Obstetrics Flashcards
What are the top causes of arrest in pregnant women?
Haemorrhage
Amniotic fluid embolism
Sepsis
Cardiac failure
Trauma
Anaesthetic complications
What is a normal foetal heart rate?
120-160bpm
When is the IVC compressed in pregnancy? How is this managed?
After 18-20 weeks gestation
Managed by lying the patient on their left side or manual displacement
When is CTG indicated in pregnant trauma?
When pregnancy >20 weeks, thought to be more sensitive than ultrasound for foetal distress/abruption
Should be applied for at least 4hrs
What is the utility of ultrasound in pregnant trauma?
No change to FAST sensitivity
Can assess for foetal HR and movement
Insensitive for excluding placental abruption or uterine rupture
What are some key positions for the uterine fundus?
24 weeks = at umbilicus
32 weeks = 1/2 way from umbilicus to xiphisternum
36 weeks at costal margin
When is the foetus most vulnerable to radiation?
The first 2 weeks of life it is most vulnerable to death from radiation
The first 8 weeks for organogenesis
What is the dose of oxytocin and when is it given during delivery?
10 units IM
Given post delivery of the shoulders in a vaginal birth
What are the risk factors for ectopic pregnancy?
- Previous ectopic
- Previous gynae/pelvic surgery
- Known reproductive tract anatomical abnormality (ie congenital or acquired)
- PID
- Presence of an IUD
- Undergoing IVF
- Endometriosis
- Age >35
- Smoking
- Previous placenta previa
What are the ultrasound findings in ruptured ectopic pregnancy?
Classic triad!
- Empty uterus (10-20% have pseudogestational sac, very rarely hetertopic pregnancy)
- Complex adnexal mass
- Free fluid in abdomen
Also tubal ring sign
What define a miscarriage vs a foetal death in utero?
In Australia/NZ a miscarriage is when the foetus prior to 20 weeks gestation
Foetal death in utero >20weeks (registered as a birth)
What is a threatened miscarriage?
Abdo pain and/or bleeding <20 weeks
- 85% chance to continue
- cervix closed, appropriate fundal height, uterus itself soft and non-tender
What is an inevitable mmiscarriage?
Abdo pain and/or bleeding <20 weeks
- Bleeding continues, products of conception still in uterus
- Cervix open +/- ROM
- Often have uterine contractions
- Not viable
What is a completed miscarriage?
Abdo pain and or bleeding <20 weeks
- BHCG falling
- U/S shows empty uterus
- Uterus contracts and OS closes
What is an incomplete miscarriage?
Partial expulsion of products of conception (RPOC), mostly occurs between 6 and 14 weeks
- cervical os remains open
- Often severe pain and worse bleeding
- If products lodge in the os will get cervical shock
- At high risk of endometritis
What is an Antepartum haemorrhage (APH)?
PV bleeding >20weeks gestation but before labor
- Occurs in 2-5% of all pregnancies
- Associated with perinatal morbidity and mortality
- Can be incidental, accidental or inevitable
What are the causes of incidental antepartum haemorrhage (APH)?
- Ruptured uterus
- Dehiscence of uterine scar
- Ruptured vasa previa
- Non-pregnant horn of uterus menstrual bleeding
- in lesion in or around the genital tract (ie haemorrhoids)
- Genitourinary infeciton
What are the causes of accidental APH?
- Placental abruption (20% all cases)
- Trauma
- Chorioamnionitis
- Labour (bloody show)
- Pre-eclampsia/HELLP associated
- Stimulant use/hypertensive bleed
- Polyhydramnios with multiple births
Can be concealed (under placenta, retroplacental haemorrhage) or revealed (blood leaks into uterus/vagina)
What are the causes of inevitable APH?
Another name for Placenta Previa with haemorrhage
- 1% of all pregnancies but 30% of all cases of APH
- When the placenta is partially or wholly in the lower segment in the 3rd trimester
- RF’s include previous PP, previous LUSCS increasing with more LUSCS, high parity, large placenta, any uterine scarring, IVF, older age, abnormal uterine anatomy and smoking
What are the 3 stages of labour?
1st stage
- Beginning of contractions until cervix fully dilated
- may take hours to days
2nd stage
- From full cervical dilatation to exulsion of the foetus
- usually 30mins-2hrs
3rd stage
- From expulsion of the foetus to expulsion of the placenta and membranes
- Usually 15mins
How is the 3rd stage actively managed?
- Syntocinon 10units IM post foetal expulsion
- Clamp/cut the cord
- placenta separates when cord lengthens and small gush of blood
- Guard the uterus and provide slow gentle cord traction
- Massage fundus as soon as placenta out
What is the Puerperium?
AKA the 4th stage of labour
- Post birth when the body returns back to normal
- immediate (24hrs), early (7 days), remote (6 weeks)
What is the definition of pre-term labour?
- Labour between 20-37 weeks
- At least 3 contractions in 30mins and then progresses
What are the risk factors for pre-term labour?
- PROM
- PHx of pre-term delivery
- Maternal distress/domestive abuse
- Trauma
- Infections
- Multiple pregnancy
- Smoking/drug abuse
- <20 or >35
- Low SES
What are the contraindications to tocolysis?
- FDIU
- Maternal haemorrhage
- Pre/eclampsia
- Chorioamnionitis
- Severe IUGR
- Non-viable pregnancy/lethal foetal malformation
What are the medications given for preterm labour?
- Betamethasone 11.4mgs 2x doses 12hrs apart
- Salbutamol OR Nifedipine, cannot be given together
- Salbutamol 7.5mg IV
- Nifedipine 20mg IR q30mins max 120mg in 24hrs
- Consider MgS04 infusion 1-2gm/hr for foetal neuroprotection
When are nifedipine and salbutamol contraindicated for tocolysis?
Salbutamol
- hypertension/pre/eclampsia
- Maternal/foetal tachycardia
- Valvular heart disease (ie MS)
- hyperthyroidism
- Maternal bleeding
Nifedipine
- Hypotension
- Concurrent MgS04 use
- Pre-eclampsia
- cardiac disease
Early pregnancy bleeding differentials?
Ectopic
Completed/threatened abortion
Cervical ectropion
Bleeding diathesis
Vanishing twin
Physiologic/implantation bleeding (10-14 days, light)
Heterotopic pregnancy
Molar pregnancy
Discharge advice to women with early pregnancy bleeding but viable pregnancy on ultrasound?
Use pads not tampons
No vaginal sex/heavy lifting while bleeding
Refer to mental health/EPAS if patient wishes to
GP/Obs review in a few days
Repeat BHCG in 48-72 hrs
Return if symptoms worsening
What is the definition of Pre-eclampsia?
- > 20 weeks gestation
- New onset (or worsened chronic) hypertension (SBP/DBP >140/90)
- New onset end organ dysfunction
End organ dysfunction
- Proteinuria >2+ dipstick or >0.3gm 24hrs
- platelets <100
- AKI
- Pulmonary oedema
- Transaminase rise
- New onset persistent headache
- Visual changes
What is the typical immediate management of pre-eclampsia (not eclampsia)?
Magnesium
- seizure prophylaxis, contraindicated in myaesthenia gravis
- 4gm IV loading dose then 1-2gm/hr infusion aiming 2.0-3.5mmol/L
Methyldopa 250-500mg PO QID
Labetalol 20mg IV
Hydralazine 5mg IV
Nifedipine 10mg PO
What is the definition of severe pre-eclampsia? What are the hallmarks?
BP >160/110
+
Signs of end organ dysfunction
Often have a rising Urate level (hallmark)
Pre-eclampsia post partum typically occurs in the 1st 7 days
Affects 5-7% of pregnancies
What are the risk factors for Pre-eclampsia?
Primigravida
Multiple Gestations
Diabetes
Extremes of age
Molar pregnancy
Previous pre-eclampsia
Pre-existing HTN
Renal disease
High BMI
Smoking actually reduces the risk of pre-eclampsia/HTN
Why are women prone to constipation in pregnancy?
- More water absorbed from the GIT than normal
- GI motility slows down
- Uterus distorts colon
How does the renal system change in pregnancy?
- Mild glucosuria and mild proteinuria are normal (100-200mg/day)
- GFR increase by 50%
- Bladder moves into abdomen
- Renal pelvices and urters dilate
Why is bimanual pelvic exam avoided in the 2nd half of pregnancy?
Due to the risk of massive haemorrhage from irritating placenta praevia, less of an issue if this has been ruled out
What are the potential intrapartum and post-partum complications of birth?
Intrapartum
- Nuchal cord
- Breech position
- Shoulder dystocia
- Uterine rupture (VBAC)
Post Partum
- PPH
- Retained placenta
- Endometritis
- Vaginal/anal lacerations/tears
- Foetal compromise/death
What medications should be given in premature labour to help the foetus?
Corticosteroids
- 11.4mg Betamethasone IM
- 12mg Dexemathasone IM
- Causes foetal lung maturation decreasing the risk of RDS
- It also decreases the risk of Necrotizing enterocolitis and intraventricular haemorrhages
- Given between 23-34 weeks
Magnesium
- IV 4gm followed by 1gm/hr infusion
- Decreases the risk of cerebral palsy
- Used in pregnancies <30weeks
What are the risk factors for foetal death in utero?
- Previous still birth
- Foetal growth restriction/IUGR
- Diabetes/Obesity/poorly controlled medical conditions
- Hypertension/Pre-eclampsia
- low or high parity (0 or >3)
- Trauma (DV, blunt, penetrating), Sepsis, severe maternal illness
- Smoking, ETOH, illicit drugs
- Indigenous, low SES, lack of antenatal care
- Post dates gestation >41 weeks
- PROM (P or T)
- Connective tissue/autoimmune disorders
- Advanced maternal age >35
What are the reassuring findings on CTG?
- Normal baseline HR (120-160)
- Normal HR vairability (5-15)
- Presence of accelerations (15bpm for 15sec)
- No decelerations
- Foetal movement detected
Broadly CTGs are interpreted as being “reassuring” or “non-reassuring”
What are the extremes of maternal age?
- <20 or >35
- Generally higher risk pregnancies outside of this age range
