Preterm Labor

Pregnancy complication Department of gynaecology and obstetrics

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Early pregnancy complication Late pregnancy complication

Late pregnacy complication  

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preterm labor pre mature rupture of membranes （ prom ） prolonged pregnancy RH isoimmunization other blood group incompatiblities Management of the pregnancy with isoimmunization

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Defination pathogenesis Clinical fingdings Laboratory studies Treatment conduct of labor and delivery Prognosis

preterm labor 

Preterm labor is defined as labor occurring after 20weeks’ but before 37 weeks’gestation.

Defination 

Labor is the process of coordinated uterine contractions leading to progress cervical effacement and dilatation by which the fetus and placenta are expelled 。

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1. contractions need to be regular and at frequent intervals 2.cervical effacement or dilation. 3.the uterine contractions need not be painful to cause cervical change and may manifest themselves as abdominal tightening ,lower back pain,or pelvic pressure.

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1.cervical incompentence cerclage placement 2.preterm uterine contracions a self-limited phenomenon that resolve spontaneously and requires no intervention

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Defination pathogenesis Clinical fingdings Laboratory studies Treatment conduct of labor and delivery Prognosis

pathogenesis   

Medical complications Surgical complications Genital tract anomalies

pathogenesis        

A Obstetric complications 1) In previous or current pregnancy 1.Severe hypertensive state of pregnancy 2.Anatomic disorders of the placenta 3.Placental insufficiency 4.Premature rupture of membrance 5.Polyhydramnios or oligohydramnios

pathogenesis 

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2)Previous premature or low birth weight infant 3)Low socioeconomic status 4)Maternal age <18or >40 years 5)Low prepregnancy weight 6)Non caucasian race 7)Multiple pregnancy 8)Short intermal between pregnancies 9)Previou abortion 10)Previous laceration of cervix or ulterus

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B Medical complications 1.Pulmonary or systemic hypertension 2.Renal disease 3.Heart disease 4.infection:pyelonephritis, acute systemic infection, urinary tract infection,genital tract infection,fetotoxic infection,maternal systemic infectin,maternal intra-abdominal sepsis

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5.Heavy cigarette smoking 6.Alcoholism or drug addiction 7Severe anemia 8alnutritin or obesity 9.Leaking benign cystic teratoma 10.Perforated gastric of duodenal ulcer 11.Adnexal torsion 12.Maternal trauma or burns

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C Surgical complications 1. any intra-abdominal procedure 2. conization of cervix 3.previous incision in uterus or cervix D Genital tract anomalies 1.Bicornuate,subseptate,or unicornuate uterus 2.Congenital cervical incompetency

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Defination pathogenesis Clinical fingdings Laboratory studies Treatment conduct of labor and delivery Prognosis

Clinical fingdings   

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1.symptoms and sings A uterine contractions B dilatation and effacement of cervix C vaginal bleeding

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A uterine contractions regular uterine contractions at frequent intervals as documented by tocomenter or uterine palpation,generally more than two in onehalf hour

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B dilatation and effacement of cervix documented cervical change in dilation or effacement of at least 1cm or a cervix that is well-effaced and dilated (at least 2cm) on admission is considered diagnositic the length of cervix is2.5-3cm

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C vaginal bleeding 1.many patients present with bloody mucous vaginal discharge or bloody show. 2.more significant vaginal bleeding should be evaluated for abruption placentae or placenta previa

Normal position of the placenta

abruption placentae

placenta previa

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2 evaluation a gestational age b fetal weight c presenting part d fetal monitoring

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A gestational age gestational age must be between 20 and 37weeks estimated gestation age (EGA)which should be calculatedc by the patient’s last menstrual period （ LMP ） or date of conception ,if known ,or by previous sonographic estimation if these dates are

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B fetal weight care must be taken to determine fetal size by ultrasonography

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C presenting part the presenting part must be noted becauses abnormal presentation is more common in earlier stages of gestation

breech presentation

prolapse of the cord

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D fetal monitoring continuous fetal monitoring should be performed to ascertain fetal well-being.

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3Laboratory studies 1completely blood cout with differential 2.urine obtained 5 speculum examination 4.amniocentesis 3.ultrasound examination 6.fetal fibronectin enzyme immunoassay

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Defination pathogenesis Clinical fingdings Laboratory studies Treatment conduct of labor and delivery Prognosis

Laboratory studies 

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1completely blood cout with differential 2.urine obtained by catheter for urinalysis,culture,and sensitivity testing

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3.ultrasound examination for fetal size ,position,and placental location.

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4.amniocentesis may be useful to ascertain fetal lung maturity in instances where EGA is uncertain,the size of the fetus is in conflict with the estimated data of conception(EDC),or the fetus is more than 34week ‘EGA

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the amniotic fluid should be tested for L/S tatio ， phosphatidyl glycerol （ PG ） level ， lamellar body count

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5 speculum examination should be performed. A wet mount should be performed to look for signs of bacterial vaginosis.

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6.fetal fibronectin enzyme immunoassay kits ， as a means to predict preterm birth in patients with preterm labor.

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Defination pathogenesis Clinical fingdings Laboratory studies Treatment conduct of labor and delivery Prognosis

Treatment  

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1 observation to determine management.

appropriate

a longer period of observation is not desirable ,because the effectiveness of therapy diminishes as labor advances .

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3.decisions regarding management are made based on estimated gestarional age ,estimated weight of the fetus ,and whether contraindications exist to suppresing preterm labor.

factors indicating that preterm labor should be allowed to continue  

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Maternal factors 1.severe hypertersive (eg.acute exacerbation of chronic hypertension,eclampsia,severe preeclampsia ) 2.pulmonary or cardiac diseaes(eg.pulminary edema,adult respiratory distress syndrome,valvular disease,tachyarhythmias)

factors indicating that preterm labor should be allowed to continue     

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Fetal factors 1.fetal death or lethal anomaly 2.fetal distress 3.intrauterine infection(chorioamnionitis) 4.therapy adversely affecting the fetus(eg.fetal distress due to attempted suppression of labor ) 5.estimated fetal weight >2500g 6.erythroblastosis fetalis 7. severe intrauterine growth fetardation

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4. expectant management or intervention . a. 24-34weeks EGA and fetalweight between 600-2500g b. beyond 34-37weeks’EGA and grater than 2500g

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1. bed rest 2.corticosteroids 3. tocolysis 4.antibiotics 5.conduct of labor and delivery

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corticosteroids the administration of corticosteroids to accelerate fetal lung maturity has become the standard of care for all women at risk of preterm delivery between 24-34weeks’ EGA. it has been shown to decrease the incidence of neonatal respiratory distress, Intraventricular hemorrhage ,and neonatal mortalit

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tocolysis goals 1. The shortterm goal is to continue the pregnancy for 48 h after steroid administration,afer which the maximum effect of the steroids can be achieved. 2.The long-term goal is to contiue the pregnancy beyond 34-37weeks ,at which point fetal morbidity and mortality is dramaticallyreduced and tocolysis van be disvontinued.

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1.Tocolytic therapy should be considered in the patient with cervical dilation less than 5cm. 2.successful tocolysis is generally considered fewer than 4-6uterine contractions per h without further cervical change.

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A beta-mimetic adrenergic agent ritodrine terbutaline B magnesium sulfate C Calcium channel blockers Prostaglandin synthetase inhibitors

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Beta-mimetics

effects maternal pulmonary edema

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(ritodrine,

hypotension

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terbutaline)

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Tocolytic

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tachycardia hyperglycemia hypokalemia cardiac arrhythmias

fetal tachycardia hyperglycemia hypoglycemia ileus

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Tocolytic magnesium sulfate

effects maternal flushing mausea/vomiting headache generalized muscle weakness shortness of breath diplopia pulmonary edema chest pain hypotension tetany respiratory depression

fetal lethargy hypotonia respiratory deprssion

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limited by dose –related major cardiovascular side effects, including pulminary edma,adult resporatory distress syndrome,,and both maternal and fetal tachcardia.other dose-related effects are decreased serum potassium and increased blood glucose,

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maternal medical contraindications to the use of beta include cardiac disease,hyperthyroidism ,uncontrolled hypertension or pulmonary hypertension,asthma requieing sympathomimetic drugs,

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B magnesium sulfate it appeara to inhibit calcium uptake into smooth muscle cells ,reducing uterine contractility less effective than rito-drine or terbutaline,magnesium sulfate is better tolerated than beta-mimetics and ,as a result ,has become the first-line agent for tocolysis in many institutions

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monitored closely for signs of toxicity with frequent chesks of deep tendon reflexes ,pulmonary exams.and strict calculations of the patienti’s fluid balance this antidote should be kept at the bedside when this drug is used

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Prostaglandin synthetase inhibitors 1.It has been show to be as effective as ritodrine for tocolysis 2.Their use has been limited by potentially serous fetal effect.

Results of tocolysis therapy  

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due to the progess of labor . 1.if cervical dilatation reaches 5 cm,the treatment should be considerde a failure and abandoned . if labor resumes after a period of quiescence,treatment may be reinstituted using the same or a different drug

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Antibiotic no benefits in delaying preterm birth in this population of patients .

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patients with preterm labor should be stated on antibiotics for prevention of neonatal group B streptococcal infection

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if the patient is well tocolysised and there is no sign of imminent delivery,the group B Streptococcus prophylaxis can be discontinued

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Defination pathogenesis Clinical fingdings Laboratory studies Treatment conduct of labor and delivery Prognosis

conduct of labor and delivery 

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1. samll premature infants should be delivered in a hospotal equipped for neonatal intensive care every effort should be made to avoid fetal hypoxis and intraventricular hemorrhage.adequate hydratin should assist in preventing

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a generoud episiotomy should be made to further reduce the risk of injury. delivery can be aided by forceps with a short cephalic curve if a cesarean is indicated,the decision to operate is based on maturity of the fetus and prognosis for survival.

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in managing the premature newborn infant ,the avoidance of heat loss is of critical importance.

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keep in mind the potential residual adverse effects of these drugs .

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.1.Bta-addreger agents may cause neonatal hypotension,hypoglycemia,hypocalcemi a,and ileus 2.magnesium sulfate may be responsible for respiratory and cardiac depression.in addition,oral maintenace doses of a beta-can produce hypoglycemia in the newborn

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Defination pathogenesis Clinical fingdings Laboratory studies Treatment conduct of labor and delivery Prognosis

Prognosis 

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1.Excellent neonatal care in the delivery room and nursery will do much to ensure a good prognosis for the preterm infant. 2.Lower-bithweight babies have a lesser chance of survial and a greater chance of permancent sequelae in direct relationship to size.

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Asherman’s syndrome is the presence of intrauterine adhesions that typically occur as a result of scar formation after uterine surgery, especially after a dilatation and curettage (D&C). The adhesions may cause amenorrhea (lack of menstrual periods) and/or infertility. DES exposure DES (diethylstilbestrol) exposure during fetal development

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Hypothalamus Anterior pituitary

inhibit

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hold-back ovulation ， when this function is stop ， the Lh peak ， ovulation （ discharge of an ovum from the ruptuing graafian follicle ） ， the Endometriais not suitable for implantation ， so the fertilized ovum move 。