Pre-term : Choriamniontis Flashcards
What is the definition of preterm labour?
Preterm labour occurs prematurely between 24 and 37 weeks of pregnancy and begins either spontaneously or by preterm rupture of membranes.
24- 30 weeks is classed as extreme preterm
30-34 weeks is classed as moderate preterm
34-36 weeks is classed as late preterm
8% or approximately 60 000 babies are born prematurely in UK every year and globally 1 in 10 births is preterm. The survival rate of babies born at 24 weeks is 60 %. This increases with higher gestational age and around 95% babies born at 31 weeks will survive.
What are the causes and risk factors of pre-term labour?
Premature labour happens as a spontaneous labour or following preterm rupture of membranes or because of iatrogenic causes.
It also happens due to uterine distention, progesterone decline, cervical issues such as cone biopsy, stress, vascular disorders, infection, poor nutrition, smoking, trauma and placental abruption or antepartum haemorrhage. Risk factors are previous preterm labour, twin pregnancy, socioeconomic status, domestic violence etc.
Speak through the physiology and pathophysiology of pre-term labour
Chorioamnionitis is an inflammation of the chorion, amnion and placenta and is caused by bacteria or fungi that can originate from skin, mouth, intestines, or urinary tract. It can be also a result of medical procedures from amniocentesis. However, the most commonly it is caused by ascending organisms from vagino-cervical region. The infection from the uterus can spread to fetus that develops inflammatory response known as the fetal inflammatory response syndrome. The fetal inflammatory response then triggers Corticothropin Releasing Hormone from fetal hypothalamus. This causes fetal adrenal glands to increase cortisol production, which stimulates the prostaglandin synthesis and contractions. Another thing that happens is that the bacteria produce endotoxins that stimulate the maternal immune system to response and cause inflammation. The inflammation through a complex chemical reaction then causes release of prostaglandins from myometrium and membranes. Prostaglandins then produce enzymes that digest the cervical collagen causing it to soften and weaken the membranes. This can again lead to contractions and rupture of membranes.
Speak through the clinical assessment of pre-term labour
- Clinical history and observations to check for risk factors and signs of infection, bleeding etc…
- Transvaginal ultrasound to measure the length of the cervix. If 15mm or more and membranes intact, she is unlikely to go into labour. If 15mm and less treat as preterm labour.
- Vaginal examination, using speculum if Preterm Premature rupture of membranes (PPROM) occurred to avoid further stimulation and shortened latent phase (British Medical Journal).If cervix is more than 3cm treat as a preterm labour
- Fetal Fibronectin test: Vagino-cervical swab can be used post 24 weeks in women with or without symptoms
Signs and symptoms:
Contractions, cramping, backpain, rupture of membranes, per vaginal bleed, cervical dilatation
CTG classification:
Define risks:
Contractions:
Baseline: is higher at preterm around 155bpm 20-24 weeks/ above 160 is always tachycardic
Accelerations: can be only 10 bpm from the baseline
Variability: can be reduced due to gestation but should be viewed with caution if reduced persistently
Decelereations: common in fetus bellow 26 weeks
HOWEVER!!! From 32 weeks should be judged as per NICE guidelines
Cervical cerclage (Cervical stitch) can be used in women 16 to 27+6 with dilated cervix and intact membranes
Preterm premature rupture of membranes PPROM
If preterm premature rupture of membranes occurs monitor the woman for signs of infection by observing vital signs, CTG for fetal tachycardia, C-reactive protein, White blood cell count.
Also give antibiotics: Erythromycin 250mg 4x a day as prophylaxis (Bed rest)
Pregnancy can be prolonged for up to 48 hours by administration of tocolysis, however bleeding, maternal cardiac condition, hepatic disease, low blood pressure and infection is contraindicated. It is beneficial in case we need in utero transfer, make sure capacity in unit prepared for preterm baby.
Tablet Nifedipine (Calcium blocker prevents calcium in uterine muscle and therefore contractions): Starting dose is 20mg/ orally and maintenance dose 10-20mg 3x-4x a day up to 48 hours.
If Nifidepin is contraindicated oxytocin antagonist Atosiban can be used
What are the IV infusions used when pre-term labour is established?
IV Administration of Magnesium Sulphate (at 24-34 weeks of gestation). This acts as a neuroprotector and reduces risk of cerebral palsy and death. Loading dose is 4g of 20 % Magnesium sulphate infused over 10-15 minutes. Maintenance dose 5g of 20% Magnesium Sulphate at rate 1g/Hour until birth or 24 hours. Aim to commence 4 hours prior delivery but don`t delay the delivery to administer if fetal or maternal emergency and need for imminent delivery. Monitor for Magnesium Sulphate toxicity, hourly observations and escalate immediately if outside of range.
Side effects are Nausea and vomiting, Flushes- give fan, thirst- give water, drowsiness, or confusion- reassure, muscle weakness leading to respiratory suppression to be monitored by Obstetrician.
IM Administration of corticosteroids: stimulate the production of surfactant in alveoli that lowers surface tension and prevents alveoli from collapsing and accelerate overall maturation of lungs. Therefore, they reduce respiratory distress, neonatal death, and neonatal intensive care admissions. Optimum time is between 7 days and 24 hours prior to delivery…two single doses of 12 Mg Betamethasone IM 12 hours apart.
IV Administration of Antibiotics: Provide speculum examination and swab to screen for GBS, however, RCOG recommends IV antibiotics for all preterm labours. Benzylpenicillin 3g loading dose and then 1.5g 4hourly until delivery. If allergic IV Clindamycin 900mg every 8 hours.
Speak through the preterm labour care
Labour care:
MDT team approach and regular updates to senior registrar and neonatal team
Contact Neonatal unit to confirm capacity and have incubator ready
Resuscitaire ready, room temperature at least 26 degrees. If less than 30 weeks polyethylene bag ready.
Neonatologist present at birth
Introduction to parents, language needs and communication, counselling them on possible outcomes, need for intubation
Consider IM steroids for lung maturation and production of surfactant in alveoli
Consider Magnesium sulphate
IV antibiotics
Continuous CTG monitoring with hourly fresh eyes and half hourly interpretation- Preterm fetal baseline is normally higher but over 160 is considered tachycardic.
Hourly observations to assess maternal wellbeing and rule out maternal sepsis
Bladder care every 4 hours to help with descent, urinalysis to rule out infection, proteinuria, monitor ketons
Hydration/ diet
Pain relief- avoid narcotic analgesia such as Pethidine as can lead to further neonatal respiratory depression
Emotional support
Documentation
Speak through postnatal care for baby
MDT approach
If gestation below 30 weeks baby should be placed into polyethylene bag immediately without drying for thermoregulation. Thermoregulation is vital as baby has little or no brown fat and hypothermia risk of mortality.
Delayed cord clamping if baby is warm improves cardiovascular stability
To be assessed by neonatologist
Maintained airway by continuous positive airway pressure to help prevent alveolar collapse on expiration/ intubation if necessary
Incubator
Oxygen saturation should be available
Transfer to Neonatal Unit as requires stabilisation due to prematurity
Vit K with consent: dose to be calculated by Neonatologist and administered with consent to prevent bleeding due to Vik K deficiency
Breastmilk is the best option to prevent Necrotising Enterocolitis
Skin to skin once baby is stable to promote thermoregulation and bonding
Speak through postnatal care for mum
Assess bleeding/ perineum/ repair
Vital signs to rule out deviation or infection
Analgesia
Emotional support to prevent PND/ wellbeing/ Debrief
Uterus/ Lochia
Mobilize/ DVT/Preeclampsia
Hydration, diet
Passing urine within 6 hours
Keep well informed of baby development
Support with expressing
Arrange visit to Neonatal unit when possible/ prepare parents for appearance of the neonate (intubation, ventilation)
Education regarding handling the baby
Discharge talk/ Follow up in community
