Genetics Flashcards

1
Q

How is the 1st trimester trisomy screen carried out?

A

Carried out by serum markers (PAPP-A, hCG) and nuchal thickness scan

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What does a nuchal scan test for?

A

measures the nuchal fold thickness. This is an area of tissue at the back of an unborn baby’s neck.

Measuring this thickness helps assess the risk for Down syndrome and other genetic problems in the baby.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

32 year old woman has a booking appointment with her midwife at approximately 8 weeks gestation. Which foetal genetic disorders can be screened for?

A

Trisomy 13 (Patau syndrome)
Trisomy 18 (Edwards syndrome)
Trisomy 21 (Down syndrome)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

NIPT has a positive predictive value of >90%. true/false?

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is a CVS?

A

Chorionic villus sampling is a form of prenatal diagnosis done to determine chromosomal or genetic disorders in the foetus.

It entails sampling of the chorionic villus and testing it for chromosomal abnormalities, usually with FISH or PCR.

Taken between 11-14 weeks gestation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is amniocentesis?

A

Amniocentesis is done to remove amniotic fluid and cells from the uterus for testing or treatment.

Carried out >15 week gestation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Reasons for doing amniocentesis?

A

Genetic testing, diagnosis of foetal information, treatment (to drain excess amniotic fluid from uterus due to polyhydramnios) or foetal lung testing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is genetic amniocentesis?

A

Genetic amniocentesis can provide information about the baby’s genes.

Genetic amniocentesis is usually done between weeks 14 and 20 of pregnancy.

Amniocentesis done before week 14 of pregnancy might lead to more complications.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Reasons for genetic amniocentesis?

A

Having positive results from a prenatal screening test.

Having an earlier pregnancy affected by a genetic condition.

Being 35 or older.

Having a family history of a genetic condition, or if the parents are carriers of a genetic condition.

Having unusual ultrasound findings.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is chromosome microarray (CMA)?

A

a powerful diagnostic tool that is used to identify genetic causes of illness and developmental problems.

CMA only tests for variations in DNA copy number. It can identify:

large deletions and microdeletions and large duplications and microduplications

most abnormalities of chromosome number (eg Down syndrome)

unbalanced rearrangements of chromosome (eg complex insertions or deletions).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Chromosome Microarray has higher resolution but only detects imbalance
true/false?

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What can CMA NOT detect?

A

does not identify:

single gene mutations
fragile X syndrome (FXS)
balanced rearrangements (eg: translocations and inversions).

So can only detect chromosomal shifts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is mutation (Pathogenic variant)?

A

Can be defined as a genetic change that causes disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is polymorphism (Benign variant)?

A

Genetic Variation that isn’t exactly disease causing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Pregnant woman diagnosed with trisomy 21 at 28 weeks gestation. What is first line medication?

A

Potassium chloride injection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

When is misoprostol commonly used in gestational period?

A

From date of last period to week 11 of gestation.

17
Q

What 2 medications are used in medabon?

A

Medabon is a combination therapy containing two medicines called mifepristone and misoprostol.

Medabon is recommended for the medical termination of a pregnancy no later than 63 days after the first day of your last menstrual period.

18
Q

Mechanism of action for mifepristone and misoprostol?

A

Mifepristone is an anti-hormone that acts by blocking the effects of progesterone, a hormone which is needed for pregnancy to continue.

Misoprostol is a prostaglandin, which is a substance that increases contraction of the womb that will help expel the pregnancy. Used 1-2 days later

The two drugs can therefore cause termination of pregnancy and must be used one after the other to give the best possible chance for the treatment to work.

19
Q

What are the uses of NIPD?

A

rhesus typing

determine fetal sex of a fetus in families affected by seriousX-linkedconditions such as Duchenne muscular dystrophy

CAH (congenital adrenal hyperplasia)

cystic fibrosis

several musculoskeletal conditions
autosomal dominantconditions when the father is affected

conditions where there is an affected sibling, but the parents do not have the variant

when both parents are carriers of different variants of anautosomal recessive condition, the father’s variant is tested for, if found to be present invasive testing may subsequently be performed to establish if the baby has also inherited the maternal variant

20
Q

Latent phase of first stage labour?

A
  • Latent phase - mild irregular uterine contractions, cervix shortens and softens, duration variable
    • May last a few days
21
Q

Active phase of first stage labour?

A
  • Active phase - 4cms onwards to full dilatation
    • Slow decent of the presenting part
    • Contractions progressviely become more rhythmic and stronger
    • Normal progress is assessed at 1-2cms per hour
22
Q

Second stage of labour?

A
  • Starts with complete dilatation of the cervix fully dilated (10cms) to delivery of the baby
  • In nulliparous women it is considered prolonged if it exceeds 3 hours if there is regional analgesia, or 2 hours without
  • In multiparous women it is considered prolonged if it exceeds 2 hours with regional analgesia or 1 hour without
  • In low risk care vaginal examinations are not always carried out to assess time of full dilatation
23
Q

Third stage of labour?

A
  • Delivery of the baby to expulsion of the placenta and fetal membranes
  • ~10 mins
  • After 1 hour, preparation made for surgical removal either by regional analgesia or under GA
  • Expectant management - spontaneous delivery of the placenta
  • Active management - use of oxytocic drugs and controlled cord traction is preferred for lowering risk of post partum haemorrhage
24
Q

What is involved in uterine contractions?

A
  • Uterine muscle - smooth muscle in connective tissue, density highest at the fundus
  • Pacemaker - region of tubal ostia, wave spreads in a downward direction
  • Synchronisation of contraction waves from both ostia
  • Polarity: upper segment contracts and retracts, lower segment and cervic stretch, dilate and relax
  • Normal contractions have a fundal dominance with a regular pattern and adequate ‘resting tone’
25
Q

What is tubal ostia?

A
26
Q

What is puerperium?

A
  • Period of repair and recovery ~ 6 weeks involving return of tissues to non-pregnant state
  • Bloodstained discharge lasts 10-14 days following birth
27
Q

Clinical features of labour?

A

Brandon Hicks contractions
True labour contractions
Signs of the third stage

28
Q

Brandon Hicks contractions features?

A
  • ‘False labour’
  • Tightening of the uterine muscles, thought to aid the body to prepare for birth
  • Can start 6 weeks into pregnancy but more usually felt in the third trimester
  • Irregular, do not increase in frequency or intensity
  • Resolve with ambulation or change in activity
  • Relatively painless
29
Q

Another name for Brandon Hicks contractions?

A

“False labour”

30
Q

True labour contractions features?

A
  • Happen under the influence of the release of oxytocin, which stimulates the uterus to contract
  • True labour is when the timing of the contractions become evently spaced, and the time between them gets shorter and shorter
  • Real contractions will get more intense and painful over time
31
Q

Signs of the third stage features?

A
  • Expulsion of placenta usually 5-10 minutes after delivery, considered normal up to 30 minutes
  • Uterus contracts, hardens and rises
  • Umbilical cord lengthens permanently
  • Frequently a gush of blood variable in amount
  • Placenta and membranes appear at introitus
32
Q

Investigations for labour?

A

Bishops score
Partogram

33
Q

What is bishops score?

A

used to determine whether if it is safe to induce labour

34
Q

Components of bishops score?

A

Position, consistency, effacement, dilation, station in pelvis

35
Q

What is a partogram?

A

a graphic record of key data (maternal and fetal) contained onto one sheet, used to assess progress of labour i.e. cervical dilatation, fetal heart rate

36
Q

Non-pharmacological analgesia methods for labour?

A
  • Exercise/movement
  • Heat e.g. warm bath, heat pack
  • TENs stimulation
  • Acupuncture
  • Hypnosis
  • Massage
37
Q

Medical name for “gas and air”?

A

Nitrous Oxide or Entonox can be used as a method of analgesia

38
Q

3 common analgesia types for labour?

A

Simple analgesia
Opiate analgesia
Epidural analgesia