How Common Is A Missed Miscarriage And What Causes It?

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In the initial months of pregnancy, there is a fear of miscarriage. That’s the reason, our elders suggest that we do not break our pregnancy news at least until we complete 10-12 weeks.

But sometimes, the miscarriage happens even without our knowledge. It is called a missed miscarriage or a silent miscarriage. Sounds confusing? Momjunction helps you learn more about a missed miscarriage, how you can identify it, and what is done in such cases.

What Is A Missed Miscarriage?

A missed miscarriage or missed abortion is defined as “an irregular pregnancy sac in which the disintegrating embryo has not developed beyond few weeks on two consecutive ultrasound examinations at an interval of one week.” (1)

A missed miscarriage (MM) occurs when there is a fetal loss before 20 weeks of gestation, without showing any signs of it. A missed abortion is of two types — embryonic (preclinical) and fetal abortion.

Embryonic miscarriage occurs when the embryo’s crown rump length is more than or equal to 5cm but lacks cardiac activity.

Fetal miscarriage happens when the fetus is of 7-20 weeks size but lacks cardiac activity.

The fetal loss can be detected through an ultrasound, which confirms the discontinued growth of the fetus.

  • An ultrasound identifies the MM through the presence of a gestational sac, which is around 25mm in diameter with no embryo.
  • The presence of embryo having a crown rump length of around 7mm with no cardiac activity also indicates an MM (2).

A missed abortion is primarily related to the absence of heart beat in the fetus. However, in some cases, there could be a heartbeat.

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How Common Are Missed Miscarriages After Seeing The Heartbeat?

There is a drop in the chances of missed miscarriage after the fetus begins to have a heartbeat noticed after six weeks of pregnancy. There are 78% chances of continuing the pregnancy. Heartbeat heard at eight weeks and ten weeks increases the chances of pregnancy continuity to 98% and 99.4% respectively. So, there is no worry of missed miscarriage (3).

A missed miscarriage does not happen randomly but due to some reasons.

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[ Read: Miscarriage: Causes, Symptoms ]

What Are The Causes Of A Missed Misscarriage?

One of the factors responsible for a missed miscarriage is a chromosomal abnormality, which can hinder the growth of the fetus (4).

A fetus inherits 23 chromosomes each from the mother and the father. Any disparity in the chromosomal divisions can result in abnormalities. Different types of chromosomal abnormalities include (5):

Numerical abnormalities, where the fetus has one chromosome less in a pair (monosomy) or one more in a pair (trisomy).

Structural abnormalities, where the structure of the chromosomes is altered in the sense that a portion of it is deleted, duplicated, transferred to another chromosome (translocation), or a chromosome has broken off or turned upside down (inversion).

Research has found that insertional translocation between chromosomes 7 and 1 is a possible cause of missed abortion (1).

Other possible reasons for missed abortion:

  • Women older than 35 years of age are at the risk of missed miscarriages due to increased chromosomal abnormalities (6).
  • A blighted ovum (7) is a condition arising due to a chromosomal abnormality, wherein an embryo does not develop. It happens between 8th and 13th week of gestation.
  • Intrauterine fetal demise is a situation, wherein an embryo stops developing and dies within the womb.

Molar pregnancy and partial molar pregnancy:

a. Molar pregnancy is associated with abnormal tissue growth in the uterus. It happens due to the absence of genetic information in either the egg or sperm (8).

b. Partial molar pregnancy occurs when the egg fertilizes with two sperms. A partial molar pregnancy is usually associated with abnormalities of the placenta and fetus.

  • Maternal health conditions like hormonal problems, uncontrolled diabetes, uterus or cervix problems, thyroid or infections.
  • Smoking, malnutrition, drug use, excessive caffeine intake and exposure to radiation or toxic substances.
  • Implantation of the egg into the uterine lining does not occur properly. What Are The Symptoms Of Missed Miscarriage?

With a missed miscarriage, you may not experience the signs of a miscarriage, such as bleeding.

However, the hormone levels will start to fall and the pregnancy signs like nausea and tenderness of breasts decrease. These signs may be difficult to analyze.

In rare cases, women may notice a red or brown color discharge with no heavy bleeding (9). If you experience such symptoms make sure to get a checkup done by your doctor.

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How To Treat A Missed Miscarriage?

A missed abortion leaves the fetal tissue remains inside the uterus. They need to be removed. The course of treatment includes:

  1. The doctor may wait for three to four weeks to check if the woman’s body ejects the fetal tissue in a naturally. The waiting period is referred to as expectant management (10).
  1. If the body doesn’t expel it naturally, the doctor may prescribe medication such as misoprostol (a single dose of 600mg) to help the body expel the fetal remains (11).
  1. If both the above steps don’t work, then the doctor may perform dilation and curettage (D&C). This prevents further bleeding and infections.

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[ Read: What To Do After A Miscarriage ]

How is D&C (Dilation And Curettage) Done?

D&C is a procedure carried out for removing pregnancy remains from the uterus and stopping uterine bleeding. The procedure includes the below steps:

  • The cervix is opened or dilated using medications or surgical tools under the supervision of the doctor.
  • After dilating the cervix, the doctor will clear the uterus using a curette, a small surgical tool.
  • It is a brief procedure, which needs general anesthesia. It doesn’t require any stitches.
  • A few days after D&C, women can get back to their routine activities. Some women may have bleeding and pain for up to two weeks or so after the surgery.
  • The doctor might advise against sexual intercourse and the use of tampons until the uterine area is completely healed.

D&C is a simple procedure, and you don’t have to worry about it.

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What To Expect After D&C?

After the D&C, women are likely to bleed for five to ten days. However, you must contact your doctor if you experience (11):

  • Prolonged or heavy bleeding
  • Changes in your vaginal discharge
  • Blood clots or strong abdominal pain
  • Fever or flu-like symptoms.

D&C is done to clean the remains of the fetus. But sometimes this simple procedure could carry risks.

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[ Read: First Period After A Miscarriage ]

What Are The Risks Of D&C?

The complications include:

  • Uterus perforations happen when the surgical instrument passes through the uterine wall
  • Adverse reactions to anesthesia
  • Scarring of the cervix, which gives rise to Asherman’s syndrome. These scars can lead to infertility and change in menstrual flow
  • Uterine or pelvic infections
  • Tear in the cervix, leading to bleeding

Make sure to consult your doctor if the bleeding, cramps, or pain continues beyond two weeks of this procedure. Follow-up with the treatment plans as suggested by your doctor.

A missed miscarriage is beyond anybody’s control. But certain care towards one’s lifestyle can help one prevent the incidence of an MM.

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How To Prevent A Missed Miscarriage?

Missed abortion happens naturally and not because you have done something wrong. However, there are some preventive measures to minimize the risks:

  • A healthy diet is important to carry forward a healthy pregnancy. Include more fruits, vegetables and whole grains in your diet
  • Stay away from fatty and processed foods
  • Engage in physical activities to stay fit
  • Take adequate amount of prenatal folic acid and recommended vitamin supplement dose. Include green leafy vegetables, citrus fruits, lentils, beans, whole wheat grain and cereals in your diet
  • Avoid alcohol consumption, smoking, drug use, and activities prone to risks while you are pregnant
  • Avoid taking mental stress

Women who have an MM go through a stressful phase. Share your feelings with your partner, parents or close friends. It would help you come out of the situation. Only after you are mentally and physically fit, can you think about getting pregnant again.

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[ Read: What To Eat & Avoid After A Miscarriage? ]

How Long After A Missed Miscarriage Should I Wait Before Trying Again?

Once the bleeding stops and your menstrual cycle gets back to normal, you can start trying for pregnancy. Usually, you will start ovulating after two weeks of an early missed miscarriage. But, as your uterus has gone through a surgery, it is ideal to give some time for the uterus to get healed properly to avoid any further complications.

A missed abortion might be agonizing if it happens repeatedly. However difficult it might be, you need to be mentally and physically strong to come out of the situation. Try to get pregnant once your body recovers and your menstrual cycle comes back to normal.

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Have an experience to share? Let us know in the comment section below.

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Dr. Anita Gondy

Dr. Anita Gondy is an Ob/Gyn at The Ob-Gyn Center in Las Vegas. In practice since 1998, Dr. Gondy began her medical training at Rangaraya Medical College in Kakinada, India and completed studies at the University of Nevada School of Medicine, where she also did an obstetrics and gynecology residency. She is also a Fellow member of The American College... more

shreeja pillai

Shreeja holds a postgraduate degree in Chemistry and diploma in Drug Regulatory Affairs. Before joining MomJunction, she worked as a research analyst with a leading multinational pharmaceutical company. Her interest in the field of medical research has developed her passion for writing research-based articles. As a writer, she aims at providing informative articles on health and pharma, especially related to... more