Obstetrics Flashcards
B-hCG rule of 10s
10 IU at time of missed menses
100, 000 IU at 10 weeks GA (peak)
10, 000 IU at term
Trimesters
T1 1-14 weeks
T2 14-28 weeks
T3 28-42 weeks
Normal pregnancy term 37-42 weeks
What is Goodell’s sign?
Cervical softening (4-6wks)
What is Chadwick’s sign?
Bluish discolouration of the cervix and vagina due to pelvic vascular engorgement (6 wks GA)
What is Hegar’s sign?
Softening of the cervical isthmus (6-8 wks GA)
Lower b-hCG levels than expected causes? (4)
- Ectopic
- Abortion
- Inaccurate dates
- Some normal pregnancies
Higher b-hCG levels than expected causes? (5)
- Multiple gestations
- Molar pregnancy
- Trisomy 21
- Inaccurate dates
- Some normal pregnancies
TVUSS signs of pregnancy at 5wks, 6wks, 6-8wks.
5 wks: gestational sac visible
6 wks: fetal pole visible
6-8wks: foetal heart activity visible
trans-abdominal US: pregnancy visible from 6-8wks
How to calculate due date?
Naegele’s rule: 1st LMP + 1year and 7 days - 3 mo.
N+V in pregnancy treatment
Normally in T1
Tx:
1. Pyridoxine monotherapy or doxylamine-B6 (Diclectin) PO
- Cyclizine (H1 receptor antagonist)
- Consider metoclopramide or ondansetron if sever
Hyperemesis gravidarum
Management:
1. doxylamine-pyridoxine
2. dimenhydrinate adjunct
3. consider metclop/ ondansetron
4. if severe, admit to hospital
Ultrasound screening dates
Dating USS: 8-12 wks
Nuchal translucency scan: 11-14 wks
Growth and anatomy USS: 18-20 wks
What does nuchal translucency screen for?
Measures amount of fluid behind baby’s neck.
Early screening for Downs Sydrome
May also detect cardiac anomalies and other aneuploidies
NIPT
At >10 wks onwards
Measures for Downs (21), Edward’s (18) and Patau’s (13)
As well as Turner’s, Di George, Cri du chat, etc.)
Only suggestive, does not confirm diagnosis.
CVS
10-12 wks GA
Offered for high risk pregnancies to test for genetic abnormalities
When do you test for rhesus status?
28 wks GA
When do you test for GBS?
35-37 wks GA
Amniocentesis
As early as 15 wks
Identify genetic abnormalities
+: screens for ONTD, more accurate than CVS
-: risk of pregnancy loss
Differentials for decreased foetal movement (4)
- Death of foetus
- Amniotic fluid decrease
- Sleep cycle of foetus
- Hunger/ thirst
Folic acid in pregnancy
0.4-1mg OD starting 2-3mo pre conception
4mg if high risk NTD
Antepartum haemorrhage definition?
Bleeding from 20 weeks to term
Placenta previa
Placenta implanted in the lower part of the abdomen
Risks of placenta previa (6)
1.Antepartum haemorrhage
2. Emergency caesarean section
3. Emergency hysterectomy
4, Maternal anaemia and transfusions
5. Preterm birth and low birth weight
6. Stillbirth
RF’s placenta previa (6)
- Previous caesarean sections
- Previous placenta praevia
- Older maternal age
- Maternal smoking
- Structural uterine abnormalities (e.g. fibroids)
- Assisted reproduction (e.g. IVF)
Investigation and management of placenta previa?
Transvaginal USS
Mx: stabilisation, keep pregnancy in uterine if possible, delivery via CS
Symptoms of placenta previa
Painless uterine bleeding
What is the role of corticosteroids in utero?
Mature the foetal lung’s (if risk of pre term delivery)
Placental Abruption
Detachment of the placenta prematurely
Features of placental abruption
Severe abdominal pain
Bleeding (unless concealed)
“woody” abdomen on palpation
Diagnosis and management of placental abruption
Clinical diagnosis
Mx:
Resuscitation
Stabilisation or delivery
What is the kleihauer-betke test?
Tests the amount of foetal cells in maternal circulation - used to calculate how much anti-D is needed
Vasa previa
Unprotected foetal vessels pass over the cervical os
Features of vasa previa
PAINLESS vaginal bleeding
Foetal distress
Investigation and management of vasa previa
Ix: Apt test -> NaOH mixed with blood to determine if source of bleeding is foetal
Wright’s stain
Management: CS
Preterm labour
Labour between 20 to 37 wks
Causes of preterm labour?
Spontaneous
Maternal infection/ co-morbidity
Foetal: genetics abnormality, multiple gestation, foetal hydrops
Uterine malformations
Prevention of PTL
- Cervical cerclage
- Progesterone
- Lifestyle
Test to predict PTL?
Foetal fibronectin: positive if >50ng/mL
Drug to help to suppress pre term labour?
Tocolytics
E.g. nifedipine, indomethacin.
Why do you give MgSO4 in at risk pregnancy?
Neuroprotection
PROM Investigation and Management
Speculum exam
Admit for expectant management
Post-term pregnancy
> 42 wks GA
induction recommended at 41 + 3 wks
Intrauterine foetal death *
Foetal death in utero after 20 wks GA
Causes:
1. Idiopathic
2. HTN, DM, erythroblastosis foetalis, congenital abnormalities, umbilical or placental complications, intrauterine infection, Antiphospholipid syndrome
Clinical features:
1. decreased foetal movement
2. absent heart tones
3. USS –> no FHR
4. High MSAFP
Management:
Investigate for secondary cause
Induction of labout
IUGR
Estimated foetal weight <10% for GA
Causes: maternal malnutrition/smoking, alcohol, co-morbidity, any disease of placental insufficiency, TORCH infections, multiple gestation, genetic abnormality
TORCH
T: Toxoplasmosis
Others: syphilis
R: Rubella
C: CMV
H: HSV
Investigation and management of IUGR?
Ix:
symphysis fundal height
USS
Doppler umbilical cord blood flow
Mx:
modify lifestyle factors
determine cause
delivery when safe via CS
Macrosomia
Infant weight >90th percentile for GA
RFs:
maternal obesity
T2DM
prolonged gestation
multiparity
Oligohydramnios
Too little amniotic fluid
Consider therapeutic amniocentesis if severe
Polyhydramnios
Too much amniotic fluid
Dichorionic versus diamniotic
Dichorionic: two placentas
Diamniotic: two amniotic sacs
Twin-Twin Transfusion Syndrome
Placental blood flow from donor twin to recipient twin
Donor: IUGR, hypovolaemia, hypotension, anaemia, oligohydramnios
Recipient: hypervolemia, HTN, polycythaemia, polyhydramnios, kernicterus
Ix: USS
Mx: fetoscopic laser ablation of anastomosis
Intrauterine blood transfusion to donor twin
Breech presentation
Management:
ECV >36wks
Vaginal breech delivery or CS
Hypertension in Pregnancy
140/90 after 20 wks GA without proteinuria in a patient who was previously normotensive
Tx: labetalol, nifedipine, hydralazine if severe
Pre-eclampsia
HTN >140/90
Proteinuria
or end organ dysfunction
or placental dysfunction
Mx: expectant management +/- delivery, antenatal steroids, MgSO4 for seizure prevention
Eclampsia
> 1 generalized convulsions in the setting of preeclampsia
Mx:
1. Roll patient into left lateral decubitus position
2. O2
3. Aggressive anti-HTNs
MgSO4
definitive treatment is DELIVERY
HELLP
Haemolysis
Elevated liver enzymes
Low platelets
Diabetes in pregnancy management: pre-pregnancy, pregnancy, and labour
Pre-pregnancy
- folic acid 1mg OD 3/12
- optimize glycaemia control (discontinue ACE-i, ARB, statins)
Pregnancy
- T2DM: insulin therapy
- increase foetal surveillance
Labour
- induce at 38-40wks
Diabetic targets in pregnancy
FPG: <5.3mmol/L
1 hr after food: <7.8
2 hr after food <6.7
Gestational DM screening
Screening btw 24-28wks GA
Step 1: RBG
<7.8 normal
>11.1 DM
7.8 - 11.1 proceed to Step 2
Step 2: FBG
>5.1
after 1 hr >10.0
after 2 hr > 8.5
Management GDM
- Lifestyle and exercise
- Insulin therapy if glucose targets not achieved in 2/52
- Stop insulin and diabetic diet post-partum
- OGTT at 6/52-12 PP
- From 36 wks GA - weekly ax of pregnancy
- offer IOL at 38-40wks
When is GBS infection screened in pregnancy?
35-37 wks GA with vaginal and anorectal swabs
Treatment of GBS?
Give prophylaxis 4 hour before delivery
UTI in pregnancy
Treat asymptomatic bacteriuria
Tx: amoxicillin first line
Treatment to expectant mother if exposed to chicken pox?
Varicella zoster Ig
Management of VTE in pregnancy?
UFH
Foetal Monitoring - Vaginal Exam
Amniotic fluid - clear, bloody, meconium
Cervical effacement
Bony pelvis size and shape
Foetal monitoring
Auscultation with Doppler very 15-30mins
Every 5 mins once pushing has begun
Normal FHR
110-160bpm
CTG
- Contractions
- Baseline rate
- Variability - reassuring 5-25bpm
- Accelerations - good sign
- Decelerations - concerning, indicate response to hypoxia
Management of abnormal FHR
POIFSON - ER
Position - LLDP
O2
IVF
Foetal scalp stimulation/ electrode/pH
Stop oxytocin
Notify physician
Examine vagina ?cord prolapse
Rule out fever, dehydration, drug effects and prematurity
Scoring to predict labour?
Bishops score
Induction of Labour - methods
- Cervical ripening
- PGE2 gel
- foley catheter for manual dilatation - Amniotomy
- Oxytocin - Pitocin
Amniotomy and oxytocin can also be used to strengthen contractions
Shoulder dystocia complications
Erb’s palsy: C5-C7 “ waiter’s tip” internal rotation of forearm
Klumpke’s: C8-T1 -MCP extension and IP flexion
clavicle, humerus or C-spine
Management of shoulder dystocia
McRobert’s manoeuvre
Anterior shoulder disimpaction
Episiotomy
Zavanelli - replace foetus in uterus and CS
Umbilical cord prolapse
Descent of cord adjacent or below presenting part
Presents with FHR changes and visible or palpable cord
Emergency CS, manually elevate the presenting part until caesarean
Uterine Rupture
Uterus tears
Tx: immediate stabilisation of mother and delivery
Amniotic fluid embolus
Amniotic fluid in maternal circulation causes anaphylactoid response
Features: sudden onset respiratory distress, cardiovascular collapse, seizures
Mx: ITU supportive measures
Chorioamnionitis
S/S: fever, maternal or foetal tachycardia, uterine tenderness, foul discharge
Tx: antibiotics
Perineal lacerations
1st: skin and vaginal mucosa
2nd: fascia and muscles of perineum
3rd: involving the anal sphincter
4th: extends into the rectal mucosa
Give single dose IV antibx for 3rd and 4th degree tears
Postpartum haemorrhage 4Ts
Tone (atony) - give oxytocin
Tissue
Trauma
Thrombin -DIC, ITP, TTP, VWD, haemophilia
Uterine inversion
Presents with profound vasovagal and shock
Mx: tocolytics, surgery
APGAR Score
Appearance
Pulse
Grimace
Activity (tone)
Respiration
> 7 good score
