Missed Abortion

Missed abortion, also known as silent miscarriage or missed miscarriage, is a type of pregnancy loss where the embryo or fetus has died but the body has not recognized the loss and expelled the pregnancy tissue. This condition often comes as a shock during routine prenatal care when no fetal heartbeat is detected, despite the absence of typical miscarriage symptoms.

Medical Disclaimer: This information is for educational purposes only and should not replace professional medical advice. If you suspect pregnancy complications, contact your healthcare provider immediately.

Overview

A missed abortion occurs when an embryo or fetus dies in the uterus but the body does not immediately recognize the pregnancy loss. Unlike a typical miscarriage where bleeding and cramping signal the loss, a missed abortion may have no obvious symptoms. The pregnancy tissue remains in the uterus, and pregnancy hormones may continue to be produced for some time, which can make detection challenging without medical examination.

This type of pregnancy loss affects approximately 1-5% of all pregnancies and is most commonly diagnosed in the first trimester, typically between 6-12 weeks of gestation. The term "missed abortion" is medical terminology that can be emotionally difficult for patients; many healthcare providers now prefer terms like "missed miscarriage" or "silent miscarriage" when discussing this condition with patients.

The emotional impact of a missed abortion can be particularly challenging because parents may have been unaware of the loss for days or weeks. The discovery often occurs during a routine ultrasound when the absence of cardiac activity is noted, or when expected developmental milestones are not met. Understanding this condition, its causes, and treatment options is crucial for both physical recovery and emotional healing.

Symptoms

Missed abortion is unique among pregnancy losses because it often presents with minimal or no symptoms initially. The body may continue to exhibit pregnancy signs even after fetal demise has occurred, making early detection challenging without medical examination.

Common Early Signs

  • Gradual disappearance of pregnancy symptoms (breast tenderness, nausea)
  • Spotting or bleeding during pregnancy - often light brown or pink
  • No fetal movement (if pregnancy was advanced enough)
  • Intuitive feeling that "something is wrong" with the pregnancy

Physical Symptoms That May Develop

Concerning Symptoms

  • Sharp abdominal pain - may indicate complications
  • Blood in stool - requires immediate medical evaluation
  • Heavy bleeding with large clots
  • Fever or chills (may indicate infection)
  • Foul-smelling vaginal discharge

Associated Pregnancy Concerns

  • Problems during pregnancy - general pregnancy complications
  • Absence of expected pregnancy progression on ultrasound
  • HCG levels that plateau or decline slowly

Causes

The causes of missed abortion are often multifactorial and may remain unknown in many cases. Understanding potential causes can help with emotional processing and future pregnancy planning, though it's important to note that most missed abortions are not preventable and are not caused by anything the mother did or didn't do.

Chromosomal Abnormalities

The most common cause of missed abortion is chromosomal abnormalities in the developing embryo or fetus. Studies show that 50-70% of first-trimester pregnancy losses are due to chromosomal issues, including:

  • Trisomy (extra chromosome) - most commonly trisomy 16
  • Monosomy (missing chromosome) - except for Turner syndrome
  • Triploidy (complete extra set of chromosomes)
  • Structural chromosomal rearrangements

Maternal Factors

  • Hormonal imbalances: Insufficient progesterone, thyroid disorders, uncontrolled diabetes
  • Uterine abnormalities: Fibroids, septate uterus, Asherman's syndrome
  • Immunological factors: Antiphospholipid syndrome, other autoimmune conditions
  • Infections: Certain viral or bacterial infections during early pregnancy
  • Blood clotting disorders: Thrombophilias affecting placental blood flow

Environmental and Lifestyle Factors

  • Advanced maternal age (risk increases after age 35)
  • Advanced paternal age (over 40)
  • Exposure to environmental toxins or radiation
  • Certain medications taken during early pregnancy
  • Severe malnutrition or extreme weight loss
  • Substance abuse (alcohol, drugs, excessive caffeine)
  • Smoking or exposure to secondhand smoke

Risk Factors

While missed abortion can occur in any pregnancy, certain factors increase the risk:

Age-Related Factors

  • Maternal age over 35: Risk increases progressively with age
  • Age 35-39: 20-25% risk of pregnancy loss
  • Age 40-44: 40-50% risk of pregnancy loss
  • Age 45+: Over 50% risk of pregnancy loss
  • Paternal age over 40: Increased risk of chromosomal abnormalities

Medical History

  • Previous miscarriages (risk increases with each loss)
  • History of ectopic pregnancy
  • Chronic medical conditions (diabetes, hypertension, kidney disease)
  • Polycystic ovary syndrome (PCOS)
  • Thyroid disorders
  • Autoimmune conditions

Lifestyle and Environmental Factors

  • Obesity (BMI over 30)
  • Being significantly underweight
  • High stress levels
  • Occupational exposure to chemicals or radiation
  • Use of assisted reproductive technologies (slight increase)

Diagnosis

Diagnosing a missed abortion typically occurs during routine prenatal care when expected pregnancy milestones are not met. The diagnosis can be emotionally challenging as it often comes unexpectedly during what was anticipated to be a routine check-up.

Ultrasound Examination

Transvaginal or abdominal ultrasound is the primary diagnostic tool:

  • Crown-rump length: Embryo measuring ≥7mm with no cardiac activity
  • Gestational sac: Mean sac diameter ≥25mm with no embryo
  • Fetal pole: Absence of cardiac activity in visible fetus
  • Lack of growth: No change in measurements over 7-14 days

Laboratory Tests

  • Serial hCG levels: Plateauing or slowly declining levels
  • Progesterone levels: Low levels may indicate non-viable pregnancy
  • Complete blood count: To check for anemia or infection
  • Blood type and Rh factor: Important for Rh-negative mothers

Diagnostic Criteria

To avoid misdiagnosis, strict criteria are followed:

  • Repeat ultrasound after 7-14 days if initial findings are uncertain
  • Correlation with last menstrual period and conception dates
  • Consideration of irregular cycles or uncertain dates
  • Second opinion or specialist consultation when needed

Treatment Options

Treatment for missed abortion involves removing the pregnancy tissue from the uterus. The choice of management depends on various factors including gestational age, patient preference, medical history, and risk of complications. All options have high success rates when appropriately selected.

Expectant Management (Wait and See)

Allowing the body to naturally expel the pregnancy tissue:

  • Success rate: 25-85% within 2-6 weeks, depending on gestational age
  • Advantages: Avoids medical intervention, natural process
  • Disadvantages: Unpredictable timing, prolonged bleeding possible
  • Monitoring: Regular follow-up to ensure complete expulsion
  • Best for: Early pregnancies, patient preference, stable condition

Medical Management

Using medications to induce expulsion of pregnancy tissue:

  • Medications: Misoprostol alone or with mifepristone
  • Success rate: 80-90% within 1-2 weeks
  • Administration: Oral, vaginal, or sublingual routes
  • Side effects: Cramping, bleeding, nausea, diarrhea
  • Follow-up: Ultrasound to confirm complete expulsion

Surgical Management

Surgical removal of pregnancy tissue:

  • Procedures: Suction curettage (D&C) or manual vacuum aspiration
  • Success rate: 95-100% immediate completion
  • Anesthesia: Local, conscious sedation, or general
  • Recovery: Same-day procedure, quick recovery
  • Risks: Rare complications include perforation, infection, adhesions

Post-Treatment Care

  • Physical recovery: Light bleeding for 1-2 weeks is normal
  • Activity restrictions: Avoid tampons, douching, intercourse for 2 weeks
  • Pain management: Over-the-counter pain relievers as needed
  • Rh immunoglobulin: Given to Rh-negative mothers
  • Contraception: Can be started immediately if desired
  • Emotional support: Counseling resources and support groups

Prevention

While most missed abortions cannot be prevented due to random chromosomal abnormalities, certain measures may help reduce the risk of pregnancy loss and optimize pregnancy outcomes.

Preconception Care

  • Start folic acid supplementation (400-800 mcg daily) before conception
  • Achieve and maintain a healthy weight
  • Control chronic medical conditions (diabetes, thyroid disorders)
  • Update vaccinations (rubella, varicella) before pregnancy
  • Genetic counseling if indicated by family history

Lifestyle Modifications

  • Avoid smoking, alcohol, and recreational drugs
  • Limit caffeine intake (less than 200mg daily)
  • Manage stress through relaxation techniques
  • Maintain regular moderate exercise
  • Avoid exposure to environmental toxins
  • Practice good hygiene to prevent infections

Medical Management

  • Review all medications with healthcare provider
  • Treat any infections promptly
  • Consider progesterone support if indicated
  • Regular prenatal care once pregnant
  • Address any problems during pregnancy promptly

When to See a Doctor

Seek immediate medical attention if you experience:

  • Heavy bleeding (soaking more than 2 pads per hour)
  • Severe sharp abdominal pain
  • Fever over 100.4°F (38°C) or chills
  • Foul-smelling vaginal discharge
  • Signs of shock (dizziness, rapid heartbeat, fainting)
  • Persistent vomiting or inability to keep fluids down

Schedule an appointment if you notice:

Follow-up care is important for:

  • Confirming complete expulsion of tissue
  • Monitoring hCG levels return to normal
  • Discussing future pregnancy planning
  • Addressing emotional and psychological needs
  • Investigating recurrent pregnancy loss (3+ miscarriages)

Related Conditions

References

  1. American College of Obstetricians and Gynecologists. Early Pregnancy Loss. Practice Bulletin No. 200. Obstet Gynecol. 2018;132:e197-207.
  2. Doubilet PM, Benson CB, Bourne T, et al. Diagnostic criteria for nonviable pregnancy early in the first trimester. N Engl J Med. 2013;369(15):1443-1451.
  3. National Institute for Health and Care Excellence (NICE). Ectopic pregnancy and miscarriage: diagnosis and initial management. Clinical guideline CG154. 2019.
  4. Kolte AM, Bernardi LA, Christiansen OB, et al. Terminology for pregnancy loss prior to viability: a consensus statement from the ESHRE early pregnancy special interest group. Hum Reprod. 2015;30(3):495-498.
  5. Magnus MC, Wilcox AJ, Morken NH, et al. Role of maternal age and pregnancy history in risk of miscarriage: prospective register based study. BMJ. 2019;364:l869.
  6. The Miscarriage Association. Managing miscarriage: Your options. 2023. Available at: www.miscarriageassociation.org.uk