Abnormal Labour - Obstetrics and Gynaecology unit summary notes. PDF

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Obstetrics and Gynaecology unit summary notes. ...

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Abnormal Labour Dysfunctional Uterine Action Prolonged labour more common in primigravidae Prolonged Latent Phase Occurs almost exclusively in primigravidae Aetiological factors: ● ● ● ●

Wrong diagnosis of labour Abnormal or high presenting part Premature rupture of the membranes Idiopathic cervical dystocia o Primary = failure of a ground substance of the cervix to soften in late pregnancy o Secondary = previous operation on the cervix causing fibrosis

Management: ● ● ● ●

Perform full vaginal examination CTG to ensure fetal wellbeing If labour ceases, let her go home If the cervix continues to efface but not dilate and progress is too slow according to partogram: o Rupture membranes (artificial rupture of membranes) o Give Syntocinon to stimulate labour

Secondary Arrest of Cervical Dilatation Women enters the active phase of labour, reaches 5-7cm dilatation and then the cervix stops Uterine contractions have also become less frequent and may even stop The fetal head engages in the occipitotransverse position and, if is well flexed and asynclitic, will rotate in the mid-cavity into occipitoanterior position ●

Poor flexion will lead to failure of rotation and persistent occipitotransverse position

IV Syntocinon will lead to regular uterine contractions that initially cause the fetal head to flex ●

In most cases, this will allow the head to rotate so that a spontaneous vaginal delivery can occur

If Syntocinon administration over 4 hours (multigravida) or 8 hours (primigravida) fails to lead to further cervical dilatation, C-section should be done Very rarely leads to fetal distress Primary Dysfunctional Labour Slow progress after the onset of established labour Very dangerous Can lead to:

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Fetal distress Increased maternal anxiety Uncoordinated uterine activity which increases maternal pain Maternal dehydration leading to maternal acidosis

Caused by release of catecholamines ● ● ●

Catecholamines stimulate uterine activity to arise from the lower segment This causes the fundus and lower segment to contract against each other Cervix fails to dilate or dilates very slowly

Maternal dehydration and acidosis can further cause dysfunctional uterine activity Causes: ● ● ● ●

Malpresentation Occipitoposterior position Relative cephalopelvic disproportion o Fetus is only just small enough to pass through the pelvis Macrosomia

Treat with Syntocinon Shoulder Dystocia Obstetric emergency Occurs when the shoulders do not spontaneously deliver after the head The anterior shoulder becomes trapped behind or above the symphysis pubis while the posterior shoulder may be in the hollow of the sacrum or above the sacral promontory Predisposing factors: ● ● ● ● ● ● ●

Previous shoulder dystocia Previous baby >4.5kg Big baby (clinically or on US) Obese women Diabetic women Secondary arrest in labour augmented by Syntocinon Prolonged second stage

Signs: ● ● ●

Fetal chin pulls against the perineum No external signs of restitution Anterior shoulder fails to deliver with contraction

Management: ●

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Change maternal position o McRoberts manoeuvre – retract woman’s knees as close to her chest as possible o Place woman on all fours – shoulders move to oblique diameter o Return to supine – external pressure on the mother’s abdomen Perform episiotomy

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Internal rotation – rotate the anterior shoulder and bring it forward Deliver the posterior arm Symphysiotomy – division of the symphysis pubis

Risks: ●

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Maternal: o Vaginal trauma o Bladder/urethral damage o Psychological trauma Neonatal o Erb’s palsy from brachial plexus injury o Cerebral palsy from hypoxia o Fractured humerus/clavicle o Neonatal death

Cephalopelvic Disproportion (CPD) Classified as: ● ●

Absolute Relative

Absolute CPD: ● ● ●

No possibility of a normal vaginal delivery Extremely rare Possible causes: o Fetal hydrocephalus o Congenitally abnormal pelvis e.g. Robert’s Naegele’s pelvis ▪ One or both sacral ala are missing leading to a narrowing of the pelvic inlet o Damaged pelvis o Pelvis distorted by osteomalacia

Relative CPD: ●

Baby is large but would pass through the pelvis if the mechanisms of labour function correctly

Can only be diagnosed after a prolonged labour Malpresentations and Malpositions Breech Presentation Aetiology: ● ● ● ● ●

Too much amniotic fluid Extended legs of the fetus can splint and prevent flexion of the fetal trunk – stops turning and causes baby to remain in breech Foetuses in multiple pregnancies can interfere in one another Obstruction in the lower segment e.g. fibroids Fetal malformations may prevent cephalic presentation e.g. hydrocephaly

Types: ● ● ● ●

Frank or extended – neither knee joint flexed so that both legs are extended o Most common Flexed – both knees flexed Incomplete – one leg flexed and the other extended Footling – both hips extended o Often occurs in very small babies

Examination: ●

Vaginal: o Confirms no head in the pelvis o Described according to the relation of the fetal sacrum to the maternal pelvis

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Abdominal examination o No head in the lower end o Head up top

Investigations – ultrasound scan Management of a breech presentation in pregnancy: ● ● ●

37 weeks’ onwards, external cephalic version (ECV) If ECV doesn’t work, do a standing CT to determine baby weight and viability of a vaginal delivery Choose birth vaginal or C-section o Good to deliver breech presentation by 41 weeks’

Management of a breech presentation in labour: ●

First stage:

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o Increased risk of premature rupture of membranes o Exclude a prolapse of the cord during vaginal examination o Epidural anaesthetic – normal delivery may change to an operative one quite quickly Second stage: o Delivered by senior obstetrician/midwife o Many different manoeuvres can be used Third stage: o Syntometrine is given with delivery of the head to reduce the risk of PPH o Placenta delivered as normal C section: o Should be done if vaginal delivery is considered too hazardous because: ▪ Mild pelvic contraction ▪ Fetus thought to be over 3.5kg ▪ Fetus in unfavourable attitude ▪ Multiple pregnancy ▪ Other complications e.g. pre-eclampsia or diabetes ▪ Non-descent of the buttocks in labour ▪ Failure of progress in labour

Risk to fetus during delivery: ●

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Hypoxia o Before delivery (prolapsed cord) o At the time of delivery (too slow delivery of the head) Intracranial haemorrhage – subdural and intracranial haemorrhage after too rapid delivery of the head

Shoulder Presentation Transverse lie Aetiology same as other Malpresentations Management: ● ● ●

Before 36 weeks’ ECV Past 37 weeks’, admission and attempt ECV each day If still unsuccessful chose between a stabilizing induction or a C section o Stabilising induction – ECV is done, fetal head held over the pelvic brim and high membrane rupture is performed ▪ Escape of amniotic fluid often cause the head to sink in the pelvis ▪ Labour follows normally

Occipitoposterior Positions Rotates back from occipitotransverse to occipitoposterior during labour Aetiology: ● ● ● ●

Pelvis – flat sacrum with loss of pelvic curve and so loss of room for rotation Uterus – poor or disorganised uterine contractions Head – poor flexion Analgesia – epidural analgesia causes pelvic floor relaxation so too lax for proper rotation of

the head Diagnosis: ●

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Pregnancy: o Abdominal palpation o Head is often not engaged at the time it would expected to be Labour o Abdominal palpation o Vaginal examination

Management: ● ●

In pregnancy = leave alone In labour o Wait and see – many rotate spontaneously o Prepare for a longer labour o Spontaneous labour can happen with Occipitoposterior position but episiotomy will probably be required o If head remains in the occipitotransverse position, consider rotational delivery or C section o Give IV Syntometrine with crowning of the head – increased risk of PPH

Face Presentation As the fetal head gets driven down the birth canal, the front of the head can become extended

Aetiology: ● ● ● ● ●

Lax uterus Multiple pregnancy Polyhydramnios Deflexed fetal head Shape of fetal head o Dolichocephalic (long head) o Anencephalic (no cranium)

Mechanism: ● ● ● ● ●

Head descends with the face leading With descent, most rotate to mentoanterior on the pelvic floor (fetal chin behind the pubis) After further descent, the chin can escape from under the lower back of the pubis and the head is then delivered over the vulva by flexion Normal delivery after In some cases, the fetus rotates from the transverse to the mentoposterior so that the fetal chin is in the curve of the mother’s sacrum o The fetal occiput and back are crushed into each other behind the pubis o Cannot descend further o C-section needed

Diagnosis: ● ●

Abdominal examination Vaginal examination

Management: ●

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In pregnancy: o Wait and see o If pelvis inadequate or fetus oversized, consider C section o Examine vaginally to exclude prolapsed cord In labour: o Mentoanterior = wait o Mentotransverse = manoeuvre or C section o Mentoposterior = C section

Brow Presentation A very poorly flexed head may present the largest diameter of the skull = mentovertex

Diagnosis: ●

Abdomen o Head feels big o Not well engaged o Groove between occiput and neck

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o Head felt on both sides of the fetus Vaginal examination o Anterior fontanelle presents o Supraorbital ridges and base of nose can be felt at edge of field

Management: ●

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In pregnancy o Wait and see o Membranes may rupture early o Examine vaginally to exclude prolapsed cord In labour o Wait and see – can resolve itself o If persists – C section

Induction of Labour A planned initiation of labour Indications: ●

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Maternal disease o Existing before pregnancy e.g. diabetes o Occurring in pregnancy e.g. pre-eclampsia Fetal disease e.g. Rh incompatibility Fetuses at risk from reduced placental perfusion Post-maturity (Term + 10-14 days) SGA Fetal death or abnormality

Use Bishops score to before induction – Bishops score determines success of induction ●

>6 = considered favourable

Before induction a membrane sweep should also be performed ● ●

A circular motion round the edge of the internal os releases prostaglandins Woman may spontaneously into labour within 48 hours

Usual process of induction:

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Give prostaglandin (PGE2) vaginally (pessary or gel) If nothing after 4 hours, repeat prostaglandin and wait another 4 hours If no action after 4 hours, rupture membranes Administer Syntocinon if uterine contraction do not follow closely or if labour becomes prolonged or abnormal

Prostaglandins: ● ●

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Prostaglandins E and F stimulate uterine activity and are involved in the initiation of normal labour Directly affects the uterine muscle cells o Secondary effect = uterus primed with prostaglandins will respond much better to IV Syntocinon Route: o Intravaginal = pessary or gel o Extra-amniotic = catheter passed through the cervix in between the membranes and the uterine sidewall ▪ Prostaglandins released through the catheter Oral = less commonly used because of side effects of GI colic and diarrhoea

Syntocinon: ●

Oxytocin analogue

Artificial rupture of membranes (ARM): ● ● ●

Rupture of the forewaters in order to induce or accelerate labour Carried out with an amnihook The fetal head or presenting part should be firmly engaged before this is attempted

Risk of induction: ● ● ●

Uterine hyperstimulation leading to fetal distress and to a C section Prolonged rupture of the membranes may increase the risk of intrauterine infection Prolonged labour may lead to a C section

Preterm Labour Labour occurring at 1000 ml

Uterine atony: ● ● ● ● ● ●

Massage uterus to stimulate contraction IV Syntocinon Bimanually compress uterus Injection of PGE2α or carboprost directly into uterus Uterine artery embolization Hysterectomy

Partly separated retained placenta: ● ●

Empty bladder If placenta still undelivered 20 minutes after delivery of the baby, manually remove

Tears of the genital tract: ● ●

Suture tear Thorough vaginal examination to determine nature of tear and if there is more than one

Blood clotting defect: ● ●

Coagulation studies Treat underlying problem

Effects of Primary PPH If not corrected it can cause: ● ● ● ●

Death Renal shutdown and subsequent anuria Damage to the pituitary portal circulation ○ Leads to necrosis and Sheehan’s syndrome Postpartum anaemia

Secondary PPH Abnormal vaginal bleeding that occurs 24 hours after delivery Women usually present with: ● ●

Passage of clots Resumption of fresh vaginal bleeding at 7 to 10 days

Causes: ● ● ● ●

Retained pieces of placenta Retained pieces of membrane Retained blood clot Infection of the residual decidua (endometritis)

Clinical findings: ● ● ● ●

Fresh red vaginal bleeding and clots Large uterus Tender uterus Open cervical internal os

Risks: ● ●

Substantial bleeding Infection ○ Septicaemia ○ Blocked fallopian tubes

Treatment: ● ● ●

Admit to hospital IV broad spectrum antibiotics Evacuation of retained products of conception

Massive Blood Loss Haemorrhage of 2 to 3 litres at delivery Treatment = massive haemorrhage protocol

Multiple Pregnancies Twins Type: ●

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Monovular = produced from one ovum fertilized by one sperm ○ Same genetic material ○ Identical twins Binovular = two separate ova fertilised by two different sperms ○ Non-identical twins ○ Different genetic material

Investigations - ultrasound Management of Twins Complications: ● ● ● ●

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Miscarriage is more frequent Preterm labour commoner Increased risk of pre-eclampsia Risk of anaemia increased ○ Iron deficiency ○ Folic acid deficiency Risk of polyhydramnios Risk of antepartum haemorrhage increased: ○ Abruptio placentae ○ Placenta praevia

Management in pregnancy: ● ●

Correct any iron or folic acid deficiency Diagnose early

Complications in labour ● ● ● ●

Delay in delivery of the 2nd twin is associated with higher mortality PPH is more common Prolapse of the umbilical cord more common Mechanical collision of leading parts

Management in labour: ● ● ●

Ensure that first twin is longitudinal If first twin transverse, C section Deliver 2nd twin within 20 minutes of the first

Triplets Rarely due to tri-ovulation Usually binovular twins with one fertilized egg dividing into two individuals or assisted conception. Usually born at an even more immature stage than twins and have double the risks.

The complications and management are as for twins Because of the immaturity of the fetuses, delivery is commonly by Caesarean section...