Block 11 - Reproduction and the growing child (pre-birth) Flashcards
3 things that sperm acquire during capacitation
Whiplash tail
Changes to the acrosome
Enzyme release
How do sperm travel the 20cm to the site of fertilisation?
Own motility
Uterine/oviduct contractions
Explain how sperm bind with the egg
Sperm release hyaluronidase to digest through the cumulus and acrosin enzymes to digest through the zone pellucida
Sperm interacts with glycoproteins ZP2/3 on the zona pellucida –> engulfed
Explain what resumes meiosis in the egg
Sperm bind –> phospholipase zeta which increases Ca causing a breakdown of maturation promoting factor, resumption of meiosis and extrusion of the 2nd polar body
Explain how only one sperm binds
Egg releases corticol granules that migrate to the edge during maturation and release components between it and the zona pellucida
Causes a conformational change in the ZP2/3 glycoproteins so no more sperm can enter
Define:
Polyspermic
Digynic
Parthenogenetic
Polyspermic: 2 sperm –> 3 pronuclei
Digynic: egg doesn’t complete meiosis –> 3 pronuclei
Parthenogenetic: no fertilisation but Ca triggered so the egg completes meiosis
What 2 things make up the zygote?
A male and a female POLAR BODY
What day is a blastocyst made?
5 days q
How and when is the zygotic genome activated?
What problems can arise?
4 cell stage
Methylation wipes and genome re-methylated to express its own genome
Problems here effect every cell in the body
Define the morula stage
The final stage before the cavity begins to grow
What hormone is stopping menstruation dependent upon?
Blastocyst produces a compound which acts on the uterine epithelium
- Signals the ovary to continue producing progesterone
- Release of hCG which signals the ovary to maintain the corpus luteum
What synthesises hCG and progesterone?
Syncytial trophoblast
What happens to the placenta if twins split at the:
- 2/4 cell stage
- Inner mass cell stage
Which one leads to nutrient stealing?
2/4 cell stage: 2 independent blastocysts with own placental membrane
Inner mass cell stage: share an outer placental sack but own inner sack (NUTRIENT STEALING)
How much does 1 round of IVF cost
£5,000
What percentage of couples under 35 become pregnant after 1 year of regular unprotected sex?
What percentage after 2 years?
80%
90%
What is the role of a GnRH agonist and antagonist?
What is the role of a FSH agonist?
GnRH: To decrease FSH and LH
FSH: To increase the number of follicles recruited when needed
5 main causes of infertility
- Male infertility (no sperm or ejaculatory failure)
- Unexplained
- Ovulatory disorder
- Tubal disease
- Endometriosis
What is the pre-implantation embryo vulnerable to?
Nutritional, biochemical, physical and metabolic changes
May lead to things such as insulin resistance or metabolic disorders
Who regulates fertility treatment?
HFEA
Who might frozen embryos benefit the most?
Older women
Trimester 1
4 foetal changes
2 maternal changes
Foetus: Fertilisation, Implantation, Placenta, Initial development
Mother: Increased weight, nausea
Trimester 2
4 foetal changes
5 maternal changes
Foetus: Nervous system, spine, proportions change, hair
Mother: heart and breast remodel, uterus rises, hypovolemia, placenta growth
Trimester 3
5 foetal changes
4 maternal changes
Foetus: Growth, lung development, brain growth, fat deposition, blood cells
Mother: Braxton hicks, tired, lactation, restricted breathing
What happens to the maternal heart rate, blood pressure and blood volume during pregnancy?
Heart rate and blood volume increase
Blood pressure stays the same
What happens to the foetal heart rate and size during pregnancy?
Heart rate increases during the 1st trimester to 180
It then decreases the 140 and remains constant
Slow increase in size from trimester 1-2
Large increase in size in trimester 3
How and when does the embryo implant into the uterine wall?
In week 4 the egg hatches from the zona pellucida
Trophoblast cells form villi which interdigitate with the uterine epithelium villi and destroy the primary decidua in the uterine wall
Where does the embryo develop in relation to the uterine wall?
Development occurs in the uterine wall and pushes into the uterine lumen
Explain how the foetus forms a blood supply with the mother
Pluriblast surrounded by cytotrophoblast cells which are then surrounded by syncytial trophoblast cells which invade into the utrine epithelium
Syncytial trophoblast cells contain trophoblastic lacunae. Invading maternal vessels anastamose with the lacunae allowing blood transfer
What is the term used for the type of support given to the foetus by the lacunae?
Histotrophic support
When does the female reproductive cycle switch from cyclical to pregnant?
Week 3-4
6 effects of an increase in oestrogen and progesterone on the mother
Supression of menses Tender and enlarged breasts Nausea and vomiting Increased urinary frequency Fatigue Constipation
Explain how the ectoderm, mesoderm and endoderm form
- Trophoblast surrounds the embryo and pluriblast in the middle
- Pluirblast splits into the Epiblast and Hypoblast
- Epiblast produces the ectoderm and mesoderm
Hypoblast produced the endoderm and grows around the internal cavity inside the trophoblast
What are the three parts of the placenta and what germ layers are they made from?
Amnion: Ectoderm and mesoderm
Chorion: Trophoblast and mesoderm
Yolk sack: Endoderm and mesoderm
Give two ways which the spiral arteries are remodelled
Why?
Increased volume and decreased pressure
Increased blood pressure in the spiral arteries is damaging
Why does histotrophic support seize?
What happens to overcome this?
What prevents mixing?
Lacunae cannot support the embryo for long
Syncytial trophoblast grow along spiral arteries
Villi form from the lacunae to the maternal blood allowing pooling
Trophoblasts form a barrier to prevent mixing
Define foetal lobule
A villi terminating in a spiral artery lacunae
Where do the villi conentrate on the uterine wall?
Chorionic plate of the placenta
How heavy is the placenta?
What is its diameter?
1/6 of the baby’s weight
20cm diameter
How does the pCO2 of foetal and maternal blood compare?
Why?
PCO2 of foetal blood is higher than maternal blood
Allows the release of CO2
What is the role of hCG in the pregnancy? (3)
Maintains the corpus luteum
Stimulates the thyroid
Promotes mammary growth
What is the role of oestrogen in the pregnancy? (4)
Relaxes pelvic ligaments
Increases elasticity of the symphysis pubis
Braxton-Hicks
Differentiation and proliferation of breast ductal system
What is the role of progesterone in the pregnancy? (4)
Increases oviduct and uterine secretions
Decreases uterine contractions
Prepares the endometrium for pregnancy
Growth of the ductal system in the breast
What is the name of the other hormone which is important in pregnancy?
Somatomammotropin
Why do levels of HcG decrease?
The placenta produces the hormones, not the foetus
How do oestrogen and progesterone cause the blood volume to increase? (6)
Vasodilation Decreased peripheral resistance Increased NO Increased aldosterone Increased thirst centre Angiogenesis
What can increased blood volume cause?
Oedema
2 things which increase the risk o UTIs
Urinary stasis
Increased glucose and amino acids in the urine
Why do you breathe deeper and increase your tidal volume
Sensitivity to chemoreceptors reduced
Increased CO2 in the blood
What is HPL
What is its role
Human placental lactogen
Mimics prolactin and GH to enlarge the breasts
What is the average weight gain during pregnancy?
When does most of the weight gain occur?
24lb (11kg)
First trimester (2-4 a week)
Then 1lb a week
5 aims of antinatal care
Monitor pregnancy progress and optimise health Partnership between mother and midwife Promotes choices and public health Recognise problems Prepare for birth and parenthood
MBRRACE-UK
Mother and Babies Reducing Risk through Audits and Confidential Enquiries
National maternity review (4)
Personalised and continuity of care (reduced case load, on call constantly)
Safer care
MDT
Mental health
When do the antenatal visits take place?
1: 8 weeks
2: 16 and (25) weeks
3: (31), 34, 36, 38, (40), 41
6 things that the blood test looks for
ABO blood group Rhesus factor Antibodies FBC Viruses e.g. Syphilis, Hep B, HIV Haemaglobinopathies
5 other parts of the physical examination other than the abdominal examination
Weight Blood pressure Urinalysis Oedema Varicosities
Define a cephalic presentation
Spine-spine
When does the baby engage?
36 weeks
Define multiparous
More than 4 children
Define gravida para
Gravida 3 Para 1+1
Third pregnancy, lost one child and has one child
8 risk factors for loss of a baby
Disease Proteinuria (pre-eclampsia) Large increase in blood pressure Significant oedema Uterus too large or small (diabetes) Bleeding (placenta detached) Infection Social/psychological problems
6 forces of retention (labour)
- Progesterone and Adrenaline (maintains)
- Cervix (hard)
- Hypovolemia (reduces hormone release)
- Relaxin
- Corticotrophin releasing hormone (inhibits prostaglandins)
7 forces of release (labour)
- Oestrogen
- Oxytocin and Vasopressin (pituitary –> uterine contraction)
- Cortisol (blocks progesterone)
- Prostaglandin (dilates and softens cervix)
- Uterine distention (uterus reaches max strength)
- Corticotrophin releasing hormone (inhibits prostaglandins)
What are the 4 stages of labour?
What are the 3 components?
Latent - 1st - 2nd - 3rd
Passage - Power - Passenger
What are the two positions of the baby’s head?
Occipital posterior (baby looks UP) Occipital anterior (baby looks DOWN)
What nerve supplies the pelvic floor
Pudendal nerve
How does the baby’s head rotate in the pelvis
Pelvic inlet is wider in transverse so baby engages in transverse
Pelvic outlet is wider in AP so head rotates round to AP
What presentation is the best for delivery?
Which can deliver?
Flexed vertex is best for delivery
Face can deliver
How long is each stage of labour?
first child vs multiple child
1st: 2-12 hours (1-9 hours)
2nd: 1 hour (15 mins)
3rd: 15 mins (15 mins)
Explain the movements of labour (7)
- Engagement (transverse)
- Descent through pelvis (muscle contractions)
- Further flexion of the head at the pelvic floor
- Head rotates from OT to OA at the pubic arch
- After the arch the head rotates to AP to exit
- Head rotates to OT outside the vagina
- Midwife removes the shoulder from the pubic arch and baby twists back to AP
How do you tell the difference between the 3 fontanelles?
Anterior: can fit finger in (diamond)
Occipital: can fit tip of finger in
Posterior: disappears during labour (head squished)
4 things which a partogram monitors
Dilation
Foetal heart
Oxytocin
Analgesia
When does a vaginal examination occur during labour?
Every 4 hours
How do you monitor the foetus
What do you monitor?
CTG
Baby’s heart and uterine pressure waves
Where are the steroid sex hormones released from?
Ovary, adrenal gland and placenta
Explain foetal breast development: Week 4 Week 8 Week 12-16 Week 28-32 Week 32-40
Week 4: Milk lines grow from axilla to groin. Epithelia thickens –> mammary glands
Week 8: Inward growth
Week 12-16: Nipples and areola differentiate. Epithelial cells form mammary buds and alveoli
Week 28-32: Canalisation (tubular epithelia develops)
Week 32: Primary milk ducts
Week 32-40: Lobes develop, ducts grow into nipple, nipple and areola develop, some colostrum production
2 hormones which cause breast development during puberty?
Oestrogen
Human Gonadotrophin Hormone (hGH)
Where are the breasts found?
Between the 2nd rib and 6th intercostal space
What is the axillary tail of spence?
What can be found here?
Breast tissue extending to the axilla
3rd nipple
What does the areola contain?
Sebaceous glands and milk secreting glands
Where are tubules of montgomery attached?
Attached to the sebaceous and milk secreting glands
What are lactiferous ducts?
Pores where the milk exits
What are the hormones involved in developing the breast during pregnancy?
Which are released from the anterior pituitary?
Oestrogen Progesterone Serum placental lactogen Prolactin (a.p) Adenocorticotrophin (a.p) Human growth hormone (a.p)
What is the pathway of milk from the breast to the nipple?
Lobe –> Lobules/alveoli –> Ductules –> Ducts –> Lactiferous ducts –> Nipple
What are the alveoli lined by?
Lactocytes
What are lactocytes?
Secretory cells which contract (myoepithelial cells) to expel milk
What is the nerve supply to the breast?
Intercostal nerve 4-6
What is the arterial blood supply to the breast?
Internal mammary artery
Lateral thoracic artery
What is the venous blood supply to the breast?
Internal and external mammary vein
Axillary veins
Explain the milk ejection reflex
Oxytocin released when baby is sensed and suckling
–> muscle contraction –> milk ejection
Milk removal –> prolactin –> milk production
What is the timescale of breast change throughout pregnancy?
Week 6: Breasts feel ‘different’ and have more blood
Week 12: Enlargement of areola and sebaceous glands produce an oily substance
Week 12-16: Colostrum secreted
What happens to glandular tissue after breast feeding?
Turns into adipose tissue
Define mammogenesis and lactogenesis
Mammogenesis: Development of breast tissue
Lactogenesis: Milk production
What is the milk like in the 3 stages of lactation?
Stage 1: Decreased volume of weak milk to allow the baby’s kidneys and bowels to adapt (24 hrs)
Stage 2: Large volume of milk (7 days)
Stage 3: Normal milk production
When do prolactin levels increase?
After the placenta has been delivered
Due to progesterone decrease
Define galacroporesis
When the body’s milk production is adjusted to the baby’s needs
What does formula milk and breast milk contain?
Both (6)
Breast (7)
Both: vitamins, minerals, water, protein, lactose, lipds
Breast: enzymes, anti-inflammatory, viral fragments, WBC, hormones, antibodies, bifidus factor
Where are oxytocin and prolactin released from?
Oxytocin: Posterior pituitary
Prolactin: Anterior pituitary
Explain the 3 ways which breast milk production is inhibited
Prolactin receptor theory: Full = lactocytes stretched so prolactin detaches (opposite if empty)
Feedback inhibitor of lactation:Whey protein in milk inhibits prolactin receptors
Prolactin inhibitory factor: Hypothalamic factors (dopamine) reduce prolacin secretion when milk not removed
What can formula milk cause?
Allergic sensitisation
What actually causes mastisis
Stasis of milk builds up pressure and causes milk to leak into interstitial tissues, activating the inflammatory response
When does mastitis pain occur?
Increased pain before feed
Much better after feed
6 ways to self-help mastitis
Warm and moist compress Warm showers to increase flow Increase fluid intake Massage breast Better feeding technique Frequent feeds
Define malformation
Primary disturbance of embryogenesis
wrong box of lego
Define disruption
Secondary disturbance due to the influence of external factors (had the right box but it is taken away)
e.g. Amniotic bands, Poland anomaly (cocaine cuts blood supply to subclavian = arms don’t develop)
Define deformation
Late changes in previously normal structures
(lego made but broken and tried to put back together)
e.g. uterus squishes baby, hip dysplasia, clubbing
Define TORCH
Toxoplasmosis Other (syphilis, varicella zoster) Rubella Cytomegalovirus Herpes
Give 8 examples of aeitological causes of congenital defects
Vitamin A Alcohol Drugs Environmental pollutants Maternal metabolic disease (e.g. diabetes) Pesticides Radiation TORCH
What are the three defects classified by timing?
Polytopic field defect e.g. Di George and V.A.C.T.R.E.L
Monotopic field defect e.g. cleft lip/palate
Organogenesis e.g. spina bifida, sequences
Give 2 causes of syndromes
Genetics
Teratogens e.g. Drugs (thalidomide), TORCH, Alcohol
How can you decrease the incidence of syndromes? (4)
Improve maternal health
Supplements e.g. folate and iodine
Rubella vaccination
Avoid risk factors e.g. alcohol, radiation, medication
Define syndrome
A set of signs and symptoms that are correlated with each other
When does gas exchange begin in a foetus?
25 weeks
What does surfactant do in the lungs?
Reduces surface tension and increases compliance
6 reasons for reduced surfactant
Congenital absense Prematurity Acidosis Hypothermia Infection Meconium aspirates
Define pneumothorax
What does it squish?
How is it treated in a baby?
Air in the chest which is not inside the lung
Squishes the heart
Removed with a needle
How many umbilical arteries and veins are there
Where do they carry blood from and to?
What is the oxygen status of the blood they carry?
2 arteries from the iliac to the placenta (deoxy)
1 vein from the placenta to the ducts venous (oxy)
What does the ductus arteriosus connect?
Pulmonary artery to aorta
What does the ductus venosus connect?
Umbilical vein to IVC
When does the ductus venosus and arterious close?
Ductus venousus in a few days
Ductus arteriosus within 24-48 hours
What happens in persistent pulmonary hypertension?
What is the treatment?
Stiff lungs and constricted arterioles mean the pressure doesn’t drop and it is easier for the blood to go through the ductus arteriosus
Baby becomes hypoxic so given oxygen, NO and surfactant
Explain how the foramen ovale is closed?
At birth, no blood from placenta reduces RA pressure
Placenta is a low resistance circuit so causes BP to increase and the LV to work harder
Breathing causes decreased resistance in pulmonary vessels so pulmonary pressure decreases and body pressure increases
Increased blood to lungs increases LA pressure
Increased RA pressure causes foramen ovale to close
Where is haemoglobin made in a baby?
Yolk sac –> Liver –> Spleen –> Bone marrow
What happens to the production of EPO in a foetus and baby?
Foetus has high rates of EPO production
Baby has reduced rates
When does adult Hb take over?
10 weeks
What do baby’s of diabetic mothers not turn on at birth?
Ketogenesis
What order do babies use their energy stores in?
Glucose - Glycogen - Gluconeogenesis - Fatty acids - Ketones
Why do babies lose weight in their first day?
They urinate
Define teratogen
If administration to the pregnant mother directly or indirectly induces structural or functional abnormlaities in the foetus or child in later life
8 examples of problems which a teratogen can induce in a foetus
Behaviour problems Chromosome abnormalities Functional impairment e.g. deafness Impairment of implantation IUGR Mental retardation Miscarriage Structural malformations
What does the teratogen MOA depend upon? (6)
Dose Drug pharmacokinetics Genetic susceptibility Placenta barrier Stage of pregnancy Synergisty
3 possible causes of spina bifida
Gene defects
Teratogens
Diabetes
5 characteristics of foetal alcohol syndrome
2 problems in later life
What is a milder form of the problem called?
Small head Thin, widespaced eyes Flat midface Thin upper lip Low nasal bridge
Growth and learning problems
Foetal alcohol spectrum disorder
What does it mean if the dose-response relationship is large?
Small increase in dose causes a large increase in effect
4 pharmacokinetic changes in a pregnant woman
Increased liver function
Increased renal excretion
Increased Vd
Reduced albumin
What 2 drugs is termination advised with?
Warfarin
Retinoids
When is the baby classed as an embryo and a foetus?
Embryo: Week 2-9
Foetus: Week 9-38
Define anencephaly
Brain not developed
What does warfarin do to the foetus? (3)
Skeletal defects, CNS abnormalities, Foetal haemorrhage
What do retinoids do to the foetus? (3)
Craniofacial, Cardiovascular, CNS effects
What do antiepileptics do to the foetus? (5)
Facial defects, Mental retardation, Neural tube defects, Autism, Asperger’s
What do benzodiazapines do to the foetus? (3)
Floppy infant syndrome, neonatal respiratory depression, withdrawal
What do ACE inhibitors do to the foetus? (8)
Anuria, Convulsions, Growth retardation, Hypocalavia (no skull), Hypotension, Lung and kidney hypoplasia, Reduced amniotic fluid (crushes)
Why do we not know how safe many drugs are during pregnancy?
Cannot carry out RCT on pregnant women
What does NICE define as the postnatal period?
Up to 8 weeks after birth
Documented and individualised plan developed after birth
When are the 3 postnatal visits?
Day 1: After discharge
Day 5: After blood spot test
Day 10: Discharge to health visitor
What happens to the levels of oestrogen, progesterone, prolactin, oxytocin, FSH and LH after birth?
Decrease in oestrogen and progesterone to non-pregnant levels within 72 hours
Prolactin and oxytocin breast feeding dependent
Increased prolactin reduces FSH and LH levels = no period
What is the difference between a post-partum haemorrhage and a secondary post-partum haemorrhage?
Secondary post-partum haemorrhage occurs 24 hours or more after birth
4 signs of a thromboembolism
SOB, Chest pain, Calf pain/swelling
When can pre/eclampsia occur after birth?
4 symptoms
Within 72 hours of birth
Headaches, visual disturbances, nausea and vomiting
How can women suffer from meningitis post birth?
Infection in the epidural site
What is the biggest cause of direct maternal death?
What is another huge cause of maternal death?
Thrombosis
Sepsis
Stages of the physical examination (woman)
Wound assessment Observations (temp, pulse, bp, resp) Measure and record first urination Assessment of uterus Note colour and circumference of calves
Define lochia
Vaginal discharge occuring after birth (mucus, blood etc.)
What is the normal rate of involution of the uterus?
cm/day
What are the two screening tests in babies?
Hearing
Blood spot
What does the blood spot test look for?
Sickle cell
Cystic fibrosis
Hypothyroidism
Metabolic disorders e.g. PKU
When do you measure for the APGAR score?
What are the scores?
When do you recussitate?
1 minute and 5 minutes
0, 1 ,2
Resuscitate under 7
What is the NIPE?
When is it carried out?
Neborn and Infant Physical Examination
72 hours and 6-8 weeks
Define IUGR
A baby less than the 10th percentile of weight for gestational age
2 measurements
Which IUGR babies will catch up?
Babies whose lungs are okay
What is the size of the baby’s head and abdomen in asymmetrical IUGR?
Normal head but small abdomen
3 causes of symmetrical IUGR
2 causes of aysymetrical IUGR
Chemicals, viruses, chromosomes
Pre-eclampsia, Placental insufficiency
Causes of IUGR
5 maternal
3 foetal
5 placental
Maternal: Smoking, Alcohol, Anaemia, Medical disease, Pre-eclampsia
Foetal: Infection, Structural or genetic abnormalities, Multiple birth
Placental: Abrupto placenta, Placenta praevia, Cord anomalies, Damaged vessels (thrombosis, calcified, atherosclerosis), Cancer
4 things measured in an ultrasound to detect IUGR
Head circumference
Abdominal circumference
Femoral diaphysis length
Liquor volume
Define the Barker Hypothesis
Programming of organ structures and functions in foetal life determines physiological and metabolic responses into adulthood
How can you use a doppler to diagnose IUGR?
Tachycardia = baby cannot push the blood through
End diastolic flow reversal = increased flow to the brain but compromised flow to the rest of the body
No slope = no diastolic flow
Absent or reversal is a risk to the neonate (neurological, anaemia, hypoglycemia, prematurity)
When and how do you deliver an IUGR baby?
Try to get to 34 weeks
Good doppler = vaginal induction
Poor doppler = c-section
What can you test biochemically for IUGR?
Placental hormones in the blood