Obstetrics Flashcards
(102 cards)
1
Q
Define the 4 stages of labour
A
- From onset of contractions to full dilation of cervix
- From full dilation of cervix to expulsion of foetus
- From expulsion of foetus to expulsion of placenta
- From expulsion of placenta onwards
2
Q
What are the 8 steps in mechanism of delivery?
A
- Engagement
- Head enters pelvic inlet in transverse - Descent
- Measured using ‘station’ from ischial spines - Flexion
- Foetal head flexes to chest in narrow mid-cavity - Internal rotation
- 90o rotation of head from transverse diameter to AP diameter (wider) - face now pointing at rectum - Extension
- Extension of head so no longer trapped under pubic symphysis
- Crowning - Restitution
- Head returns to normal position - External rotation
- Shoulders rotate to AP plane
- Occiput follows - Shoulders are delivered
- Anterior first then posterior, then rest of body
3
Q
Describe what occurs during the first stage of labour
A
3 stages: LATENT - Onset of regular contractions --> 4cm dilation - Cervical effacement ACTIVE - Accelerated cervical dilation to 8cm - Increased force and duration of contractions TRANSITIONAL - Full dilation of cervix to 10cm
4
Q
Describes what occurs during the second stage of labour
A
- Urge to push
- Forceful, expulsive contractions
- Crowning
5
Q
Describes what occurs during the third stage of labour
A
- Placental delivery <30mins after foetal expulsion, any longer and placenta is retained
- Placental separation: rush of blood, lengthening of cord
6
Q
Describes what occurs during fourth stage of labour
A
- Breastfeeding
- Monitoring of vital signs for evidence of PPH
- Ensure fundal constancy (must be firm) - no uterine atony
- Vaginal/perineal repair
7
Q
What is the management of labour during the ONSET of labour?
A
- Monitor vital signs
- Note time of ROM - assess every 30min
- Assess liquor
- Analgesia
8
Q
What is the management of labour during the PROGRESS of labour?
A
- Palpate abdo every 30 min
- Vaginal every 4hrs
- Assess vitals - partogram
9
Q
What is the management during the 2nd stage of labour?
A
- Assess foetal HR every 5min
- Monitor contractions, maternal effort, presenting part
- Collect cord blood if Rh negative
- Dry/keep baby warm
10
Q
What is the management during the 3rd stage of labour?
A
- Cord traction, placental delivery
- Prophylactic syntocinon IM
- Estimate blood loss
- Examine placenta (lobes), membranes, cord
11
Q
What is the management during the 4th stage of labour?
A
- Vaginal/perineal repair
- Monitor vital signs
- Assess fundus
12
Q
What are 4 different indications for the induction of labour?
A
- Prolonged pregnancy (post-date)
- Foetal growth restriction
- Pre-eclampsia / other maternal HTN disorders
- Pre-labour rupture of membranes
- Chorioamnionitis
- Unexplained antepartum haemorrhage
- Maternal medical problems - diabetes, renal
- Logistics (distance from hospital)
13
Q
What is the mechanism of action of syntocinon and why is it given in stage 3 of pregnancy?
A
- Oxytocin mimic
- Stimulates uterine contraction
- Given in stage 3 to accelerate phase and decrease risk of bleeding and retained placenta
14
Q
What are some contraindications for induction of labour?
A
- Placenta previa or vasa previa (placental cord running close to the os)
- Transverse fetal lie
- Previous classical uterine incision
- Active genital herpes
- Pelvic structural abnormalities
15
Q
What defines the 1st trimester?
A
1-13 weeks
16
Q
What defines the 2nd trimester?
A
14-27 weeks
17
Q
What defines the 3rd trimester?
A
28-40 weeks
18
Q
Where would you expect the uterine fundus at 12 weeks gestation?
A
Pubis symphysis
19
Q
Where would you expect the uterine fundus at 22 weeks gestation?
A
Umbilicus
20
Q
Where would you expect the uterine fundus at 36 weeks gestation?
A
Xiphisternum
21
Q
How do you calculate due date for pregnancy?
A
1st day of LMP + 9 months + 1 week
More accurate to do dating U/S
Use a gestational wheel
22
Q
How do you define IUGR? Small for gestational age? Low birth weight?
A
IUGR: a fetus that has not reached its growth potential because of genetic or environmental factors, estimated foetal weight <10th centile for gestational age
- Head circumference is normal with reduced abdo circumference
SGA: INFANT whose birth weight is <10th centile for gestational age
- 50-70% of SGA fetuses are constitutionally small but healthy
LBW: <2500g regardless of age
23
Q
If both the head circumference and abdominal circumference are reduced, what does this indicate?
A
Symmetrical IUGR usually suggests a chromosomal disorder. In a healthy baby the head circumference should remain normal, even if there is significant placental insufficiency, as the body makes sure the brain receives the necessary fuel at the expense of the rest of the body
24
Q
What is the cause of a normal head circumference and reduced abdominal circumference?
A
Asymmetrical IUGR caused by placental insufficiency
25
Where would you expect the uterine fundus at 28 weeks gestation?
Half way between the umbilicus and xiphisternum
26
What are some common causes of IUGR?
Smoking, HTN, pre-eclampsia, GDM, Alcohol
27
What is the use of misoprostol during labour?
Misoprostol is a synthetic prostaglandin inserted vaginally and causes effacement of the cervix in addition to uterine contraction
28
What is the role of syntocinon during pregnancy
Syntocinon is a synthetic form of oxytocin. Oxytocin causes uterine contractions and cervical dilatation.
29
When would a nulliparous woman start to feel foetal movements?
Most women will become aware of foetal movements around 18-20 weeks. However if a women has had previous pregnancies they often notice movements earlier (around 15-18 weeks).
30
Define hypertension in pregnancy
BP>140/90 after 20 weeks gestation
| At least 2 measurements 4hrs apart
31
Explain the different types of monozygotic twins depending on timing of cell division
DCDA - within 3 days conception
MCDA - 4-8 days
MCMA - >8 days
Conjoined - >12 days
32
Define zygosity
Number of fertilised eggs
33
Define chorionicity
Number of placentae
34
Define amnionicity
Number of amniotic cavities
35
What are the 4 T's causing PPH?
Tone - uterine atony
Trauma - lacerations, episiotomies, rupture, inversion
Tissue - retained placenta, placenta accreta
Thrombin - coagulopathies, HELLP, aspirin
36
What are some red flags on a CTG?
* Prolonged bradycardia (<100 bpm) for > 5 min
* Absent BL variability
* Sinusoidal pattern
* Complex variable decelerations with ↓BL variability
* Late decelerations with ↓BL variability
37
How do you define PPH?
Blood loss >500mL during or after childbirth
38
What is the difference between primary and secondary PPH?
Primary - occurs in 24hrs
| Secondary - occurs between 24hrs and 12 weeks post partum
39
What are some antepartum risk factors for PPH?
```
Previous PPH, retained placenta
LOTS of para
Placenta previa
Anaemia
APH
Overdistension of uterus (Multiple gestation, polyhydramnios, macrosomia)
Fibroids
Coagulopathies
```
40
What are some intra and postpartum risk factors for PPH?
```
Prolonged labour
Mismanaged 3rd stage
Syntocinon-augmented labour
Assisted birth
Retained placenta
Operative delivery
Trauma
Inversion / rupture
```
41
What stage of gestation do you offer Anti-D to Rh negative mothers?
28 weeks, 34 weeks
42
What happens at a first antenatal visit? 6-10 weeks
*Confirm pregnancy (bedside urine) - confirm EDD
History:
- How do they feel about being pregnant, LMP, usual cycle, PMHx, meds, FHx, pap smears, immunisations, previous pregnancies, smoking, alcohol, activity, drug use, support networks
Examination:
- BMI, BP, urinalysis, urine sent off for MCS
Blood tests:
- FBC: anaemia
- Screen for: Rubella, Hep B, Syphyllis, Hep C, HIV (**REQUIRES CONSENT)
- Blood type and Rh factor
* Pap smear if due for one
* Dating U/S if LMP unclear
* Talk about need for 12 week NT scan
* Talk about diet, supplements, lifestyle
*** START YELLOW CARD ***
43
What questions and examinations should occur at EVERY antenatal visit?
```
History: foetal movements, bleeding, swelling, visual changes, psychological state, symptoms of pregnancy, DV, expectations and concerns
Examination: BMI, BP, urinalysis, evidence of oedema
Abdo exam
- Feel for foetal movements
- Palpate uterus
- Fundal height >20 weeks
- FHR >16 weeks
- Presentation at >26 weeks
```
44
At how many weeks do you check for GBS?
Low vaginal and anal swab at 36 weeks
45
What is the difference between complete, partial, and marginal placenta praevia?
Complete: Placenta completely covers the internal os
Partial: Placenta partially covers internal os
Marginal: Edge of placenta lies within 2cm of internal os
46
What constitutes a low-lying placenta? What is meant when this becomes 'resolved'?
```
Low-lying = within 2-3.5cm of internal os
Resolved = moves back (85% of low-lying placenta identified in week 15-20 migrates away eventually)
```
47
What is the clinical presentation of placenta praevia?
History: PAINLESS vaginal bleeding, diagnosis on ultrasound
Exam: No vaginal/cervical cause evident on speculum exam, Uterus not tender, increased likelihood of foetal malpresentation
48
What is the difference between placenta accreta, increta, and percreta?
Accreta: chorionic villi attach to myometrium
Increta: chorionic villi invade myometrium
Percreta: chorionic villi grow through myometrium down to serosa and underlying organs (bladder)
49
How does placenta accreta present?
- Usually asymptomatic antenatally
- Can see on U/W
- Post-partum, placenta fails to deliver
- Partial separation can result in massive PPH but if completely attached, no bleeding
50
What is vasa previa and how does it usually present?
- Foetal vessels are present in membrane covering the internal os
- Drop in FHR on pelvic examination that returns to normal
- PV bleeding upon ROM
51
How do you define gestational HTN, pre-eclampsia, eclampsia, HELLP?
Gestational HTN = HTN after 20 weeks not present before pregnancy WITHOUT proteinuria
Pre-eclampsia = gestation HTN PLUS something else (proteinuria, end-organ damage (HELLP, other renal/liver dysfunction), placental dysfunction/IUGR
Eclampsia = development of convulsions in women with pre-eclampsia
HELLP = haemolysis, elevated liver enzymes, low platelets
52
Describe the pathophysiology of pre-eclampsia
Failure of normal placental invasion --> maternal spiral arterioles don't dilate properly --> inadequate blood supply to placenta --> chronic placental ischaemia --> ischaemia reperfusion injury --> oxidative stress --> breakdown of syncitiotrophoblasts + production of SFlt-1 --> maternal inflammatory response --> diffuse maternal end-organ damage
- Peripheral vasoconstriction --> hypertension
- Increased intravascular pressure + endothelial dysfunction --> increased vascular permeability --> oedema
- Glomeruloendotheliosis --> impaired filtration --> proteinuria
53
What are some risk factors for developing pre-eclampsia?
- Primipara
- High BMI >35
- Previous Pre-eclampsia
- FHx
- Age >35
- Twins
54
What is the common presentation of pre-eclampsia?
- Usually asymptomatic
- Headache
- Swollen ankles
- Visual disturbances
* Flu-like symptoms
- RUQ pain = HELLP
55
What investigations should you perform in a women you suspect has pre-eclampsia?
- BP
- Urinalysis (+ protein), protein:Cr ratio
- FBC, Coags (HELLP), LFTs, bilirubin, EUCs
- Fetal CTG/U?S
56
What should you give to a woman experiencing acute hypertension? What is the mechanism of action and 2 side effects?
Hydralazine - direct smooth muscle relaxant --> vasodilation --> decreased TPR
- Reflex SNS activation causing tachycardia, tremor, fluid retention (oedema)
57
What are the different pharmacological treatment options for gestational hypertension? What is a side effect of each?
- Methyldopa - central alpha-2 antagonist --> reduce SNS tone. S/E sedation, depression
- Labetalol - inhibits alpha-R in peripheral arterioles, beta2-R in heart. S/E: postural drop, dizziness, bronchospasm
- Nifedipine (CCB) - headache, constipation, oedema
- Hydralazine - direct smooth muscle relaxant. tachycardia, oedema
58
What is the pathophysiology of HELLP?
SIRS with oxidative stress --> damaged endothelium
- Platelets aggregate --> low platelets
- Aggregation of platelets obstruction capillaries in the liver --> elevate liver enzymes + swelling of liver --> RUQ pain
- RBC smash into the big plt complexes --> haemolysis
59
How do you examine a woman with pre-eclampsia?
- BP
- Urinalysis (better to get 24hr urine >0.3g)
- Visual disturbances
- Oedema
- Listen for pulmonary oedema
- RUQ pain
- Reflexes (hyper-reflexive and clonus)
- Reduced foetal movement
- Foetal growth restriction
60
What are the treatment options for pre-eclampsia?
1. ADMIT to hospital
2. Give steroid shot
3. Transfer to tertiary facility
4. Anticipate delivery
5. Give anti-hypertensives
- Methyldopa (central a2 antagonist)
- Labetalol (peripheral alpha blocker, inhibits B receptors in heart)
- Nifedipine (peripheral CCB)
- Hydralazine - used with severe cases (direct SM relaxant)
61
What are some indications for early delivery (<34 weeks)?
1. Inability to control maternal blood pressure despite anti hypertensives.
2. Maternal pulse oximetry <90%, or pulmonary oedema unresponsive to initial diuretics
3. Progressive deterioration with a HELLP
4. Eclampsia
5. Placental abruption
6. Reversed end-diastolic flow in the umbilical artery doppler velocimetry, a non reassuring CTG, or stillbirth.
62
Describe pathophysiology of gestational diabetes and how GDM leads to macrosomic babies
Human placenta produces human placental lactogen (HpL) --> acts as an anti-insulin increased lipolysis + inhibit gluconeogenesis) --> aims to increase maternal BG (to give enough to baby) --> maternal pancreas needs to respond by increasing insulin production --> if not enough insulin produced --> maternal hyperglycaemia --> maintained maternal hyperglycaemia --> foetal pancreas produces more insulin --> acts as a growth factor --> macrosomic baby
63
How frequently should a pregnant woman have an antenatal visit?
Monthly til 28 weeks, fortnightly til 36 weeks, weekly until birth
64
Describe the fundal height measurements in relation to gestation. What about with twins?
```
12 weeks - just above pubic bone
20-36 weeks - cm measurement should = week gestation
36-38 weeks - at or under sternum
40 weeks - baby may drop
Twins - about 4 weeks ahead of due dates
```
65
If GDM, what investigations are required post-partum?
75g OGTT at 6-8 weeks
66
What infective organism do pregnant women try to avoid?
Listeria
67
What foods should a pregnant woman avoid?
Raw/cold/processed meats, raw/cold seafood, soft cheese, unpasteurised dairy, pre-packaged salads, bean sprouts
68
What are the screening tests available for chromosomal abnormalities?
Non-invasive prenatal test (Harmony test) >10 weeks
- Maternal blood test, find foetal DNA fragments for DNA chromosomal analysis
- Sensitive and specific for Down's
Nuchal translucency + 11-14(13+6) weeks
- Measure nuchal fold, PAPP-A, free b-HCG, maternal age
- Trisomy 21, 13, 18, neural tube defects
69
What are the diagnostic tests available for chromosomal abnormalities?
CVS 11-14 weeks
- Sample the placenta tissue, 0.5-1% risk miscarriage
Amniocentesis >15 weeks
- Sample amniotic fluid, 0.5-1% risk miscarriage
70
What supplementation should a pregnant woman be taking?
Folic acid for first 12 weeks, 5mg daily
| Iodine 150mcg daily
71
How and when is GDM diagnosed?
75 gm GTT done routinely at 28 weeks gestation, earlier if there is a clinical suspicion (12 weeks)
- All women need to be tested
- Fasting glucose ≥5.1 and/or
- 1 hour ≥10.0
- 2 hour ≥8.5
- Diagnosis made with one or more values are abnormal
72
Explain the components of the APGAR score
```
Appearance (colour)
Pulse rate
Grimace (reflexes)
Activity (tone)
Respiratory rate
```
73
How do you manage APH?
1. Assess blood loss (onset, duration, amount, colour)
2. Maternal wellbeing (ABCs)
3. Foetal wellbeing (CTG, U/S - fetal heart sounds, presentation)
* *** DO NOT PERFORM PV EXAM ****
4. IV fluids, anti-D, corticosteroids, prepare for delivery if required
74
What are the drug therapies for PPH?
Syntocinon 10units IMI, 5units IVI, 40units in 1L
Hartmann’s/Saline infusion.
Ergometrine IV 0.25mg IM 0.5mg
Misoprostil 800 – 1000mcg (tab per rectum)
Prostaglandin F2 alpha Intramyometrium up to 3mg
75
What are the complications of PPH?
```
Iron deficiency anaemia
Delay or failure of lactation due to pituitary effects
Pituitary infarction
Exposure to blood products
Haemorrhagic shock & hypotension
Coagulopathy
Acute tubular necrosis
Coma
The need for further surgical intervention
Prolonged hospital stay
```
76
What are the most common and other less common causes of APH?
1. Abruptio placenta 30%, Placenta praevia 20%
2. Heavy blood show; Ca cervix; polyps; trauma; varicosities; cervical or vaginal infection; invasive placenta, vasa praevia
77
What are some tocolytic drugs that can be administered or pre-term labour?
Oxytocin-R antagonists
Salbutamol
CCB (nifedepine)
78
Describe the differences in dosing for Anti-D
```
Sensitising events:
- 1st trimester: 250U
- After 1st trimester: 625U
Antenatal prophylaxis at 28 and 34 weeks: 625U
Post-partum: 600U
```
79
What are some maternal and foetal factors that would constitute a high risk pregnancy?
Maternal: age <15 or >35, previous obstetric complications, >5 previous pregnancies, VDAC, placenta previa, comorbidities: pre-eclampsia, HTN, DM
Foetal: exposure to infection, toxic medications (e.g. valproate), smoking, alcohol, congenital abnormality noted on prenatal screening
80
How do you interpret a CTG?
DRCBRAVADO
- Determine risk
- Contractions (4-5 per 10mins, >5 = hyperactivity)
- Baseline rate
- Accelerations
- Variability
- Decelerations
- Overall assessment
81
What are the different methods for assessing foetal wellbeing?
Clinical
- Foetal movements
- Fundal height
Investigations
- CTG
- Ultrasound (abdo circumference, head circumference, femoral length, estimate foetal weight)
- Doppler (assess blood flow, MCA/UA ratio)
82
What is the harmony test / NIPT and how does it work? When can it be done?
Tests for foetal DNA present in the maternal blood stream - Tests for risk of chromosomal abnormalities (NOT diagnostic)
- Done at 10 weeks gestation
83
Why do we still back up NIPT with amniocentesis?
Because it's a screening test for risk rather than for diagnosis of chromosomal abnormality
84
When can you do CVS and amnio?
CVS at 12 weeks
| Amniocentesis at 14 weeks
85
What are the causes of polyhydramnios?
No swallowing of urine
- Oesophageal atresia
- TOF
- Neuromuscular disorders
86
What are the causes of oligohydramnios?
Renal disorders in babies - not enough urine produces --> decreased amniotic fluid production
- Posterior valve
- Poor kidney perfusion
87
What do you do if you see umbilical artery reverse end diastolic flow (REDF)?
Panic! Very bad sign - send for continuous monitoring and arrange for delivery
The feature is seen as a result of a significant increase in resistance to blood flow within the placenta, usually IUGR
88
What is the best foetal surveillance for anaemia?
Serial peak MCA velocity in doppler studies
89
What is the most common gynaecological malignancy at age 35?
Ovarian
90
For a woman having a blood pressure of 140/90 mm of Hg at 16 weeks of pregnancy. The treatment of choice is
Methyldopa
91
Dystocia is defined as a rate of cervical dilation of less than
0.25 cm per hour
92
During pregnancy, varicose veins in the legs are exacerbated due to increased
Portal venous pressure
93
What information can potentially be obtained from the placental examination?
- Presence of a fetal infection with Cytomegalovirus
- Presence of a fetal chromosomal anomaly
- Presence of a maternal thrombophilia
94
Which of the following lung volumes and/or capacities is DECREASED in a normal pregnancy?
Residual volume
95
How do ACE inhibitors and hormones cause teratogenic effects?
Disrupt foetal RAS metabolism leading to prolonged fetal hypotension and hypoperfusion --> renal ischemia, renal tubular dysgenesis --> anuria, oligohydramnios --> affects lung development and causes limb contractures --> growth restriction, relative limb shortening
96
What are some medications to avoid in pregnancy as they are teratogens?
```
Teratowa
Thalidomide (anti-morning sickness medication)
Epileptic drugs (phenytoin, valproate)
Retinoids
Alcohol
Third element (Lithium)
OCPs and other hormoens
Warfarin
Ace inhibitors, ARB
```
97
What are the TORCH infections?
Infections that have vertical transmission (from mother to child)
Toxoplasmosis
Other (Coxsackievirus, Chickenpox, Chlamydia, HIV, Syphilis)
Rubella
CMV
Herpes simplex
98
How does drug dosing need to be altered during pregnancy?
Dosing intervals need to be shortened as maternal GFR increases by 40-50% --> more blood filtered per unit time --> increased drug filtering by kidneys --> drugs are cleared more quickly
99
What measurement is required to determine the level of foetal exposure to a drug?
Free drug level (the active portion) rather than the protein bound (inactive)
100
At what point during pregnancy does teratogen exposure most often cause major malformations / birth defects?
The most sensitive period for inducing birth defects is during the "embryonic period"
(organogenesis) , which is from 2 – 8 weeks post-conception
- Known as the 'classical teratogenic period'
101
When is fetal heart beat first detectable on ultrasound?
xx
102
Describe the levels of risk categorisation for drug use in pregnancy
A - controlled studies show no foetal risk
B - no evidence of risk in humans (studies in pregnant women have failed to confirm or demonstrate a risk to the foetus despite animal studies showing a possible adverse effect OR no risk in animals but no studies in humans to confirm)
C - human risk cannot be ruled out (animal studies show an adverse foetal effect but there are no adequate human studies OR no studies in humans OR animals)
D - postive evidence of human risk (benefits MAY outweigh risks in an emergency)
X - Contraindicated during pregnancy (benefits do NOT outweigh the risks)
