Miscarriage: Trends, Incidence, and Causes

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Miscarriage Trends, Incidence, and Causes

• Meghan McGillivray

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• American Family Physician
• 20 of women have had a miscarriage
• 5 have had two or more miscarriages
• 15 of all recognized pregnancies end in
  miscarriage
• Clouded and complex issue
• Talk about
• Definitions
• Diagnosis and Categorizations
• Incidence rates
• Possible causes/correlations with increased
  incidence

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Definitions

• Present some difficulties in studies
• Early termination of a fetus within the first
  twenty weeks of pregnancy, and without outside
  interferences.
• Distinguished from a stillbirth according to size
  and weight
• 500 grams or less

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Diagnosis of a Miscarriage

• Lab tests
• HCG
• Pathology
• Clinical Examination
• Ultrasound

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Categories of Miscarriage

• Threatened
• Inevitable
• Incomplete
• Complete
• Missed
• Septic

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Threatened Abortion

• Likelihood of an abortion not inevitable in all
  cases
• Vaginal bleeding
• Cervical os is closed
• No passage of tissue from the uterus
• Cause for bleeding found
• Bed rest

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Inevitable Abortion

• Similar to threatened
• Differences
• Cervical os is open
• Tissue passage from uterus
• Uterine contractions cause cramping
• Abortion is inevitable and will occur within the
  next few hours or days

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Incomplete Abortion

• Retention of products of conception in the uterus
  or cervix
• Can turn very dangerous quickly
• Incite hemorrhaging of mother
• D and C to remove tissue out of uterus and cervix

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Complete Abortion

• All tissue is passed from the uterus
• Disappearance of pregnancy symptoms
• Contracted and small uterus
• Closed cervical os

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Missed and Septic Abortion

• Missed
• Miscarriage not detected and retention of fetal
  tissue within uterus
• Will stop showing signs of growing pregnancy
• Very often results in a Septic abortion

• Septic
• Prolonged retention causes an infection
• High fever
• Decrease in last few decades
• Improvements in contraceptives
• Improvements in medicine
• Legalization of intentional abortions

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Incidence

• 15 of recognized pregnancies
• Unknown or unrecognized pregnancies?
• Study
• HCG levels
• 43
• 25 of these early pregnancies were recognized at
  time of miscarriage
• True incidence estimated to be 50-75 of all
  conceptions

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National Incidences
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National Incidences
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South Dakota Incidences
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South Dakota Incidences
16
District of Columbia
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District of Columbia
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Causes of Spontaneous Abortion

• Fetal
• Maternal/Paternal
• External

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Fetal Causes

• 62 of all miscarriages
• Render it incapable of survival to term
• Chromosomal abnormalities
• Placental abnormalities
• Chromosomal
• 50 of all spontaneous abortions

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Maternal/Paternal Causes

• Much more ill-defined
• Maternal age
• Over 45 yrs old 33
• Over 47 yrs old 80
• Polycystic ovaries, uterine abnormalities,
  alcohol and tobacco consumption, any maternal
  illness that causes maternal and fetal hypoxia
• Pneumonia and Influenza

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Maternal/Paternal Causes Continued

• Increased incidence of miscarriage
• Diabetes Mellitus
• 15 in women with good control
• 45 in women with poor control
• Insulin Resistance
• Study
• Causes a diabetic-like state in the fetal
  environment that results in increased first
  trimester loss

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Maternal/Paternal Causes Continued

• Paternal Causes
• Quote
• 8 to 10 sperm from normal men had chromosomal
  abnormalities
• Flawed sperm are fierce competitors for
  fertilization
• Could account for genetic abnormalities of fetus
  that cause 50 miscarriages

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Paternal/External Factors

• Occupational toxins
• Bring home to pregnant partner
• Damage sperm and fertility
• Transmitted to seminal fluids
• Lead, Boron, Cadmium, Manganese, Mercury,
  Nitrates, Chlorine
• Organic Compounds
• Carbon Disulfide, Chloroprene, many forms of
  Pesticides

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Nitrate Example

• LaGrange County Indiana 1991
• Neighborhood had high incidence of miscarriages.
• Six miscarriages in three women in two years
• Well contaminated with nitrates from pig
  containment area, double or more the EPA
  recommended level
• Upon investigation found that nine other women
  had been having recurrent miscarriages

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Conclusion

• Overwhelming number of correlations,
  associations, etc.
• Epidemiologically and from a public health view,
  extremely complicated