Placenta, Parturition, Pregnancy Flashcards
Which part of the blastocyst produces the positive pregnancy test?
Syncitiotrophoblast, outer layer of trophoblast produces hCG which signals to corpus luteum to continue producing progesterone until placenta is developed enough to take over
What are the aims of implantation?
Anchor placenta
Establish basic unit of exchange between fetus and mother- chorionic villus
Establish maternal /fetal blood flow within placenta
Describe formation of chorionic villus
Primary villus-syncytiotrophoblast penetrated by cords of cytotrophoblast day 13
Secondary villus penetrated by fetal mesenchymal cells day 15-16
Tertiary villus-penetrated by fetal vessels: Chorionic villi day 23
Stalk attaching fetus to placenta forms umbilical vessels
What further changes occur to the chorionic villus during development of the pregnancy?
Thinning of placental barrier
Margination of fetal vessels
Massive expansion of surface area by arborisation
What is the name for coiled up chorionic villi?
Cotyledons
What changes occur to the Feto-maternal interface/ interhaemal distance as the pregnancy progresses?
Up to week 20: 4 layers - Syncitiotrophoblast, cytotrophoblast, mesoderm, capillary endothelium
After 20 weeks: 2 layers - Syncitiotrophoblast, capillary endothelium
Describe the Early stage formation-day 6/7 of the placenta
Blastocyst-inner cell mass / trophoblast - forms placenta
Establishment of placenta takes precedence
Invasion of endometrium-day 7
Syncytium-outerlayer
Cytotrophoblast-inner layer
Decidual reaction-limits invasion/initial nutrition/QA
Describe the structure of the umbilical cord
2 umbilical arteries-deoxygenated blood from fetus
1 umbilical vein-oxygenated blood-from mum
Helical
Wharton’s jelly
30-90cm
Describe the Maternal –fetal bloodflow system and what factors can affect it
Low pressure / high flow
500-750ml/min at term
Factors-fetal heart / vessels
umbilical vessels
uteroplacental flow- mumHow many placentas will there be in a dizygotic pregnancy?
2 placentas or fused
dichorionic diamnionic
How many placentas could there be in a monozygotic twin pregnancy?
Splits very early: dichorionic/diamnionic
Before day 9: monochorionic/diamnionic
After day 9: monochorionic/monoamnionic
What are the functions of the placenta?
Endocrine: steroid and peptide hormones
Transfer: Nutrition / waste / gas exchange
Immunity
What are the peptide hormones secreted by the placenta?
Human chorionic gonadotropin: Peaks at 10-12 weeks, Maintains corpus luteum, Basis of pregnancy tests
Human placental lactogen-hPL: Rise steadily during pregnancy, Glucose metabolism
What steroid hormones are secreted by the placenta?
Progesterone: maintains uterine quiescence, maternal adaptations, suppresses HPO
Oestrogen: Substrate for increased maternal oestriol is in fetal adrenal gland
What forms of transport and transfer does the placenta do?
Governed by MW, solubility, charge Simple diffusion, Facilitated diffusion, Active transport Pinocytosis / transcytosis
Which molecules move across the placenta by simple diffusion?
Gases-O2 /CO/ CO2
Water
Electrolytes
Urea and uric acid-waste products
Which molecule moves across the placenta by facilitated diffusion?
Glucose
Which molecules move across the placenta by active transport?
Amino-acids
Water soluble vitamins
Iron
What is pinocytosis? And which molecules are transported across the placenta in this way?
Receptor mediated transcytosis
Engulfed into cytoplasm of the trophoblast
Extruded into fetal circulation
Globulins, phospholipids, immunoglobulins
Describe the immune function of the placenta
Most antibodies of the IgG group cross readily
Receptor mediated pinocytosis
Passive immunity
IgG in fetal circulation exceeds concentration in maternal circulation as term approaches
What dysfunctions can occur with the placenta?
Position / Development: Inappropriate site-ectopic, praevia, Abruption, Uncontrolled invasion- accreta, increta,percreta
Growth: Uncontrolled growth, Gestational trophoblastic disease, Molar / choriocarcinoma
Transport bad stuff: Smoke, Drugs-eg, cocaine, Alcohol-Fetal alcohol syndrome, Infectious agents-eg, rubella, Antibodies-Rh disease
Blood flow compromised: Inadequate placentation, HTN &pre-eclampsia, maternal vascular disease, IVC compression, maternal haemorrhage / hydration
What is placenta praevia?
Placenta implants low down close to cervix
Risk of major haemorrhage during delivery
What is Abruption of the placenta?
Trauma or cocaine
Rips Placenta off attachment
What is placenta accreta, increta and percreta?
Uncontrolled invasion of the placenta
Accreta: into myometrium
Increta: outside uterus
Percreta: into abdomen, other organs
What types of placent praevia can occur?
Marginal
Low lying
Complete
What types of Abruption could occur?
Revealed
Concealed
Concealed and revealed
What blood flow dysfunction could occur with a placenta? What could be consequences of this?
Inadequate placentation: HTN &pre-eclampsia
Impairment: maternal vascular disease, gestational age, post dates
Mechanical: IVC compression
Volume: maternal haemorrhage / hydration
Consequences: fetal growth restriction / fetal compromise / fetal death
What is a marker for dysfunction in foetal blood flow?
Amniotic fluid volume
What happens to the placenta as it ages?
Placenta matures to meet increasing demands of fetus
Surface area increases
Interhaemal distance decreases
Ultimately may be exceeded, post dates
When is the placenta delivered?
3rd stage of labour, afterbirth. Controlled cord traction to get it out
Inspection
Why is dating a pregnancy important?
Monitor normal progress of pregnancy (both for mum & baby)
Educate mum / reassure / expectations
Early detection of problems in mum or baby / intervention
Prepare mum / family / health care team
Know if pregnancy is too short / possible prematurity
Know if pregnancy is too long / post dates
What dates are normal for pregnancy?
Term: 37-41 completed weeks Preterm: 24-37 weeks Post term: > 41 weeks Three trimesters Embryonic period first 8 weeks, Foetal period 8 weeks to term
What are methods of dating a pregnancy?
LMP: Naegele’s Rule Early sono: CRL crown rump length Symphysio –fundal height from PS to fundus Later sono: BPD bi parietal diameter UK standard is BPD at 12 weeks
What are flaws to pregnancy dating?
Overweight lady measurements would be difficult
Not accurate in twins
What anatomical changes occur in pregnancy?
Mechanical effects as uterus enlarges
Compression of multiple structures: Bladder / Ureters, Gut, Diaphragm / Lungs, Heart / Aorta / Vena cava
Skin / Muscle stretching
Lumbar spine exaggerated lordosis
Why do we use a wedge when measuring pregnant ladys blood pressure?
Compression of aorta & IVC in supine position
What hormone changes occur in pregnancy?
First trimester: Human chorionic gonadotropin, morning sickness
Second trimester: Progesterone dominates/ oestrogen also high
Progesterone= Smooth muscle relaxant so Ureters-Dilated, Bladder-less tone, Gut-delayed peristalsis, full stomach, Decreased vascular resistance, fall in BP, Skin-pigmentation, Dark nipples, linea nigra
Human placental lactogen: glucose metabolism
Prolactin: preparing for lactation
Give an overview of antenatal care
Early visits: Establish due date, Check medical history, Check OB history, Discuss lifestyle
Later visits: Monitor maternal adaptations / changes, Monitor foetal growth & development, Educate / advise / prepare
Throughout pregnancy there should be identification of risk factors that could affect maternal and foetal outcomes
What is reflective functioning in pregnancy? And how can it be assessed?
Mother’s imagined relationship with her baby
Look at mother’s mental representations of unborn baby using Working Model of the Child Interview
When do Maternal Representations of the Developing Foetus occur?
During antenatal period pregnant women build up maternal representations or images of their developing foetus
Particularly apparent between the fourth and seventh month of gestation when foetal movements can be felt by pregnant women
What factors can affect a women’s reflective functioning and maternal representations of their unborn baby?
Biological changes
Psychological factors
Social factors including environment and relationships of mother to be
What maternal representations do women who suffer domestic abuse have? And what is the significance?
Have more negative representations of their developing foetus
Babies more likely to be insecurely attached once they are born
What does the Working Model of the Child Interview do? What are the domains that women can be divided into?
Identifies whether women are Balanced, Disengaged or Distorted
Balanced: can provide richly detailed, coherent stories about experiences of their pregnancies and positive and negative thoughts and feelings about their foetuses
Disengaged: uninterested in foetus or their relationship with it and demonstrate few thoughts about the babies future traits and behaviours or themselves as mothers
Distorted: tend to digress or express intrusive thoughts about their own
experiences as children, often viewing their foetuses as an extension of
themselves or their partners
Why are maternal representations important?
Stable over time so women with distorted or disengaged prenatal representations still have them at 1year post-partum
Predict observed parenting behaviours and child attachment at 12 months
Highlights need for identification of unplanned pregnancies, substance abuse, domestic violence and unresolved parenting so that women can be supported through early intervention
What is Intergenerational Transmission of Trauma?
Trauma and neglect in childhood have effects that last throughout life course
Ghosts in the Nursery: process by which traumatised children become
unresolved parents who then re-enact trauma they experienced with their own baby. Result of parent’s mental representations of their child and the way they act towards their child
What is ghosts in the nursery?
Ghosts from parent’s childhood invade the parent-infant relationship by unconsciously influencing the way parents think about and behave towards their baby
Parents enact with their baby, scenes from their own unremembered, but painfully influential early experiences of helplessness and fear
What are unresolved parents?
Carry issues from their childhood that have not been addressed
May be less able to parent because infants distress triggers their own stress and painful memories of vulnerability and dependence
Unable to respond to infant in terms of his or her current functioning
Unable to mentalise about distress of their infant and make inaccurate assumptions about the reasons for such behaviours, For example, might suggest that baby is crying to annoy her or describe the baby in critical and inappropriate terms (she is evil)
Unresolved parents tend to become very withdrawn or very intrusive in their parenting
How can parents go from unresolved to resolved?
Need opportunity to address issues from their childhood
Need help to learn how to mentalise
What is mentalisation?
Ability to understand mental state of oneself and others which underlies overt behaviour
Ability to understand actions of oneself and others as meaningful because they are underpinned by intentional mental states such as personal desires, needs, feelings, beliefs, and reasons
What is resilience?
Dynamic process encompassing positive adaptation within the context of significant adversity
What is a key source of resilience in early life?
Secure attachment to at least one primary caregiver, or a stand-in caregiver
What is Angels in the nursery?
Process by which children acquire protective experiences despite a wider context of abuse which enables them not to re-enact the abuse with their own children
This happens in moments of particular connectedness which enable the child to identify with a loving parent, and so enables the child when they become a parent not to re-enact other traumas that they may have experienced
What systems undergo major maternal adaptations?
CVS Respiratory Urinary / renal Blood Glucose Metabolism
What adaptations occur to the cardiovascular system in pregnancy?
Occur early- by 12-16 weeks
Heart Enlarges, Apex displaced up and laterally
Increased output up to 6.0 L/min /more in labour
Rate increases 10-15bpm
Stroke Volume increases
MAP falls by about 10mmHg, rises to normal as term approaches
Vascular resistance falls
What antenatal checks can be performed for cardiovascular system?
Hx of CVS disease
BP check at every visit
When is cardiac output highest in pregnancy?
Right after delivery due to release of aorta-caval compression and uterine contraction (autotransfusion)
What adaptations occur to the respiratory system in pregnancy?
Rib cage and breast enlargement
Diaphragm pushed cranially- changes in lung volume
↑ mucosal engorgement due to plasma volume expansion, nasal epistaxis
Increased respiratory rate / maternal awareness/ mild respiratory alkalosis
What antenatal checks would you do for respiratory system?
Hx of respiratory disease
Smoking
What is normal acid base status for a term pregnant lady?
Respiratory alkalosis with metabolic compensation
What adaptations occur to the urinary system in pregnancy?
Increase in renal size
Changes in RAAS Promote plasma expansion (Na + water retention)
Renal plasma flow and GFR are increased
Creatinine Clearance is increased
Renal indices are lower (creatinine / BUN)
Lower absorption thresholds / glucose / protein
Increased risk of infection; dilated ureters /stasis/
What antenatal checks would you do for the urinary system?
Hx of renal disease
UA urinalysis
C&S culture and sensitivity
What adaptations occur to the blood in pregnancy?
Plasma Volume expands 45%
Red cell mass expands by 15% so Hb conc / Hct / RBC fall
Physiologic / dilutional anaemia by 28-34 weeks
Toleration of blood loss is increased for delivery
Many coagulation changes, generally pregnancy is pro-thrombotic
What antenatal checks would you do to check blood?
Weight oedema nutrition Feanaemia labs advice travel Hx of thrombosis
What are average blood losses during delivery?
600 ml with vaginal delivery
1000ml with C/S
Maternal adaptation allows gravidas to tolerate haemorrhage better before showing a drop in BP
PPH still occurs
What adaptions occur to glucose metabolism in pregnancy?
Pregnancy is diabetogenic due to placental hormones (Placental lactogen, HGH, cortisol, progesterone)
Increased appetite/ fat deposition
Insulin resistance increases in pregnancy and levels rise
Post prandial glucose levels increase
Facilitates transfer to baby
Adaptive capacity of pancreatic insulin output may be overwhelmed Gestational diabetes
What antenatal checks would you do for glucose metabolism?
Risk assessment
screening for GDM
UA urinalysis
nutrition
What is gestational diabetes Mellitus?
Appears in 4% of pregnancies
Not enough insulin to counteract diabetogenic hormones which increase in pregnancy
Obesity also increasing in the population
Tends to recur in future pregnancies
Increases risk for type 2 DM later in life
Increases risk to baby of macrosomia
What is pre eclampsia?
Systemic disease
Failed adaptation to pregnancy
Linked to inadequate placentation
High blood pressure: Failure of reduced vascular resistance, Failure of renal adaptation to pregnancy
Proteinuria: Leaking of glomeruli
Odema: Leaking of capillaries with increased volume
Which groups are more at risk of pre eclampsia?
Young or older gravidas
Higher incidence in primigravidas
What can result from pre eclampsia?
Maternal and / or foetal compromise and death
What antenatal checks can you do for pre eclampsia?
Risk factors BP at every visit in same position Urinalysis check for PROTEIN Symptom advice / education Check weight and oedema
Describe CO2 removal from the foetus
Maternal hyperventilation stimulated by progesterone
Maternal pCO2 falls
Facilitates placental transfer of CO2 by simple diffusion
Foetus cannot tolerate higher pCO2 than mother, Acid-base problems
Describe oxygen and CO2 movement in the foetus
Oxygenated blood arrives at foetus in umbilical vein
Delivered to venous side of foetal circulation
Foetus must cope with low pO2 blood arriving in wrong place
What shunts are present in the foetal circulation?
Ventricles work in parallel rather than in series
Preferential flow of blood
Ductus venosus: Around liver
Foramen ovale: Flow from inferior vena cava directed selectively to left atrium
Ductus arteriosus: Pulmonary artery to aorta, Distal to branch to head
How do we monitor the foetal cardiovascular system?
Structure Rate Responsiveness Timing Flow: umbilical artery flow doppler
What circulatory adaptations occur after birth?
After first breath: pulmonary vascular resistance decreases causing left atrial pressure to rise above right atrial pressure, closing foramen ovale
Ductus arteriosus contracts due to high pO2 sensitivity of smooth muscle
Both shunts close within minutes after birth. Complete closure normally occurs within a few weeks
Ductus venosus remains partially open but closes with two-three months after birth
Describe foetal lungs and their development
Thin walled air sacs for gas exchange Surfactant to reduce surface tension and allow sacs to expand 4 stages of development Pseudoglandular: 5-17wks Canalicular: 16-25wks Terminal sac: 24-40wks Alveolar: upto 8 years
What is the function of foetal lungs? And what significance does this have for a preemie?
Foetus makes breathing movements irrigating lungs with amniotic fluid (diaphragmatic)
Surfactant produced by type II pneumocytes increase significantly after 30 weeks
Surfactant deficiency in pre-term infants can cause respiratory distress
How do we monitor Foetal lung development?
Foetal Breathing movements
Amniotic fluid analysis: look for surfactant levels
Outline the main features of development of the foetal nervous system
At 8-10 weeks: Local stimuli evoke response Swallowing:10 w Breathing Movements :12-16 w Ability to suck: 24 w Integration of nervous and muscular function increase rapidly in third trimester Hears sound: 24-26 w Eye sensitive to light: 28 w Mum feels movements 18-20 weeks
How do we monitor foetal nervous system?
Foetal movements
Foetal responses
Foetal position / posture / tone
Outline the development of the foetal GI system
Swallowing: 10-12 w
Peristalsis and transport of glucose: 10-12 w
Amniotic fluid volume regulated by swallowing
Hydrochloric acid and digestive enzymes: stomach and small intestine, early fetus
Movement of fluid in GI enhance growth and development of GI tract
Outline the development of the foetal urinary system
Pro and mesonephros degenerate by 11-12w
Failure to form or regress result in anomalies
Between 9-12 w, ureteric bud and nephrogenic blastoma interact to
produce metanephros
14 w, loop of Henle functional
Kidneys start producing urine at 12 w
Describe the foetal urinary system
Most waste excreted via placenta
Full development of urinary system by 4-5 years
Urine enters bladder empties every 40-60mins into amniotic fluid
At 25 weeks foetus produces about 100ml hypotonic urine per day
Rising to about 500 ml at term
Foetus swallows amniotic fluid constantly
Absorbs water and electrolytes
Debris accumulates in foetal gut forms meconium
How do we monitor foetal urinary system?
Foetal kidney number / size /structure
Amniotic fluid volume
Bladder activity
What is amniotic fluid and what does it do?
Surrounds foetus: Mechanical protection, Moist environment, About 10ml at 8 weeks, Rising to 1L at 38 weeks, Then falls to 300ml at 42 weeks
Early pregnancy: ultra filtrate of maternal plasma
Second trimester: extracellular fluid (diffuses through fetal skin)-composition: foetal plasma
After 20 w: foetal urine
What is Polyhydramnios and Oligohydramnios?
Polyhydramnios =too much amniotic fluid
Oligohydramnios= too little amniotic fluid
What is foetal programming?
Adverse influences during foetal life alter structure and function of distinct cells, organ systems or homoeostatic pathways, so programming individual for an increased risk of developing cardiovascular disease and diabetes in adult life
What can be causes of foetal programming?
Decreased blood flow to foetus
Overexposed to glucocorticoids as a result of maternal cortisol crossing placenta
Impact of stress on trans placental transfer
What is Nature v Nurture ?
Genes account for 50-80% of individual’s characteristics
Environment plays a role in influencing which genes are expressed
What is epigenetics?
Genes being turned on or off as a result of chemical changes that do not alter the basic structure of gene but whether that gene becomes active
What can be short term after birth consequences of poor maternal mental health?
Very severe stress in the first trimester has been associated with an increase in congenital malformations
Less severe stress with low birth weight and reduced gestational age
Altered sex ratio fewer males to females in an unstressed population
Impact on neurodevelopmental functioning of new borns
Psychopathological outcomes of infants and toddlers (difficult temperament)
Sleep problems
Lower cognitive performing and increased fearfulness
What can be longer term outcomes of poor maternal mental health during pregnancy on the child?
Stress and neurodevelopmental outcomes in children age 3-16 years
Emotional problems
Anxiety and depression
ADHD
Conduct disorder
Stress thermostat can be miss-set and remain so across the life-course
Cortisol
What are the functions of progesterone?
Suppresses myometrial contractions throughout pregnancy
Promotes formation of mucous plug in cervical canal
Prepares mammary glands for lactation
Essential for gestation
What are the functions of oestrogen?
Proliferative effect on: Uterus, Breasts, Ductal structure
Preparation of uterus and cervix for labour
Induction of pro-labour genes
How is placental progesterone made?
Cholesterol from mum converted in the placenta and returned to maternal circulation
How is placental oestrogen made?
Cholesterol from mum taken across placenta to the foetal adrenal cortex where it is converted to Dehydro-epiandrosterone sulphate
(DHEA-S). This is transported to placenta where it is converted to oestrogen and travels back to maternal circulation
What are the layers between baby and uterine lining?
Amnion
Chorion
Decidua
Myometrium
What signals lead to uterine activation ready for labour?
Oxytocin released from posterior pituitary activates prostaglandin receptors, oxytocin receptors and gap junctions in the uterus
Release of cortisol from the foetal adrenal gland increases placental oxytocin, placental CRH and prostaglandins which activate PGE and oxytocin receptors and gap junctions too
What changes occur in the uterus in the process of parturition? And when do they occur?
Increased coupling Increased ion channels Increased receptors Decreased NO Resulting in increased excitability and contractility and a decrease in relaxation All acute events at term
What changes occur in the cervix during the process of parturition? And when do they occur?
Increased inflammatory response Increased collagenolysis Decreased NO Results in ripening of the cervix (dilatation) Chronic events 25 weeks to term
What changes occur to the foetal membranes during the process of parturition? And when do they occur?
Increased extra cellular matrix degradation
So decreased tissue integrity, eventually rupture
Chronic event, 25 weeks to term
What is parturition?
Expulsion of products of conception
If parturition occurs before 24 weeks, what is it called?
Spontaneous abortion
What are the phases and stages of parturition?
Phase 0: quiescence
Phase 1: preparation for labour
Phase 2 stage 1: onset of contractions til cervix is 10cm dilated
Phase 2 stage 2: until baby is delivered
Phase 3 (stage 3): delivery of placenta, involution
What will the uterus look like at the time of delivery?
Active segment, most contractions here
Passive segment
Cervix fully dilated and flattened away and continuous with vagina
What is the progesterone paradox?
No progesterone withdrawal at term, levels remain high
But administration of progesterone nuclear receptor antagonist plus prostanoids initiates labour
What initiates labour?
Prostaglandins and inflammation
What is the Ferguson reflex?
Positive feedback loop
Baby’s head stretches cervix
Cervical stretch excites fundic contraction by oxytocin
Fundic contraction pushes baby down, stretching cervix further
Cycle repeats over and over
How does oxytocin stimulate contractions? What is its mechanism of action?
Acts on GPCR Gq which activates phospholipase C
This cleaves PiP2 and DAG to give IP3 which acts via ER to cause calcium release and L type ca channels to cause influx
Ca binds calmodulin which causes phosphorylation of myosin light chain kinase to cause a smooth muscle contraction
Describe involution of the uterus following parturition
Weight of uterus increase from a non-pregnancy weight of ~50 to ~1100 grams during pregnancy
Following delivery of baby the uterus continues to contract so shearing the placenta, Aided by prostaglandins and oxytocin, Critical to preventing blood loss
Oxytocin given IM in 3rd stage reduces risk of PPH by 40%
Uterus ½ size after 1 week and pre pregnancy size 4 weeks after delivery, In lactating mothers
What can be complications of pre term delivery?
Broncho pulmonary dysplasia
Pneumothorax
Necrotising enterocolitis
Cerebral bleeds
How do you diagnose labour?
Regular contractions
Uncomfortable / Painful
Bring about cervical dilation 4cm & more
Bring foetus down into the birth canal
What are the 3 stages of active labour?
1st: onset of regular contractions to full dilatation of cervix 10cms
2nd: full dilatation of the cervix to the birth of the baby
3rd: birth of the baby to delivery of the placenta and membranes and control of associated bleeding
What are the 3 Ps in parturition?
Powers: contractions, regular / frequency /effective
Passage: birth canal, bony pelvis adaptations, soft tissues/pelvic floor, cervix /vagina/vulva/
Passenger: size / positioning/coping
All 3 interact to have a successful outcome
What are the powers in labour?
Oxytocin from posterior pituitary, positive feedback loop
Palpable contractions Increase in strength / frequency
Ferguson reflex
Brachystasis: push baby downwards
Difficult to stop: tocolysis
What is the passage in parturition?
Cervical ripening due to prostaglandins
Effacement / dilation
Stretching perineum
Episiotomy if required
What is the passenger in parturition?
Positioning to navigate the birth canal
Size: Macrosomia
Coping with labour
What is foetal lie?
Relationship between long axis of foetus to that of mother
Can be longitudinal, transverse or oblique
What is foetal positioning?
Part of foetus which lies at pelvic brim or presenting to the birth canal
Vertex most common foetal presentation 96% of all term pregnancies , cephalic presentation. Could also be face, chin, brow
Non Cephalic presentations: breech, bottom or feet first (common in preemies)
If the foetal lie is transverse what bony part is likely to present?
Shoulder
What is foetal station?
Level of presenting part relative to bony pelvis /ischial spines
Engagement means presenting part at level of ischial spines / pelvic floor= station 0
How do we assess the foetal positioning?
Abdominal examination / Leopold manoeuvres
Cervical examination
Ultrasound
How do we test if a foetus is coping with labour?
Foetal heart rate
Meconiumin in amniotic fluid suggests stress
What are two types of foetal monitoring to see how a baby is coping with labour?
Intermittent foetal monitoring
Continuous foetal monitoring
What can be used to measure baby’s HR?
Cardiotocography
What does NICE recommend in terms of foetal monitoring?
Woman who is healthy and has had an otherwise uncomplicated pregnancy, intermittent auscultation should be offered and recommended in labour to monitor foetal wellbeing
Frequency of monitoring depends on stage of labour
With certain risk factors the advice is for continuous monitoring
What are reassuring features of a foetal heart beat?
Baseline 110-160 (bpm)
Variability (bpm) = >5
Decelerations : none
Accelerations : present
What is Meconium? And when can it be a bad sign?
First stool, blackish green and tenacious
When present in liquor/ AF it may be an indication of foetal distress
What is the Graphic record of a labour?
Partogram
What support should we give around labour?
Expectations /Preparation before labour
Birth Plans / Companion
Mobility / Nutrition
Pain relief
What interventions can be given to facilitate birth?
Augmentation with oxytocin IV if already in labour but slow progression
Amniotomy to release prostaglandins, break waters to help bring baby down
Instrumental forceps, operative delivery c section
What is an induction and when is it used?
Bring on labour, expedite the birth of baby when it is agreed that foetus and/or mother will benefit from a higher probability of a healthy outcome than if birth is delayed
Should only be considered when vaginal delivery is considered appropriate
Often more painful, Maybe less efficient
Epidural and instrumental delivery more common
Relatively common
Needs to be justified
On what occasions might an induction be appropriate?
Post term Pre eclampsia IUGR Mum is unwell Baby is unwell
What are the main methods of induction?
Membrane sweep
Prostaglandins (PGE2) given vaginally
Artificial Rupture of Membranes (ARM)
Oxytocin given as infusion (preferably after rupture of membranes)
Describe immediate post partum care aspects for mum
Vital signs Bladder / bowels Perineum / Lochia / sutures Fundus Breasts
What is immediate post partum assessment for baby?
APGAR score Appearance Pulse Grimace Activity Respiration
What is immediate post partum care for baby?
Kindness and respect of new born baby should involve gentle handling and avoidance of excessive noise
Why is skin to skin contact important?
Babies can lose heat quite dramatically after birth
Important for bonding
Why is suctioning of the new born not done? What is the exception to this?
Routine suctioning of new born’s oral and nasal passages not recommended as baby is capable of clearing fairly large amounts of lung fluid
Exception could be if Meconium in the amniotic fluid so baby at risk of respiratory distress
When should breastfeeding be encouraged?
Encourage initiation of breastfeeding within the first hour of birth
What is important when discussing vitamin K vaccine after birth?
Administration of Vit K requires informed consent, explanation and
education regarding Vit K deficiency bleeding, signs and symptoms
What is a newborn examination?
Holistic and detailed physical (eyes, Testes, hips, heart) examination taken within 72 hours after initial examination immediately after birth
What are key areas of the new born examination?
Appearance: colour, breathing, behaviour, activity, posture
Head: face, nose, mouth, ears, neck, symmetry, circumference
Eyes: opacities, red reflex
Neck, clavicles, limbs, hands, feet and digits: proportions, symmetry
Heart: position, rate, rhythm, sounds, murmurs, femoral pulse
Lungs: effort, rate, sounds
Abdomen: shape, palpate for organomegaly, umbilical cord
Genitalia, anus: completeness, patency, undescended testes
Spine: palpate, integrity of skin
Skin: colour, texture, birth marks, rashes
Central nervous system: tone, behaviour, movements, posture, reflexes
Hips: symmetry of limbs, skin folds, Barlow and Ortolani’s manoeuvres
Cry: note sound
Weight
What are the mammary glands and where do they feed into? And what are lobes?
Specialised accessory glands of skin
Consist of a system of ducts embedded in connective tissue
Ducts are connected to a nipple
Nipple surrounded by areola
15-20 lobes Radiate from the nipple, Separated by fibrous septae, Lobes: blood vessels, lactiferous ducts
Describe the development of breast tissue
Birth-few ducts
Puberty: ducts sprout and branch, adipose tissue, lobes develop, fibrous septae under control of oestrogen
How does the breast change in pregnancy?
Lengthening and branching of ducts Development of secretory alveoli Vascularity increases Nipples enlarge Areola becomes more prominent Lobular structure more prominent
How do the breasts change to promote the development of milk secretion? And what hormones promote this?
Clusters of alveoli develop at ends of branching ducts
Develop under influence of progesterone and prolactin
Alveoli cells differentiate and become capable of milk production
High levels of progesterone and oestrogen limit lactation during pregnancy
Why is there not much lactation during pregnancy?
High progesterone / oestrogen ratio
Favours growth of the breast
What changes occur to promote milk secretion after delivery? Describe the first milk that is produced?
Progesterone and oestrogen levels fall
First week- colostrum 40ml / day
Less water, fat, sugar, More protein
Immunoglobulins IgA
Describe what mature milk is like
Over 2-3 weeks, Igs and protein declines
Fat and sugar increase
90% water; 7%sugar (lactose), 2%fat
Minerals Vitamins
Describe where milk production occurs
In alveolar cells: fat in smooth endoplasmic reticulum, protein in Golgi apparatus
What controls milk secretion?
At birth, progesterone level falls, oestrogen less so, ratio changes
Alveolar cells become sensitive to prolactin
Prolactin promotes milk secretion
What is prolactin and what controls its release?
Polypeptide produced in Anterior pituitary
Controlled by dopamine from hypothalamus – tonic inhibition
Reduction in dopamine –promotes prolactin secretion
What stimulates prolactin production?
Suckling
Neuro-endocrine response from breast to hypothalamus
Reduction in dopamine so inhibition of prolactin production reduced
What is breast turgor?
Milk accumulates in the ducts
Breasts become swollen and engorged
What is the milk let down reflex?
Oxytocin from posterior pituitary
Neuro endocrine reflex- anticipation (hear crying, see baby)
Contracts the myoepithelial cells
Milk is ejected-not sucked out
Oxytocin also aids further contraction of uterus
What promotes maintenance of lactation?
Regular suckling-promote prolactin, remove accumulated milk
If suckling stops- prolactin falls
What can be done to inhibit lactation?
Lactation suppression-Turgor, let breasts fill up and leave them
Binding, prevent them filling up
Pharmacy-oestrogen, bromocriptine (dopamine agonist)
Why might you want to prevent lactation?
If women dont want to breast feed
Still birth
Given up baby for adoption
What are advantages of breast feeding for baby?
Lower risk of: gastro-intestinal infection respiratory infections necrotising enterocolitis (preterm babies) urinary tract infections ear infections allergic disease (eczema and wheezing) insulin-dependent diabetes mellitus sudden infant death syndrome childhood leukaemia
What are advantages of breast feeding for mum?
Increased skin to skin contact with baby Promotion of attachment Involution of uterus Lower risk of breast and ovarian cancer Lower risk of hip fractures Prevention of rheumatoid arthritis
Who should not breast feed?
Alcohol misuse Certain drugs-methotrexate, cyclosporine,lithium Active TB HIV Breast Cancer Rx Infant with galactosemia
What might be problems with breast feeding?
Cracked nipple
Mastitis
S. Aureus
Preemie
What proportion of women have problems breast feeding?
2/3
What is the UNICEF Baby Friendly Initiative?
Standards for maternity, neonatal, health visiting (or specialist public health nursing) and children’s centre services
To be certified as baby friendly according to UNICEFs initiative you must be:
Building a firm foundation: policies and procedures
Plan an education programme: allow staff to implement standards according to their role
Have processes for implementing, auditing and evaluating standards
Ensure no promotion of breast milk substitutes, bottles, teats or dummies
What should hospitals do with regards breastfeeding promotion?
Support pregnant women to recognise importance of breastfeeding and early relationships for health and well-being of their baby
Support all mothers and babies to initiate a close relationship and feeding soon after birth
Support mothers to make informed decisions regarding introduction of food or fluids other than breast milk
What did the NHS Infant Feeding Survey show?
Proportion of babies breastfed at birth in UK rose from 76% to 81% from 2005 to 2010
Exclusive breastfeeding at six weeks was much lower: 24% in England. 22% in Scotland, 17% in Wales, 13% in Northern Ireland
Exclusive breastfeeding at six months remains at around 1%
Which mothers are most likely to breast feed?
Aged 30 or over From minority ethnic group Left education aged over 18 In managerial and professional occupations Living in the least deprived areas
What are economic considerations for breastfeeding?
Increase in breastfeeding could save NHS £40m a year
Reduction in childhood diseases and breast cancer rates would
lead to considerable savings for health service
Increasing breastfeeding rates in neonatal units from 35% to 75% save £6 million per year by reducing incidence of necrotising enterocolitis
What is the correct latch position for a baby to breast feed?
Correct latch – nipple to nose
What is the surface area of the chorionic villus by term?
10-14m2
The power of compensation of the placenta may be exceeded, when would this commonly happen? What could be a result of this?
Third trimester when foetus is growing rapidly
Foetal growth may be restricted
Mean birthweight of children from twin pregnancies lower
IUGR (intra-uterine growth restriction) commonly results from this placental insufficiency
What else besides the placenta is expelled during the 3rd stage of labour ?
Decidua
When does the fetal period begin?
8-9 weeks gestation
If nutritional supply is limited across the placenta which part of the fetus receives preferential supply?
Brain
From where does the respiratory system arise?
Outgrowth of gut tube
Respiratory diverticulum appears week 4 and has many branches
When does the fetus begin to have functioning respiratory epithelia?
Cells lining bronchioles begin to change into alveolar cells, respiratory epithelia, as foetus approaches 24-26 weeks
Type II alveolar cells begin to produce surfactant with the amounts increasing during the third trimester
Does a fetus breathe?
Foetal lungs do not respire but foetus does have fetal breathing movements of diaphragm which can be seen by ultrasound
These movements draw fluid into the developing lungs and are important for conditioning respiratory muscles
Surfactant is not secreted in clinically significant amounts until 34-35 weeks of gestation. If a woman is in pre-term labour at 29 weeks what can obstetric team give to the pregnant woman to enhance foetal lung development ready for extra uterine life?
Steroids have been shown to enhance fetal lung maturity and production of surfactant
How does blood enter the fetal left atrium?
Most of blood entering the right atrium will be directed into the left atrium via the foramen ovale. This flow is pressure driven
What does the term ‘variability’ mean with reference to the fetal heart beat? Is variability a sign of well- being or not?
Variability means constant fluctuations around a normal baseline
Normal or reassuring variability is > or = 5bpm
What does the kidney develop from?
Metanephros and the ureteric bud
When does the kidney ascend to its adult position, and when does it start producing urine?
Ascends to its adult position between week 6-9
Begins to secrete urine from about 12 weeks, at first in small amounts but increasing to >500ml/day at term
What is the main component of amniotic fluid (liquor) at term?
Foetal urine
What change in the volume of the amniotic fluid would you expect if a fetus has renal agenesis?
oligohydramnios
Fetal gut development requires swallowing of amniotic fluid. If a fetus has duodenal atresia what change in amniotic fluid volume might be present?
polyhydramnios
At 33 weeks an ultrasound reveals a fetus to have lower than expected amniotic fluid volume. The fetus is smaller than it should be for its gestational age. The fetal head circumference is on the 50% for growth but the fetal abdominal circumference is on the 15% for growth. No abnormalities are seen.
In this case what pattern of intra-uterine growth restriction is developing?
Asymmetric: head growth has been spared but abdominal growth (which largely reflects liver size, related to amounts of glycogen stored) has declined
If a fetus is small because of a genetic condition what pattern of growth restriction would you expect?
Symmetric
Why are growth restricted foetuses at higher risk during labour?
Often have decreased amniotic fluid to cushion them
Already been under stress from poor nutrition and gas exchange
What simple question can you ask in obstetric history to begin your assessment of the fetal musculoskeletal and nervous systems?
Has baby started moving? Women usually begin to feel movements at about 18- 20 weeks. It may be earlier in some women especially if she has had prior pregnancies
Anna is having contractions, healthy woman, non- smoker with a history of regular ante natal care, LMP dates = 30 weeks, Ultrasound done at 12 weeks gives 30 weeks, Symphysis-Fundal Height 30cm, Cervix is 4 cm dilated. A diagnosis of labour is made, Ultrasound now = 2100g; normal amount amniotic fluid
What do we prepare for?
Preterm labour. Consider giving steroids if labour can be delayed a day or two. Prepare for a premature infant
Monitoring during labour as a hi-risk pregnancy
Annie is having contractions, heavy smoker with a history of poor attendance for antenatal care, LMP dates = 38 weeks, Ultrasound done at 16 weeks = 38 weeks, Symphysis-Fundal Height 30cm, Ultrasound now = 2100gm, HC>AC, Amniotic fluid volume is decreased
What do we prepare for?
At term with a growth restricted baby. Prepare for a small term baby who may be quite stressed
Monitoring during labour as a hi-risk pregnancy
Can the environment in the uterus affect the foetus?
Foetal programming: low birth weight babies (who had inadequate nourishment via the placenta in foetal life) can have consequences across the life-course
What are some short term outcomes of maternal stress in pregnancy?
Severe stress in first trimester: increase in congenital malformations
Less severe stress: low birth weight, difficult temperaments, lower cognitive performance
What are longer term outcomes of maternal stress during pregnancy?
Emotional problems, stress and neurodevelopmental outcomes, ADHD, anxiety and depression
What is labour? What is it called before 24 weeks?
Parturition which occurs after 24 weeks of gestation
Spontaneous abortion or miscarriage
Labour that occurs before the 37TH week of gestation is known as:
Pre term
When has labour begun?
Contractions become more regular, frequent and forceful
Cervical dilatation is facilitated by structural changes known as?
What brings about these changes in the cervix?
Cervical ripening/effacement
Prostaglandins
Which 2 hormones are involved in the process of labour?
Prostaglandins: enhancing release of calcium from intracellular stores
Oxytocin: peptide hormone secreted from the posterior pituitary under control of neurons in hypothalamus. Lowers threshold for triggering action potentials
What is brachystasis?
At each contraction muscle fibres shorten, but do not relax fully, particularly fundal region shortens progressively. This pushes presenting part toward the birth canal and stretches or dilates the cervix over it
How long does the second stage of labour usually last?
Normally lasts up to 1 hour in multiparous woman
2 hours or more in primigravida
Outline the second stage of labour
Descending head flexes as it meets pelvic floor, reducing diameter of presentation
Internal rotation to bring shoulders through bones of the pelvis
Sharply flexed head descends to vulva and stretches the vagina and perineum (crowning)
Once head is delivered, shoulders rotate and deliver followed rapidly by the rest of the fetus
How long does the delivery of the placenta usually take?
10-30 minutes
How do you score the apgar?
At 1 and 5 mins post birth, score each 0-2 Colour: White, Blue, Pink Tone: Flaccid, Rigid, Normal Pulse: Impalpable, 100 bpm Respiration: Absent, Irregular, Regular Response: Absent, Poor, Normal
What should Immediate care of the new-born include?
Gentle handling and avoidance of excessive noise
Skin-to- Skin contact with mum
Suctioning is not usually required but would be carried out if there had been meconium stained liquor to prevent meconium aspiration
Initiation of breast feeding within an hour (if appropriate)
Are any vitamins offered to new born babies?
Vitamin K
