RCSI NB OG Flashcards
Preterm Labour (PTL) def incidence
before 37 weeks of gestation
11% of all live births
Labour prior to 24 weeks =
threatened miscarriage
PTL Causes
1/3 spontaneous PPROM
1/3 iatrogenic
1/3 idiopathic
Iatrogenic PTL Causes
- Preeclampsia
- IUGR
- Maternal disease necessitating delivery
Spontaneous Preterm Delivery Causes
- PTL
- PPROM
- Cervical incompetence
PTL risk factors
Non-pregnancy related
- Low socio-economic group
- Extremes of age
- Poor nutritional status
- Smoking
- Drug abuse
PTL risk factors
Pregnancy related
- Multiple pregnancy
- PPROM
- Uterine anomalies
- History of preterm delivery in prior pregnancy
- Placenta praevia
- Placental abruption
- Polyhydramnios
- Medical complications of pregnancy eg PET
- Intrauterine infection
Predict Preterm Delivery with two tests
Fetal Fibronectin
Transvaginal ultrasound
Tell me about Fetal Fibronectin/ Partosure
- Glue-like protein binding the fetal membranes
- Cervicovaginal swab at 23 and 35 weeks gestation should be negative
- Positive swab - increased risk preterm delivery
- Good negative predictive value <1% chance of delivery within a week – high specificity
Tell me about Transvaginal ultrasound
Short cervix (<25mm) predicts 75% cases preterm delivery Shorter the cervix = higher the chance of preterm delivery
Preterm Delivery Prevention
No proven preventative strategies
Progesterone for Prevention of Preterm Birth
Weekly IM injections of 17α-hydroxyprogesteone caproate
Reduced incidence of preterm delivery by 1/3 in patients with prior preterm delivery
NEJM
Preterm Labour – Role of Antibiotics
no benefit when membranes are still intact
ONLY FOR PPROM
GBS, listeria, mycoplasma, bacteroides, ureaplasma –> 15 - 20% of PTL
Tx GBS prophylaxis
3g benzylpenicillin IV
THEN 1.8g 6 hourly (clindamycin if penicillin allergic)
Cervical Cerclage
For high-risk cases, short cervix on transvaginal U/S
Preterm Delivery – Prevention
prophylactic vaginal progesterone or prophylactic cervical cerclage to women:
- with a history of spontaneous preterm birth or mid trimester loss between 16+0 and 34+0 weeks of pregnancy and
- in whom a transvaginal ultrasound scan has been carried out between 16+0 and 24+0 weeks of pregnancy that reveals a cervical length of less than 25 mm.
Preterm Delivery – Prevention
prophylactic vaginal progesterone to women
with no history of spontaneous preterm birth or mid trimester loss in whom a transvaginal ultrasound scan has been carried out between 16+0and 24+0 weeks of pregnancy that reveals a cervical length of less than 25 mm.
Preterm Delivery – Prevention
prophylactic cervical cerclage for women
transvaginal ultrasound scan between 16+0 and 24+0 weeks of pregnancy that reveals a cervical length of less than 25 mm
Hx P-PROM
LLETZ
Preterm Labour Dx
- Regular contractions
- Cervical change
- Cervical dilatation
Preterm Labour – Management
- Administer antenatal corticosteroids
Dexamethasone 6mg 12 hourly x 4 doses
or
Betamethasone 12mg IM 24hrly x 2 doses - Tocolysis
- Transfer to tertiary level facility with NICU
Antenatal Corticosteroids
24 and 36 weeks
Reduction in Respiratory Distress Syndrome, neonatal mortality, Intraventricular Haemorrhage, Necrotising Enterocolitis and PDA
Commonly used tocolytics:
Atosiban: oxytocin receptor antagonist
Nifedipine: calcium channel blocker
Ritodrine or Terbutaline: beta adrenergic agonist
Magnesium Sulphate: competitive antagonist to calcium
Indomethacin: interferes with prostaglandin synthesis
Preterm Delivery Neonatal Complications
- Respiratory distress syndrome (RDS)
- Necrotising enterocolitis (NEC)
- Intraventricular haemorrhage (IVH)
- Periventricular leukomalacia (PVL)
- Sepsis
- PDA
PPROM
Preterm Premature Rupture of the Membranes
before 37 weeks gestation
1% to 3% of all pregnancies
Premature ROM
rupture of the chorioamniotic membranes prior to the onset of labour, and may occur at term
Prolonged ROM
ROM > 24hrs
PPROM Dx
Hx gush of fluid, constantly wet
Physical Exam pooling of fluid in the posterior vaginal fornix
Amnisure – for placental alpha-microglobulin 1 in cervicovaginal fluid. High sensitivity and specificity.
Ferning - broad fern pattern on microscopy vs narrow fern pattern of amniotic fluid
Vaginal swab pH - Nitrazine sticks turn blue in presence of amniotic fluid
Cervico-vaginal fetal fibronectin
Intraamniotic instillation of indigo carmine dye
Ultrasound
PPROM causes
- Spontaneous / Idiopathic (most cases)
- Infection: Chlamydia, GBS, Bacteroides
- Smoking
- Placental abruption
- PPROM in prior pregnancy
- Incompetent Cervix
- Multiple Pregnancy (twins / triplets etc)
- Polyhydramnios
- Iatrogenic (after amniocentesis)
PPROM Risks
Risk of infection Intrauterine infection Placental abruption Cord compression Fetal demise (1% - 2% of PPROM cases)
PPROM Surveillance
• Maternal signs of infection • Fetal signs of infection • Serum markers of infection • Ultrasound markers of fetal compromise – Altered biophysical profile (BPP) • CTG abnormalities
Signs of maternal infection
- Pyrexia
- Tachycardia
- Uterine tenderness
- Preterm labour
- Foul smelling vaginal fluid
Signs of fetal infection
• Fetal tachycardia • Non-reactivity / reduced variability on CTG / variable decelerations • Alteration in biophysical profile – Loss of breathing movements – Decrease in gross body movements
Amniotic fluid markers of infection
- Amniotic fluid glucose is low
- Amniotic fluid white cell count is high
- Amniotic fluid Gram stain / culture are positive
- Amniotic fluid C-reactive protein > 20 mg/l
Mid trimester PPROM(16-25 wks)
Pulmonary hypoplasia less than 26 weeks gestation
overall survival is 50-75%
50% deliver within a week, 20% continue for over a month after occurrence of PPROM
When PPROM occurs, WHAT significantly improved perinatal outcome
10 day course of Erythromycin 250mg QDS
All cases of PPROM should be delivered by
37 weeks
OR immediately if fetal compromise or infection, even without evidence of fetal lung maturity
Outpatient management of PPROM
- patient clinically very well for the first few days after PROM (no pain, no bleeding, no signs of infection)
- no major co-morbidities in the pregnancy
- corticosteroids are complete
- lives in close proximity to the hospital
- good support at home
- the patient at home four hourly temperature monitoring
- the hospital has an appropriate day care unit where the patient can come in regularly for assessment of fetal and maternal wellbeing
Threatened Miscarriage -
Vaginal bleeding associated with a viable intrauterine pregnancy up to 24 weeks gestation
Antepartum Haemorrhage
Vaginal bleeding from 24 weeks until the onset of labour
Intrapartum Haemorrhage
Vaginal bleeding from the onset of labour until the end of the 2nd stage of labour
Postpartum Haemorrhage
Vaginal bleeding from the third stage of labour until the end of the puerperium (6 weeks postpartum)
APH causes
Placenta Praevia 30%
Placental Abrupti 20%
Local Causes 5%
Unclassified 45%
Placenta praevia
def
Incidence
partially or wholly situated in the lower uterine segment
1 in 20 at 24 weeks
1 in 200 at 40 weeks
Nulliparous 0.2% Multiparous 0.5%
Placenta praevia
what do you want to know
ant or post
ant –> accreta/percreta if Hx C-S
Placenta praevia
grade I
Minor
If the leading edge of the placenta is within 2cm of the internal cervical os
(low lying placenta)
Placenta praevia
grade II
Minor
Reaches the internal os (marginal)
There is little if any difference between marginal and partial degree of placenta praevia
Placenta praevia
grade III
Major
Covers the os but asymmetrically situated
Placenta praevia
grade IV
Major
Covers the os, centrally located
Risk Factors for Placenta Praevia
Prior Uterine Surgery Caesarean Section (10x risk after 3 c-sections) Curettage Myomectomy Surgical TOP (2x Risk after 2 TOPs) Increased parity Advanced maternal age 9 x risk in >40 vs <20yrs Multiple pregnancy Smoking
P/C Placenta previa
Painless vaginal bleeding which can be unprovoked or occurs post coitus or following uterine contractions
First episode of haemorrhage usually not severe & typically painless
Often asymptomatic: Incidental diagnosis seen on routine obstetric ultrasound
Physical exam Placenta previa
- Uterus soft and non-tender
- Fetal heart rate is usually normal
- Typically high presenting part or malpresentation, because head cannot descend into pelvis
Never do what in Placenta previa
VAGINAL EXAM
Dx Placenta previa
TVUS
risks of Placenta previa
maternal
- Haemorrhage
- Co-existent abruption
- Placenta Accreta (15%)
- Hysterectomy
- Death
Risks of Placenta previa
fetal
• Preterm birth • IUGR – Common in women with multiple bleeds. – Overall rate 15% in praevia • Death
Placenta previa Immediate Management
IV Line (14G x 2) FBC/Coag/X-match 4 units IV Fluids O Negative blood Call for senior help (obstetric and anaesthesia) NICU
Subsequent management of placenta praevia:
Has bleeding stopped? Was it mild bleeding? Was it a life-threatening bleed? Is fetal testing non-reassuring? What is gestational age?
Immediate delivery OR
Expectant management
Immediate delivery for placenta previa if
severe haem
non reassuring CTG
34-36 wks +/- steroids
Expectant management of praevia
exceptional / stable circumstances in women who have never had significant vaginal bleeding and live close to the hospital with good immediate family supports
Aim for delivery at 37 weeks
Mode of delivery of praevia
Elective C-section + spinal/epidural
unless type 1 and formation of lower segment has resulted in vertex passing the edge of the placenta
Placenta Accreta
cause?
use MRI and/or colour doppler USS
chorionic villi in contact with myometrium (80% of cases)
primary deficiency of or secondary loss of decidual elements (decidua basalis)
Placenta Increta
chorionic villi invade into myometrium (15% of cases)
Placenta Percreta
chorionic villi invade into serosa or beyond (5% of cases)
abnormal placentation a/w
Hx prior c section
uterine instrumentation fibroid surgery
prior placenta praevia
patient with suspected placenta accreta should be fully counselled before CS about possibility of
caesarean hysterectomy massive intrapartum haemorrhage
blood transfusion
Placental Abruption
Incidence:
Recurrence risk in subsequent pregnancy:
Premature separation of normally sited placenta
1 in 150 deliveries
5 –15%
Abruption classification
Revealed haemorrhage vs Concealed haemorrhage
Risk factors for Placental Abruption
Chronic hypertension / preeclampsia Abdominal trauma Cocaine use Smoking Prolonged PROM/chronic chorioamnionitis High parity Abruption in prior pregnancy Maternal thrombophilia (factor V leiden etc)
Symptoms of Abruption
Clinical Signs of abruption:
Abdominal pain
Backache
+/- Vaginal bleeding
Faint or collapse = shock
Uterus Wood-like, Irritable
Fetal parts difficult to palpate and fetal heart may be inaudible
Diagnosis of abruption:
clinical
U/S to rule out placenta previa
Management of abruption:
IV Line: FBC, Group and x match 4 units, Coagulation screen
Continuous CTG
If baby is alive - emergency c section
If fetus already dead amniotomy & vaginal delivery
Complications of abruption:
Coagulopathy = decreased fibrinogen level, decreased platelets & raised fibrin degradation products
30%
DIC
Hypovolemia
Local Causes of APH
U/S r/o placenta praevia speculum examination r/o cervical cancer
cervical ectropion
cervicitis
foreign body
safe to take a cervical smear in pregnancy
Vasa Praevia
vessels of the umbilical cord run in the fetal membranes and cross the internal cervical os = velamentous insertion of the cord
Rare: 0.1%
P/C intrapartum haemorrhage at SROM or AROM
rapid fetal haemorrhage/ bradycardia/ death
emergency caesarean section
All rhesus negative women should receive anti-D injection
Routine Antenatal prophylaxis
Following any sensitising events (PVB/ Invasive fetal testing (Amniocentesis or CVS)/ post trauma/ cervical cerclage/management of a miscarriage or ectopic pregnancy)
Post partum if the infant is confirmed Rh Positive
Kleihauer test
estimates the volume of fetomaternal haemorrhage
calculate appropriate dose of anti D
5 Rh antigens
D; C; c; E; e.
Rh neg mom and first Rh pos pregnancy
Fetal Rh Antigen
–> Anti- D IgM, which cannot cross the placenta to cause fetal haemolysis
Rh Tx
in utero blood transfusion
delivery
>34 weeks followed by neonatal exchange transfusion or Neonatal top- up transfusion
continuous monitoring
Cord blood should be sent for Direct antiglobulin test, heamoglobin and bilirubin levels
Neonatal observation for jaundice and /or anaemia
Regular feeds
rh monitoring
Maternal Anti D titres
Every 4 weeks until 28weeks gestation
Every 2 weeks until birth
Fetal Biometry and Biophysical Profile
Fetal Middle Cerebral Artery peak systolic velocities (MCA-PSV) weekly
Referral to fetal medicine
Anti-D level >4 IU/ml
MCA PSV >1.5 MoM (Multiples of Mean)
Hydrops
Hypertension in pregnancy
BP of at least 140mmHg systolic or 90mmHg diastolic on at least 2 occasions 6 hours apart that occurs after 20 weeks’ gestation
Proteinuria
Excretion of ≥ 300mg of protein in 24h
Pregnancy induced hypertension
Hypertension that develops as a consequence of the pregnancy and that regresses in postpartum
Pregnancy aggravated hypertension
Underlying hypertension worsened by pregnancy
PREECLAMPSIA or PET (Proteinuric pregnancy induced hypertension)
- hypertension during pregnancy
- Proteinuria
- +/- pathological oedema
ECLAMPSIA
Seizures + pre-eclampsia
25% seizures post-partum
Pre-eclampsia 2 theories
Vascular: reduction in placental blood flow secondary to abnormal placentation or maternal microvascular disease
poorly perfused placenta releases circulating factor’s target maternal vascular endothelium
Immune: Maternal alloimmune reaction triggered by rejection of the fetal allograft