正常分娩(英文)課件

1、1 Normal Labor or Delivery 2ObjectiveDefinition of labor.Determinate Factors of LaborAnatomical considerations:The female pelvis.The fetal skull.The stages of labor.The mechanism of labor (vertex, LOA). Management of normal labor.3Definitions：Labor is the process by which contractions of the gravid

2、uterus expel the fetus and the other products of conception after 28 weeks from the last menstrual period. It begins when uterine contractions of sufficient intensity, frequency & duration are attained to bring about progressive effacement & dilatation of the cervix as well as descent of the present

3、ing part. Spontaneous or inducedTerm or preterm4Term Delivery：A term delivery occurs between 37 and 42 weeks from the last menstrual period.Premature Delivery：Preterm labor is that occurring before 37 weeks of gestational age.Postdate pregnancy：Postdate pregnancy occurs after 42 weeks .5These mechan

4、isms are not well defined in humans.Cervix ripend and lower uterine segment development theory.Endocrine regulating theory.Mechanical theory.Neurohumor theory.Immunologic theory.The etiology of laborMaturation of fetus and change of uterus function is necessary.6The progress and final outcome of lab

5、or are influenced by 4 factors .the powersthe passagethe passenger the psycheFour Determinate Factors of Labor7The Expulsive Forces(The powers) The power that expulse the fetus and the other products of conception is called the expulsive forces, which include Uterine contraction Intra-abdominal pres

6、sure Levator ani muscles contractions. 8Uterine Contractions Have three unique characteristics:Rhythm: increase in frequency and duration,is the important marker of in labor。rhythm Symmetry and polarity Symmetry and polarity Retraction Retraction9Periods of relaxation between contractions are essent

7、ial to the welfare of the fetus.RhythmIncrease in frequency and duration宮縮間歇期宮縮極期進(jìn)行退行10 The intensity of the upper segment of the uterus is the most strong Symmetry and PolarityRetraction12The Intra-Abdominal PressureIt is a necessary auxiliary to uterine contractions in second stage of labor.After

8、the placenta has separated, its spontaneous expulsion is aided by the mother increasing intra-abdominal pressure.13腹肌子宮收縮力膈肌肛提肌14 Form a V-shaped sling that tends to rotate the occipital anteriorly(internal rotation). Help the fetus extension and delivery.Help the expulsion of the placenta. Levator

9、ani muscles contractions15Passage including: the bony pelvis and soft tissues of pelvisTrue vs. false pelvis. True pelvis:Pelvic brim.Pelvic cavity.Pelvic outlet.16骶 骨Os sacrum髂 骨 os ilium 恥骨聯(lián)合Symphysis publis骶 尾 關(guān) 節(jié)Sacro-iliac jiont尾 骨Os coccyx坐骨結(jié)節(jié)Os ischiumbony pelvis17The bony pelvis (the true pe

10、lvis) Pelvic inlet plane Pelvic midplane Pelvic outlet planeThree pelvic plane:18The Pelvic InletShape:Oval & in one plane.Boundaries:Anteriorly: SP.Laterally: upper margin of pubic bone & iliopectineal line.Posteriorly: sacral promontory.Dimensions:AP=11 cmTransverse=13.5 cm.19The true conjugateThe

11、 transverse diameterThe inclined diameter2021Three anteroposterior diameters of the pelvic inlet22The smallest plane of the pelvis, particular importance in obstructed labor.Anteroposterior diameter of mid pelvis,average 11.5cm.Transverse diameter of mid pelvis,alse be called interspinous diameter,a

12、verage 10cm.Pelvic Midplane23Anteroposterior diameter of mid pelvisTransverse diameter of mid pelvis24Transverse diameter of the midpelvis25Four diameters,Anteroposterior, diameter of outlet, 11.5cm。Transverse outlet, the distance between the inner edges of the ischial tuberosities,9cmAnterior sagit

13、tal diameter,6cmPosterior sagittal diameter,8.5cm Pelvic Outlet Plane2641、Transverse outlet2、 Anterior sagittal diameter3、 Posterior sagittal diameter4、 Anteroposterior diameter of outlet 2728Pelvic axis and Inclination of pelvicPelvic axis：The axis of the pelvis refers to the curve of the birth can

14、al as described by a line drawn through the center of each of the four planes.Inclination of pelvic :The angle of the pelvic inlet plane with ground level when women stand.always 60 degree. 29 pelvic axis 骨盆軸 inclination of pelvic 3031The Soft Part of the Birth Canal Formation of lower uterine segme

15、nt,cervix, vagina,soft tissue in the floor of pelvis.32The Lower uterine segment Developed from the isthmus of the uterus of nonpregnant women. Physiologic retraction ring : The actively contracting upper segment becomes thicker as labor advances,the lower uterine segment is relatively thin compared

16、 with the upper segment,between them a physiologic retraction ring appear.333435Changes of cervixEffacement of cervixThe upper segment contracts, retracts, and expels the fetus; in response to the force of the contractions of the upper segment, the ripened lower uterine segment and effacement of cer

17、vix.3637 Dilatation of Cervix In response to the force of the contractions of the upper segment, effacement of cervix and dilatation, through which the fetus can be extruded.38Change of cervix during laborprimigravidamultiparaEffacement of cervixdilatation of cervix39A crook canal formed by the vagi

18、na、tissue of pelvic floor and perineum as the fetal descending.40Fetus(weight,position,presentation, malformation)Fetal weight, 2500g - 4000gFetal lie, the relation of the fetal long axis to that of the mother.Fetal presentation, the presenting part is either foremost within the birth canal or in cl

19、osest proximity to it.LOA LOP LOT ROA ROP ROTPassenger41Size of the fetus head Very important for delivery。The vault is composed of 2 frontal bones,2 parietal bones, 2 temporal bone and one occipital bone. They are slightly separated from one another at the margins of abutment and by wider spaces, t

20、he anterior and posterior fontanelles.42Four diameter of fetus head： Biparietal diameter,The greatest transverse diameter of the head,which extends from one parietal bone to other. Average 9.3cm. Occipito-frontal diameter：Which follows a line extending from a point just above the root of the nose pr

21、ominent portion of the occipital bone. Average 11.3cm.43Suboccipito-bregmatic diameter.Which follows a line drawn from the middle of the large fontanel to the undersurface of the occipital bone just where it joins the neck. Average 9.5cmOccipito-mental diameter：From the chin to the most prominent po

22、rtion of the occiput. Average 13.3cm44Suboccipito-bregmaticoccipito-frontalOccipito-mental diameter4546Position of the fetus Fetal position of a particular presentation refers to the relationship of an arbitrary reference point on the fetus to a specific point in the right or left side of the matern

23、al pelvis.47Psychologic Factors A high level of anxiety during pregnancy has been associated with decreased uterine activity and with longer and dysfunctional labor。48Diagnosis of laborThreatened laborFalse labor:Contractions occur at irregular intervals.Intervals remain long.Intensity remains uncha

24、nged.Discomfort is chiefly in lower abdomen.Cervix does not dilate.Discomfort is usually relieved by sedation.49LightentingThe settling of the fetal head into the brim of the pelvis.Bloody Show The mucus plug is expelled from the cervix mixing with a little blood.50In laborOnset of labor is spontane

25、ous uterine contraction with progressive dilation of the cervix uterine contraction interval 30 intensity is middle or heavy51 Mechanism of normal labor in occiput presentation include these cardinal movements of labor.engagement descentflexioninternal rotationExtensionexternal rotation,and expulsio

26、n. Mechanism of Labor52Engagement The mechanism by which the biparietal diameter,the greatest transverse diameter of the fetal head in occiput presentations,passes through the pelvic inlet is defined engagement.53Descent Descent continues progressively until the fetus is delivered;the other movement

27、s are superimposed on it.54FlexionIn flexion,the chin is brought into more intimate contact with the fetal thorax,and the appreciably shorter suboccipitobregmatic diameter(9.5cm) is substituted for the longer occipitofrontal diameter(11.3cm).55Internal rotation Internal rotation is a turning of the

28、fetus occiput gradually moves from its original position anteriorly toward the symphysis pubis about 45 degrees. Its always finished in the end of the first stage of labor. 56ExtentionExtention brings the base of occiput into direct contact with the inferior margin of the symphysis pubis.57Restituti

29、on The fetus head rotates to the position it occupied at engagement after it deliveried, following this the shoulders descend in a path similar to that traced by the head.External rotationThe anterior shoulder rotates internally about 45 degrees to come under the pubic arch for delivery.The head con

30、tinutly rotates left about 45 degrees to its position at birth.58Flowing these maneuvers, the body,legs,and feet are deliveried.59Duration of Labor and Satges The total stage of labor begins with the regular uterine contractions and ends when delivery of the placenta complete.Normal labor is a conti

31、nuous process which has been divided into three stages for purposes of study. Normal Labor and Delivery60First stage of laborThe first stage begins with the onset of labor and ends when dilation of cervix (10cm) is complete. The average duration of the first stage of labor in a primigravida is 11-12

32、 hours;in a multipara 6-8hours.Clinical finding:Rhythm contractionCervical dilationDescend of presentationRupture of membranes61Clinical course and treatment in first stage Contraction Dilation of cervix and decent of presentation the latent phase ( onset to 6cm, 3cm to 10cm, 1.5-2h)Rupture of membr

33、anes62Management of the first stage:Blood pressure、 fetal heart rate 、cervical dilation、fetus descending、uterine contraction； When the membranes ruptured,please check the fetal heat rate,fluid colour and amount at onceFetal heart rate 120160bpm latent stage 12h fetal heat rate active stage 15-30 minute Need for subsequent vaginal examinations to identify the status of the cervix and the station and position of presenting part will vary considerably.63Second stage of labor The second stage of labor