Midwifery and Genetics: Key issues for current practice

1
Midwifery and Genetics Key issues for current
practice

• Pauline McGrath RN, MNLead, FHGSA
• Genetic Counsellor
• Genetic Health Queensland/Royal Brisbane and
  Women's Hospital

2
Midwifery and Genetics

• What does a Genetics Department do?
• How current is my genetic knowledge?
• Genetics and womens reproductive health
• Screening for Down Syndrome
• Invasive testing
• What does the future hold?

3
Genetic Health Queensland

• Paediatrics, adult and womens health
• Now 60 of patients adults
• Recently incorporated into RBWH from RCH
• Cancer one of the most common referrals
• New areas such as familial cardiac conditions
• Offices all over Queensland

4
Genetic Health Queensland

• Clinical Geneticist
• Medical Doctor
• FRACP
• Genetic Counsellor
• Can come from various backgrounds (ie nursing,
  science, psychology)
• Masters level qualification
• 2 years professional training

5
Genetics and the Impact on Midwifery Practice

• Midwives need knowledge and skills in
• Genetic literacy
• Understanding screening tests Vs diagnostic tests
• Understanding and communicating risk
• Models of decision making - ADEPT (A DEcision aid
  for Prenatal Testing)
• Psychology of decision making

6
Genetics and the Impact on Midwifery Practice

• Important to take an accurate family history and
  understand the implications of the data
• A large number and complex range of screening
  tests available and offered to women/couples and
  newborns
• A new taxonomy of disease and identification of
  subtypes which may lead to targeted care and
  treatment of pregnant women ie CAH

7
Family History

• Family pedigree

8
Genetics and the Impact on Midwifery Practice

• New dilemmas
• Greater autonomy for patients burden of choice

9
Where to begin?

• Normal male chromosomes

10
Where to begin?

• Normal female chromosomes

11
Autosomal Dominant Inheritance
12
Autosomal Recessive Inheritance
13
X-linked Recessive Inheritance
14
Prenatal Screening /-Diagnosis

• An increasingly complex field
• Genetic screening becoming part of routine care
• Genetic diagnosis is not routine
• Ideally genetic counselling for single gene
  defects should occur before a pregnancy
• Ideally counselling for ultrasound outcomes
  should come before the scan

15
Invasive PND generally offered to women

• Over the age of 35 years although now changing to
  offering screening first
• Who have had a previous pregnancy with a
  chromosome abnormality
• Who carry or whose partner carry a chromosome
  abnormality
• Who have previously had a child with a genetic
  disease that can be detected by invasive testing

16
Invasive PND generally offered to women

• With a family history of certain disorders (eg
  cystic fibrosis) for which DNA testing is
  available
• At increased risk of abnormality following a
  screening test ie nuchal translucency, maternal
  serum screening

17
Factors Considered When Offering PND

• Is the disorder sufficiently severe or are the
  genetic risks great enough for an invasive
  approach to be warranted
• Is an accurate test available
• What are the wishes of the women/couple concerned

18
The Counselling Process

• Parental age
• Race and ethnic background
• Obstetric history
• Maternal health history
• Exposure history
• Assessing the need for prenatal diagnosis
• The abnormal fetus
• Termination of pregnancy
• Continuing the pregnancy
• Adoption
• Follow up

19
Maternal age risk
20
First trimester screening

• The hair is not black, as in the real Mongol,
  but of a brownish colour, straight and scanty.
  The face is flat and broad, and destitute of
  prominence. The cheeks are roundish, and extended
  laterally. The eyes are obliquely placed, and the
  internal canthi more than normally distant from
  one another. The palpebral fissure is very
  narrow. The forehead is wrinkled transversely
  from the constant assistance which the levatores
  palpebrarum derive from the occipito-frontalis
  muscle in opening of the eyes. The lips are large
  and thick with transverse fissures. The tongue is
  long, thick, and is much roughened. The nose is
  small. The skin has a slight dirty yellowish
  tinge, and is deficient in elasticity, giving the
  appearance of being too large for the body.
• Dr Langdon Down 1866

21
First Trimester Screening

• Every woman has a risk that her fetus/baby has a
  chromosomal defect
• In order to calculate the individual risk, it is
  necessary to take into account the background
  risk (which depends on maternal age, gestation
  and previous history of chromosomal defects) and
  multiply this by a series of factors
• Fetal nuchal translucency and maternal serum
  biochemistry (free b-hCG and pregnancy-associated
  plasma protein (PAPP-A)) at 1114 weeks can
  identify about 90 of affected fetuses

22
First trimester screening
23
Trisomy 21 Down syndrome

• 47,XY,21

24
Down Syndrome
25
Trisomy 18

• 47,XY,18

26
Trisomy 18
27
Trisomy 13 - Patau syndrome

• 47, XY, 13

28
Trisomy 13
29
Fluorescent in situ hybridization (FISH)
trisomy 21 (A), trisomy 18 (B) and trisomy 13
(C).
30
Chorionic Villus Sampling (CVS)

• First trimester method of PND
• Most commonly transabdominal biopsy of the
  developing placenta
• Routinely performed after 10 completed weeks of
  pregnancy although able to perform throughout
  pregnancy
• Tissue can be analysed directly or cultured

31
Chorionic Villus Sampling (CVS)

• Results take 2 weeks although a direct analysis
  may give a chromosome count in less than 24 hours
  if aneuploidy suspected
• Biochemical or DNA results may vary depending on
  the complexity of analysis

32
Chorionic Villus Sampling (CVS)
33
CVS Complications

• Minor bleeding may occur in up to 40 of women as
  the sampling is from a vascular site
• Spontaneous abortion rate of 0.5-1
• Maternal contamination if the cells are not
  properly cleaned before analysis
• Confined placental mosaicism reported in up to 2
  of cases

34
CVS Complications

• CVS can be performed prior to 9 weeks gestation
  although available data suggests an increased
  risk of transverse limb defects. The basis of
  which may be vascular

35
Amniocentesis

• Involves the aspiration of amniotic fluid with a
  fine needle for amniotic fluid cell culture
• Performed after 16 weeks gestation
• Approximately 20ml of amniotic fluid withdrawn
• Results take 2-4 weeks
• Biochemical and DNA results take longer

36
Amniocentesis
37
Amniocentesis Complications

• Spotting and amniotic fluid leakage which are
  usually short lived
• Spontaneous abortion rate 0.5
• Fetal injury (small risk)

38
Who are these women? (Who has pregnancy testing?)

• Overwhelming majority of women have at least 1
  scan during pregnancy perceived need for
  testing a recent phenomena
• Pregnant women want to know as much as possible
  about their pregnancies why?
• Reassurance health, how many, gestational stage
• Other positive aspects of screening eg see the
  baby, make pregnancy real, for the partner,
  learn gender
• Preparation for foetal problems
• Self-evident act no reason NOT to participate
• Dissidence with why health professionals screen

39
Psychological responses to TOP

• Predictive factors for poor psychological
  outcome
• Delay in seeking termination
• Pre-existing/concurrent psychiatric illness
• Ambivalence towards termination
• Feeling of coercion
• Poor psychosocial support
• Abandonment by partner
• Poor decision making skills
• Avoidance of making decision
• Midtrimester of pregnancy
• History of emotional disturbance

40
Psychological responses to TOP

• Women who TOP for medical/genetic termination are
  at higher risk for experiencing significant
  negative psychological outcomes more
  psychologically disruptive than TOP for social or
  contraceptive reasons
• Acute grief, anxiety and depression for up to
  6/12 (including tearfulness, sadness, lethargy,
  insomnia, incapacitating grief, somatic symptoms,
  complete withdrawal)
• Psychological morbidity 4-5 times greater than
  non-puerperal and post-partum populations

41
Counselling implications

• Stressful, difficult decision, but most say would
  make same decision given same circumstances
• Up to 40 feel they did not really have control
  i.e. was not a decision just no other
  alternative

42
Other counselling implications

• Failure as a mother let the baby down
• Different rates of grief relationship impacts
• Meaning-making - what did I do?
• Normal grief counselling
• Sympathy for self what a waste

43
Other counselling implications

• Avoidance some do not want long-term follow-up
  - put it behind me
• Avoidance future pregnancies
• Sparse support available
• urgent need to make follow-up available (within
  6/52)
• Genetic counselling essential for all women
  having TOP for foetal abnormality
• Helpful to have liaison between antenatal clinics
  and GPs

44
Medicare

• The Pregnancy Support Counselling initiative
  commenced on 1/11/06. Medicare benefits paid for
  non-directive pregnancy support (NDPS)
  counselling services for women concerned about a
  current pregnancy, or a pregnancy in the
  preceding 12 months, by an eligible medical
  practitioner or allied health professional on
  referral from a medical practitioner.

45
Free Fetal DNA

• A decade ago, it was found that the blood of
  pregnant women contains DNA from the fetus. The
  discovery of this 'free fetal DNA' (ffDNA) has
  led to the development of non-invasive prenatal
  diagnosis, where genetic characteristics of the
  fetus can be analysed a mere few weeks into
  pregnancy by studying a sample of the mother's
  blood.
• ffDNA testing may put an end to the anguish
  couples experience when making the very difficult
  decision of whether or not to test their fetus
  for a genetic condition, by providing a safe
  alternative to invasive procedures, such as
  amniocentesis, which carries a risk of
  miscarriage.

46
Free Fetal DNA

• An added benefit of ffDNA testing is that it can
  be carried out much earlier in the pregnancy,
  giving the couple longer to decide whether or not
  to terminate an affected pregnancy or to gather
  more information on the implications of bringing
  an affected child into the world.

47
Free Fetal DNA

• However, there is still much concern that the
  emergence of a test with no negative
  repercussions for mother or baby will lead to an
  increase in abortions, with some parents deciding
  to terminate for trivial reasons, such as gender
  or minor disability.
• The Daily Mail reported last week that 'ffDNA
  testing has raised fresh fears over 'designer
  babies'', though what evidence there is to
  suggest it will inevitably lead to parents
  wanting anything more than a 'healthy' baby is
  open to scrutiny.