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NORMAL LABOUR. Prof. OSMAN DONIA. NORMAL LABOUR DEFINITIONS Labor "Tocia": Labor is the process of expulsion of the fetus from the uterus after viability. Viability: Is a reasonable chance of the fetus for extrauterine survival (28 weeks in Egypt, 22 weeks in USA)
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NORMAL LABOUR Prof. OSMAN DONIA Osman Donia
NORMAL LABOUR DEFINITIONS Labor "Tocia": Labor is the process of expulsion of the fetus from the uterus after viability. Viability: Is a reasonable chance of the fetus for extrauterine survival (28 weeks in Egypt, 22 weeks in USA) Normal labor “Eutocia”: Normal labour entails the spontaneous expulsion of a single living full term fetus, in a vertex cephalic presentation, through the natural birth canal after spontaneous onset of true labor pains, without assistance and without complications to the mother or fetus. The average duration of normal labour: 12-18 hours in the primigravida 6-10 hours in the multigravida Osman Donia
INCIDENCE: • It should be noted that “normal labor” is a retrospective diagnosis. The majority of labours are normal however the true incidence is difficult to estimate. • POSITIONS: • Left and Right occipitoanterior (LOA and ROA). • 2. Left and Right occipitotransverse (LOT and ROT). Osman Donia
STAGES OF LABOUR • First stage: From start of labour to full dilatation of cervix. It is divided into latent phase and active phase • Second stage: From full dilatation to birth of baby • Third stage: From the time of delivery of fetus to expulsion of placenta and membranes • Fourth stage: Upto 6hrs after birth to rule out post partum haemorrhage
MECHANISM OF DELIVERY It is the changes in the attidude and position that the foetus undergoes during its passage though the birth canal. A. DELIVERY OF THE HEAD 1- Descent: - A continuous movement throughout labor due to: - Uterine contractions & retractions. - Auxiliary force in the 2nd stage of labor. - Straightening of the fetus caused by contraction & retraction of the uterus. 2- Engagement: Is the passage of the widest transverse diameter of the presenting part through the plane of the pelvic inlet.In cephalic presentation it is the passage of the biparietal diameter through the plane of the pelvic brim. Osman Donia
3- Increased flexion: When the head meets resistance during its descent, the force applied on the sinciput is greater than that on the occiput leading to increased flexion. It is explained by the two armed lever theory, where the head is represented bytwo armes of unequal lengths: - A shortarm : extends from the occiput to the atlanto-occipital joint. - A longarm : extends from the sinciput to the atlanto-occipital joint. Results of increased flexion: - The head enters the pelvis with the smallest suboccipito-bregmatic diameter (9.5 cm). - The occiput meets the pelvic floor first preparatory to internal rotation. - The part of the head occupying the plane of the greatest dimensions is like a circle, as the biparietal & suboccipito-bregmatic diameters are both equal (9.5 cm). This will facilitate internal rotation of the head. Osman Donia
4- Internal rotation: This means anterior rotation of the occiput 1/8th of a circle (45°) as it meets the pelvic floor first. It occurs at the level of the plane of the greatest pelvic dimensions Internal rotation is explained by: -Direction of the forward sloping gutter of the levator ani muscles. The direction of the gutter is downwards forwards and medially. -Rifling action of the pelvis : The largest available diameter at the inlet is the oblique, while at the outlet is the antero-posterior diameter. %90of cases of occipitoposterior rotate 3/8th of a circle to become occipito-anterior. These cases will be delivered as in occipito-anterior. Osman Donia
5- Extension: The suboccipital region hinges under the symphysis pubis. The head is acted upon by 2 forces at this level in the pelvis: Downward & forwardforce of the uterine contractions, Upward & forwardforce of the pelvic floor. The net result is passage of the head forward i.e. extension. 6- Restitution: The occiput rotates 1/8th of a circle in an opposite direction to internal rotation, to undo the twist of the neck caused by internal rotation. 7- External rotation: Rotation of the occiput 1/8th of a circle in same direction as restitution. It is due to internal rotation of the anterior shoulder, 1/8th of a circle from the oblique to the anteroposterior to the posterior diameter Osman Donia
B. DELIVERY OF THE SHOULDERS AND BODY • - The anterior shoulder hinges below the symphysis. • The posterior shoulder is delivered first by lateral flexion • of the spine. • The anterior shoulder then follows, then the rest of the • body. Osman Donia
Cardinal Movements of Normal Delivery Osman Donia
FRIEDMANNS CURVE Progress in labour
Engagement and descent • Fetal head descends through the birth canal • Defined relative to the ischialspinIsssssches • 0 station = top of head at the spines (fully engaged) • +2 station = 2 cm past (below) the ischial spines
Abdominal examination • Vertex, breech or transverse lie • Palpate vaginally • Leopold’s Maneuvers
MANAGEMENT OF LABOUR Initial Assessment History Onset of labour pains and their quality. Presence of show & escape of liquor. In case of ROM: its colour and amount. Presence and pattern of foetal movement. General Examination Pulse, Blood pressure, and Temperature Degree of anxiety. Degree of dehydration Observation of height and weight. Osman Donia
Abdominal examination • Frequency, duration and intensity of uterine contraction • To determine the lie, presentation and position. • Engagement of the presenting part • F.H.S. (site, rate, rhythm) • The foetal heart sounds should be checked especially at the end of a contraction and immediately thereafter, to identify pathological slowing of the heart rate. Osman Donia
Vaginal examination: - To exclude contracted pelvis. - To assess dilatation and effacement of the cervix. - To determine foetal presenting part (presentation, Position, and degree of flexion). - To detect condition of membranes and if ruptures the presence or absence of meconium. - Presence of prolapse of the cord. Station of the presenting part: When the lowest part of the fetal head is felt at the level of the ischial spines, this is called zero station. Station + 1, +2 & +3, means that the lowest part of the head is 1,2 or 3 cm lower than the ischial spines. Station -1, -2 & -3, means the lowest part of the head is 1,2 or 3 cm higher than the ischial spines. Osman Donia
Frequency of vaginal examination: This depends on the obstetrician, but at least it is done twice; - At the start of labor. - If rupture of membranes occurs to exclude cord prolapse. Electronic FHR monitoring: (CST): Done during and inbetween uterine contractions whenever indicated. Osman Donia
MANAGEMENT OF THE 1ST STAGE OF LABOR Preparation Antisepsis:The vulva is shaved & cleaned with an antiseptic. Evacuation of the bladder & rectum: - This is done to prevent reflex uterine inertia. - The bladder is evacuated by frequent micturition or by a catheter. - The rectum is evacuated by an enema, which also prevents contamination. Osman Donia
2. Observation: For the mother, fetus, and progress of labour a. The mother:for - Pulse, blood pressure, temperature and respiratory rate. - Uterine contractions: § Contractions are observed for frequency, strength and duration; § By the palm of the hand applied on the abdomen. § By a toco-dynamometer i.e. a deviceapplied on the abdomen . - Cervical dilatation. - Descent of the fetus i.e. pelvic station. - Rupture of membranes. b. Fetal heart sounds (FHS): - Normally the FHS are regular with a rate of 120-160 beats / minute. - The aim of auscultating the FHS is to detect fetal distress e.g. bradycardia. - Methods of detection of the FHS: § Intermittent by the sonicaid or Pinard stethoscope every 30 minutes. § Continuous electronic monitoring is indicated in high-risk cases. Osman Donia
3. Nutrition: - Early in labor i.e. in the latent phase, oral sugary fluids are given. - In the active phase, oral feeding is avoided, as delayed gastric emptying may lead to vomiting & aspiration if general anesthesia is needed at any time "Mendelson syndrome" - If labor is prolonged more than 8 hours, IV fluids as glucose 5% and saline are given. 4. Pain relief: - Pethidine 50 mg IM is commonly used. Pethidine causes fetal respiratory depression & should be stopped 2 hours before the 2nd stage of labor, to avoid fetal respiratory depression at birth. - Epidural analgesia is an alternative. Osman Donia
5. Instructions: • - If the membranes are ruptured: Rest in bed in the lateral position. • - If the membranes are intact: • - Walking is allowed in between uterine contractions. • Straining (bearing down) should be avoided because: • § It is useless & exhausts the patient. • § It predisposes to genital prolapse. Osman Donia
“Partogram” This is a graphic record of labour which allows an instant visual assessment of the rate of cervical dilatation against an expected norm according to parity of the women so that active management can be instituted immediately. Other observations can be recorded on the chart as the frequency and strength of contractions the descent of the head, timing of rupture membranes, medications given and the basic observations as the blood pressure, pulse rate and temperature. Figure for partogram Osman Donia
MANAGEMENT OF THE 2ND STAGE OF LABOR Identification of the 2nd stage: 1-Full dilatation of the cervix (10 cm or 5 fingers): The most sure sign. 2-Desire of the patient to evacuate the rectum. 3-Reflex desire to bear down. 4-Bearing down is accompanied by an expiratory grunt. 5-Rupture of membranes: - In 1st stage, the amniotic sac is divided by contact of the headand cervix into (A): The bag of hind-waters (B): The bag of fore-waters i.e. the head forms a ball valve mechanism between both bags. - After full cervical dilatation,The hind & fore-waters become continuous leading to increased pressure in the fore-waters & rupture of membranes. - It should be noted that rupture of membranes may occur early before the 2nd stage of labor. Osman Donia