Normal labor

Dr. S. R. OtivConsultant, KEM Hospital, Pune

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Flexed vertex Deflexed vertex Brow Face

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Fetal skull

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Diameters of the fetal skull

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Fetal head - pelvis relationship

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QuickTime™ and a decompressor

are needed to see this picture.

Mechanism of labor

Cardinal movements in labor

• Engagement• Descent• Flexion• Internal rotation• Extension• External rotation• Expulsion

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Flexion

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Mechanism of labor video

save-video2.mp4

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Course of labor with OP

• Engagement• Descent• Flexion• Long IR 135o

• Extension• Restitution• Ext rotn• Lat flexion

• Engagement• Descent• Flexion• Short IR 45o

• Flexion• Extension• Restitution• Ext rotn• Lat flexion

• Engagement• Descent• Deflexion• DTA or POP

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OP: Failure of cardinal movements

• Engagement occurs late after onset of labor

• Descent is slow

• Flexion is inadequate or absent

• Long internal rotation does not occur

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Engagement

Descent

Flexion

Internal rotation

Extension

External rotation

Expulsion

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Why does the fetal head remain high after onset of labor?

• Extension of fetal spine – misdirection of fetal axis– deflexion of fetal head

• Deflexion of fetal head larger diameter of presenting part

Engagement

Descent

Flexion

Internal rotation

Extension

External rotation

Expulsion

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Why does slow descent occur in OP labor?

• Deflexion leads to oblong presenting diameter that does not dilate the cervix properly. The resulting weak Ferguson reflex leads to inadequate uterine contractions

• Misdirected uterine force: vertically down rather than inclined posteriorly into the brim

Engagement

Descent

Flexion

Internal rotation

Extension

External rotation

Expulsion

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Why does flexion fail?• Fetal spine lies against convexity of

maternal spine. Extension of fetal spine --> deflexion

• Tight maternal abdomen in primi exaggerates deflexion

• Weak uterine force

• Other - brachycephaly, steep angle of inclination

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Engagement

Descent

Flexion

Internal rotation

Extension

External rotation

Expulsion

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Failure of internal rotation• Deflexed head - sinciput reaches pelvic

floor and is rotated anteriorly, occiput posteriorly

• Inadequate uterine contractions

• Shoulder caught against maternal spine

• Shallow or flat sacrum in android pelvis

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Engagement

Descent

Flexion

Internal rotation

Extension

External rotation

Expulsion

Management of labor

• Initial assessment• Monitoring• Pain relief• Emotional support• Nursing care• Intervention

Initial assessment

• Assess baseline status to determine progress

• Medical or obstetric conditions that need to be addressed – prenatal record

• Development of new disorders

• Evaluate fetal status

Examination

• General: P, BP, temp, wt• Systemic – CVS , RS,

• P/A – scars, presentation, position, anterior shoulder, head level, FHR location, contraction freq / duration / baseline tone

• CTG trace

Internal examination

• Lesions of genital herpes• Cervix – dilatation, effacement, consistency,

direction, how well applied to pp• Presenting part - ?, station, moulding,

position, caput, asynclitism, descent during contraction

• Bag of fore water – intact / absent, size • AF – clear / colored• Pelvis

Lab tests

• Check reports – Hb, HCT, blood group, HIV HbsAg, GBS screen

• Urine albumin, HIV, HbsAg,

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Prenatal record

• History• E• Serology• USG – IUGR, dates,

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Deep transverse arrest

Arrest of fetal head at the ischial spines after more than 1 hour of full cervical dilatation in spite of adequate contractions.

Causes – epidural analgesia– narrow outlet

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Management of DTA

• Digital rotation• Manual rotation• Forceps rotation – Smellie Scanzoni maneuver with Simpson forceps– Kjelland forceps

• Vacuum extraction• C-section

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Manual Rotation of head

• Adequate amniotic fluid• Normal fetal heart• Head should be on pelvic floor• Dis-impact head before rotation

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Simpson Forceps

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Prevention

•Maternal positions (upright, non supine and hands/knees) in labor

•Augmentation of labor reduces likelihood of persistent OPP

•Manual rotation of the fetal head to occiput anterior after 7cm to full dilatation improves the rate of occiput anterior deliver

•Epidural analgesia does not facilitate rotation

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Thank you !