Antenatal Care DR. Yasir Katib MBBS, FRCSC Perinatologist
Case I 20 y old lady newly married for 4 months. Known case of DM since age of 2 years old. She is planning to get pregnant and visiting your clinic for pre-conceptional visit. What we should do?
Preconception Preconceptional visit Medical diseases control Medications review Diet, smoking and illicit drugs Immunization Supplementations Consultation
Prevention Folic acid Reduces the risk of neural tube defects, (?required for normal cell division) 400 micrograms/day for all women in the childbearing years 4 mg/day starting 3 months prior to conception and continue at least through the 1st trimester of pregnancy for high risk population
Case II 20 y old lady newly married 4 months ago. Known case of DM presented with a delayed period and her LMP 5 weeks ago. She had a positive home pregnancy test and visit your clinic for antenatal care What we should do?
Antenatal care (ANC) goals and strategy Explain the components and objectives of prenatal goals Describe the frequency and aim of each prenatal visit Genetic counseling and its available tools Risks and benefits of the genetic tests
ANC Objectives To ensure the birth of a healthy baby with minimal risk for the mother by Early, accurate estimation of GA Identification of the patient at risk for complications Ongoing evaluation of the health status of both mother and fetus Anticipation of problems and intervention, if possible, to prevent or minimize morbidity Patient education and communication
ANC Prenatal care is not a single intervention “Quantity" Vs. “Quality" of ANC A systematic review of observational studies and randomized trials concluded that there was no conclusive evidence that prenatal care improved birth outcomes Randomized trials have also shown that enhanced prenatal care did not result in improved outcomes compared to routine prenatal care
ANC Components HISTORY PHYSICAL EXAMINATION LABORATORY TESTS DIAGNOSTIC IMIGING PATIENT EDUCATION MEDICATIONS
HISTORY Personal and demographic information Past obstetrical history Personal and family medical history Past surgical history Genetic history Menstrual and gynecological history Current pregnancy history Psychosocial information
Physical examination A complete physical examination Specially… Uterine size and shape Evaluation of the adenexea Baseline blood pressure, weight, and height
LABORATORY TESTS 1st visit A standard panel of laboratory tests (Routine) CBC Blood gp & antibodies screen HbS Ag Rubella VDRL Urine C&S Cervical PAP smear
LABORATORY TESTS 1st visit In high risk population Chlamydia swab HIV TFT
LABORATORY TESTS others N. gonorrhea TB Toxoplasmosis HCV BV Others HB electrophoresis, cystic fibrosis, phenylalanine level …etc
Follow-up visits Major goals (PET, malpresentation) Components Wt, B/P, SPH, FH auscultation, FM, presentation Patient’s concerns Education
Follow-up visits Uncomplicated pregnancies Every 4 weeks until 28 wks Every 2 to 3 weeks from 28 to 36 wks Weekly until delivery
Follow-up visits Laboratory follow-up GDM screening at 24-28 wks CBC & antibodies screen GBS screening (recto-vaginal swab)
DIAGNOSTIC IMIGING Ultrasound Minimum requirement Usefulness Limitations Others MRI
1st Trimester U/S Confirm pregnancy Viability Assess GA (Dating) Multiple gestations (chorionicity / amnionicity) Maternal pelvic anomalies AIUM Standards and Guidelines
2nd Trimester U/S Fetal normality: • Head shape and size and internal structures (cavum pellucidum, cerebellum, ventricular size at atrium < 10 mm) • Spine: longitudinal and transverse • Abdominal shape and content at level of stomach • Abdominal shape and content at level of kidneys and umbilicus • Renal pelvis < 5 mm anterior–posterior measurement • Longitudinal axis abdominal–thoracic appearance (diaphragm and bladder) • Thorax at level of a four-chamber cardiac view • Arms: three bones and hand (not counting fingers) • Legs: three bones and foot (not counting toes)
VALUE OF PRENATAL GENETIC DIAGNOSIS: Why do we do it? Reassurance Increases options Antenatal fetal treatment Preparation for outcome Avoidance of obstetric complications Selective termination
Prenatal Screening Modalities
Allows adjustment of age-related risk Improved detection rate Screening at 11-20 wks 10 12 14 16 18 20 wks Allows adjustment of age-related risk Improved detection rate Courtesy Dr J Johnson and the Fetal Medicine Foundation
Non-invasive prenatal diagnostic tests Maternal Serum Screen Nuchal Screen Nuchal plus biochemistry Ultrasound
Maternal Serum Screen Three biochemical markers BHCG AFP Estriol Gives age adjusted risk Screens for Down’s and NTD
MSS 1/1 1/378 Risk = age X OR BHCG X OR uE3 X OR AFP
MSS Limitations Sensitivity 70 % Specificity 95% ( False positive 5%) Two reasons for a false positive: Wrong dates Twins
1/200 chance of abnormality Maternal age-based screening Rationale 70% 30% 1/200 risk of miscarriage 1/200 chance of abnormality = =
Assessment of Background Risk Maternal Age 0.0001 0.001 0.01 0.1 1 10 20 25 30 35 40 44 Years Trisomy 21 47xxx/xxy/xyy Risk % Trisomy 18 Trisomy 13 45x Triploidy Courtesy Dr J Johnson and the Fetal Medicine Foundation
Assessment of Background Risk Gestational Age % 20 40 60 80 100 10 14 18 25 30 35 Weeks Trisomy 21 Trisomy 18 Trisomy 13 Triploidy 47xxx/xxy/xyy 45x Courtesy Dr J Johnson and the Fetal Medicine Foundation Snijders et al 1999
Nuchal Translucency “the skin is deficient in elasticity. . . . . . too large for the body” Langdon Down Observations on an ethnic classification of idiots. Clinical Lecture Reports, London Hospital 1866;3:259. Courtesy Dr J Johnson and the Fetal Medicine Foundation
Gestation 11-14 wks CRL 45-84 mm Mid-sagittal view Image size >75% Nuchal Translucency Gestation 11-14 wks CRL 45-84 mm Mid-sagittal view Image size >75% Neutral position Away from amnion Maximum lucency Callipers on-to-on Courtesy Dr J Johnson and the Fetal Medicine Foundation
Significance of increased Nuchal fluid Chromosome abnormalities Birth defects (cardiac, d.hernia) Genetic syndromes Increased mortality (> 3.5 mm) Courtesy Dr J Johnson and the Fetal Medicine Foundation
Pathophysiology of increased nuchal translucency Abnormal or delayed lymphatic development Venous congestion Cardiac failure Altered composition of extracellular matrix Failure of lymphatic drainage due to fetal hypokinesia Fetal anemia or hypoproteinemia Congenital infection Courtesy Dr J Johnson and the Fetal Medicine Foundation
Courtesy Dr J Johnson and the Fetal Medicine Foundation
Courtesy Dr J Johnson and the Fetal Medicine Foundation
First Trimester Biochemical Markers PAPP-A: Pregnancy associated plasma protein A Produced by placental trophoblast Increases in 10-14 week period Lower in DS pregnancies (0.43 MOM) Associated with 42 % DR at 5% FPR. Free - hCg: Free subunit of human chorionic gonadotrophin. Placental protein Decreases in T1 like total hGC Higher in DS pregnancies (1.79 MOM) Associated with 23% DR at 5% FPR Courtesy Dr J Johnson and the Fetal Medicine Foundation
Fetal NT + Maternal age + ßhCG + PAPP-A at 11-14 wks Screening at 11-14 wks Fetal NT + Maternal age + ßhCG + PAPP-A at 11-14 wks Invasive Testing 5% All 20 40 60 80 100 % Age ßhCG PAPP-A Detection Rate 30% 89% 72% 60% NT Courtesy Dr J Johnson and the Fetal Medicine Foundation
INVASIVE TECHNIQUES FOR EARLY PRENATAL TESTING Chorionic Villus Sampling Amniocentesis
Amniocentesis http://wchs.health.wa.gov.au/health/a/amnio.htm
Amniocentesis
Amniocentesis Performed at or more 15 weeks Takes 2-3 weeks for Karyotype Pregnancy loss risk 1/200 Can get result of trisomies 13,18,21 and Turners Syndrome X0 in 48 hours with FISH (Florescent Insitu Hybridization)
Chorionic Villus Sampling
Chorionic Villus Sampling Performed at 10-14 weeks Takes 2-3 weeks for the result Pregnancy loss rate 1/100 Operator experience important Link to limb abnormalities (still controversial) Placental mosaicism up to 3%, but little effect on outcome
Post Test A standard panel of laboratory tests (Routine) dose not include Rubella TFT VDRL Urine C&S Cervical PAP smear
Post Test First trimester scan does not include Fetal morphology Viability Assess GA (Dating) Multiple gestations (chorionicity / amnionicity) Maternal pelvic anomalies
Post Test Which of the following is not a cause for an abnormal MSS Down’s syndrome IUFD Twins Wrong dates Congenital heart disease
Post Test A false positive on the MSS occurs in 1/20 tests True False
Post Test List Two advantages of Amniocentesis over CVS Decreased miscarriage rate Lower risk of mosaicism No association with limb reductions
Post test Which of the following tests is the best at detecting Down’s Syndrome MSS Nuchal Nuchal plus PAPP A and Free BHCG
Post Test What is the miscarriage rate with amniocentesis? 0.5% 3% 5% 10%
Post Test List one advantage of CVS over amniocentesis Early results