正常分娩(英文)(课堂PPT)

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

2、erus expel the fetus and the other products of conception after 28 weeks from the last menstrual period. Term Delivery：A term delivery occurs between 37 and 42 weeks from the last menstrual period.,4,Premature labor：Preterm labor is that occurring before 37 weeks of gestational age. Postdate pregnan

3、cy：Postdate pregnancy occurs after 42 weeks .,5,Not sure: 1、Cervix ripend and lower uterine segment development theory； 2、Endocrine regulating theory； 3、Mechanical theory； 4、Neurohumor theory ； 5、Immunologic theory；,The etiology of labor,Maturation of fetus and change of uterus function is necessary

4、.,6,The progress and final outcome of labor are influenced by 4 factors . (1)the powers (2)the passage (3)the passenger (4)the psyche,Four Determinate Factors of Labor,7,The expulsive forces(The powers),The power that expulse the fetus and the other products of conception is called the expulsive for

5、ces, which include uterine contraction intra-abdominal pressure levator ani muscles contractions.,8,Uterine contractions,Have three unique characteristics: Rhythm: increase in frequency and duration,is the important marker of in labor。 Symmetry and polarity Retraction,9,Periods of relaxation between

6、 contractions are essential to the welfare of the fetus.,Rhythm Increase in frequency and duration,宫缩,间歇期,宫缩,极期,进行,退行,10,Characteristic of normal uterine action,11,Symmetry and Polarity The intensity of the upper segment of the uterus is the most strong,12,Retraction:The myometrium of the upper uter

7、ine segment does not relax to its original length after contractions;rather, it becomes relative fixed at a shorter length.,13,The intra-abdominal pressure,Created by contraction of the abdominal muscles simultaneously with forced respiratory efforts with glottis closed. It is a necessary auxiliary

8、to uterine contractions in second stage of labor。 After the placenta has separated,its spontaneous expulsion is aided by the mother increasing intra-abdominal pressure。,14,腹肌,子宫收缩力,膈肌,肛提肌,15, Form a V-shaped sling that tends to rotate the occipital anteriorly(internal rotation)。 Help the fetus exten

9、sion and delivery。 Help the expulsion of the placenta。,levator ani muscles contractions,16,Passage The passage of the fetus delivery, including: the bony pelvis and soft tissues of pelvis,骶 骨 Os sacrum,髂 骨 os ilium,耻骨联合 Symphysis publis,骶 尾 关 节 Sacro-iliac jiont,尾 骨 Os coccyx,坐骨结节 Os ischium,17,The

10、bony pelvis (the true pelvis) Pelvic inlet plane Pelvic midplane Pelvic outlet plane,Three pelvic plane:,18,Pelvic inlet plane Have three diameters:,(1)Anteroposterior diameter or The true conjugate: average 11cm. (2)Transverse diameter:average 13cm. (3)Inclined diameter:average 12.75cm,19,The true

11、conjugate,The transverse diameter,The inclined diameter,20,21,Three anteroposterior diameters of the pelvic inlet,22,The 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 in

12、terspinous diameter,average 10cm.,Pelvic midplane,23,Anteroposterior diameter of mid pelvis,Transverse diameter of mid pelvis,24,Transverse diameter of the midpelvis,25,Four diameters: Anteroposterior: diameter of outlet： 11.5cm。 Transverse outlet： the distance between the inner edges of the ischial

13、 tuberosities。9cm Anterior sagittal diameter：6cm。 Posterior sagittal diameter ：8.5cm。,Pelvic outlet plane,26,4,1、Transverse outlet 2、 Anterior sagittal diameter 3、 Posterior sagittal diameter 4、 Anteroposterior diameter of outlet,27,28,Pelvic axis and inclination of pelvic Pelvic axis：The axis of th

14、e pelvis refers to the curve of the birth canal 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,骨盆轴,Inclination of pelvic,30,31,The soft part of t

15、he birth canal Formation of lower uterine segment、cervix、 vagina 、soft tissue in the floor of pelvis.,32,The 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

16、 lower uterine segment is relatively thin compared with the upper segment,between them a physiologic retraction ring appear.,33,34,Changes of cervix Effacement of cervix dilatation of cervix The upper segment contracts, retracts,and expels the fetus; in response to the force of the contractions of t

17、he upper segment, the ripened lower uterine segment and cervix dilate and thereby form a greatly expanded、thinned-out muscular and fibromuscular tube through which the fetus can be extruded.,35,36,分娩过程中宫颈的变化,primigravida,multipara,Effacement of cervix,dilatation of cervix,37,A crook canal formed by

18、the vagina、tissue of pelvic floor and perineum as the fetal descending.,38,Fetus ( position ,presentation, weight) Long axis of mother LOA LOP LOT ROA ROP ROT Estimation of fetal weight :2500g - 4000g,Passenger,39,Size of the fetus head,Very important for delivery。 The vault is composed of 2 frontal

19、 bones,2 parietal bones,and one occipital bone. They are slightly separated from one another at the margins of abutment and by wider spaces, the anterior and posterior fontanelles.,40,Four diameter of fetus head： Biparietal diameter：The greatest transverse diameter of the head,which extends from one

20、 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 prominent portion of the occipital bone. Average 11.3cm.,41,Suboccipito-bregmatic diameter. Which follows a line drawn from the middle of the large fontanel t

21、o the undersurface of the occipital bone just where it joins the neck. Average 9.5cm Occipito-mental diameter：From the chin to the most prominent portion of the occiput. Average 13.3cm,42,Suboccipito-bregmatic,occipito-frontal,Occipito-mental diameter,43,Fetal Skull,Vault. Face. Base.,44,Position of

22、 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 maternal pelvis.,45,Psychologic Factors A high level of anxiety during pregnancy has been associated with decreased uter

23、ine activity and with longer and dysfunctional labor。,46,Diagnosis of labor Threatened labor False labor: Contractions occur at irregular intervals.; Intervals remain long; Intensity remains unchanged; Discomfort is chiefly in lower abdomen; Cervix does not dilate; Discomfort is usually relieved by

24、sedation.,47,Lightenting The settling of the fetal head into the brim of the pelvis. Bloody Show The mucus plug is expelled from the cervixmixing with a little blood,48,In labor Onset of labor is spontaneous uterine contraction with progressive dilation of the cervix uterine contraction interval 30

25、intensity is middle or heavy,49,Mechanism of labor Mechanism of normal labor in occiput presentation include these cardinal movements of labor : engagement descent flexion internal rotation extension external rotation,and expulsion.,50,Engagement The mechanism by which the biparietal diameter,the gr

26、eatest transverse diameter of the fetal head in occiput presentations,passes through the pelvic inlet is defined engagement.,51,Descent Descent continues progressively until the fetus is delivered;the other movements are superimposed on it.,52,Flexion,In flexion,the chin is brought into more intimat

27、e contact with the fetal thorax,and the appreciably shorter suboccipitobregmatic diameter(9.5cm) is substituted for the longer occipitofrontal diameter(11.3cm).,53,Internal rotation Internal rotation is a turning of the fetus occiput gradually moves from its original position anteriorly toward the s

28、ymphysis pubis about 45 degrees. Its always finished in the end of the first stage of labor.,54,Extention Extention brings the base of occiput into direct contact with the inferior margin of the symphysis pubis.,55,Restitution : The fetus head rotates to the position it occupied at engagement after

29、it deliveried,following this the shoulders descend in a path similar to that traced by the head. External rotation： The anterior shoulder rotates internally about 45 degrees to come under the pubic arch for delivery.The head continutly rotates left about 45 degrees to its position at birth.,56,Flowi

30、ng these maneuvers, the body,legs,and feet are deliveried.,57,Mechanism of Labor,58,Total Stage of Labor and Treatment The total stage of labor begins with the regular uterine contractions and ends when delivery of the placenta complete. Normal labor is a continuous process which has been divided in

31、to three stages for purposes of study.,59,First stage of labor The 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 hours;in a multipara 6-8 hours.,60,Second stage of labor The

32、second stage of labor extends from full dilation of the cervix to the birth of baby and varies from a few minutes to about two hours depending on both fetal and maternal factors. primigravida 2h multipara 1h Third stage of labor From the birth of the infant to delivery of the placenta 515min, 30min,

33、61,Total stage of labor ：24h First stage of labor （cervical dilation stage） primigravida is 11-12 multipara 6-8 hours. Second stage of labor （fetus expulsive stage） primigravida is 1-2 h multipara few minutes Third stage of labor （placenta expulsive stage） 515min 30min,62,Clinical course and treatme

34、nt in first stage 1,Contraction and dilation of cervix,Chart of labor stage the latent phase ( onset to 3cm to 10cm, 8h) 2,Decent of presentation 3,Rupture of membranes,63,The active phase have been divided into three stages； Acceleration phase:cervical dilation from 3cm to 4cm.1.5h； Maximum acceler

35、ation phase: cervical dilation from 4cm to 9cm，2h; Deceleration phase: cervical dilation from 9cm to 10cm ，30min。,64,The decent of the fetal head is measured to assess the progress of labor The level of the presenting fetal part in the birth canal is described in relationship to the ischial spines,w

36、hich are halfway between the pelvic inlet and the pelvic outlet.,65,Management: 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 once Fetal heart rate 120160bpm latent sta

37、ge 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.,66,Management of second stage of labor Manifestation Uterine contraction may last 1.5 minutes and recur at times after a resting phase of no more than a