What Is a Missed Abortion? Symptoms and Causes

A missed abortion is a type of miscarriage that occurs without symptoms and can have fatal consequences for the woman. Learn more about this condition below.
What Is a Missed Abortion? Symptoms and Causes

Last update: 02 August, 2022

In any pregnancy, there’s at least a 20% chance that the pregnancy will be terminated before term. Miscarriages are usually accompanied by abdominal pain and bleeding, through which the embryonic tissue formed inside the uterine cavity is expelled. However, there are some cases in which spontaneous abortion isn’t accompanied by any type of symptomatology, as the embryo or fetus is retained in the uterus. This is known as a missed abortion, and we’ll tell you about it below.

What is a missed abortion?

A missed or delayed abortion is a termination of pregnancy in which the embryo or lifeless fetus isn’t expelled from the mother’s body. This happens because the woman’s body doesn’t detect the loss of the baby and the placenta continues to function for a few more days.

In turn, the uterus doesn’t contract to expel the embryonic and placental remains. This is the reason why, in this type of abortion, the characteristic symptoms such as bleeding, cramping, and pain don’t occur.

The woman may keep the lifeless fetus in her body for several days, even weeks, and thus increase the risk of serious complications such as systemic infection.

A man comforting his partner.
In a missed abortion, the pregnant woman’s body doesn’t expel the fetal remains, and therefore, the usual symptoms don’t occur.

Know the causes of missed abortion

The causes of missed abortion are the same as those that cause symptomatic terminations and among them, the following stand out:

  • Genetic alterations in the embryo, such as chromosomal abnormalities.
  • Problems in the uterine cavity: Myomas, bicornuate uterus, uterine hypoplasia, or cervical incompetence, among others.
  • Autoimmune disorders, such as systemic lupus erythematosus.
  • Endocrine problems: These cause 5 to 10 % of miscarriages and include diabetes mellitus, polycystic ovary syndrome, thyroid diseases, and some hormonal disorders.
  • Maternal infections: Sexually transmitted diseases can interfere in the correct evolution of pregnancy, as well as mycoplasma or cytomegalovirus infections and toxoplasmosis, among others. All of them directly attack the embryo or fetus in formation and can cause congenital malformations and even death.
  • Coagulation problems: Thrombophilias and other blood diseases can trigger miscarriages.
  • Other maternal diseases, such as cancer, heart disease, or uncontrolled high blood pressure.

Along with this, the retention of the missed abortion in the uterus may be related to a narrowing of the cervix that doesn’t allow the expulsion of the tissues formed in gestation. Also, with the absence of contractions or with the lack of detachment of the embryo from the endometrium.

What are the symptoms that accompany a missed abortion?

The particularity of this type of abortion is that, in general, it isn’t accompanied by characteristic symptomatology. That is, there’s usually no bleeding or abdominal pain suggesting that something is happening inside the uterus.

Some women may have mild symptoms, such as mild pelvic discomfort or sudden disappearance of pregnancy symptoms (nausea, breast tenderness, or drowsiness, among others).

A woman receiving the news of a missed abortion.
Missed abortion can be detected by ultrasound or other specific tests.

How is a missed abortion diagnosed?

In the absence of symptoms, missed abortion can only be detected by specific tests, such as ultrasound. During such an examination, the doctor won’t detect a fetal heartbeat. In other cases, a gestational sac without an embryo may be seen.

It’s also possible to diagnose a missed abortion by means of blood tests, such as a serial blood test for human chorionic gonadotropin hormone. The results will show a sharp drop in the levels of this hormone.

Early diagnosis of missed abortion is key to maintaining a woman’s health. Retained embryonic tissue can lead to life-threatening complications, such as intra-abdominal infection, sepsis, consumption coagulopathy, or hydropic degeneration of the chorionic villi.

What treatment should be performed?

When a specialist detects a missed abortion, they must decide on the appropriate treatment to bring about its expulsion. One can wait for natural resolution or proceed with pharmacological or surgical treatment.

When gestation is less than 8 weeks, the doctor can indicate pharmacological treatment with Misoprostol, which is a medication that dilates the cervix and produces contractions. This favors the natural expulsion of the embryonic contents.

If the missed abortion occurs after this stage, the most appropriate option is surgical treatment. This consists of a uterine curettage, which aspirates or removes the fetal remains and remaining uterine tissues.

In most cases, missed miscarriages are unavoidable. However, complications can be prevented. Therefore, it’s best to go to prenatal consultations in a timely manner and follow the specialist’s recommendations to a tee.

After a miscarriage, pregnancy can be attempted again. However, it’s best to wait at least 2 or 3 menstrual cycles so that the woman is prepared, both physically and psychologically, for a new beginning.

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