Preterm Labor

Saeed esmailian

Kerman University of Medical Sciences

DefinitionDefinition

regular uterine contractions

by progressive cervical dilation and/or effacement at less than 37 weeks

Significance

Preterm birth is the leading direct cause of neonatal death (death in the first 28 days of life).

It is responsible for 27 percent of neonatal deaths worldwide, comprising over one million deaths annually

The risk of neonatal mortality decreases as gestational age at birth increases, but the relationship is nonlinear (figure 1

preterm birth is the second most common cause of-death (after pneumonia) in children younger than 5 years.

Survival in Premature Infants

survival chance is directly proportional to the maturity

26 wks – 80%27 wks – 90%28-31 wks – 90 to 95%

32-33 wks – 95%34-36 wks – approaches term survival rates

Complications of PrematurityComplications of Prematurity RDS IVH Feeding difficulties/NEC Apnea PDA Infection Jaundice Hypothermia Neurobehavioral ROP Anemia

Prevalence

Worldwide11 percent (range 5 percent [parts of Europe] to 18 percent [parts of Africa]),

15 million children each year (range 12 to 18 million)

United States in 2011, 11.73 percent

Risk Risk factorsfactors

Signs and symptomsSigns and symptoms

1. Painful or painless uterine contractions

2. Menstrual-like cramping3. Mild, irregular contractions4. Low back ache5. pressure sensation in the vagina6.6. Vaginal discharge Vaginal discharge of mucus, which

may be clear, pink, or slightly bloody (ie, mucus plug, bloody show)

Diagnostic critiriaDiagnostic critiria

Uterine contraction Uterine contraction 4 in 20 mins8 in 60 mins with cervical change

Cervical dilatation > 1 cmCervical effacement > 80%

Initial evaluation

Maternal vital signs:(temperature, blood pressure, heart rate, respiratory rate) Fetal monitoring:

 fetal heart rate and contraction (frequency /duration /intensity)

Uterine contractions are evaluated continuously using a contraction monitor, palpation, and the patient’s subjective assessment.

patient’s past and present obstetrical and medical history and GA

 Examination of the uterusfirmness, tenderness, fetal size, and fetal position.

Initial evaluation

Speculum examination using a wet non-lubricated speculum

cervical dilation and effacement uterine bleeding (abruptio placenta or placenta previa) fetal membranes, ( intact or ruptured) fetal fibronectin (fFN). bactrial culture (B streptococcal,gonorrhea and

chlamydia)

Fetal FibronectinFetal Fibronectin (fFN)- it is a glue like protein binding choriodecidual membrane

Present in vaginal secretions between 23-34 weeks and signifies onset of labor

Bedside test can be done – if negative it rules out preterm labor in next two weeks

P/V examination gives false positive result for 24 hours

Between 24-32 weeksfFN – 25ng/ml + cervical length of 25 mm shows significant risk

Initial evaluation

Ultrasound examination Assess amniotic fluid index. Determine (+/ - 3 weeks) gestational age. Transvaginal scan for cervical length. Normal cervical length = 35 mm Significant cervical length = 25 mm Funnelling of membrane

Management

1.  BBetamethasone  (24- 34w)etamethasone  (24- 34w)

2.2. Tocolytic drugs (before 34w)Tocolytic drugs (before 34w) for up to 48 hours

3.3. AntibioticsAntibiotics ( GBS chemoprophylaxis, Appropriate antibiotics to women with positive urine culture results)

Bed rest (+) Hydration (-) Emergency cerclage (+)

Glucocorticoid

BetamethasoneBetamethasone

12mg IM stat and 24 hours later

Effective: 24 hours after initial doseEffect up to 7 days

Adverse effect: Pulmonary edema Infection Difficult glucose control in DM women

Tocolytic drugsTocolytic drugs

Magnesium SulfateMagnesium Sulfate

Calcium antagonistCleared almost by renal excretion4 g loading dose 2 g/hr continuous doseTherapeutic range:

4~7 mEq/L 1 mEq/L = 1.2 mg/dl = 0.5 mmol/L

Deep tendon reflex disappear 10 mEq/L

Respiratory arrest 12 mEq/L

Beta-Adrenergic Agonist

RitodrineRitodrine Beta-adrenergic receptor desensitization Side effect:

Pulmonary edema Hyperglycemia Arrhythmia

Prostaglandin Inhibitors (Nsaid)

IndomethacinIndomethacin< 48 hours

< 30-32 weeks' gestation)

Not > 200mg/day.

Side effect: Oligohydramnios (reversible)

Prostaglandin Inhibitors (Nsaid)

Capsule 25mg oral Amp 50mg

Rectal Supp 100 mg

50 mg Loading dose

Then 25-50mg /6hs

Calcium Channel Blockers

Nifedipine (adalat)Nifedipine (adalat)

Higher delaying of delivery for >48 H.

Lower risk of RDS &Neonatal jundice.

Lower admission to NICU

Fewer maternal adverse effects

Side effect: Hypotension Decrease uteroplacental perfusion

Dose:

20mg initial

10-20 mg /4-6 h

Available forms

Adalate capsule : 10mg

Adalate retard Tablet: 20 mg

Atosiban

Nonapeptide oxytocin analogue Competitive antagonist of oxytocin-induced

contractions Side effect:

Nausea, vomiting, headache, dizziness, money loss 18000 NTD/day

Reffrences

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