Abnormal labor and Dystocia Soochow university Xu Jianying

Abnormal Labor : Dystocia Abnormal labor ,also called dystocia. When we last talked about childbirth ,there are four major influencing factors. When one or more factors abnormal or uncoordinated as abnormal labor. that may exist singly or in combination.

Definition Generally, abnormal labor is very common whenever there is disproportion between the presenting part of the fetus and the birth canal. Dystocia literally means difficult labor and is characterized by abnormally slow progress of labor.

Categories of dystocia According to the factors divided to 3 types Abnormalities of the powers (uterine contractility and maternal expulsive effort) either uterine forces insufficiently strong or inappropriately coordinated to efface and dilate the cervix — uterine dysfunction — or inadequate voluntary muscle effort during the second stage of labor.

Categories of dystocia Abnormalities of passenger (the fetus) excessive fetal size , malpositions ,congenital anomalies , multiple gestation Abnormalities of the passage (the birth canal) pelvic contraction , soft tissue abnormalities of the birth canal , masses or neoplasia , aberrant placental location

1.Abnormalities of the powers Uterine dysfunction hypotonic primary uterine inertia secondary Uterine hypertonic Dysfunction uterine hypercontractility

Abnormalities of the powers -----uterine inertia 1.Etiology of uterine inertia Cephalopelvic disproportion or Fetal malposition Abnormal of uterine muscle psychical-factors Imbalance of endocrine system Administration of analgesia Others

Cephalopelvic disproportion or Fetal malposition The fetal head or presenting part could not close presses to the cervix and lower uterine segment. fetopelvic disproportion arises from diminished pelvic capacity, excessive fetal size, or malpresentation Failure to progress in either spontaneous or stimulated labor .This term is used to include lack of progressive cervical dilatation or lack of fetal descent.

Abnormal of uterine muscle Uterine muscle malfunction can result from uterine overdistention or obstructed labor, or both. Muscle fiber excessive elongation and contractility decline . Polyhydramnios , macrosomia, Multiple births (twins). Muscle fiber degeneration (Past history of repeat uterus infection , abortion , induction of labor ,or operation), myoma , pelvic tumors, myogenic dysplasia or malformed uterus (didelphus uterus , unicornous uterus ).

psychical-factors Fearing labor pain , anxiety, tension Worried about fetal safety, labor hemorrhage, injury and dystocia which eventually lead to Uterine dysfunction and occur uterine inertia

Other factors hormonal mechanism of uterine activity (deficiency of oxytocin , estradiol, prostaglandin) excessive sedation ,anesthesia ,unripe cervix fatigue , early abdominal pressure, overactive bladder filling (fetal presentation descent) .

2.Clinical findings hypotonic uterine dysfunction (coordinated): Although there are still normal uterine contraction and maintain the polarity , symmetry, and a certain rhythm, but the contraction is weak and feeble, with short duration , long Interval and irregular. when the contractions in the acme, no uterus uplift and stiffen.

When uterine contractions: the intrauterine pressure in the lower, and often <15 mmHg, As a finger pressing on the fundus of uterus a depression could appear Maternal relative quiet , prolonged process. (painless or can endure ) fetal heart rate changes lately (no anoxia or lately)

2.Clinical findings hypertonic uterine inertia and Uncoordinated contractions : often occur together ,elevated resting tone of the uterus the exciting site of contraction is not from the horn of uterus, and in a particular or multiple site, and with uncoordinated rhythm, polarity inversion

when uterine contracts the fundus is no firm, and the mid or lower uterine segment harder than that. The uterus can not be completely relaxed, uterine cavity pressure lasting with higher state, but the cervix no dilation and fetal head no descent progressively Maternal lasting abdominal pain and fidgety fetal heart rate changes early (anoxia)

2.Clinical findings Failure to progress Lack of progressive cervical dilatation (primiparas) Prolonged latent phase >16hs Prolonged active phase >8hs , cervix dilation<1.2cm/hs Protracted active phase >2hs Prolonged second stage >2hs

Lack of fetal descent Prolonged descent >1cm/h Protracted descent >1h Prolonged labor >24hs (the total stage of labor)

Labor-process range plan

4.Effect on maternal and fetus maternal fatigue (Prolonged progress) acidosis , or dehydration infection (Prolonged progress , prom) postpartum hemorrhage (insufficient contractility) cesarean section rate laceration fetus distress , (uterine blood flow and fetal oxygenation ) birth injury ,Intracranial trauma (obstructed labor , rare) prolapse of umbilical cord stillbirth

5.management Hypotonic: the rule of treatment--Strengthen contractions and prevent PPH the first stage of labor General management : rest, eat more liquid food ,sedation, correct acid , intravenous injection Physical methods: massage uterus , emptying the bladder stimulation nipple , artificial rupture of membrane (AROM) enema

diazepam 10mg iv Drugs : (Softening the cervix) oxytocin 2.5U + 5%GS 500ml ( 5mU/ml ,8drop／min, at the begining) diazepam　10mg iv (Softening the cervix)

Cesarean section : Following the above management still ineffective or fetal distress

The second stage of labor Forceps or vacuum extractor : second stage of labor ,cervical fully dilated, membranes ruptured and fetal survival, presenting part below the level of ischial spine Cesarean section : presenting part upward the level of ischial spine or fetal distress

Hypertonic: the rule of treatment-- Adjusted contractions and resume a normal polarity and rhythm Sedative: Dolantin or Morphine for adjusted and resume to a normal contractions Cesarean section Otherwise

Abnormalities of the powers ----- uterine hypercontractility 1.Clinical findings and diagnosis Coordinated uterine hypercontractility : uterine contraction is normal and maintain the normal polarity , symmetry, and a certain rhythm, but the intensity strength and frequency enhanced the contraction with : long duration , short Interval

precipitate delivery ( multiparas ) the total stage of labor <3hs , The process of labor is too fast Birth injuries lacerations of the soft birth canal fractures, intracranial hemorrhage of the newborn Postpartum hemorrhage, uterine inversion, Infections, fetal distress, death

2.Effect on maternal and fetus rupture of uterus PPH , infection soft birth canal trauma fetal distress fetal death stillbirth

3.management Prophylaxis reduced obstetric brutal operation. Must be gentle , slightly and carefully Tocolytic therapies sedatives inhibited contractions : meperidine, magnesium sulfate. Forceps , Vacuum extractor Cesarean section.

1)forceps operations 2)Vacuum extractor

3)Cesarean section

Abnormalities of passage the birth canal pelvic contraction , soft tissue abnormalities of the birth canal , masses or neoplasia , aberrant placental location

Contractions of the pelvic Bony pelvis a main composing part of birth canal ,its size and shape have the direct relation to the course of labor and delivery. Any contraction of pelvic diameter that diminishes the capacity can create dystocia. There may be contractions of the pelvic inlet, the midpelvis, the pelvic outlet, or a generally contracted pelvis caused by combinations of these.

Contracted pelvic inlet 1.simple flat pelvis promontory of sacrum ( dotted line ) forward dislocation 2.rachitic flat pelvis (past history of rickets)

Contracted pelvic inlet Clinical findings: Fetopelvic disproportion , malposition or malpresentation face and shoulder presentations are encountered three times more frequently uterine inertia and prolonged progress of labor prolonged latent phase , early active phase and protracted active phase cord prolapse ( loophole) occurs four to six times more frequently

Midpelvic—outlet contraction Funnel shaped pelvic the spines are prominent, the pelvic sidewalls converge

Midpelvic—outlet contraction Clinical findings: Fetopelvic disproportion persistent occiput posterior position or deep transverse arrest , molding of head and caput succedaneum protracted active phase or prolonged second stage secondary uterine inertia Uterine rupture , perineal tears obstructed labor

Generally contraction pelvic Each pelvic plane is 2cm less than normal value or more Can be seen in shape more short and small , well-balanced women of type of figure.

Diagnosis A history of Rickets, bone tuberculosis, polio or pelvic fracture (warrants careful review of previous radiographs and possibly computed tomographic pelvimetry later in pregnancy). Physical examination height, spine, lower limb disability (Height <150cm , lateral curvature usually associated with contracted pelvis)

Diagnosis Pelvic measurement external pelvimetry internal pelvimetry sterile vaginal examination

Diagnosis Pelvimetry diagonal conjugate 12.5~13cm bi-ischial diameter 10cm incisura ischiadica 5~6cm angle of subpubic arch 900

Diagnosis The fetal position and dynamic monitoring of labor after onset of labor ,in primipara ,fetal head unengagement ,breech, shoulder presentation; birth process has been slow. (Prompt the contraction of pelvis)

management Trial labor under the effective uterine contractions observed the progress of labor There is no reliable method for evaluating the adequacy of the lower pelvic, the sterile vaginal examination should be performed early in the course of labor. with continuous fetal monitoring ,fetal well-being may be ensured

management true inlet contracted : cesarean section Midpelvic—outlet contraction: fetal head biparietal diameter reached the level of the spines, and can be depressed farther ,the fetal presentation beyond station plus 2 , vaginal delivery usually is possible .midwifery.  otherwise cesarean section. Administration of oxytocin should avoided in true Midpelvic—outlet contraction

management Generally contraction pelvic term fetus (birthweight > 3000g) needed cesarean section The fetus is not big , fetopelvic is adaptation and without complication can try to labor Deformed pelvic cesarean section

Soft--tissue dystocia Soft tissue canal :lower part of uterus, cervix, vagina previous scar of the birth canal laceration , cervic conization and cauterization , cesarean section , rape injury in a small child , or caustic abortifacient injury to vaginal vault and cervix. Previous scaring of the birth canal may cause tissue rigidity and dystocia . cesarean section is generally required

Abnormalities of passenger Fetal dystocia caused by malposition or malpresentation , excessive size of the fetus ,or fetal malformation. If no disproportion exists, the head readily enters the pelvis, and vaginal delivery can be predicted.

malposition and malpresentation a. vertex malposition persistent occiput posterior persistent occiput transverse 5% sincipital presentation 1.08% anterior asynclitism posterior asynclitism 0.5%~0.81% b. brow presentation 0.03%~0.1% c. face presentation 0.08%~0.27% d. breech presentation 3%~4% e. abnormal fetal lie transverse or oblique lie 0.25%

Persistent occiput posterior or transverse position (POP, POT) Definition : Up to later stage of delivery the occiput can’t rotate anteriorly , persistent occiput posterior (POP) or transverse position (POT). Most often , the result of malrotation of occiput anterior position during labor(2/3). Etiology : Abnormal pelvic Anthropoid and android , transverse narrowing of the midpelvis , the fetal head often engages in OP or OT

Etiology Bad flexion fetal backbone near the maternal backbone , which disadvantages fetus flexion . Uterine inertia influence fetal descent , flexion , internal rotation . Cephalopelvic disproportion the pelvic cavity is narrow , which limits fetal descent , flexion , internal rotation . Others placenta praevia , filling of bladder ,myoma

Clinical finding Symptoms Fetal head engages later at the onset of labor Concordant uterine inertia and slow dilatation of cervix ,induces prolonged active phase or second stage Early use abdominal pressure before the cervix full dilate

Treatment The first stage Strengthen contractions , trial labor Latent phase: sufficient rest and nourishment . ( Pethidine or diazepam ) Active phase: AROM cervix 3-4cm , membranes intac . To induce fetal head descending , strengthen contraction , and internal rotation . Oxytocin intravenous drip infusion (small dose , 2--2.5u) Cesarean section after treatment the labor is still not progressing or fetal distress occurs

The treatment of the second stage Midwifery BPD arrive the ischial spine plane or below , s> +2 , to rotate the occiput to OA , vaginal delivery forceps Cesarean section fetal head is much high or CPD

The treatment of the third stage To prevent PPH prolonged labor readily cause bleeding of uterine inertia . Oxytocin large dose , intravenous drip infusion (20u) Suture lacerations Antibiotic

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