Abnormal Labor Or Dystocia

Abnormal labor or dystocia

Definition of dystocia Dystocia is characterized by abnormally slow or fast progress of labor, which is caused by the abnormalities of at least one factor of the following: •expulsive forces, or powers •birth tract or passage •fetal itself or fetus

Forces or powers (changeful)

Pelvis

fetus

(changeless

(changeful

or

constant)

or

variable)

Section 1 Abnormalities of expulsive forces

Classification of abnormalities of expulsive forces (or uterine contraction)

Classification: primary Hypotonic uterine dysfunction

order or coordinate (weak tension)

secondary

disorder (strong tension) order ( lead to precipitate labor) Hypertonic uterine dysfunction

all muscle disorder part muscle (narrow ring)

Convulsively contraction ring

Coordinately hypotonic uterine dysfunction

1.Etiology 1).Psychological factors 2).Abnormalities of fetal position or CPD(Cephalo-pelvic disproportion) 3).Uterine factors 4).Disorders of endocrine function 5).Drug 6).Other factors

2.Clinical feature Symptoms: coordinate weaken long interval short duration slow progress of labor

Sigh: uterine wall is not hard dilation of the cervix is delayed speed of the presentation descent is slow labor is prolonged intraamnion cavity pressure is low

Characters of main abnormal labor curves: • Prolonged latent phase: the duration of the latest period is longer than 16 hours. • Prolonged active phase: the duration of the active period is longer than 8 hours. • Prolonged second stage: The duration of the second stage of labor is longed than 2 hours. • Protracted labor: the duration of the whole labor progress is longer than 24 hours. • Precipitate labor: the duration of the whole labor progress is shorter than 3 hours.

3.Management The first stage Strengthen the uterine contraction. The main methods is follow: • amniotomy ( rupture membrane by artificial methods) • oxytocin little amount low degree (2.5u ivgtt) observe the change of UC,FHR,BP • valium 10mg iv

The second stage Strengthen the UC. If the S<+3, take cesarean section (c.s.). If the S>+3, helped labor through the vagina. The third stage of labor Prevent postpartum hemorrhage (use oxytocin 20u im) Prevent puerperal infection (use antibiotic)

Section 2 Abnormalities of the Reproductive Tract (bony canal)

1.Classification •Narrowness of pelvic brim ( flat pelvis) •Narrowness of midcavity and pelvic outlet (Always exist at the same time,such as funnel type pelvis, anthropoid type pelvis ) •Narrowness of all the three pelvic plane (Every diameter is at least 2 cm smaller than normal. It is called generally contracted pelvis.) •Deformities of pelvis

flat pelvis

Funnel pelvis

generally contracted pelvis

Deformities of pelvis

2.Diagnosis History: •Malnutrition or lacking of sunlight in childhood •Rickets •TB •Trauma •Dystocia history

Examination General examination Examination of obstetrics Evaluate the cephalopelvic relationship(CPD) Check whether the fatal head is riding on the symphysis pubis or not (called pubis-riding sign). Measurement of the pelvis

The method of evaluating CPD: Gravida: empty bladder,lie on her back,make two legs straight. Examiner: put one hand on the fetal head press toward the pelvis. Diagnosis of pubis-riding sign: Negative: The head can get into the pelvis, the head surface is lower than that of the symphysis (indicates cephalo-pelvic proportion,CPP). Positive: The fetal head is higher than the symphysis (indicates CPD). Doubtful positive: Two surface is at the same level (indicates doubtful CPD).

Standard of diagnosis: Narrowness of brim: DC<11.5cm. EC<18cm. Narrowness of midpelvis (midcavity): Incisura ischiadica < two flat fingers. Bi-ischial diameter<10cm. Narrowness of outlet: TO<8cm. Sum of TO and posterior sagital diameter of outlet <15cm. Angle of subpubic arch<90 degree. Motion scope of sacro-coccygeal joint should be noted.

3.Management •Obvious CPD or narrowness: Take cesarean section. •Slight CPD or narrowness: Take trial of vaginal delivery. Trial may be successful or failed. The trial time is about 4-6 hours. •Narrowness of midcavity and pelvic outlet: Generally don’t take trial of vaginal delivery. •Deformity pelvis: CS.

Section 3 Fetal Abnormalities

Classification •Abnormalities of fetal presentation: Breech~, face~, shoulder~, brow~, compound~. •Abnormalities of fetal position: Persistent occipito-posterior~, persistent occipito-transverse~, elevated straight~, anterior asynclitism~. •Abnormalities of fetal shape: Macrosomia, monster, hydrocephalus etc.

face presentation

Brow presentation

Persistent occipito-posterior~

elevated straight~

anterior asynclitism~

hydrocephalus

Breech presentation

1.Causes Space of fetal movement in uterine cavity is too large such as multipara, hydramnion. Space of fetal movement in uterine cavity is too small such as twin pregnancy, uterine deformity. Engagement is impeded such as placenta previa, narrowness of pelvis, tumor in the birth tract.

2.Clinical classification Frank breech presentation both hips (coxa) are fully flexed, the knees are extended. Complete breech presentation (or flexed breech) both hips and knees are all flexed Incomplete breech presentation presentation is one foot or two feet, one knee or two knees, one foot and one knee.

3.Diagnosis  The hard, spherical fetal head is felt in the fundal region of the uterus.  FHS are heard above the maternal umbilicus at term..  Ultrasound examination.  When take vaginal examination or rectal examination, we should distinguish foot from hand, breech from face, anus from mouth.

4.management •During pregnancy: Take knee chest position for 15 minutes Bid. Continuous one week. •During labor: Choice or select the method of delivery.Generally take CS.

FINISH

External conjugate

Diagonal conjugate

Transverse outlet

posterior sagital diameter of outlet

Incisura ischiadica

Bi-ischial diameter or interspinous diameter

Angle of subpubic arch

Prolonged latent phase

0

6

12

18

24

Prolonged active phase

0

6

12

18

24

Prolonged second stage

0

6

12

18

24