JC109 (O&G) - Pre-marital, Pre-pregnancy & Prenatal Counselling Flashcards
Outline the reproductive risks to mother and fetus
Maternal:
- Pre-existing medical conditions (effect on fertility/ pregnancy)
- Pregnancy related complications
- Operatie risk
- Psychosocial problems (maternal mental health, economic status, wellbeing of future child)
Fetus:
- Growth problems - e.g. growth restriction vs macrosomia
- Congenital anomalies: chromosomal, genetic, structural, functional
- Infection - vertical transmitted pathogens
- Birth trauma
Compare globin gene expression before and after birth
Switch from gamma to beta globin occurs shortly after birth:
Beta thalassemia major only presents after birth
Alpha thalassemia major occurs in fetal life already
Define the 4 severities of alpha thalassaemia and genotype
α- deletion or αα: nondeletional - ‘Silent carrier’
α- /α- trans deletion or –/αα: cis deletion - α-thalassemia minor / trait
α-/– 3 deletions or 2 deletions + 1 non-deletional mutation - Hemoglobin H (HbH) disease
–/– (all deleted) - Hemoglobin Bart’s hydrops fetalis (γ4) or α thalassemia major
Differentiate the concept of a healthy child vs a normal child
Healthy:
- a state of physical, mental, intellectual, social and emotional well-being
- Not just absence of disease or infirmity
Normal:
- Normal genetic complement (chromosomes and genes)
- Potential for normal growth and development
- Abnormal: chromosomal, genetic or structural abnormalities
Goals of Premarital and pre-pregnancy counselling
Goals:
- Safe and healthy pregnancy, from conception to birth
- Increase chance of having a “healthy” child
- Lower chance of having adverse pregnancy outcome
- Understand available prenatal screening and diagnostic tests
Timing of pre-pregnancy counselling
Objectives for counselling sessions
Timing:
- Reproductive-aged patient currently using contraception/ planning pregnancy
- Several times during a woman’s reproductive lifespan
Objectives:
- Detect, assess and manage specific health problems in woman or her partner before pregnancy
- Give general advice about optimizing personal healthcare and lifestyle
Maternal and fetal causes of intrauterine growth restriction and macrosomia
IUGR:
Maternal - mostly hypertension (restrict blood flow to fetus)
Fetal - syndromal conditions, infection during pregnancy
Macrosomia
Maternal - poor control of gestational diabetes
Fetal - syndromal conditions
Outline history taking questions for pre-pregnancy counselling.
General:
- Age of woman
- Ethnicity - diseases with higher prevalence in ethnic groups (e.g. Cystic fibrosis in caucasians)
- Consanguinity: risk of autosomal recessive and multifactorial disorders
Family history:
- congenital/ genetic/ chromosomal disorders
Medical history and Surgical history:
- Effects between pregnancy and medical conditions
- Vaccinations
Obstetric history:
- Birth abnormalities, still birth, neonatal death…etc
Medication/ drug history, drug allergies:
- Assess appropriateness and teratogenic potential
Occupational history: social background, exposure to teratogens
Social:
- Smoking, drinking, substance abuse
- Lifestyle, STI, intimate partner violence
- Nutrition habits
Travel and environmental risks (e.g. Zika)
Outline plans for optimizing a woman’s health before pregnancy
Family history of genetic anomalies: refer to pre-pregnancy genetic counselling
Medical conditions: stabilize pre-existing conditions; multidisciplinary pre-pregnancy planning
Medication: adjust medication to control disease and minimize teratogenic risk
Social: stop unsafe lifestyle habits; optimize nutrition, diet and weight; Periconceptual folic acid supplementation
Vaccination: Seasonal influenza vaccine; HepB, rubella and varicella vaccine for immunocompromised mother
Past obstetric conditions that require pre-pregnancy counselling and intervention
Congenital anomalies Stillbirth, neonatal death Recurrent pregnancy loss (explore underlying cause) Grand multiparity Difficult delivery, birth trauma
Outline P/E for pre-pregnancy counselling and assessment
Blood pressure, body mass index (underweight/ obese)
General examination
Cardiovascular system (auscultation of heart sound)
Respiratory system
Abdominal examination
Cervical screening (pap smear: opportunistic screening) + pelvic examination
Breast examination
+/- other tests as indicated
6 dates for antenatal screening
List the tests performed in each booking
First booking: alpha- thalassemia screening, blood grouping, infection screening
11 - 13 weeks - 1st trimester tests: Down syndrome ultrasound screening
16 - 19 weeks - 2nd trimester tests: Down syndrome biochemical screening
18 - 22 weeks - Fetal morphology tests
28-30 weeks - Gestation diabetes tests (OGTT)
36 weeks - Group B Streptococcus screening
First booking for antenatal counselling
- Tests performed
Complete blood picture (including women’s Hb, MCV) – antenatal thalassemia screening
Blood group, Rhesus factor, red cell antibody
Infection
- Hepatitis B
- Rubella antibody
- VDRL/FTA-ABS (syphilis)
- HIV antibody (opt out)
- toxoplasma, CMV, HSV
1st trimester antenatal counselling
List all tests performed
Combined Down syndrome screening:
- Ultrasound examination of foetal nuchal translucency
- Maternal serum markers (pregnancy-associated plasma protein A (PAPP-A)
- B-hCG test
Low risk = foetal anomaly ultrasound examination
High risk = 2nd -tier screening by non-invasive prenatal testing (NIPT): test maternal plasma cell-free foetal DNA
18-22nd week antenatal counselling
List all tests performed
Fetal morphology scan – foetal anomaly ultrasound examination
- Detect structural anomaly: head, cleft lip, heart, spine…etc
- Amount of amniotic fluid (liquor volume)
- Placenta position
2nd trimester biochemical Down Syndrome screening
List all tests performed
Combination of biochemical tests:
- AFP
- B-hCG
- uE3
- Inhibin A
- PAPP-A
Prenatal Down syndrome diagnosis
List tests performed to confirm Dx
Amniocentesis (14-16th week gestation)
FISH
Chorionic villi sampling (10-12th week gestation)
Prenatal diagnosis of fetal diseases:
- Objective of prenatal diagnosis
- Counselling and tests done
Objective:
- Offer timely treatment to prevent irreversible damage
- Support for couple if treatment is unavailable
Counselling:
- Help couples choose screening or diagnostic tests
- Counsel risks of tests to mother and fetus
Tests:
- Fetal sampling
- Foetal anomaly ultrasound examination
Fetal sampling for prenatal diagnosis
- Sampling techniques
- Assays and tests on samples
Techniques:
a) Chorionic villus sampling
b) Amniocentesis
c) Cordocentesis (fetal blood sampling)
Tests:
- PCR rapid aneuploidy test for Down syndrome
- Karyotyping for Aneuploidies, Gross structural chromosomal abnormalities
- Chromosomal microarray (CMA) molecular karyotyping for microdeletions and microduplications
Compare chorionic villus sampling and amniocentesis
- Period of gestation for sampling
- Samples
- Pain
- Miscarriage risk
- Failure rate
Compare chorionic villus sampling and amniocentesis
- Test accuracy
- turnaround time
- Maternal risk
Treatment options after prenatal diagnosis of fetal disease
Low risk disease - routine antenatal care and delivery, paediatrics follow-up
High risk disease:
a) Pregnancy termination, confirmation study by post-mortem exam, and genetic counselling
b) In-utero treatment (e.g. in utero transfusion for fetal anemia) with delivery or followup
c) Delivery and surgical treatment with follow-up
Describe the purpose of genetic counselling
Genetic counselling;
- 2-way process to explain medical conditions and enable the couple/ mother to decide
- Help couples understand the impact of fetal condition on the family
- Help couples choose the course of action for management of fetal abnormality that they will not regret e.g. termination of pregnancy
