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PRETERM LABOUR

PRETERM LABOUR. Dr. Sally Mary Abraham Professor. DEFINITION :- - Preterm labour is defined as onset of labour between 28 to 37 completed weeks.

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PRETERM LABOUR

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  1. PRETERM LABOUR Dr. Sally Mary Abraham Professor

  2. DEFINITION:- - Preterm labour is defined as onset of labour between 28 to 37 completed weeks. • Occurrence of regular uterine contractions one in 10mins. with cervical changes (effacement equal to or greater than 80% and dilatation equal to or greater than 2cm). • The lower limit in developing countries is 28 weeks whereas in developed countries is 20 weeks or fetus weighing more than 500gms. • INCIDENCE: 6-15%

  3. Etiology: In about 50%, the cause of preterm labour is not known. I- Complications in present pregnancy : Maternal : • Genital tract infection(12.25%)- Bacterial vaginosis, beta hemolytic streptococcus, bacteroides, Chlamydia and mycoplasma. • Pregnancy complications – preeclampsia(12%), antepartum hemorrhage(3%),premature rupture of membranes(35%), polyhydramnios(3.4%). • Uterine anomalies such as malformation of uterus(1-3%), cervical incompetence(5%).

  4. Medical or surgical illness- fever, acute pyelonephritis, diarrhea, acute appendicitis, toxoplasmosis. chronic diseases such as hypertension, nephritis, Diabetes, decompensated heart lesion, severe anemia(13.2%), low body mass index. Fetal- multiple pregnancy(4.1%),congenital malformations(1%), intrauterine death. Placental – infarction, thrombosis, placenta praevia or abruption.

  5. II. Others: There is an increased incidence of preterm labour in cases such as - previous history of induced or Spontaneous abortion(14.4%) or preterm delivery(14.3% after 1 prev preterm and 28% after 2). • Asymptomatic bacteriuria or recurrent urinary tract infection(8.4%). • Cigarette Smoking is associated 1.2 to 2 fold risk of preterm delivery, 2-5 fold risk of preterm prematurely ruptured membranes and 1.5-3.5 fold risk of fetal growth restriction. • Low Socio – economic and nutritional status.

  6. III. Iatrogenic – Elective induction with wrong estimation of gestational period. IV. Idiopathic- premature effacement of the cervix with hyper- irritable uterus and early engagement of the head are often associated.

  7. ( CRH,  cortisol) •  PGE2, f2α •  TXA2, leukotrienes •  PG dehydrodenase •  proteases • Chorio decidual bacterial colonisation • ( TNF, IL-1,6,8) Etiopathogenesis of preterm labour. • Activation of fetal HPA axis. Chorion, amnion and decidua • Pathologic uterine enlargement • (Polyhydramnios, multiple pregnancy) •  mechanical stretch,  IL – 8 •  gap junction,  PG synthetase •  myometrial contraction • Cervical ripening Preterm labour & delivery

  8. Warning symptoms &signs of preterm labour: • Menstrual like cramps (constant or recurrent), just above the pubic bone. • Low, dull backache (constant or recurrent) • Pressure(feels like the baby is pushing down, feels heavy) • Abdominal cramping (with or without diarrhea) • Increase or change in vaginal discharge (may be mucous, watery, blood stained). • Fluid leaking from the vagina. • Uterine contractions that are 10 or less minutes apart. • Short cervix (the distance between the insertion of the vagina in the anterior or the posterior aspect of the cervix and the external cervical os is less than 1cm). • Lower uterine segment thinned and presenting part deep in the pelvis.

  9. Predictors of Preterm labour: • If the ultrasound shows a cervical length less than 2.5 cm, the women is at high risk for preterm delivery. • Presence of fibronectin in the cervicovaginal discharge between 24-34 weeks is a predictor of preterm labour. Fibronectin- it is a glycoprotein that binds fetal membranes to the decidua.It is normally present in the cervicovaginal secretions before 22 weeks and after 37 completed weeks. When the normal interrelation between the chorioamnion and the decidua is altered because of contractions or infections, fibronectin is released and appears in the cervicovaginal secretions.

  10. If the amount of cervicovaginal fibronectin is <50ng/ml (negative result), the woman is at low risk of preterm delivery .when the test is negative it reassures that delivery will not occur within next 7 days or within 2-3 weeks. • If the test is positive > 50ng/ml, the risk of preterm delivery in the following 2 weeks is approximately 35% • Sexual intercourse, speculum or digital examinations, endovaginal ultrasound examination interferes with the accuracy of the test. • In such cases, it is necessary to wait for 24-48 hours before the test is performed.

  11. 3.Vaginal infections are also predictors of preterm labour. • Organisms which are known to cause preterm labour are Trichomonas vaginalis, Chlamydia trachomatis, Candida, ureaplasma urealyticum ,gardnerella vaginalis. • Bacterial vaginosis may precipitate preterm labour . when vaginal secretions contains sialidase but not prolidase, there is significant increased risk of preterm delivery. • Chlamydia trachomatis is associated with short cervix- ↑risk of preterm labour. • Ureaplasma urealyticum is a bacterium most frequently found in amniotic fluid & placental cultures of women who deliver preterm.

  12. 4. Salivary estriol – there is associated risk between increased maternal salivary estriol and subsequent preterm labour. salivary estriol level >2.1ng/ml of saliva is a positve indicator of preterm labour. 5. Periodontal disease – it is associated with increased preterm labour. • Oral bacteria especially fusobacterium nucleatum and capnocytophaga species have been associated with upper genital tract infection in pregnant women. 6. Prior preterm delivery.

  13. Diagnosis of preterm labour: • Uterine contractions 1 in 10 mins. With cervical changes 80% effaced 2cms dilated.

  14. Advanced preterm labour Digital P.V examination:- 1. Cervix 80% effaced Dilated ≥ 2 cm 2. Cervix 80% effaced Dilated > 1 but <2 cm 3. Cervix < 80% effaced Dilated < 1 cm Early preterm labour Transvaginal ultrasound Cervical length < 2.5cm Cervical length > 2.5cm Threatened preterm labour False labour

  15. Yes Allow labour to continue A. Identification of women who need to be delivered: 1.Chorioamnionitis 2.Severe placental insufficiency 3.Congenital abnormalities 4.Fetal lung maturity No Infection, fetal distress, preterm labour recurs • Tocolysis • Steroids • Antibiotics Continue expectant management Contractions subside

  16. 1. Acute chorioamnionitis. • Occurs in 0.5-1% of all pregnancies. • The clinical marker of acute amniotic infection is the presence of fever. • Other symptoms & signs are uterine tenderness, fetal and maternal tachycardia, foul smelling vaginal discharge, leukocytosis, marked elevation of CRP, resistance to tocolytic agents.

  17. Diagnosis of acute chorioamnionitis :- - fever (maternal temperature > 100.4º F or > 37.8ºC ) - and two or more of :-maternal tachycardia(>100bpm) -fetal tachycardia(>160bpm) -uterine tenderness -Foul odour of amniotic fluid -Maternal leukocytosis (>15,000/mn3) -C-reactive protein >2.7mg/dl • Acute chorioaminonitis in women in preterm labour is an indication for discontinuation of tocolysis, initiation of antibiotic treatment and delivery .

  18. Delivery is the most important measure because the infection will not resolve until the fetus is delivered • The objective of antibiotic treatment is to prevent dissemination of infection in mother & fetus until delivery is achieved. • Steroid treatment is contraindicated in presence of overt infection. • It is a serious obstetrical complication which has significant association with cerebral palsy and bronchopulmonary dysplasia that develops in fetuses. • Patients with chorioamnionitis have abnormal uterine activity, protracted cervical dilatation and descent.

  19. Antibiotic treatment : - Single agent- • Penicillin G 5million units IV stat followed by 2.5 to 3 million units IV - 4th hrly. till delivery. • Or ampicillin injection 2gms IV stat and 1gm 6hrly. till delivery.

  20. Pencillin allergy : • Not at high risk of anaphylaxes – Cefazolin 2gms IV followed by 1gm IV 8th hrly. until delivery. • High risk of anaphylaxes and susceptible to clindamycin • Clindamycin 900mgIV 8hrly. • High risk of anaphylaxes and resistant to clindamycin – vancomycin 1gm IV 12hrly. • Clindamycin 900 mg IV 8th hrly plus ceftriaxone 2gm IV 24hrly or cefotaxime 2gm IV 8th hrly.

  21. -Antibiotics have to be continued till the patient is afebrile for atleast 24 hrs.-Maternal complications: postpartum endometritis,puerperal septic thrombophlebitis,adult respiratory distress syndrome,septicemia.-neonatal complications: (immediate)low 5 minute apgar score,respiratory distress syndrome,intraventricular haemorrhage,periventricular leukomalacia, necrotising enterocolitis seizures in 1st 24hrs of life,sepsis and death. (long term) –chronic lung disease and cerebral palsy.

  22. 2. Subclinical chorioamnionitis- occurs frequently in women in preterm labour without evidence of overt infection. • These patients present with cervical dilatation of 3cm or more and their contractions respond poorly to tocolytic agents. • Determination of plasma CRP concentration is a sensitive test to identify women in preterm labour who have sub clinical amniotic infection.

  23. (women in early or advanced preterm labour) • > 1.6 mg/dl • ≥ 0.8 and <1.6mg/dl • Expectant management • Tocolysis • Antibiotics • Steroids if < 34 weeks • Repeat CRP in 24 hours • Decreasing • Continue expectant management Amniocentesis Infection positive infectionNegative Diagnosis and management of subclinical amnionitis: Deliver CRP < 0.8mg/dl Expectant management Increasing

  24. 3. Severe placental insufficiency : • If the ultrasound examination in a women with preterm labour reveals an estimated fetal weight below the 10th percentile and the expected date of delivery is reliable, the most likely etiology for the preterm labour is placental insufficiency. • If the amniotic fluid is decreased and assessment of umbilical & middle cerebral arteries with Doppler ultrasound reveals increased placenta impedance or brain sparing effect labour in these patients is clearly a mechanism of fetal defense against a hostile intrauterine environment and should not be interrupted.

  25. If the umblical artery does not show reversed diastolic flow and fetal heart rate monitoring is not ominous it will be acceptable to delay delivery for 24-48 hours to administer steroids.

  26. B. Women in preterm labour and no indication for immediate delivery: • if there is no maternal & fetal complications the contractions can be stopped using tocolytics • Steroids should be given – Inj. Betamethasone is given 12mg im – 2 doses 24 hours apart or Inj.Dexamethasone 6mg im every 12 hours for four doses. • Monitoring of vital signs is mandatory • Maternal tachycardia above 120bpm and B.P < 100/60mmHg, fever, pulse oximetry <95%, are reasons for discontinuation of treatment and to allow preterm labour to continue.

  27. II Management of Early preterm labour: • In women with early preterm labour the cervix is soft, 80% effaced or more, and dilated more than 1cm but less than 3cm. • 60-65% of women in early preterm labour will respond to tocolysis. • All women in early preterm labour should have ultrasound examination of the fetus, placenta, amniotic fluid, umblical, cerebral & uterine artery Doppler, materal serum CRP, high vaginal swab for C/S, TC, DC.

  28. Women with cervical length greater than 2.5cm: - The risk of preterm delivery will not be greater than that in the overall obstetrical population. • Women with a long cervix (>2.5cm) have less than 3% risk of preterm delivery – spurious or false labour. • After a period of observations, when the contractions become irregular & disappear they can be discharged & sent home.

  29.  Measures to arrest preterm labour:- • Bed rest in left lateral position. • Adequate hydration is maintained. • Antibiotics – The main reason to use antibiotics in women with preterm labour is the prevention of neonatal group B streptococcal infection. • The antibiotic of choice for the prevention of GBS infection is penicillin. • Dosage – 5mu IV as initial dose, followed by 2.5mu IV every 4 hours until delivery. • Penicillin is irritant to the veins

  30.  Or ampicillin 2g IV initial dose followed by 1g every 4th hourly can be given. • For women allergic to penicillin, the antibiotics used are clindamycin 900mg IV 8th hrly and erythromycin 500mgIV every 6th hrly. or cefazolin can also be given. D. Tocolytic agents – are used to inhibit uterine contractions. • It is used as a short term therapy • Objectives – to delay delivery for atleast 48hours for glucocorticoid therapy to the mother to enhance fetal lung maturation.

  31. In utero transfer of the patient to a unit more able to manage a preterm neonate.  Contraindications:- • Maternal – uncontrolled diabetes, thyrotoxicosis, severe hypertension, cardiac disease, haemorrhage in pregnancy like placenta praevia or abruption. • Fetal – fetal distress, fetal death, congenital malformation, pregnancy beyond 34 weeks. • Others – Ruptures of membranes, chorioamnionitis, cervical dilatation > 4cm.

  32. Delivery of preterm labour: • The principles of management of preterm labour – (1) to prevent birth asphyxia and development of RDS. (2)To prevent birth trauma. • Duration of labour is usually short.  First stage – The patient is put to bed to prevent early rupture of the membranes. • To ensure adequate fetal oxygenation by giving oxygen to the mother by mask, • Strong sedative should be avoided.

  33. Epidural analgesia is of choice. Labour should be watched by intensive clinical monitoring or with continuous electronic monitoring.  Second stage:- The birth should be gentle & slow to avoid rapid compression and decompression of the head. • Episiotomy may be done under L.A. to minimise head compression if there is perineal resistance. • Tendency to delay is curtailed by low forceps. • The cord is to be clamped immediately at birth to prevent hypervolemia & hyperbilirubinemia. • To shift the baby to the intensive neonatal care unit under the care of a neonatologist.

  34.  Prevention of preterm labour: • Primary care is aimed to reduce the incidence of preterm labour by reducing the high risk factors (e.g. infection) • Secondary care includes screening tests for early detection & prophylactic treatment (eg. – tocolytics) • Tertiary care is aimed to reduce the perinatal morbidity & mortality after the diagnoses (use of corticosteroids).

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