妇产科学教学课件：正常分娩（5年制英文）

1、1 Normal Labor 2 Objective Definition of labor. Determinate Factors of Labor Anatomical considerations: nThe female pelvis. nThe 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

2、uterus 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 pregn

3、ancy：Postdate pregnancy occurs after 42 weeks . 5 Not sure: 1、Cervix ripend and lower uterine segment development theory； 2、； 3、； 4、 ； 5、Immunologic theory； The Etiology of Labor Maturation of fetus and change of uterus function is necessary. 6 The progress and final outcome of labor are influenced

4、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 forces, which include uterine contraction intra-abdominal pre

5、ssure levator ani muscles contractions. 8 Uterine Contractions Have three unique characteristics: Rhythm: 。 Symmetry and polarity Retraction 9 Periods of relaxation between contractions are essential to the welfare of the fetus. Rhythm Increase in frequency and duration 宫缩宫缩 间歇期间歇期 宫缩宫缩 极极期期 进行 退行 1

6、0 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 uterine segment does not relax to its original length after contractions;rather, it becomes relative fixed at a shorter len

7、gth. 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 to uterine contractions in second stage of labor。 After the placenta has separated,its spontaneous expulsion is aided b

8、y 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 extension and delivery。 Help the expulsion of the placenta。 Levator ani muscles contractions 16 Passage The passage of the fe

9、tus delivery, including: the bony pelvis and soft tissues of pelvis 骶骶 骨骨 Os sacrum 髂髂 骨骨 os ilium 耻骨联合耻骨联合 Symphysis publis 骶骶 尾尾 关关 节节 Sacro-iliac jiont 尾尾 骨骨 Os coccyx 坐骨结节坐骨结节 Os ischium 17 The Bony Pelvis (the true pelvis) Pelvic inlet plane Pelvic midplane Pelvic outlet plane Three pelvic plan

10、e: 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 conjugate The transverse diameter The inclined diameter 20 21 Three anteroposterior diameters of the p

11、elvic 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 interspinous diameter,average 10cm. . Pelvic midplane 23 Anteroposterior diameter of Anteroposterior dia

12、meter of mid pelvismid pelvis Transverse diameter Transverse diameter of mid pelvisof 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 tuberosities。9cm Anterior sa

13、gittal diameter：6cm。 Posterior sagittal diameter ：8.5cm。 Pelvic outlet plane 26 4 1、T 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 the pelvis refers to the curv

14、e 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 Inclination of pelvic 30 31 The soft part of the birth canal Formation of low

15、er 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 lower uterine segment is relat

16、ively 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 the upper segment, the ripened l

17、ower 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分娩过程中宫颈的变化 primigravida multipara Effacement of cervix dilatation of cervix 37 A crook canal formed by the vagina、tissue of

18、 pelvic floor and perineum as the fetal descending. 38 F Passenger 39 Size of the fetus head Very important for delivery。 The vault is composed of 2 frontal bones, 2 temporal bone, 2 parietal bones, and one occipital bone. They are slightly separated from one another at the margins of abutment and b

19、y 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 parietal bone to other. Average 9.3cm. Occipito-frontal diameter：Which follows a line extending from a point just above the

20、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 to the undersurface of the occipital bone just where it joins the neck. Average 9.5cm Occipito-mental diameter：From the chin t

21、o 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 the fetus Fetal position of a particular presentation refers to the relationship of an arbitrary reference point on the fetu

22、s 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 uterine activity and with longer and dysfunctional labor。 46 include these cardinal movements of labor : engagement descent flexi

23、on internal rotation extension external rotation,and expulsion. Mechanism of labor in occiput presentation 47 Engagement 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. 4

24、8 Descent Descent continues progressively until the fetus is delivered;the other movements are superimposed on it. 49 Flexion In 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

25、 occipitofrontal diameter(11.3cm). 50 Internal rotation Internal rotation is a turning of the 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. 51 Extention Extention brings the

26、 base of occiput into direct contact with the inferior margin of the symphysis pubis. 52 Restitution : 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 rotation： The anteri

27、or 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. 53 Flowing these maneuvers, the body,legs,and feet are deliveried. 54 Mechanism of Labor 55 Diagnosis of labor Threatened labor False

28、labor: 1. Contractions occur at irregular intervals.; 2. Intervals remain long; 3. Intensity remains unchanged; 4. Discomfort is chiefly in lower abdomen; 5. Cervix does not dilate; 6. Discomfort is usually relieved by sedation. . 56 Lightenting The settling of the fetal head into the brim of the pe

29、lvis. Bloody Show 57 In labor Onset of labor is spontaneous uterine contraction with progressive dilation of the cervix uterine contraction interval 30 intensity is middle or heavy 58 Total Stage of Labor and Treatment The total stage of labor begins with the regular uterine contractions and ends wh

30、en delivery of the placenta complete. Normal labor is a continuous process which has been divided into three stages for purposes of study. 59 First stage of labor nThe first stage begins with the onset of labor and ends when 60 Second stage of labor Third stage of labor From the birth of the infant

31、to delivery of the placenta 515min, 61 Total stage of labor ：24h First stage of labor （cervical dilation stage） Second stage of labor （fetus expulsive stage） Third stage of labor （placenta expulsive stage） 515min 30min 62 Clinical course and treatment in first stage Chart of labor stage 1,Contractio

32、n and dilation of cervix 63 Acceleration phase:cervical dilation from 3cm to 4cm.1.5h； Maximum acceleration 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 lev

33、el of the presenting fetal part in the birth canal is described in relationship to the ischial spines,which are halfway between the pelvic inlet and the pelvic outlet. 65 Management: Blood pressure、 、cervical dilation、fetus descending、uterine contraction； When the membranes ruptured,please check the

34、 fetal heat rate,fluid colour and amount at once Fetal 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. 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 minute. The woman typ