Prenatal Care: Introduction and Family Context

1. Prenatal Care: Introduction and Family Context T. Villela, MD Family and Community Medicine San Francisco General Hospital

2. Objectives List important components of obstetric risk assessment Describe essential content of prenatal care Define common screening tests in pregnancy, including advantages and disadvantages Discuss context of prenatal care within a family, and interventions within that context

3. Obstetric Risk Assessment Preconception Similar to antenatal assessment Can concentrate more on prevention Folic acid supplementation (0.4 mg/d) Sexually transmitted infections Nutrition [MMR, varicella, OPV] � delay conception 3 months Td, Hep B Decrease exposure to: tobacco, drugs, alcohol Antenatal

4. Obstetric Risk Assessment Antenatal Goal is to plan for special risk care, consultation, or referral Tools: risk-scoring systems; continuous re-evaluation May not apply to low-risk pregnancies Real vs. theoretical risks. Many risks develop intrapartum and cannot be predicted Outcomes vary in number and specificity; e.g. perinatal mortality vs. apgar score

5. Obstetric Risk Assessment

7. Content of Prenatal Care Diagnosis Urine PT adequate; positive at time of missed menses, or about an HCG level of 25 mIU/ml Dating LMP +/- 2 weeks Bimanual +/- 2 weeks Exam at 16 weeks or 20 weeks +/- 2 weeks Ultrasound prior to 19 weeks +/- 8% 6 days at 10 weeks 10 days at 18 weeks

8. A Brief Pause For Citrus Discussion

9. Content of Prenatal Care Risk assessment Psychosocial evaluation Nutrition evaluation Review of medical history Review of reproductive history Review of family history Physical examination Blood pressure and pulse Height and weight Pelvic and pap

10. Visit Frequency Up to 32 weeks Once every 4 weeks, and as needed 32 � 36 weeks Once every 2 weeks 36 weeks to delivery Once weekly Post partum 2 weeks (optional) 6 weeks

12. Screening Tests: Initial Blood Pressure Height and weight Blood Type, Rh, antibody screening Hgb/Hct HepBSag RPR or VDRL Chlamydia HIV antibody Rubella Serology Hemoglobinopathy screening Amniocentesis or chorionic villus sampling for maternal age >35 yrs Urine culture at 12-16 weeks or first visit PPD Pap smear Early GLT

13. Screening Tests: Initial Blood Pressure Preeclampsia screening Good association with improved outcomes Height and weight Good association with improved outcomes Blood Type, Rh, antibody screening Incidence of isoimmunization decreased from 10 to 1.3 per 1000 births since introduction of RhoGAM RhoGAM at 24 � 28 weeks and at delivery if newborn is Rh pos Hgb/Hct < 10 mod risk < 8 high risk

14. Screening Tests: Initial HepBSag ~ 20,000 births/year among women with active infection Newborn vaccine + HepBIg at least 75% effective in preventing transmission RPR or VDRL Transplacental infection can lead to fetal death in up to 40% of patients Spec ~75%; confirm with MHA-TP Chlamydia 155,000 women infected at time of delivery Half of newborns will develop pneumonitis or conjunctivitis

15. Screening Tests: Initial HIV antibody ARV therapy in third trimester and at delivery can decrease transmission from 23% to less than 8% Rubella Serology Infection prior to 16 weeks associated with worst outcomes Vaccine contraindicated in pregnancy � must delay pregnancy by three months Immunity is not 100% effective Hemoglobinopathy screening Identified carriers are offered screening of partner

16. Screening Tests: Initial Amniocentesis or chorionic villus sampling for maternal age >35 yrs 14 weeks vs. 10 weeks gestation CVS cannot detect neural tube defects Miscarriage rates 0.25 vs. 0.5% Genetics counseling referral Urine culture at 12-16 weeks or first visit Asymptomatic bacteriuria common, ~5% Untreated, up to 25% will develop pyelonephritis Treat >100,000 of a single species of organism

17. Screening Tests: Initial PPD Recommended for immigrant populations and other high risk groups Post partum prophylaxis, include pyridoxine Treatment of active disease no different, except for the following contraindications: streptomycin, pyrazinamide, ethionamide Pap smear Colposcopy if cervical dysplasia is found Treatment of non-invasive disease is usually postponed until after pregnancy Early GLT Previous LGA birth, strong family history

18. Screening Tests: 16 � 18 weeks Offer triple marker testing at 15-20 weeks: correct dating of pregnancy critical to interpretation of results Alpha-fetoprotein (AFP) -- produced by fetal liver. Increased in open neural tube defect, twins. Decreased in Down syndrome Unconjugated Estriol (UE) -- produced by the placenta and fetal liver. Decreased in Down syndrome Human Chorionic Gonadotrophin (hCG) -- produced by the placenta. Increased in Down syndrome CXR if indicated for + PPD

19. Screening Tests: 24 � 28 weeks GLT (50 gm) 140: PPV 22%, NPV 99.7% 130: PPV 17% 3 hour GTT (100 gm) is used for diagnosis: F 105; 1h 180; 2h 155; 3h 140 Abnormal fasting or any two other abnormal values is diagnostic Hgb/Hct RPR or VDRL If Rh neg: recheck antibody screen and administer RhoGAM

21. Preconception: Anticipation, Disappointment

22. First Trimester: Adjustment, Ambivalence

23. Second Trimester: Exploration, Fear

24. Third Trimester:Anticipation, Impatience

25. Fourth Trimester:Delight, Chaos

26. Resources CHN prenatal website Referral guidelines Diabetes diagnosis and management Antenatal testing Much more�. Daisy Gin, RN: 206-5067 BAPAC Perinatal treatment warmline: 800-933-3413 Genetics Testing Center