Preterm Labour And Preterm Premature Rupture Of Membranes Flashcards
Preterm Premature Rupture of Membranes (Felix Lai)
Infection appears to be both a cause and consequence of PPROM
Risk factors:
1. ***Previous PPROM
- Strong risk factor for recurrence
- ***Antepartum bleeding
- Antepartum bleeding in 1st trimester is associated with higher risk of PPROM - ***Genital tract infection
- Women with PPROM are more likely to have pathogenic microorganisms in amniotic fluid than women with intact membrane
- Women with PPROM have higher rate of histologic chorioamnionitis than women without PPROM
- Frequency of PPROM is higher in women with lower genital tract infection such as bacterial vaginosis than in uninfected women - ***Smoking
- 2-4x risk compared to non-smokers
S/S:
1. **Sudden gush of clear or pale yellowish fluid from vagina
2. **Intermittent / **Constant leaking of small amount of fluid
3. **Sensation of wetness within vagina or perineum
Course:
- Majority of PPROM deliver within **1 week of rupture
- Cessation of fluid leakage **rare except in amniocentesis
Sequelae:
1. **Maternal infections
- Chorioamnionitis and funisitis
- Endometritis
- Septicaemia
2. **Placental abruption
3. **Cord prolapse
4. **Malpresentation (∵ preterm gestational age + reduced amniotic fluid volume)
5. **Pulmonary hypoplasia, facial deformation and orthopedic abnormality (∵ prolonged **oligohydramnios)
History taking of Preterm labour / PPROM
DDx (Felix Lai):
- Urinary incontinence
- Vaginal discharge
- Perspiration
-
**Details of leaking
- Timing
- **Colour (Blood / Meconium stained)
- **PV bleeding
- Amount
- **Continuous
- ***Tissue
(- Odour) - Other symptoms
- **Abdominal pain (OPQRST, Intermittent / Continuous)
- **Urinary symptoms
- **Fever
- **Fetal movements - History of present pregnancy
- Obstetric history
- Gynaecological history
- Menstrual history
- Sexual history
- Marital status
- Past medical history
- Past surgical history
- Social history
- Family history
P/E of Preterm labour / PPROM
- BP, Pulse
- Temp (infection)
- Urine protein, sugar, ketone, liquor (give positive protein)
- General condition
- Alertness, Conscious level (signs of sepsis)
- Pallor (bleeding) - Abdominal examination
- Inspection
- Palpation (Tenderness, Symphysio-fundal height, PLPEL)
- Auscultation - Speculum examination
- **Pool of liquor (present if PPROM)
—> Colour (clear, meconium stained, blood stained)
—> Thin / Thick
- **Cough impulse (leaking of liquor seen from cervical os if PPROM)
- **Status of cervix (closed and tubular / dilated)
- **Cord prolapse (must exclude)
- **Endocervical + High vaginal swabs —> Culture (exclude intrauterine infection (Felix))
- **Low vaginal swab + Rectal swab —> GBS screening
Investigations of Preterm labour / PPROM
- CBC
- **Leukocytosis (infection, note WBC higher in pregnancy (usually at ULN))
- CRP
- LRFT (contraindications for Tocolytic)
- **Type + Screen (prepare for C/S)
- Blood culture - Swabs
- **Endocervical + **High vaginal swabs —> Culture (exclude intrauterine infection (Felix))
- **Low vaginal swab + **Rectal swab —> GBS screening - ***MSU
- Microscopy + Culture - USG
- **Presentation: Cephalic / Breech / Transverse —> determine **mode of delivery
- **Estimated fetal weight: Biparietal diameter, Head circumference, Abdominal circumference, Femur length
- **Liquor volume: ***Amniotic fluid index —> ↓ in PPROM
- Doppler: Umbilical artery S/D - Cardiotocography
- ***Fetal HR: Baseline (fetal tachycardia might be sign of fetal infection), Variability, Acceleration, Deceleration
- Uterine contractions: Presence + Frequency —> frequent + regular uterine contractions might be sign of preterm labour
Management of Preterm labour / PPROM
General principles (Felix):
1. **NOT intervene to effect delivery prior to 34 weeks in **absence of complications but expeditious delivery is indicated when
- **Intrauterine infection
- **Placental abruption
- **Non-reassuring fetal testing
- **High risk of cord prolapse
(- **Meconium / Blood-stained liquor (self notes)
- **GBS colonisation
- ***Prolonged rupture of membrane)
- Evidence of intrauterine infection —> **Delivery under antibiotic coverage **irrespective of gestation
- NO evidence of intrauterine infection + Gestation <34 weeks
- ***Expectant management to allow pregnancy to continue - NO evidence of intrauterine infection + Gestation >34 weeks
- **Expectant management / **Induction of labour can be undertaken
- Induction of labour considered when:
—> **Prolonged rupture of membrane >=24 hours on admission / by 7 am the next day
—> **History of GBS colonisation of vagina
—> Other risk factors as considered significant by senior staff such as ***meconium-stained liquor
Management:
1. Monitor symptoms
- **Abdominal pain: Preterm labour, Infection, Placenta abruption
- **Colour of liquor: Consider earlier delivery if evidence of meconium / blood-stained liquor
- **Vaginal bleeding
- **Fetal movement
- ***Temperature
- Daily blood
- CBC (**leukocytosis common after steroid injection)
- **CRP - ***Non-stress test (NST)
- Determine fetal wellbeing and evidence of cord compression (Felix) - Antibiotics (if **<34 weeks)
- **Oral Erythromycin 250mg Q6H for 10 days
AND
- **IV Ampicillin 2g Q6H for 48 hours —> **Oral Amoxicillin 250mg Q8H for 5 days
—> if genital swabs positive for GBS —> complete above antibiotics (i.e. 連埋Amoxicillin)
—> if genital swabs negative for GBS —> complete whole course of oral Erythromycin + complete IV Ampicillin
—> if allergic to penicillin —> ***Vancomycin
- Organisms detected on swabs should be treated accordingly -
Corticosteroid injection (for fetal lung maturation) (26-34 weeks)
- Standard regimen: **Betamethasone 12mg IMI Q24H / Q12H for **2 doses
- Alternative regimen: **Dexamethasone 6mg IMI Q6H for **4 doses
(- Other functions: Prevent NEC, IVH (SpC OG)) - Tocolytics
- Aim to delay delivery for **>=48 hours to enable effect of steroid to enhance fetal pulmonary maturation
- **Consider when presence of **regular uterine contractions
- **Expectant management can be considered in PPROM if no evidence of infection / regular uterine contractions
- Decision regarding Tocolytics should be taken by senior staff —> should only be considered if ***no evidence of infection - Neonatal ICU
- Ensure availability of neonatal ICU cots —> if no neonatal ICU cots available —> liaise with other Paediatric / Obstetric units in other hospitals —> may need to consider in-utero transfer
(9. MgSO4 (SpC OG)
- Prevent cerebral palsy of fetus)
Corticosteroid
Maximum neonatal benefits achieved when preterm birth occurs between 24 hours - 7 days after maternal corticosteroid administration
- 65% reduction in respiratory distress syndrome (RDS) for babies delivered >24 hours - <7 days, after completion of medication
- 20% reduction in RDS still observed among babies born <24 hours
- Also help to reduce intraventricular haemorrhage, necrotising entercolitis, neonatal death
No strong evidence that a single course of steroid is associated with increased maternal + neonatal sepsis in PPROM
- ***Multiple courses of steroid in PPROM may be associated with an increased risk of early-onset neonatal sepsis
Used with caution in combination with **Tocolytics because of risk of maternal **pulmonary edema
Contraindications to Tocolytics
- Gestation ***>34 weeks
- Fetal death in-utero
- Fetal malformation where palliative care is planned
- Suspected fetal compromise as determined by USG / CTG warranting delivery
- Placental abruption
- Chorioamnionitis
- Pre-eclampsia
Relative CI:
1. Maternal cardiac disease
2. DM
3. Thyrotoxicosis
4. Ruptured membranes
5. Abnormal fetus
Forms of Tocolytics (記: NAT)
記: NAT
1st line: Nifedipine
- **Hypotension (in normotensive patients, effects on BP are minimal)
- **Tachycardia, palpitation
- Flushing, headache, dizziness
- Nausea
- Dyspnea
2nd line: Atosiban (Oxytocin receptor antagonist)
- Chest pain
- Palpitations
- **Tachycardia
- **Hypotension
- Dyspnea
- N+V
- Headache
- Pulmonary edema
3rd line: Terbutaline (Beta agonist)
- Used with caution in **DM (∵ hyperglycaemic effect)
- Patient will have increased risk of developing **pulmonary edema if used with steroid
- When to stop treatment
—> Maternal tachycardia (>120)
—> Severe hypotension (Drop of DBP >20 mmHg)
—> Cannot tolerate SE of terbutaline
CI of Terbutaline:
- Allergy
- Significant maternal cardiac disease
- Poorly controlled DM
- Poorly controlled thyrotoxicosis
- Hypotension
SE of Terbutaline:
- **Hypotension
- **Tachycardia, palpitation
- Dyspnea
- HypoK
- ***Hyperglycaemia
- Fluid overload
Antepartum haemorrhage (Case Discussion)
Definition: Bleeding from /intogenital tract, occurring from 24+0 weeks of pregnancy and prior to birth of baby (RCOG guideline)
Causes:
1. **Placental abruption (30%)
2. **Placenta previa (20%)
3. **Vasa previa
4. **Uterine rupture
5. Bloody show associated with labour
6. Minor causes (Cervical, Vaginal, Uterine pathologies (e.g. polyps, infection, trauma, GTD, ectropion))
7.Unknown origin (APH-UO)
Placental abruption
Premature separation of a normally implanted placenta from decidua before birth of fetus
Classification:
- Partial / Complete
- Revealed / Concealed / Mixed
- Mild / Severe (presence of>=1 complications)
- Antepartum (56%) / Intrapartum (44%)
Pathophysiology:
Rupture of maternal vessels in decidua basalis (rarely fetal-placental vessels)
—> Accumulation of blood which splits decidua
—> Separation of decidua with placental attachment
Risk factors:
Maternal:
- **Previous abruption (10-15 fold)
- **Hypertension (5 fold), Preeclampsia
- Uterine structural abnormalities (e.g. fibroid)
- **Severe trauma
- Rapid uterine decompression (e.g. birth of first twin / release of polyhydramnios)
- **Smoking
- ***Cocaine abuse
Fetal:
- Polyhydramnios
- ***Multiple pregnancy
Clinical features:
Maternal:
- Vaginal bleeding
- Sudden onset of abdominal pain,Uterine tenderness
- ***Uterine contractions (“Hard uterus”)
- Back pain (if placenta on posterior wall)
Fetal:
- Fetal distress
- Reduced fetal movement
Complications:
Maternal:
- Hypovolaemic shock
- DIC
- Multiorgan failure
- Hysterectomy
- Emergency C-section
- PPH
- Couvelaire uterus (Atonic)—> PPH
- Death
Fetal:
- Non-reassuring fetal status
- IUGR
- SGA
- Preterm birth
- Intrauterine hypoxia
- Stillbirth /Death
Management:
- Severe abruption(>=1 complications)—> **C/S
- Stable mother + Reassuring fetal status
—> **<34 weeks—> **Corticosteroids + ?Tocolytics
—> **34-36 weeks—> **Delivery via vaginal birth / Expectant if asymptomatic + stop bleeding
—> **>36 weeks—> ***Delivery via vaginal birth
Placental previa
Placenta in lower segment of uterus, near / reaching / covering the internal os of cervix
Classification:
Type I: Low lying placenta near the internal os
Type II:”Marginal”, reaching the os
Type III / IV: Covering the ox
Risk factors:
- **Previous placenta previa
- **Previous Caesarean section
- **Multiple pregnancy
- Previous uterine surgical procedure
- Increasing parity
- **Increasing maternal age
Pathophysiology:
- Occur when shearing forces applied to inelastic placental attachment site, leading to partial detachment
—> uterine contractions
—> gradual changes in the cervix and lower uterine segment
- May be provoked by vaginal examination or coitus
- Source of bleeding:
—> Bleeding is primarily maternal blood from the intervillous space
—> Fetal bleeding can occur if fetal vessels in the terminal villi are disrupted
Clinical features:
1. ***Asymptomatic finding on mid-trimesterroutine USG examination
- 90% of placenta previas identified on USG before 20 weeks of gestation resolve before delivery (because placental edge overlying the cervix atrophies)
- Predicting the presence PP at delivery
—> lack of resolution by the third trimester
—> extension over the os by more than 25 mm
—> posterior previa
- ***Painless bleeding
- MOST common symptoms in second half of pregnancy
- 1/3 before 30 weeks
- 1/3 between 30-36 weeks
- 1/3 after 36 weeks
- 10-20% may have similar presentation as placental abruption (pain, uterine contraction, bleeding)
Investigations:
- NO digital vaginal or rectal examination unless placenta praevia excluded —> Risk of provoking heavy bleeding —> USG should be performed beforehand
Diagnosis:
Sonographic identification of echogenic homogeneous placental tissue extending over the internal cervical os on a 2nd / 3rd trimester imaging study
- Transabdominal ultrasound(asscreening)
- If the distance between the edge of the placenta and the cervical os is **<=20 mm on TAS
—> Transvaginal ultrasound can better define placental position and make the diagnosis
—> when the placental edge is **<20 mm from, but not over internal os, the placenta is labeled “low-lying”
Associated findings:
1. Placenta previa-accreta spectrum
2. Malpresentation
3. Vasa previa and velamentous umbilical cord
4. Fetal growth restriction,Congenital anomalies
Management:
1. Asymptomatic 18-22 weeks
- FU TVUS at **32 weeks
—> with Accreta —> C/S at 34-36 weeks
—> without Accreta —> TVUS at 36 weeks
—> PP / Low-lying at **36 weeks —> C/S at 38-39 weeks
—> No PP / Low-lying —> Routine prenatal care
- Active bleeding
- Stabilise
—> Avoid excess physical activity, including sexual intercourse
—> **Corticosteroid therapy if <34 weeks for lung maturation
—> **Anti-D Ig prophylaxis if needed
—> ***C/S at 38-39 weeks
—> Plan for possibility of PPH
- C/S:
—> Active labour
—> Fetal distress
—> Haemodynamic stability cannot be achieved
—> Significant vaginal bleeding after 34 weeks
Vasa previa
- Fetal vessels traversing through membranes over internal cervical os and below fetal presenting part
- Unprotected by placental tissue or the umbilical cord
Classification:
Type 1: Velamentous cord insertion + fetal vessels run freely overlying / close (2cm) to cervix
Type 2: Succenturiate lobe / Multilobed lobe + fetal vessels connecting 2 placental lobes overlying / close (2cm) to cervix
Risk factors:
1. **Velamentous cord insertion
2. **Succenturiate placental lobe or bilobed placenta
3. ***Low-lying placenta in 2nd trimester
4. IVF
5. Multiple pregnancy
Clinical features:
1. ***Fresh vaginal bleeding
- Spontaneous / artificial membrane rupture
-
**Fetal heart rate abnormalities
- decelerations, bradycardia, a **sinusoidal trace or fetal demise
Pathophysiology:
- Source of bleeding: Fetal circulation
- ROM —> rupture of unprotected fetal vessels —> fetal hemorrhage, exsanguination, death
Diagnosis:
1. Clinical
- Vaginal bleeding / Intrapartum by palpation or visualisation
2. Transabdominal + Transvaginal Colour Doppler USG
Management:
- Confirm persistence of vasa previa by USG in 3rd trimester
- **Prophylactic hospitalisation from 30–32 weeks
- **Corticosteroids for fetal lung maturity from 32 weeks
- ***Elective C/S ideally before onset of labour —> Planned C/S at 34–36 weeks reasonable in asymptomatic women
Uterine rupture
Definition: full thickness tear through the myometrium and serosa
Classification:
- Complete: Uterine cavity directly communicate with peritoneal cavity
- Incomplete: Uterine & peritoneal cavities separated by visceral peritoneum / broad ligament
Pathophysiology:
1. Rupture of unscarred uterus
- Obstructed labour
- Post-term, Macrosomia, Polyhydramnios, Hydrocephalus (distending lower segment in cephalic presentation)
- Uterine hyperstimulation during induction of labour
- Rupture of scarred uterus
- Previous uterine surgery
- Previous uterine trauma
Clinical features:
1. Acute abdominal pain
2. PVB / Intra-abdominal bleeding —> Maternal shock
3. **Cessation of uterine contractions
4. Fetal distress
5. **Fetal misplacement
Management:
1. Resuscitation
2. Urgent laparotomy / C/S
3. Repair of uterine rupture / hysterectomy
4. Counselling about future pregnancy (increased risks of rupture in subsequent pregnancy)
- Tubal ligation
- Contraception
Oligohydramnios
Maternal:
1. Uteroplacental insufficiency
- Preeclampsia/ Chronic hypertension
- Collagen vascular disease
Fetal:
1. PPROM
- Leaking of amniotic fluid after rupture of membranes
- Congenital abnormalities resulting in decreased urine production
- Renal agenesis
- Multicystic dysplastic kidney
- Infantile type of polycystic kidneys (ARPKD) - Obstruction of lower urinary tract
- Posterior urethral valve
- Urethral atresia
- Prune belly syndrome - IUGR
- Redistribution of blood flow away from the kidneys which decreases fetal urine production - Twin-twin transfusion syndrome (TTTS)
Polyhydramnios
Maternal:
1. Maternal DM
- Fetal hyperglycemia leading to polyuria
Fetal:
1. Congenital abnormalities interfering with swallowing and/or fluid absorption
- Neuromuscular disorders: Anencephaly
- Esophageal atresia/ Duodenal atresia/ Intestinal atresia
- Gastroschisis/ Omphalocele
- Congenital abnormalities resulting in increased urine production
- High fetal cardiac output state (e.g. any conditions resulting in anemia)
- Congenital mesoblastic nephroma —> Increased urine production due to renal hyperperfusion - Trisomy 18 (Edwards syndrome)
- IUGR and polyhydramnios especially in a fetus with abnormal hand position (clenched hands) are suggestive - Twin-twin transfusion syndrome (TTTS)
