Obs notes Flashcards
At what week does the heart start to beat ?
- Week 6
What are the 3 layers of the fetal pole ?
- Ectoderm
- Mesoderm
- Endoderm
What parts of the body come from the endoderm
- GI tract
- Lungs
- Liver
- Pancreas
- Thyroid
What parts of the body come from the mesoderm
- Heart
- Muscle
- Bone
- Connective tissue
- Blood
- Kidneys
What part of the body comes from the ectoderm
- Skin
- Hair
- Nails
- Teeth
- CNS
What produces hCG
- Syncytiotrophoblasts
- This maintains the corpus luteum in the ovary allowing it to continue to continue to produce progesterone and oestrogen
Ovulation occurs following a surge of what hormone ?
- LH surge from the pituitary causing the smooth muscle of the theca externa to squeeze the follicle to burst
- Follicular cells also release digestive enzymes that puncture a hole in the wall of the ovary allowing the ovum to pass through
What is the function of the placenta ?
- The only source of oxygen for the fetus
- Fetal haemoglobin has a higher affinity for oxygen than adult and this oxygen transfers from one to the other across the placental membrane
What is the role of hCG
- Helps maintain the corpus luteum until the placenta can take over the production of oestrogen and progesterone
- hCG can cause symptoms of nausea and vomiting
- Levels increase in early pregnancy and plateau around 10 weeks
What is the role of oestrogen in pregnancy ?
- The placenta produces oestrogen which helps soften the tissues and make them more flexible
- Allows the muscles and ligaments of the uterus and pelvis to expand and the cervix to become soft and ready for birth
- (Also enlarges the breasts and prepares them for breastfeeding)
What is the role of progesterone in pregnancy ?
- The placenta takes over production of progesterone by 5 weeks
- The role of progesterone is to maintain pregnancy
- It relaxes the uterine muscles (preventing contraction and labour) and maintains the endometrium
What are side effects of progesterone in pregnancy ?
- Causes relaxing of other muscles too
- Lower oesophageal sphincter (causing heartburn), the bowel (causing constipation) and the blood vessels (hypertension, headaches and flushing)
- Also raises body temp between 0.5-1
What is gestational age ?
- Refers to the duration of pregnancy starting from the date of the last menstrual period
Gravida
- Number of pregnancies
Para
- Number of times a patient has given birth after 24 weeks gestation, regardless of whether the fetus is alive or still born
G&P of A pregnant patient with three previous deliveries at term
- G4 P3
G&P of A non-pregnant person with a previous birth of healthy twins
- G1 P1
G&P of A non-pregnant person with a previous miscarriage
- G1 P0+1
G&P of A non-pregnant person with a previous stillbirth (after 24 weeks gestation)
- G1 P1
Conditions identified with parental screening ?
- Trisomy 21 Down’s
- Trisomy 18 Edward’s
- Trisomy 13 Patua’s syndrome
- 45XO Turner’s syndrome
- 47XXY Klinefelter’s syndrome
What is the combined screening test ?
- USS (Nuchal)
- Blood test – PAPP-A and b-hCG
Quadruple tests – 15 weeks
- AFP reduced
- Oestriol reduced
- hCG increased
- Inhibin A increased
What is a CTG ?
- Cardiotocography
- Electrotonic monitoring of the fetal heart rate correlated with any uterine contractions
What is normal cardiotocography ?
- The baseline fetal heart rate is between 110 and 160 and varies from that baseline by 5-25bpm
- The heart rate should speed up by at least 15bpm for at least 15s (accelerations) 2 accretions should be seen in 20 mins (reactive)
- There should be no slowing of the fetal heart rate from the baseline (decelerations)
What is abnormal cardiotocography ?
- A baseline heart rate not between 110 and 160 and
- A baseline that varies by more or less than 5-25 bpm
- Decelerations
High bishops score
- Score of over 8 indicates that spontaneous labour will be successful
- An induction is likely to be successful
Moderate bishops score
- Between 6-7 means it is unlikely labour will start soon
- An induction may or may not be successful
Low bishops score
- Score of < 5 Labour is less likely to start
- Induction is unlikely to be successful
Features of an APGAR score
- Breathing effort
- Heart rate
- Muscle tone
- Relex irritability
- Skin colour
Good Apgar score
- Above 7
What are the stages of labour ?
- First stage – from the onset of labour until 10cm cervical dilation
- Second stage from 10cm dilatation to delivery of baby
Things to check prior to induction
- Lie and position of foetus
- Volume of amniotic fluid
- Tone of uterus
- Ripeness of cervix (bishops score)
Contraindications for induction of labour
- Severe degree of placenta previa
- Transverse fetal lie or severe cephalopelvic disproportion
- Cervix < 4 bishops score
Reasons for induction of labour
- Prolonged pregnancy (70% induced after 41 weeks)
- Premature rupture of membranes – where labour does not then start
- Diabetic mother > 38 weeks
- Rhesus incompatibility
What is required for diagnosis for onset of labour
- Show (mucus plug of the cervix)
- Rupture of membranes
- Regular painful contractions
- Dilating cervix on examination
What is the second stage of labour ?
- 10cm dilation to the delivery of the baby
- Success depends on the 3Ps – power, passenger and passage
What is power in the 2nd stage of labour ?
- Strength of uterine contractions
What is passenger in the 2nd stage of labour ?
- The baby =
- Size – of head
- Attitude – posture of the fetus
- Lie – position of the fetus
- Presentation – e.g. cephalic
What is passage in the 2nd stage of labour ?
- The size and shape of the passageway mainly the pelvis
What is cephalic presentation ?
- Head first
What is breech presentation ?
- Legs are first
What is a complete breech ?
- Hips and knees flexed
Frank breech ?
- Hips flexed and knees extended, bottom first
What is a footling breach ?
- Foot hanging through the cervix
What are the 7 cardinal movements of labour
When does the 1st stage of labour start and end ?
- From onset of true contractions until cervix is fully dilated
- Mucus plus will fall out
- Latent phase – 0-3cm dilation irregular contractions
- Active phase – 3-7 (1cm per hour) 3-4 contractions per 10 minutes regular and frequent
- Transition phase 7-10, strong an regular contractions, full dilation, head visible
What happens during the 3rd stage of labour
- From complete birth of the baby to the delivery of the placenta
- Physiological management = if the placenta is delivered naturally
- Haemorrhage or more than 60 min delay should aid in delivery of the placenta
- IM oxytocin helps uterus to contract
How is labour induced ?
- Membrane sweep
- Prostaglandin gel or (misoprostol) pessary high in vagina
- Amniotomy
- Oxytocin
Non-pharmacological methods of labour pain relief
- Education e.g. breathing exercises and relaxation techniques
- Acupuncture, homeopathy and hypnosis
- Transcutaneous electrical nerve stimulation
- Water birth
Pharmacological methods of pain relief during labour
- Nitrous oxide – gas and air
- Entonox – SE = nausea, vomiting and fainting
- Narcotic agents – Diamorphine/pethidine SE = drowsiness, nausea and vomiting
- Pudendal nerve block – for instrumental delivery
- Local anesthetic – lidocaine – before episiotomy and before suturing vaginal tears
Epidural analgesia
- Pain fibers carried by T10-S5
- Can be regularly topped up by catheter left in space
- Can help lower BP in PE
What are the different roles of the placenta
- Respiration
- Nutrition
- Excretion
- Endocrine
- Immunity
How does the placenta do respiration ?
- Oxygen in
- C02, hydrogen ions, bicarbonate and lactic acid out
How does the placenta do Nutrition ?
- Glucose, vitamins and minerals to the fetus
- Can also transfer harmful substances such as medications, alcohol, caffeine or cigarette smoke
How does the placenta do excretion ?
- Urea and creatinine
How does the placenta do endocrine ?
- In early pregnancy the Syncytiotrophoblasts produces hCG which maintains the corpus luteum until the placenta can take over the production of oestrogen and progesterone
How does the placenta do immunity ?
- The mothers ABs can transfer across the placenta to the fetus during pregnancy
