Causes of Missed Miscarriage

In the first trimester of pregnancy, a missed miscarriage can occur. Its causes are multiple, but chromosomal factors stand out.
Causes of Missed Miscarriage

Last update: 05 December, 2021

About 20% of pregnancies end in miscarriages before 20 weeks of gestation. Among these, some can occur as a missed miscarriage, which is the retention of the embryo or fetus without life within the uterine cavity.

In this type of miscarriage, there’s no spontaneous expulsion of the gestational sac as normally occurs. Rather, it can spend days or weeks inside the uterus, without the body detecting it.

In general, the mother doesn’t experience bleeding or other characteristic symptoms. And in the event that they do occur, they’re usually very mild. Find out more in the following article.

Why missed miscarriage occurs

There are several causes for missed miscarriage, which usually occurs in the first trimester of pregnancy. Below, we’ll mention the most outstanding ones.

Genetic alterations

Several studies confirm that chromosomal disorders are the leading cause of spontaneous miscarriages in early pregnancy.

These inconveniences are generated at the moment of conception and can be duplications, triplications, or alterations in the shape of the chromosomes. Any of them can condition the viability of the pregnancy.

A floating chromosome.

Anatomical problems in the mother

If there are anatomical alterations in the uterus, such as fibroids, the presence of two cavities (bicornuate uterus), or cervical incompetence, these can lead to spontaneous miscarriages.

Endocrine diseases

Thyroid gland problems, polycystic ovaries, corpus luteum insufficiency, or low progesterone levels often cause problems in keeping the baby alive.

Hematologic abnormalities

Alterations in blood clotting, most notably thrombophilias, are an important cause of missed miscarriage.

Immune problems

When there are autoimmune diseases, such as lupus, the mother’s antibodies can attack the fetus and promote miscarriages.

Maternal infections

Some maternal infections can cause alterations in the fetus and cause miscarriage. For example, toxoplasmosis, mycoplasma and cytomegalovirus infection, or listeriosis.

Other causes of missed miscarriage

Certain systemic and chronic diseases of the mother such as cancer, diabetes, high blood pressure, and heart problems can cause miscarriages. Likewise, severe trauma, drug use, and drug abuse.

On the other hand, the impediment of the gestational sac being expelled from the uterus can be the result of the following conditions:

  • Narrowing of the cervix
  • Inhibition of uterine contractions
  • Problems in the detachment of the embryo (after week 10)

Symptoms of missed miscarriage

This type of miscarriage is characterized by being asymptomatic. That is, there are no warning signs–bleeding or the expulsion of vaginal fluids don’t usually occur.

Similarly, there’s no abdominal pain or uterine contractions, so doctors need to perform specific diagnostic tests in order to detect it. Among them, the following stand out:

  • Abdominal ultrasound: An embryo is visualized with an absence of a heartbeat or the presence of an empty gestational sac.
  • Blood test: Human chorionic gonadotropin levels begin to decline abruptly.

This retention can bring serious complications to the mother, such as intra-abdominal infection or septicemia, consumptive coagulopathy, or hydropic degeneration of the villi. If not treated in time, these conditions could be fatal.

What should be done about a missed miscarriage?

Carrying out strict prenatal controls is very important in order to detect missed miscarriages, as a specialist’s evaluation through ultrasound is the only way to diagnose them.

If a specialist detects this condition, the doctor will proceed to perform a uterine curettage. This is a surgery that consists of aspirating or removing the remains of the embryo and other structures of the pregnancy.

Depending on the case, the specialist may prescribe certain drugs (such as misoprostol) to dilate the cervix and promote uterine contractions. Even so, most often, they’ll perform surgery to reduce the risk of maternal infections.

A sad woman sitting near an empty crib.

About missed miscarriage, we can say…

A miscarriage is always a hard blow to the mother, who’s looking forward to the arrival of her baby, and to the rest of the family. However, this doesn’t mean that pregnancy can’t be sought again later.

Ideally, women should try to identify the cause of the missed miscarriage and follow the recommendations of specialists in preconception consultations to a tee.

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