Obstetrics Flashcards
What are the key components of a history in pregnancy?
Amenorrhoea Previous periods Contraception Whether planned pregnancy Date positive pregnancy test Smoking, alcohol, drugs, infections, blood group
What are the criteria for instrumental delivery?
Adequate analgesia
Abdo exam: head either 1/5 or 0/5 palpable
Vaginal exam: fully dilated, known fetal position
Adequate maternal effort and regular contractions for ventouse
Empty bladder
What are the complications of instrumental delivery?
Genital tract trauma Haemorrhage Infection Fetal scalp oedema Bruising Facial nerve palsy
What are the indications for emergency C-section?
Placenta praevia Breech Abnormal CTG Cord prolapse Delay in 1st stage
What are the indications for elective C-section?
2 previous LSCS Maternal disease eg pre-eclampsia Maternal request Active genital heroes HIV depending on viral load Twin pregnancy if twin 1 not cephalic
What are the complications of C-section?
Haemorrhage Gastric aspiration Bladder or bowel injury Infection VTE Future pregnancy
What should be done at a pregnant lady’s first contact with a healthcare professional?
Folic acid 400mcg daily
Food hygiene
Smoking cessation, drug and alcohol use
Screening: haemoglobinopathies, anomaly screen and screening for down’s
When is the “booking” appointment?
Ideally by 10 weeks
Who should have screening for gestational diabetes?
BMI over 30 Previous macrosomic baby >4.5 kg Previous gestational diabetes 1st degree family history Ethnicity Hypertension Pre-eclampsia
What are the risk factors for pre-eclampsia?
>40 Nulliparity / pregnancy interval >10y Family history Previous history BMI>30 Hypertension Renal disease Multiple pregnancy
What are the symptoms of pre-eclampsia?
Severe headache Problems with vision Severe pain just below ribs Vomiting Sudden swelling of face, hands or feet
What is the routine screening for Down’s syndrome?
Combined test between 11 and 14 weeks
Nuchal translucency, beta-hCG and PAPP-
Confirmatory diagnostic CVS or amnio if positive
What is the quadruple test for Down’s syndrome?
Can be used from 14+2
hCG, AFP, uE3 and inhibin-A
What is defined as high risk for Down’s?
1 in 150
This is the level at which patients are offered further testing (CVS or amnio)
When is the anomaly scan done?
Between 18 and 21 weeks
What is the purpose of the anomaly scan?
Reproductive choice (TOP)
Parents can prepare
Managed birth in a specialist centre
Intrauterine therapy
How many appointments do women have in an uncomplicated pregnancy?
10 for primips
7 for multi
What happens at every antenatal visit?
BP and urinalysis
From 24: symphysis-fundal heigh
From 36: check presentation
When is anti-D prophylaxis given?
28 weeks
What are the common symptoms of pregnancy?
Nausea and vomiting Heartburn Constipation Haemorrhoids Vaginal discharge Varicose veins Backache
What happens in pregnancy over 41 weeks?
Offer membrane sweep
Induction if beyond 41
If IOL declined after 42 weeks, increased surveillance with CTG and USS
What is the management of breech presentation at term?
Offer external cephalic version in uncomplicated singleton
What is the management of baby blues?
If not resolved after 10-14 days, assess for PND. If symptoms persist then seek urgent further action
How do you manage perineal pain postnatally?
Offer to assess
Signs of infection, wound breakdown or non-healing require urgent action
NSAIDs, topical cold therapy
What life-threatening conditions may present postnatally?
PPH Infection or genital tract sepsis Pre-eclampsia / eclampsia PE DVT
What does smoking in pregnancy increase risk of?
Premature rupture of membranes Placental abruption Placenta praevia Premature birth Small placenta Umbilical cord problems Pregnancy-induced hypertension
What are the effects on a newborn child of smoking during pregnancy?
Low birth weight
Sudden infant death syndrome
Cerebral palsy
Future obesity
How does smoking affect breastfeeding?
Decreases milk production
Alters milk composition
Nicotine can enter breast milk
How should you examine a woman with a gravid uterus?
Not lying flat
Risk of postural supine hypotension syndrome - pregnant uterus compresses aorta and reduces blood flow back to maternal heart
What are the components of abdominal palpation of a pregnant woman?
- Uterine size
- Number of foetuses
- Fetal lie
- Fetal presentation
- Engagement
- Position of presenting part
- Liquor volume
How do you palpate for uterine size?
Use medial border of hand and move down starting at the xiphisternum
Measure distance from fundus to symphysis pubis in cm
What levels equate to what weeks of pregnancy?
Symphysis pubis 12 weeks
Umbilicus 20 weeks
Xiphisternum 36 weeks
What is fetal lie?
Relationship of long axis of fetus to long axis of uterus
Longitudinal, transverse or oblique
What is fetal presentation?
The part of the fetus that presents to the maternal pelvis
Cephalic, breech, oblique
What is malpresentation?
Any presentation other than cephalic
When is the fetus engaged?
When the widest diameter of the head (biparietal diameter) has passed through the pelvic brim
How do you determine whether the fetus is engaged?
Determine what proportion of the fetal head is palpable abdominally
>3/5 palpable per abdomen means it is not engaged
How do you decide the position of the presenting part?
Relationship of the denominator of the presenting part (eg occiput in cephalic) to the maternal pelvis
How can you clinically assess liquor volume?
Best by USS, but can determine if:
SFD uterus & easily palpable fetal parts - decreased liquor vol
LFD uterus, smooth and rounded and fetal parts difficult to palpate - increased liquor volume
What is the vulva likely to look like in pregnancy?
Swollen and oedematous due to engorgement ( increased blood flow in pregnancy)
How do you determine dilatation?
In fingers’ breadth: 1 finger is 1cm
What is the normal length of the cervix (when not in labour)?
3cm
What happens to the length of the cervix in labour?
Shortens as it effaces
What happens to the consistency of the cervix as pregnancy progresses?
Softens
Can be firm, mid-consistency or soft
What is the Bishop score?
Evaluates the ripening or favourability of the cervix
Higher the score, more favourable the cervix and the more likely induction of labour will be successful
What features are used to calculate the Bishop score?
Dilatation in cm Cervical length Station of presenting part Consistency of the cervix Position
What aspects should be taken into account when commenting on progress in labour?
Engagement of head Cervical dilatation Cervical effacement Station of head in relation to ischial spines Position of head Liquor colour
What is term?
37 weeks
What is pre-term?
24-37 weeks
What are the main problems with premature babies?
Brain damage
Poor lung maturation
Jaundice
Small size
What questions should you ask in a patient presenting to MAU?
Abdominal pain Bleeding Discharge Pelvic pain Fetal movements Lower urinary tract symptoms Bowels Generally well?
What are the symptoms of pre-eclampsia?
Dizziness
Oedema
Visual disturbance
Epigastric pain
What are the signs of labour?
Contractions (CTG)
Regular uterine contractions that are increasing in frequency
Cervix dilated and effaced
Show should have been lost
What is the show?
Cervical mucus plug
What is the key differential for abdominal pain in the 2nd and 3rd trimester?
Is the pain obstetric or non-obstetric?
What are the obstetric differentials for abdo pain in the 2nd and 3rd trimester?
Labour Placental abruption Symphysis pubis dysfunction Ligament pain Pre-eclampsia / HELLP syndrome Acute fatty liver of pregnancy
What are the other differentials for abdo pain in the 2nd and 3rd trimester?
Gynae
GI
GU
What are the features of placental abruption?
Pain more commonly associated with PV bleed
Uterus tender on palpation
Symptoms/signs of pre-eclampsia
What are the symptoms of acute fatty liver of pregnancy?
Epigastric / RUQ pain
Nausea and vomiting
Anorexia
Malaise
How do you listen to the fetal heart?
Before 26 weeks used pinard or sonicaid
CTG after 26 weeks
How is pregnancy established?
Blastocyst enters uterine cavity 4-5 days after fertilisation
After a day or so it implants into the endometrium
Interaction between trophoblast cells and uterine epithelium
What happens to the placenta during pregnancy?
Becomes progressively thinner as the needs of the fetus increase
What are the aims of implantation?
Establish basic unit of exchange
Anchor the placenta
Establish maternal blood flow within the placenta
Name 2 implantation defects
Ectopic pregnancy
Placenta praevia
What is decidualisation?
Decidual reaction
Provides balancing force for invasive force of the trophoblast
Stimulated by progesterones
Why do spiral arteries remodel?
To create a low resistance vascular bed which maintains high flow to meet fetal demand
In pathophysiological terms, what is pre-eclampsia?
Placental insufficiency
Due to lack of low-resistance, high-flow vasculature
What forms the maternal part of the placenta?
Decidua basalis
What are the intervillous spaces?
Filled with maternal blood
Between chorionic and decidual plates
What are the placental compartments?
Cotyledons
Decidual septae project into intervillous space but don’t reach the chorionic plate, so divide the placenta into cotyledons
What is the placenta like in the 1st trimester?
Barrier to diffusion still thick
What is the term placenta like?
Surface area for exchange increased
Placental barrier thin
How many umbilical arteries are there and what do they do?
2
Carry deoxygenated blood from the fetus to the placenta
How many umbilical veins are there and what do they do?
1
Carries oxygenated blood from the placenta to the fetus
What are the maternal blood vessels of the placenta?
80-100 spiral arteries - Carry blood to cotyledons
Endometrial vein carries blood back from the chorionic plate
What factors affect diffusion across the placenta?
Concentration gradient
Barrier to diffusion
Diffusion distance
Why is pre-conception counselling so important?
Organogenesis occurs in the 1st 9 weeks of pregnancy
This is the time when teratogenic medications have the greatest impact - so important for women on these meds
What hormones does the placenta produce?
hCG
hCS
Progesterone
Oestrogen
How does oxygenated blood reach the fetus?
Via umbilical vein from the placenta
What is the ductus venosus?
Allows blood to bypass fetal liver
What is the foramen ovale?
Oxygenated blood passes from the right atrium to the left atrium
What is the ductus arteriosus?
Allows blood to avoid the lungs
Goes from pulmonary artery to the aorta
What are the fetal lungs like?
Very high resistance due to hypoxic pulmonary vasoconstriction
What happens to the fetal lungs after birth?
Hypoxic pulmonary vasoconstriction removed when neonate takes its first breath
What happens to the foramen ovale at birth?
Closes within minutes
Due to greater venous return to left atrium, increasing its pressure above that of the right atrium
What happens to the ductus arteriosus and the umbilical artery after birth?
Increased O2 sats and decreased prostaglandins causes constriction of both
What happens to the ductus venosus and umbilical vein after birth?
Stasis of blood causes clotting and closure due to fibrosis
Describe the oxygenation of fetal blood
ppO2 in fetal blood very low compared to adult
Fetal HbF has much higher affinity for O2, so carries more O2 at a lower pH
Higher Hb levels than adult
Describe fetal haemoglobin
HbF has much higher affinity for O2 than adult meaning it carries more O2 at lower partial pressure
Fetus has higher level of Hb (180 at birth)
How is placental CO2 transfer made more efficient?
Lower maternal pCO2 due to hyperventilation (stimulated by progesterone) means diffusion gradient is more
What are the functions of amniotic fluid?
Mechanical protection
Moist environment to prevent dehydration
What is the quantity of amniotic fluid at 8 weeks and at term?
8 weeks: 10ml
38 weeks: 1 litre
How does amniotic fluid production change during pregnancy?
Early: formed from maternal fluids and from fetal ECF
Later turnover is by fetus
How is fetal urine produced?
Metanephros is functional embryonic kidney
Fetus swallows amniotic fluid constantly, absorbs water and electrolytes and debris accumulates in fetal gut
What happens to fetal bilirubin?
Fetus can’t conjugate
Bilirubin crosses placenta and is excreted by mother
Neonate becomes jaundiced if conjugation doesn’t establish quickly - exposure to light stimulates this
