Obstetrics Book

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Pregnancy Risk AssessmentAka: Obstetrical Risk Assessment, Preconception Risk Assessment

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  1. See Also
    1. Preconception Counseling
    2. First Trimester Education
    3. First Obstetric Visit
  2. Epidemiology
    1. Risk of congenital anomaly if low risk mother: 2-4%
  3. Timing:
    1. All women of childbearing age
    2. Routine Health Maintenance exams
    3. Following negative Pregnancy Test
    4. Treatment for Sexually Transmitted Disease
  4. Pathophysiology
    1. See Teratogen Exposure
  5. History: Obstetrical and Menstrual
    1. Anovulatory Bleeding (Metrorrhagia)
      1. Polycystic Ovary Syndrome
      2. Female Athlete Triad
      3. Premature Ovarian Failure
    2. Infertility history
      1. More than 6 months of actively trying to conceive
    3. Contraception History
    4. Recurrent Pregnancy Loss
      1. Couples with history of pregnancy loss
        1. Ultimately 70-80% will have a successful pregnancy
      2. Evaluation for 2-3 prior Spontaneous Abortions
        1. Karyotype
          1. Balanced chromosomal Rearrangements
          2. Translocations or Inversions
        2. Lupus Anticoagulant
          1. Activated Partial Thromboplastin Time (PTT)
          2. Kaolin Clotting time
    5. Preterm Labor (Pursue correctable factors)
      1. Cervical incompetence
      2. Uterine anomalies
      3. Maternal infections
    6. Birth defects
      1. See Pregnancy Risk Assessment for ethnic risks
      2. Cystic Fibrosis
      3. Nonsyndromic Hearing Loss
  6. History: Medical
    1. Thyroid Disease
    2. Phenylketonuria (PKU)
    3. Asthma
    4. Cardiac Disease
    5. Kidney Disease
    6. Systemic Lupus Erythematosus
      1. High fetal loss rate, esp. with high SLE activity
      2. Clowse (2005) Arthritis Rheum 52:514
    7. Hemoglobinopathies
    8. Cancer
    9. Diabetes Mellitus
      1. See Diabetes Mellitus Preconception Counseling
    10. Obesity
      1. Associated Neural Tube Defect (NTD) Risk
        1. Weight 80-90 kg: NTD Relative risk 1.9 fold
        2. Weight over 100 kg: NTD Relative risk 3 fold
    11. Chronic Hypertension
      1. See Anti-Hypertensive Medications in Pregnancy
      2. Antihypertensives safe in pregnancy
        1. Methyldopa
        2. Calcium Channel Blockers (IUGR risk)
      3. Avoid agents associated with congenital defects
        1. ACE Inhibitors
        2. Angiotensin Receptor Blocking Agents
        3. Thiazide Diuretics
    12. Epilepsy
      1. Associated with 4-8% risk of congenital anomalies
      2. Folic Acid supplementation at 1 to 4 mg qd
    13. Deep Vein Thrombosis (DVT) or other thromboembolism
      1. Risk of recurrence in pregnancy 7 to 12%
      2. Test for Thrombophilia
      3. Consider Low Molecular Weight Heparin in pregnancy
    14. Major Depression
      1. Tricyclic Antidepressants
      2. Selective Serotonin Reuptake Inhibitors
    15. Anxiety Disorder
      1. Benzodiazepines associated with Cleft Lip and palate
  7. History: Advanced Maternal Age-Related Risks
    1. Chromosomal Abnormalities
      1. Trisomy 13
      2. Trisomy 18
      3. Trisomy 21
    2. Age associated risk
      1. Age 35 year old Risk: 1 per 200 pregnancies
      2. Age 45 year old Risk: 1 per 20 pregnancies
    3. Diagnostic options
      1. Chorionic Villus Sampling: 9-11 weeks
      2. Early Amniocentesis: 12-14 weeks
      3. Traditional Amniocentesis: 15-16 weeks
      4. Fetal Blood Sampling: 2nd-3rd trimester
    4. Advanced Paternal Age
      1. Maternal age risk doubled if father's age >55 years
  8. History: Family related risk (consider genetic counselor)
    1. Cystic Fibrosis
    2. Congenital Heart Disease
    3. Hemophilia
    4. Fragile X Syndrome
    5. Phenylketonuria (PKU)
    6. Dwarfism
    7. Spina bifida
    8. Limb abnormalities
    9. Duchenne Muscular Dystrophy
    10. Myotonic dystrophy
  9. History: Ethnicity (screen parents for carrier status)
    1. Sickle Cell Trait (screen with sickle cell smear)
      1. Black
      2. Indian
      3. Middle Eastern Descent
    2. Tay-Sachs Disease (screen with Hexosaminidase A)
      1. Ashkenazi (East European) Jewish
      2. French Canadian
    3. Alpha or beta-Thalassemia (Screen for MCV<70)
      1. Southeast Asian (Laotian, Cambodian, Hmong, Thai)
      2. Mediterranean
      3. Black
      4. Indian
      5. Middle Eastern
  10. History: Occupational Exposures
    1. General
      1. Teratogens cause birth defects, stillbirths, IUGR
      2. See Teratogen Exposure
    2. Metals (Lead, Mercury)
    3. Solvents (Trichloroethylene, Chloroform, Benzene)
    4. Plastics (Vinyl chloride)
    5. Pollutants (Polychlorinated or Polybrominated Biphenyl)
    6. Pesticides (Organophosphates)
    7. Gases (Carbon Monoxide, Inhalation Anesthetics)
    8. Radiation (e.g. XRay)
  11. References
    1. Wilkins in Ryan (1999) Kistner's Gynecology, p. 451
    2. Brundage (2002) Am Fam Physician 65(12):2507
    3. Leuzzi (1996) Med Clin North Am 80:337
    4. Morrison (2000) Prim Care 27(1):1

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