Block 11 Flashcards
What does the term congenital mean?
A defect that was present at birth. Does not denote the aetiology of the defect.
What is the combined incidence of congenital abnormalities?
~ 2-3%
What is the main cause of peri-natal deaths.
Congenital abnormalities > 80% for children below 1m.
Give some examples of single 1˚ congenital defects.
DDH
Cleft lip/palate
Neural tube defects (spina bifida)
Cardiac septal defects
What are the classifications of single 1˚ congenital defects?
Malformation
Disruption
Deformation
What is the aetiology of a congenital malformation?
Genetic or environmental influence during ORGANOGENESIS (multifactorial)
What is the aetiology of a congenital disruption?
A destructive process after organ formation
- amniotic bands = limb amputation
- cardiovascular events = poland anomaly
What is the aetiology of a congenital deformation?
Moulding of a body part that has differentiated normally - a result of mechanical forces (DDH)
What is a teratogen? Give some examples.
An environmental agent that causes congenital abnormalities of either form or function.
Medication (thalidomide)
Infectious agents (TORCH)
Physical (ionising radiation)
Recreational drugs (cocaine, alcohol, smoking)
Maternal metabolic disorders (high blood glucose in diabetes)
In what stage of division is the oocyte released from the ovaries?
In the process of the metaphase of meiosis 2. It has already undergone one meiotic division forming a polar body. Meiosis 2 continues to form the 2nd polar body after entry of the sperm.
What are the components of the female reproductive system that aid movement of the sperm and egg?
Egg: cilia, fimbrea
Sperm: contractions of fallopian tubes, oxytocin (also male seminal fluid)
In what part of the female reproductive tract is it most common for eggs to be fertilised?
The ampulla of uterine tube.
What are the different sections of the uterine tube from ovary to uterus?
Fimbrae –> infudibulum –> ampulla –> isthmus –> pars uterina
What is capacitatoin?
The process which the sperm must undergo if it is to be capable of fertilising the oocyte. It occurs in the beginning of the female reproductive tract, taking around 7h. Its main function is to increase the affinity of the sperm for the receptors on the zona pellucida (ZP-3) on the oocyte.
- Activation of Ca2+ channels
- Increase in intracellular cAMP
- removal of seminal de-capacitation factors from the head of the sperm
What are the 3 layers of the oocyte?
Oolema = oocyte cell membrane
(perivitelline space )
Zona pellucida
Corona radiata
When does the oocyte fully mature?
Just after entry of the sperm. This triggers resumption of the 2˚ meiotic division and expulsion of the 2nd polar body into the perivitelline space. This is when the oocyte becomes truly haploid (albeit for a short period of time).
What happens to the oocyte directly after it has been fertilised?
Post-perfusion reaction = 2 stages
- depolarisation of the oolemma to prevent polyspermy by electrical block FAST
- Cortical reaction = fusion of cortical granules to the zonal pellucida causing degradation of ZP-3 receptors and formation of perivitelline barrier.
What are the different stages of early embryogenesis? (up to 3 weeks)
Zygote Morula Blastocyst Bi-laminar disk (8-10) Gastrulation (16-18) Tri-laminar disk Notochord formation Neurulation Mesoderm differentiation (18-22) Separation of mesoderm Folding of amniotic cavity (23)
What is a morula?
A mass of 16 cells which is the same size as the original zygote.
What is a blastocyst?
Formes from a morula when it gets too large and has to form cavity for nutrient diffusion. Composed of inner and outer cell masses.
What is a bi-laminar disk?
Early stage of embryo formation. Division of the inner cell mass of blastocyst to form epiblast and hypoblast. All of embryo comes from epiblast.
What are the different areas of the blastocyst at the time of the bi-laminar disk?
Outer cell mass (trophoblast) Amniotic cavity Epiblast Hypoblast Blastocyst cavity (primitive yolk sac)
Describe the process of gastrulation.
Epiblast differentiates to: primitive streak, primitive pit and primitive node. Epiblast cells migrate through the primitive streak and repopulate the hypoblast to form 3 new layers.
Endoderm
Mesoderm
Ectoderm
What is the notochord?
An important signalling structure within the mesoderm. Formed from a ectoderm invagination
Describe the process of neurulation.
Ectoderm folds to form neural groove and neural folds. Neural groove deepens to form neural tube within the mesoderm. On top of the notochord.
What are the different sections which mesoderm differentiates into?
Centrally = somatic mesoderm surrounding neural tube
Laterally = intermediate mesoderm
More laterally = lateral plate mesoderm (differentiates into splanchnic and parietal mesoderm)
Describe the folding of the mesoderm layers and the formation of the basic body shape.
Splanchnic mesoderm and endoderm fold inwards - pinching off the primitive yolk sac to form the gut tube.
Parietal mesoderm along with endoderm fold round the outside to form the exterior body wall. Bringing with them the amniotic cavity which finishes surrounding the foetus.
What is the vitelline duct and what does it contain?
Formed when the foetus folds round to create the body tubes. It is formed from the pinching of the primitive yolk sac by the endoderm and ectoderm. It is obliterated at ~ 6w development when the primitive yolk sac disappears.
Describe how a pregnancy test works.
Tests for the presence of HCG which is secreted in large amounts during early pregnancy.
Lines on the strip.
1 = monoclonal HCG antibody
2 = polyclonal HCG antibody
3 = reative goat antibodies
The 1 and 3 strips are for control. Urine carries 1 up to 3 where it binds, forming a colour = control strip.
If -ve, HCG binds with 1 and the bound 1 binds again with 2 to create a coloured line. Not all of 1 binds with HCG so unbound can bind to 3 to give a 2nd line.
What is the reason for the control line on a pregnancy test?
To reduce the rates of false negative results.
Because if no lines then indicative of error or faulty strip etc. If the control line wasn’t there then no way to tell between real and false negatives.
Describe the formation and function of HCG in early pregnancy.
Human Chorionic Gonadotropin (HCG) is produced by the trophoblast cells of the implanted embryo and can be measured in the blood ~ 8 days after fertilisation as it takes this time for the embryo to implant.
Prevents involution of the corpus luteum in the ovaries, therefore preventing menstruation. In early pregnancy the corpus luteum produces protective oestrogen and progesterone which prevent menstruation.
After 7w the placenta takes over this function so the CL is no longer required and the levels of HCG dip.
Levels peek ~7w and then decrease but remain elevated throughout pregnancy
What is the function of oestrogen in pregnancy?
Causes organ enlargement:
- uterus
- breast (enlargement and ductal differentiation)
- external genitalia
ALSO relaxation of pelvic ligaments (symphysis pubis) to allow freer movement of pelvic joints.
What is the function of progesterone in pregnancy?
Development of endometrial decidual cells
Decreases contractility of pregnant uterus
Increases nutrient secretion of uterine tubes and uterus
Preparation of the breasts for lactation.
What are the different methods of assisted reproduction?
IVF Surrogacy Medication Gamete intra-fallopian transfer Artificial insemination Reproductive surgery
What is the single biggest risk with IVF and what is being used to combat it?
Multiple pregnancy: miscarriage, anaemia, haemorrhage, early labour, pre-eclampsia, gestational diabetes
Elective single embryo transfer (eSET) = no more than 2 embryos should be transferred.
Under what eSET conditions can 2 embryos be transferred?
<37 = 2nd if no top quality and 3rd time 37-39 = 1st and 2nd if no top quality 39 = always
What are the risks of multiple pregnancy?
BABY: Premature birth Small birth weight Cerebral palsy Improper separation Miscarriage
MOTHER:
20% with pregnancy induced hypertension
Increased risk of preeclampsia
Increased risk of gestational diabetes
What is ovarian hyper stimulation syndrome?
Is a major risk of many different forms of assisted reproduction. Occurs as a result of HCG injections after oocyte maturation
3 stages: mild, moderate, severe
Mild = slightly enlarged ovaries, ascites, abdo pain, nausea, diarrhoea
Moderate = as mild w/: excessive weight gain, vomiting, thirst, oligurea
Severe: as moderate w/: SOB, pleural effusion, anurea, chest pain, haemoconcentration, thrombosis
What is the incidence of difficulty conceiving?
3.5 million = 1 in 7 in UK
What are the broad categories of couple infertility?
Female = 1/3:
polycystic ovaries, early onset menopause, chronic illness, womb damage, fallopian tube damage, pelvic inflammatory disease, endometriosis
Male = 1/3:
Low sperm count, low sperm motility, abnormal sperm, testicular damage, ejaculatory disorders, erectile dysfunction
1/3 = unknown
What are three patient factors which can have a big impact on fertility?
Stress (reduced sperm, reduced ovulation, partner relations, reduce libido)
Age (20% at 30 – 5% at 40)
Weight
What are the two categories of support that would be of use to infertile couples? Give some examples of each.
Emotional support:
coping strategies, frustration, stress, social pressures, continued access to professional support
Therapeutic support: Grief work (impact of infertility), alternative life goals, conflict resolution, interpersonal problems
Give the number of couples who haven’t conceived by: 1month, 6months, 12months, 18months, 24months.
1 month = 20% 6 months = 70% 12 months = 85% ----> cut off for 'difficulty conceiving' 18 months = 90% 24 months = 95%
What are the main categories of physiological change within pregnancy?
Weight Metabolism Cardiovascular system Respiratory system Urinary system
Describe weight gain in pregnancy.
Normal to gain ~ 11kg (mainly in the last 2 trimesters)
- foetus = 3kg
- amnion = 2kg
- uterus = 1kg
- breasts = 1kg
- extra fluid (blood etc.) = 3kg
- fat = 1-2kg
However, weight gain can be as large as 30kg due to the increased appetite of pregnancy = FAT
What is the symphysis-fundal height?
A measure of the size of the ‘baby bump’ from the symphysis pubis to the funds of the uterus. Is around the same in cm as number of weeks gestation.
What are the cardiac changes in pregnancy?
Cardiac output increases by ~40%
Rate increases 20%
Stroke volume increases 20%
Size increases 12% (athletic remodelling)
Increased blood volume –> increased preload –> increased atrial size
Blood volume increases ~20% = 1-2 litres. This is due mainly to H2O retention and is to give a safety factor incase of parturition haemorrhage.
What are the respiratory changes in pregnancy?
Increased respiratory effort 20% more O2 consumed Elevated diaphragm Rib cage displaced upwards Chemoreceptor sensitivity increased = deeper breathing Ventilation rate increased 50%
What are the urinary changes in pregnancy?
Enlargement of the kidneys
= increased waste excretion
= increased Na+ reabsorption
= increased blood flow and haemodilution
Decreased bladder tone and displaced ureters = increased probability of vesicoureteral reflux = increased UTI
Why are UTIs more common in pregnancy?
Increased vesicoureteral reflux
Increased urinary stasis
Increased glucose excretion
What are the foods to AVOID during pregnancy?
Vitamine A = liver and multivitamin tablets
Mouldy cheese
Undercooked meets
Pate
Raw fish
Un-pasturised milk (All these may contain listeria)
What are the main medications to be aware of in pregnancy?
Paracetamol = safe Laxatives = safe Antihistamines = chlorphenamine is safe
IBUPROFEN IS NOT SAFE
Consult doctor before taking other medications
What are the main supplements to be aware of in pregnancy?
FOLIC ACID = most important
Vit. D = recommended for pregnancy and breast feeding
Iodine = take or leave
Iron = increased risk of iron deficiency anaemia in pregnancy (increased haematopoiesis)
Why is folic acid so important in pregnancy?
Reduces the risk of improper neural tube formation and neural tube defects = congenital malformation
This occurs early in pregnancy so it is important to take folic acid when trying for a baby because the neural tube formation may have already occurred by the time you find out you are pregnant.
What are the things that must be done if a doctor is to conscientiously object to a procedure?
Inform employer
Inform patients ideally in advance
Be open with patients and colleagues
MUST’NT compromise patient care
Dont cause distress to the patient
Dont imply judgement on the patient
Tell the patient they have the right to speak with other professionals without the same view
Advise them objectively about the procedure
Make sure patient can go to another doctor, if necessary refer them personally
MUST NOT OBSTRUCT PATIENT
MUST BE RESPECTFUL OF PATIENTS VIEWS AND DIGNITY
What effects can smoking have on pregnancy?
Increases the risk of miscarriage
Slows babies growth: low birth weight, premature birth, still birth
What are the main lifestyle choices to avoid in pregnancy
Smoking
Alcohol
Recreational drugs
Dangerous sports/activities
What effects can alcohol have on pregnancy?
Increases risk of premature birth
Increases risk of brain damage
High intake can cause foetal alcohol syndrome = brain damage, low birth weight & facial deformities
Are exercise and sex safe during pregnancy?
Yes
Exercise: moderate (safe) exercise recommended 30mins per day
Sex: generally safe but avoid with vaginal bleeding. Orgasm can give Braxton-Hicks contractions which aren’t real and go away after a time.
Why is antenatal care important?
Improves maternal, perinatal and neonatal outcomes
What are the two important aspects of antenatal care?
Give all mothers the important information about their pregnancy and newborn care
Identify the women who will require extra specialist support during and after pregnancy
What are the main aims of antenatal care?
Provide suitable (quality and understandable) information to mothers
Provide an informed choice about antenatal pathways
Screen for and identify maternal complications
Screen for and identify foetal complications
Assess maternal and foetal wellbeing throughout pregnancy
Provide advice and education on the normal symptoms of pregnancy
What professionals are part of the MDT responsible for antenatal care?
GPs Community midwives Hospital midwives Obstetricians Physiotherapists Social workers
What are the 7 criteria for a screening test?
Disease is a significant halt problem
Must be a pre-clinical stage to the disease
Must be a suitable test for the disease (low false positive and false negative rate)
Test would be acceptable to general population
Agreed policy on who to treat after +ve result
Acceptable and effective treatment for +ve patients
Cost effective
What are some categories of women who will require additional care during pregnancy?
Maternal chronic disease Overweight or underweight >40 yrs Difficult previous pregnancy or birth Previous abnormal babies
What is the importance of the 10w antenatal booking appointment?
Identify women who might require additional care
Measure normal standards for woman (BP, height, weight etc.)
Determine risk factors for pregnancy
Offer screening tests (rhesus D, blood diseases, chlamydia, downs etc.)
Offer gestational abnormalities scans
Identify possible mood disorders
Inform woman on normal pregnancy
Inform about nutrition and supplements
Arrange further appointments
What is procreative autonomy?
To have control over ones reproductive capabilities. The freedom to choose whether or not to have children
What are the 3 main ethical objections to the use of IVF?
It involves the destruction of embryos
It is harmful to those trying to conceive (low success rate)
It is ‘unnatural’
What is the average success rate for a round of IVF?
1/3
Although varies dramatically with factors such as: age, weight, lifestyle etc.
Decreases steadily to <2% by 45yrs
What is ‘the right to an open future’
The ethical argument that children should be given the maximally open future. An argument often given for the termination of embryos that will grow to have serious disabilities/illnesses.
What is the ‘welfare criterion’ of ART and come criticisms of this?
That a woman shall not be provided with ARTs unless the welfare of the future child has been accounted for. Including the need for supportive parenting.
“supportive parenting” used to say “father”
1) Unfair because not with fertile couples
2) Predicting welfare is difficult
What is PIGD and some possible uses of it?
Screening of cells before implantation to ensure embryo doesn’t have certain genetic traits.
Cystic fibrosis, downs, sex selection, ‘saviour siblings’
What UK law legalised abortion?
The abortion act 1967 (amended 1990)
What are the criteria for legalised abortion in the UK?
< 24 weeks
Continuation would cause severe mental or physical damage to mother
Continuation would involve risk to life of mother
Substantial risk of mental or physical abnormalities to the child if born.
What are the 3 categories of errors that, combined, can lead to adverse events in hospitals?
Active failure = frontline error
System failure = an error in the management
Equipment failure = can be front line or system
What is the difference between a random and systematic error?
A systematic error is within the ‘system’ and all give the same error of the same amount and type each time. Predictable.
A random error is unpredictable, caused by the individual and is different each time.
What are the main reasons for a doctor not following the set rules for a specific situation?
Routine = has become normal behaviour within a peer group.
Optimising = motive is to improve work situation.
Situational = context dependant (staffing levels)
Reasoned = deliberate deviation thought to be in patients best interest at that time
Malicious = deliberate act intended to had patient or organisation.
What are some general factors which can lead increased risk of errors?
Unfamiliarity Inexperience Shortage of time Inadequate checking Poor procedures Inadequate or incorrect equipment
What are some factors which can lead to individual errors?
Fatigue Stress Hunger Illness Language or cultural factors Hazardous attitudes or environment
