O&G Case 8, 15, 17, 18 Flashcards
Whats the DDX for preterm labour?
● Preterm labour
● APH
pregnancy
● Placental abruption
● Uterine rupture
What is preterm birth and how common is it?
● Defined as “delivery before completion of 37+0 weeks gestation”
○ Later preterm: 34-37
○ Early preterm: <34
○ Very preterm: 28-<32
○ Extremely preterm: <28
● Apprxomimately 8% of births
● Threatened <3cm cervical dilation
What are the relative contributions of iatrogenic and spontaneous preterm birth?
● 2⁄3 spontaneous
○ Can have ROM without labour and can labour without ROM
○ Preterm prelabour rupture of membranes (PPROM)
● 1⁄3 iatrogenic preterm delivery for maternal or fetal indications
○ Preeclampsia
○ IUGR
○ Placenta praevia
Whatcan preterm birth cause in terms of morbidity (particularly neurodevelopmental) and perinatal mortality?
● Neurosensory issues
● Respiratory distress
○ Apnea of prematurity (cessation of breathing for >20s)
○ Transient tachypnoea of the newborn (TTN)
○ Bronchopulmonary dysplasia (BPD)
● Feeding intolerance and necrotising enterocolitis (NEC)
● Hypoglycaemia
● Hypothermia
● Jaundice at birth
What factors prior to pregnancy increase the risk of preterm birth?
- Prev preterm and/or PPROM
- Prev late miscarriage
- Cervical incompetance / fibroids
- Previous surgery i.e lETZ
- Hx of termination <1cm, or C-section at full dilation
What factors during a pregnancy increase risk of preterm birth?
- Maternal age <20 or >40
- Low or high BMI
- Polyhydraminos
- Infection
- Smoking
- Placental abruption
- ART
What are the common causes of preterm labour?
● Any stimulus for inflammation can precipitate preterm labour:
○ Infection
○ Bleeding
○ Uterine distension (due to multiple pregnancy or polyhydramnios)
● Premature activation of maternal or fetal hypothalamic-pituitary-adrenal axis
● Decidual haemorrhage
How can preterm labour be predicted?
● Risk scoring
● Cervical length (TVUS)
○ Shorter cervix → higher risk
● Vaginal biomarker swabs (mostly fFN)
○ Elevated fFN from 22-37 weeks gestation associated with higher risk of preterm labour
○ Can also use placental alpha macroglobulin-1 and phosphorylated insulin like growth factor binding protein 1 (Never heard of this in clincial practice)
How can preterm labour be prevented?
● Cervical cerclage
(between 12-14 weeks)
● Rescue cerclage
○ Already dilated cervix but no contractions yet
● Progesterone
○ For high risk woman
● Antibiotics
● Prophylactic tocolysis
○ Use to buy time for steroids to be taken and take effect or to transfer them to
appropriate centre for care
○ Nifedipine
○ Suppress premature labour
○ Calcium channel blocker
■ Stops influx of calcium which prevents uterine contractions
What must you give to a women with suspected preterm labour?
● Steroids
○ To prevent respiratory distress by accelerating pulmonary surfactant production
○ 11.4mg betamethasone x 2 24 hours apart
○ Give to women;
■ Increases risk of delivery <34+6 weeks gestation
■ When preterm birth is planned or expected within next 7 days (even within 24
hours)
What is the role of administering magnesium sulphate to women at preterm delivery?
● Magnesium sulphate
○ Usually in more preterm woman
○ Neuroprotection for infant
○ Reduces risk of cerebral palsy
○ Given as IV infusion over 4 hours just before birth
How would your management of a woman in preterm labour differ in a rural vs a tertiary hospital setting?
● Rural hospitals may not have NICU so need to factor in transfer of women to tertiary centre
● Tocolysis (nifedipine) will delay delivery by >48 hours to allow for transfer and administration
of antenatal corticosteroids and magnesium sulphate
What is the fetal fibronectin test and what is its role in assessing a woman in suspected preterm labour?
● fFN test detects the fFN (glue that attaches the fetal membranes to the decidua basalis) in the cervicovaginal fluid
● Elevated levels from 22-37 weeks associated with risk of preterm labour
● Strong negative predictive value → >99% of women with negative test will not delivery in next
10 days
● Do test before vaginal examination, ROM, or >48 hours from last sexual intercouse, if cervical
dilation <3cm → false positives (but can still be reassuring if negative)
What is tocolysis? What drug is commonly used for tocolysis in New Zealand?
● Tocolytics = medications used to suppress labour
● Nifedipine most common in NZ
○ Calcium channel blocker
■ Stops influx of calcium which prevents uterine contractions
○ Side effects
■ Transient palpitations
■ Headache
■ Flushing ○ Contraindications
■ Suspected or confirmed IU infection
■ Placental abruption
■ Significant hypotension
■ Maternal shock
What investigations might be useful when assessing a woman in suspected preterm labour?
● Blood test
○ FBC
○ CRP
○ G&h
● MSU
● High vaginal swab
● fFN (<34+6weeks)
● TVUS
○ Cervical length >30mm = negative
○ Cervical length <15mm = positive
● CTG (cardiotocography)
● Other vaginal biomarkers (PAMG-1)
● Ferning
○ Vaginal secretions mixed with amniotic fluid make a “fern-like” pattern under microscope
● Nitrazine test
○ Paper strips that detect pH changes in the vagina (amniotic fluid has higher pH than
vaginal fluid) ● USS
○ Fetal height and measurements
○ Liquor volume
○ Measurement of amniotic fluid volume to determine PPROM
What are the general principles of management for women in preterm labour?
Admit
- Confirm reg contractions
- FFN
- Cervical length and dilatation
Monitoring
● IV line → FBC, CRP, G&H, blood cultures if suspicious of infection
● Confirm fetal presentation by USS
● Continuous CTG (if in labour)
Give medicines
What medicines do you give for a preterm labour?
○ Administer corticosteroids
○ Magnesium sulphate (<30weeks)
○ Tocolysis (Nifidipine)
○ Prophylactic antibodies for threatened labour → UTI etc (to settle uterus down)
○ Prophylactic antibodies for group B (if in labour)
During labour what do you for a preterm?
Delayed cord clamping (if in labour)
● Prolongation of the time between the delivery of a newborn and the clamping of the umbilical
cord
● 60 seconds at birth
● Reduces neonatal mortality
How do you manage PPROM?
● Same management +
○ 10/7 oral erythromycin (reduce preterm birth)
○ Conservative management until >37 weeks gestation then IOL
How do you treat stress and urge incontinence?
- Pelvic floor training
- Estrogen cream
- Bladder training
- Surgical intervention
- Duloxetine, Oxybutinin
- Botox
What are the surgical interventions for incontinence?
○ Suspension/sling operations to elevate bladder neck and support urethra
○ Mid-urethral slings
■ Mesh tape is placed under the urethra through two to three small incisions in order to support the urethra
■ Increases sub-urethral support
○ Intramural urethral bulking agents
■ Bulking materials injected into the urethra and bladder neck which helps to close the lumen of the urethra
■ Increasing tissue mass increases outflow resistance
■ Evidence limited
What is prolapse?
Prolapse = muscles and tissues supporting pelvic organs become weak or loose Traditional terms describing pelvic organ prolapse
What is the new descriptive terms for prolapse?
● Anterior prolapse
○ Front wall of the vagina has herniated inward
○ Usually caused by the bladder or/and urethra shifting position and placing
pressure on the vaginal wall
○ This term includes the possibility of a cystocele, urethrocele and cystourethrocele.
● Posterior
○ Rectum to herniate into the vagina
○ Due to weakening of the musculature and connective tissue or damage to the
rectovaginal septum
○ This term includes the possibility of a rectocoele or enterocoele
● Apical
○ Tissue supporting the uterus weakens and the uterus slips downward, placing pressure on the vagina
○ Usually associated with trauma in childbirth
● Vaginal vault prolapse
○ Roof of the vagina collapses
○ Usually following hysterectomy
■ Will also have an enterocoele present
