’t the only silent issue surrounding this type of pregnancy loss. While there are stats on miscarriages in general, the numbers aren’t as clear for missed miscarriages. Research on ultrasound screenings at 10 to 13 weeks gestation, published in the journal Ultrasound In Obstetrics and Gynecology, found that this type of loss affected just over 62 percent of women in the study’s sample who had an early pregnancy failure. Of the 17,870 women participating in a 10 to 13-week ultrasound, the screening detected 313 missed miscarriages and 188 blighted ovum pregnancies.
What are the First Signs?
The silent nature of this type of early pregnancy loss means there are no signs, typical miscarriage symptoms, or red flags to look for. Again, this type of miscarriage won’t 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 fade or disappear.
How Do You Know You're Having a Silent Miscarriage?
Without noticeable warning signs, it's not likely you will know that you're having a miscarriage. This makes routine prenatal care a valuable resource. Failure to detect a fetal heartbeat alone typically isn't enough to diagnose a missed miscarriage-- especially if it's still early on 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.
The majority of pregnancy losses (80%) happen in the first trimester, according to the ACOG. But you may not have an ultrasound scheduled during this time. The ACOG notes expectant mothers typically have a standard ultrasound sometime between 18 and 22 weeks of pregnancy. If you have a seemingly healthy pregnancy and don't have other issues, such as high risk of miscarriage or problems with the placenta, don't expect an early ultrasound. Given that it's more likely your OBGYN will listen for the fetal heartbeat before prescribing an ultrasound, low or no cardiac activity is a red flag that a health care provider won't ignore. Even though they may have already told you to wait until well into your second trimester to get an ultrasound, changes are they'll order this test ASAP if they suspect a miscarriage.
Along with a fetal doppler (listening for the heart rate) and an ultrasound scan, 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. By eight weeks, pregnant women should have an hCG level 31,366 and 149,094 mIU/mL. This number should increase during your first trimester, with a level between 27,107 and 170,409 mIU/mL at 12 weeks. HCG levels that are significantly below normal or continue to fall could indicate a silent miscarriage.
Can a Missed Miscarriage Go Unnoticed?
A silent miscarriage is exactly what the name implies-- and this silence can make a miscarriage go completely unnoticed by the mother. Even though you aren't likely to notice the miscarriage, your doctor, midwife, or obstetrics provider should not miss it. As your pregnancy progresses, routine prenatal check-ups should include fetal heart rate monitoring. Again, failure to hear the heartbeat is often the first sign that a healthcare provider should or will notice.
If you have regular visits scheduled with your healthcare provider, this type of early pregnancy loss should not go unnoticed. But this doesn't mean you will know about it immediately. You may go through several days or even weeks before your appointment. This makes it challenging to know when the miscarriage (end of pregnancy) actually happened.
What Happens After a Silent Miscarriage?
This type of pregnancy loss has physical, emotional, and mental health implications. Retained products of conception (also known as RPOC) is placental or fetal tissue that, as the name says, the woman’s body retains. Left untreated, RPOC can put the mother at risk for uterine infection or severe bleeding.
A miscarriage that doesn’t progress typically requires medical intervention. The three primary treatment options include:
• Expectant management - This is a watch and wait approach. A 2006 article in the journal American Family Physician noted that expectant management is an effective first trimester choice that has a lower rate of pelvic infections, compared to surgical treatment. But the same article also points out that a wait and see strategy does come with a higher bleeding risk and may lead to an incomplete miscarriage. An incomplete miscarriage will require further treatment. Research published in BJOG: An International Journal of Obstetrics and Gynecology found that just over 24 percent of women who chose expectant management (in the study participant group) had a complete miscarriage. Sixteen percent had an incomplete miscarriage and needed surgery.
- Medical management - The medications mifepristone and misoprostol induce miscarriage. Some women will only need to take misoprostol. But a 2020 study published in The Lancet did find the combination of medications were more effective than misoprostol alone. A medical approach is usually faster than expectant management and may lower the likelihood of an incomplete miscarriage.
- Surgical management. Surgical removal of the missed miscarriage pregnancy through a
- procedure such as dilation and curettage can remove the remaining fetal tissue from the uterus. This option is often necessary if the wait and see or medical approaches don’t work completely.
Along with inducing miscarriage, women experiencing
this pregnancy-related trauma may also need to seek mental health treatment from a licensed therapist or a counselor-led support group. A mental health provider can help you to work through the pain of a pregnancy loss and the powerful emotions that come with a silent, and often sudden, miscarriage.
Do you want to learn more about pregnancy, complications, and miscarriages? Read about pregnancy-related losses and more here.
Was this article helpful?
Based in Pittsburgh, Pennsylvania, Erica is a mom and former preschool teacher with degrees in Art History and Applied Developmental Psychology (child development).