Obstetrics document Flashcards
What day does the blastocyst form
Day 5
What is the blastocyst
Term used to describe when the embryo has divided into two separate cell masses
What are the two cell masses in a blastocyst made up of
Inner cell mass: develops in the embryo.
Outer cell mass: the trophoblast, which is responsible for initial production of progesterone and is involved in the process of implantation
What does the blastocyst go on to develop into
the placenta
When is the placenta fully developed and functional
By Week 5 of pregnancy
What are the 3 main functions of the placenta
Hormone secretion
Gas exchange
Nutrient and waste exchange
Which two hormones does the placenta secrete
HCG
Progesterone
What are the only two electrolytes that can only travel from mother to baby
Calcium
Iron
When do HCG levels peak during pregnancy
Week 10
What is the function of HCG secreted by the placenta
Simulation of corpus luteum to produce testosterone, which will prevent endometrial shedding
What is the function of progesterone during pregnancy
Prepare and maintain endometrium.
Decreases uterine contractions
Where does oestrogen come from during pregnancy
Placenta
What is the function of oestrogen during pregnancy
Enlargement of the uterus.
Development of the breasts.
Relaxation of the pelvic ligaments
What do Prolactin and Oxytocin do in terms of breast milk
Prolactin - stimulates production of milk
Oxytocin - stimulates contraction and thus expulsion of milk
What is the Ferguson reflex, with regards to pregnancy
Involves stretching of the cervix, which stimulates release of oxytocin, with this causing further stretch of the cervix and activation of the reflex
How does Progesterone act during the onset of labour
This keeps the uterus settled.
It prevents the formation of gap junctions
Hinders the contractibility of myocytes
How does Oestrogen act during the onset of labour
This makes the uterus contract
Promotes prostaglandin production
How does Oxytocin act during the onset of labour
Oxytocin initiates and sustains contractions
Oxytocin acts on decidual tissue to promote prostaglandin release
What are Braxton-Hick’s contractions
False contractions not associated with labour and can be experienced throughout pregnancy. Can be differentiated from true labour contractions as they are less painful, do not increase in frequency or intensity and can resolve by lying down or changing position
Which three parameters are used to measure contractions
Frequency
Duration
Intensity
What is the normal frequency of contractions
At peak, the normal number of contractions is 3 – 4 / 10 minutes
What is the normal duration of contractions
Initial length = 10 – 15 seconds.
Maximal length = 60 seconds
What is the main determinant of the passage of the baby
Shape of the maternal pelvis
Name 2 maternal indications for induction of labour
Prolonged pregnancy (>41 weeks) Premature rupture of membranes
Name 2 fetal indications for induction of labour
IUGR
Macrosomia
Name 3 contra-indications for induction of labour
Placenta Praevia
Cord prolaps
Fetal Distress
What must have occurred before IV syntocinon can be administered
Membranes must have ruptured
What is the maximum acceptable time for stage 2 of labour for a nulliparous woman with anaesthesia
3 hours
What is the maximum acceptable time for stage 2 of labour for a nulliparous woman WITHOUT anaesthesia
2 hours
What is the maximum acceptable time for stage 2 of labour for a multiparous woman WITHOUT anaesthesia
1 hour
What is the maximum acceptable time for stage 2 of labour for a multiparous woman with anaesthesia
2 hours
Why is active management preferred for stage 3 of labour
Reduces risk of PPH
What are the Bishop score cut offs which indicate pregnancy likely to occur and pregnancy likely to require induction
<5 likely requires induction
>9 probably will happen spontaneously
What is the most effective form of analgesia in pregnancy
Epidural
What are some maternal side effects of an epidural
Headache
Urinary retention
Hypotension
Which analgesic is the main choice for C-section
Spinal
What is the difference between spinal and epidural anaesthetic
Spinal
What is the difference between spinal and epidural anaesthetic
Spinal is into the subarachnoid space, whereas epidural is in the epidural space
When is the risk of VTE highest
Puerperium
What does a category 1 C-section mean
Immediate threat to life of woman or baby
What is the normal fetal scalp pH
> 7.25
Why might the McRobert’s position be adopted
Managing shoulder dystocia
Which palsies can be a complication of shoulder dystocia
Erb’s
Klumpke’s
When is Uterine Rupture most commonly seen
Vaginal birth after a previous C-section
What is the difference between a 2nd degree and 3rd degree tear
3rd Degree has involvement of anal sphincters
What is an episiotomy
An episiotomy is a surgical postero-lateral incision through the skin and perineal muscles that is made from the vagina to the ischio-anal fossa
What is the purpose of an episiotomy
Widen the birth canal.
Reduce the risk of 3rd and 4th degree tears by directing any further tears away from the anal sphincters
Which antibiotic should you give for cover in the case of preterm rupture of membranes
Erythromycin
Which two drugs must be given when preparing for the delivery of a premature baby
Dexamethasone
Magnesium Sulphate
Define placental retention
Failure to completely pass the placenta within:
30 minutes of active management of 3rd stage
60 minutes of passive management of 3rd stage
What is the Johnson manoeuvre
Pushing the uterus back into place after inversion
What is the management of PPH
uterine massage
bladder emptied
Ergometrine IV
Define PPH
Blood loss >500mls following delivery
What is the difference between primary and secondary PPH
Primary - within 24hrs of delivery
Secondary - 24hrs - 6 weeks after delivery
What management options should you consider if medical management of PPH fails
Balloon tamponade
Interventional radiology
Hysterectomy
When are Anti-D injections given
28 and 34 weeks
When should Nuchal thickness be measured
11- 13+6 weeks
What is the quadruple test and what is is used to test for
bHCG, AFP, Inhibin A, unconjugated estriol
15-20 weeks for Down’s Syndrome
What is trisomy 18 also called
Edward Syndrome
What is trisomy 13 called
Patau Syndrome
When can chorionic villus sampling be carried out
> 12 weeks
When can amniocentesis sampling be carried out
> 15 weeks
How can the whole genome be analysed
Array CGH
How are targeted genes analysed
FISH
Define large for dates
Symphyseal - fundal height >2cm than expected for dates
Define small for gestational age (SGA)
Corrected birth weight <10 centile
What is a normal baby birth weight
2.5 - 4.0 kg
Define the terms Zygosity, Chorionicity and Amnionicity
Zygosity: number of eggs.
Chorionicity: number of placenta.
Amniocity: number of amniotic sacs
All dizygotic twins will have how many placentae and amniotic sacs
2 placentae and 2 amniotic sacs
DCDA
What is a normal volume of amniotic fluid
500-1500mls
What is the normal amniotic sac measurement on ultrasound
> 2cm but <8cm
Define Polyhydramnios
Excessive amount of amniotic fluid (>1500ml, >8cm)
What is hydrops fetalis
An accumulation of fluid, or oedema, in at least two fetal compartments
What is Potter’s Syndrome
Potters syndrome is a group of characteristic changes seen as a result of oligohydramnios:
- Club feet.
- Pulmonary hypoplasia.
- Potters sequence -> flat nose, recessed chin, low set ears, skeletal abnormalities
What is the primary problem in Potter’s syndrome
Kidney failure
What is the Kleihauer–Betke test
A blood test used to measure the amount of fetal hemoglobin transferred from a fetus to a mother’s bloodstream
What does an indirect coomb’s test tell you in rhesus pathology
Tells you whether mum is sensitized or not.
Positive: sensitized.
Negative: not sensitized
What are the three possible scenarios when Anti-D can be given
Mother negative.
Baby positive.
Mother is coombs negative
When should folic acid be started with regards to pregnancy
3 months pre conception to end of 1st trimester
What do Ace inhibitors or ARB’s cause in babies
Renal hypoplasia
What do Valproate and Phenytoin cause in babies
Valproate - Spina bifida
Phenytoin - Cleft lip
Which cardiac abnormality can lithium cause
Ebstein’s abnormality
What can tetracyclines cause in babies
Hypoplasia of teeth enamel and yellowing
What treatments are safe for UTI during pregnancy
Trimester 1 - nitrofurantoin/cephalexin
Trimester 2 & 3 - Trimethoprim/Cephalexin
What is given for VTE prophylaxis in hyperemesis gravidarum
Heparin
How can you replace Thiamine in Hyperemesis Gravidarum
Pabrinex
Which anti-emetic is best in pregnancy
Cyclizine
Describe the trend of blood pressure over pregnancy
Falls due to expansion of utero-placental circulation - lowest at week 24
Will steadily rise after this
Name 3 fetal associations with hypertension in pregnancy
IUGR
Still Birth
Placental Abruption
When should low dose aspirin be started for those at risk of pre-eclampsia
Start 75mg at 12 weeks
What is the diagnostic triad of pre-eclampsia
Hypertension
Proteinuria
Oedema
What is the main cause of death in pre-eclampsia
Pulmonary Oedema
What are the 2 diagnostic criteria for gestational diabetes
Fasting glucose > 5.1 mmol
2 hour OGTT > 8.5 mmol
When is OGTT offered during pregnancy
24 – 28 weeks
When is pyelonephritis most common in pregnancy and how is it treated
Most common around 20 weeks
Co-Amoxiclav
Which is the only SSRI reccomended for use in breastfeeding
Sertraline
What do atypical anti-psychotics have a risk of causing during pregnancy
Gestational diabetes
IUGR
Define antepartum haemorrhage
Vaginal bleeding after 24 weeks gestation but before birth
In the case of Antepartum haemorrhage, what should you always do before carrying out a PV exam
Rule out placenta praevia with ultrasound
What is Vasa Praevia
Vasa Previa is when the fetal blood vessels develop within the membranes
When the membranes rupture, the fetal vessels will too, resulting in a catastrophic bleed
When can fetal blood sampling be carried out
18 weeks onwards
When can the Combined oral contraceptive pill be started postpartum if a woman is breastfeeding
6 weeks onwards
Define Lactational Amenorrhoea
Exclusively breastfeeding
Amenorrhoea
<6 months postpartum
How effective is Lactational Amenorrhoea as contraception
98%
