Obstetrics Book

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Pregnancy Risk Assessment

Aka: Pregnancy Risk Assessment, Obstetrical Risk Assessment, Preconception Risk Assessment
  1. See Also
    1. Preconception Counseling
    2. First Trimester Education
    3. First Obstetric Visit
    4. Teratogen Exposure
    5. Embryo Organ Development
    6. Radiation Exposure in Pregnancy
    7. Medications in Pregnancy
    8. Substance Abuse in Pregnancy
    9. Intimate Partner Violence
    10. Genetic Syndrome
    11. Mercury Content in Fish
  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. Systemic Lupus Erythematosus
      1. High fetal loss rate, esp. with high SLE activity
      2. Clowse (2005) Arthritis Rheum 52:514-21 [PubMed]
    2. Diabetes Mellitus
      1. See Diabetes Mellitus Preconception Counseling
      2. Avoid ACE Inhibitors, Angiotensin Receptor Blocking Agents (ARB), and Statin agents
      3. Metformin may be continued, but other oral antiantidiabetic medications should be discontinued
      4. Optimize Blood Glucose control with goal Hemoglobin A1C <7%
        1. Hyperglycemia is Teratogenic in first 12 weeks
        2. Start Insulin as indicated
        3. Monitor for Hypoglycemia (be aware of decreased Hypoglycemia awareness)
        4. Observe for Diabetic Ketoacidosis
    3. Bariatric Surgery
      1. Avoid pregnancy in the first 18 months after Bariatric Surgery
        1. Allow for weight loss and nutritional status to stabilize prior to pregnancy
      2. Increased risk of Internal Hernia following Bariatric Surgery
        1. Internal Hernia is especially more common in first 18 months following Bariatric Surgery
      3. Unexpected pregnancy is more common
        1. Oral Contraceptive absorption is reduced and fertility improves with weight loss
      4. Nutritional deficiency is common in Bariatric Surgery
        1. Deficiencies include Vitamins A, B1, B6, B9, B12, C, D, E, K and iron
        2. Check standard Bariatric Surgery labs at recommended intervals (as for non-pregnant patients)
        3. Supplements recommended prior to pregnancy and continue throughout pregnancy
          1. Multivitamin 2 daily
          2. Iron 65 mg daily (in addition to Multivitamin)
          3. Folic Acid 400 mcg daily
          4. Vitamin D 400-800 mcg daily
          5. Vitamin B12 350 mcg daily
    4. Obesity (BMI >27-30 kg/m2)
      1. Obesity general risks
        1. Risk for Gestational Diabetes and Hypertension
        2. Higher risk for Fetal Macrosomia (associated with Shoulder Dystocia, operative delivery)
        3. Higher risk for Neural Tube Defect, IUGR, congenital anomalies, Spontaneous Abortion and Stillbirth
      2. 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
    5. Underweight (BMI<18.5 kg/m2)
      1. Associated with nutritional deficiency and infants with Gastroschisis
      2. Evaluate for Eating Disorders prior to pregnancy
    6. Chronic Hypertension
      1. See Hypertension in Pregnancy
      2. See Anti-Hypertensive Medications in Pregnancy
      3. Maternal Hypertension is associated with preterm birth, Placental Abruption, IUGR, PIH and fetal death
      4. Antihypertensives safe in pregnancy
        1. Methyldopa
        2. Calcium Channel Blockers (IUGR risk)
      5. Avoid agents associated with congenital defects
        1. ACE Inhibitors
        2. Angiotensin Receptor Blocking Agents
        3. Thiazide Diuretics
        4. Atenolol (associated with IUGR)
    7. Epilepsy
      1. See Epilepsy in Pregnancy
      2. Associated with 4-8% risk of congenital anomalies
      3. Folic Acid supplementation at 1000 to 4000 mcg daily starting 1-3 months before pregnancy
      4. Avoid Valproate, Phenytoin, Carbamazepine and phenobarbital in pregnancy due to Teratogenicity risk
      5. Attempt to decrease antiepileptics to a single safe agent, at the lowest effective dose
      6. Seizures worsen during pregnancy in as many as one third of patients
    8. Deep Vein Thrombosis (DVT) or other Thromboembolism (or Thrombophilia)
      1. Risk of recurrence in pregnancy 7 to 12%
      2. Test for Thrombophilia
      3. Consider Low Molecular Weight Heparin in pregnancy
      4. Avoid Warfarin (Teratogenic)
    9. Major Depression
      1. See Depression Management in Pregnancy
      2. Tricyclic Antidepressants
      3. Selective Serotonin Reuptake Inhibitors
    10. Anxiety Disorder
      1. Avoid Benzodiazepines (associated with Cleft Lip and Palate)
    11. Asthma
      1. See Asthma in Pregnancy
      2. Inhaled Corticosteroids should be continued
      3. Optimize Asthma Management to minimize the risk that oral Corticosteroids will be needed
      4. Oral Corticosteroids are associated with IUGR, Cleft Palate and Preeclampsia risk
        1. Use oral Corticosteroids when the risk of Severe Asthma to mother and fetus exceeds that of Corticosteroid risk
    12. Acne Vulgaris
      1. Do not become pregnant on Isoretinoin (Accutane) due to serious Teratogenic effects
    13. Hypothyroidism
      1. See Hypothyroidism
      2. See Levothyroxine for dosing protocol
      3. Avoidance of Hypothyroidism in Pregnancy is critical
        1. Obtain endocrinology Consultation
        2. Check Thyroid Stimulating Hormone (TSH) at earliest pregnancy diagnosis
        3. Increased dose required from earliest diagnosis of pregnancy until delivery
          1. Anticipate increasing dose by 30% as early as 4-6 weeks Gestational age
        4. Decrease dose to baseline immediately after delivery, and recheck TSH in 6-8 weeks
        5. Recheck TSH every trimester at minimum
    14. Hyperthyroidism
      1. First trimester: Propylthiouracil (PTU)
        1. Switch to Methimazole after first trimester due to hepatotoxicity risk with PTU after first trimester
        2. Methimazole should be avoided in first timester due to possible Teratogenicity during that trimester
      2. Second trimester: Methimazole (Tapazole)
      3. Third trimester: Methimazole (Tapazole)
    15. Miscellaneous conditions with an impact on pregnancy
      1. Phenylketonuria (PKU)
      2. Congenital Heart Disease (and other cardiac disease)
      3. Chronic Kidney Disease
      4. Hemoglobinopathies
      5. Cancer
      6. Intimate Partner Violence (physical abuse)
  7. History: Medications
    1. See Medications in Pregnancy
    2. Switch chronic medications with risk (Class D or X) to safer medications prior to conception
    3. Reduce medications to the lowest dosages and continue only the ones with significant benefit
  8. 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
  9. History: Family related risk (consider genetic counselor if positive history)
    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
  10. 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
  11. History: Teratogen Exposure
    1. See Teratogen Exposure
      1. Includes Occupational Exposures in Pregnancy
      2. Includes Herbal Teratogens
    2. See Nutrition in Pregnancy
      1. Includes food Teratogens
      2. See Mercury Content in Fish
    3. See Radiation Exposure in Pregnancy
    4. See Medications in Pregnancy
    5. See Substance Abuse in Pregnancy
  12. References
    1. Wilkins in Ryan (1999) Kistner's Gynecology, p. 451
    2. Brundage (2002) Am Fam Physician 65(12):2507-14 [PubMed]
    3. Farahi (2013) Am Fam Physician 88(8): 499-506 [PubMed]
    4. Johnson (2006) MMWR Recomm Rep 55(RR-6): 1-23 [PubMed]
    5. Leuzzi (1996) Med Clin North Am 80:337-74 [PubMed]
    6. Morrison (2000) Prim Care 27(1):1-12 [PubMed]

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