PRETERM LABOR

DR V L DESHMUKH

ASSO PROF

DEPT OBGY

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INTRODUCTION

• Gestation age –40 wk

• 37 wk

• Less than 37 wk

• Baby is affected

• Before 37 wk and after 28 wk

• Early preterm –28 to 34 wk

• Late preterm-34 to 37 wk

Intro---

• Commonest perinatal problems

• 45% of pt with threatened preterm –deliver within 48 hrs

• 55% of pt with threatened preterm stop contracting and do not deliver

• Cause largely not known

• Controversy in inv and t/t part

defination

• Labour before 37 wk

• Between 28 to 37 wk

• Before 28 wk –abortion

• With PROM-prognosis is guarded

• Sufficient urine contractions to cause cx dilation and effacement

• Show may or maynot be present

incidence

• 10%

• Early preterm-critical with resoect to survival rate, handicap risk and overall morbidity and mortality

• Late preterm-prognosis is better

• Costs of t/t is tremendous

• Cost and ges age go hand in hand togather

epidemiology

• Teen age

• low SES

• Illiteracy

• ht <140cm

• Wt <45 kg

• Anaemia

• Malnourished

Epi---

• Smoking

• Bacterial vaginosis

• UTI

• Twins

• Ut abnormality

• Previous h/o preterm labour

• Previous h/o PROM

Epi---

• Genetic predisposition

• Polyhydramnions

• Mother is herselves born as preterm

• Diseases requiring preterm induction eg PIH

• Cx incompetence

• Idiopathic

aieteology

• 75%-no cause is found• 10-20%-infection eg-UTI, Bacterial vaginosis• 10% associated with PROM• ABRUPTIO PLACENTA, FIBROID UTERUS• Twins,triplets quadriplets-(34-36 wk)• Quadriplets even earlier• Cx incompetence• Abd trauma,abd operations

• 5

pathophysiology

• Many theories on why preterm occurs

• None is proved

• But all may explain why preterm occurs

• This includes infection,role of nitric oxide,prostaglandin, and cx changes

Patho---

• Infection-chorioamnitis, UTI,bacterial vaginosis

• Myometrial NO/PG balance-CONTROL MYOMETRIAL CONTRACTILITYdisturbance may lead to preterm contractions.NO IS A SMOOTH MUSCLE RELAXANT.PG has both relaxant and contracting property.

Patho---

• Cx is a complex fibromuscular organ which carries the pregnancy upto term

• If the cx softens, dilates and gets hydrated,it gets altered in form rapidly.

• This change in cx alters the quiescence of uterine muscles

• Predispose to preterm labor

Clinical features

• Painful uterine contractions

• Asso with PROM

• Cont are regular, frequent

• Cx effacement and dilatation occurs

• Only backache may be the complaint

• Sense of heaviness in pelvis

• Difficulty in walking

symptoms

• Abdominal pain

• Backache

• Decreased fetal movements

• Nausea,vomiting

• Diarrhoea

• Increased vaginal discharge

• Vg bldg

Symp---

• Important to exclue gastroenteritis or UTI

• H/O NAUSEA,VOMITING, LOOSE MOTIONS, DYSURIA

• H/o amniocentesis,ut anamokies

• Or bldg in early pregis relevant

Symp--

• Check dates.is it relly preterm?

• Ash h/o fetal movements (IUFD)

• RULE OUT PL ABRUPTION

• RULE OUT PROM

signs

• Tachycardia

• Mild pyrexia

• Palpable contractions

• Cx ffacement and dilatation

• Membranes+/_

• Show+/-

General exam

• Rule out systemic disorders

• Temp, pulse, BP,

• Skin turgur

• Hydration status

Per abdominal exam

• Look for rebound tenderness, guarding, rigidity.may suggest pyelonephritis or appendicitis as a cause of preterm labor

• Rule out pl abruption .tenderness,stony hard• Fibroid(lump in abd)• Keep in mind horioamnitis• Obs exam-ut ht, presentation, FHS,

contractions

P/v

• Aseptic precautions

• Cx dilatation

• Cx effacement

• Membranes+/-

• Station

• Bldg p/v

treatment

• Pt comfrtable

• Reduce anxiety

• Antibiotics

• Correct dehydration

• Decide which tocolytic is appropriate

• Give steroids for lung maturity

investigations

• Urine-micro• High vg swab• CBC• ESR• TVS EXAM-for the maturity of baby,

liquor, presentation, pl previa, pl abruption,baby wt, ut anamoly cx length, FHS+/-

ANTIBIOTICS

• INFECTION may lead to uterine irritabilitydue to the liberation of cytokines

• UTI-antibiotic of choice is with gr –ve spectrum 3RD generation cephalosporinis recommended

• BV• PPROM-ANTIBIOTIC for mother and

baby both

steroids

• For lung maturity

• Dexamethasone or betamethasone

• Given Imly

• 12 hrs apart

• Reduce RDS

• NO HARM TO FETUS

• Act after 48 hrs

tocolytics

• Drugs used to decrease uterine contractility• Act as smooth muscle relaxant• Give time-may be 48 hrs after steroid

administration or till transfer to tertiary centre

• Contraindications-PROM,chorioanitis,fetal anamoly,APH

• Prolong pregnancy significant time

Toco---beta agonists

• Act on beta 2 recepters• Ritrodrine,salbutamol,terbutaline• Given IV, IM, orally• Quite effective in t/t of preterm labor• In theraupeutic doses it can cause

tachycardia, sweating,headache and rarely life threatening CVS comprimise with pulmonary edema

Calcium chanel blockers

• Nefidepine

• Given orally

• Acts as a smooth muscle relaxant

• Side effects are maternal

• Cause headache and flushing

• Rarely used

NSAID

• ANTIPROSTAGLANDINS• PG play a major role in causation of labor• Acts to prevent uterine contraction• Given orally or rectally• Sideeffects are fetal and cause

oligohydramnions,IVH,PDA which requires surgical ligation

• Hence not used

Glyceryl trinitrite

• GTN-nitric oxide donor

• Causes smooth muscle relaxation

• Relatively safe

• Well tolerated

• Effective

• Transdermal patches/IV

• costly

Toco---

• Choice is difficult

• All prolong the pregnancy effectively

• Sideeffects are significant

• Combination drug therapy leads to multiple sideeffects and offer no therapeutic benefit

• Safe ones are GTN and calcium blockers

• Hupotension is really troublesome

Mgt of labor

• If labor is established then certain aspects differ from normal labor

• Good analgesia

• Hydration

• Neonatologist available

• Antibiotic cover

• Monitoring for FD

LABOR

• Membranes preserved as far as possible

• Breech presentation demands LSCS to avoid head entrapment and fetal demise

• IVH is also a possibility

• Forceps are used in 11 stage of labor. They protect the fetal head from excessive compression

Fetal fibronectin

• Protein present at the choriodecidual junction

• Excreated in excess in preterm labor• Values >50 ng/ml are significant• Results are promising if raised FFN present

along with reduced cx length• Negative predictive value is more

significant

summary

• Preterm occurs in 7% • PPROM is asso with highmorbidity and mortality• Aieteology is unknown in 50% of cases• Tocolytics are only moderately effective• H/o preterm labor is important factor for having

preterm labor again• Measurement of cx length at 22-24 wk is

predictive of preterm labor