Preterm labour

Preterm labour 18

definition
Pretem labour occuring 24w - 36w+6 days It is either : Indicated preterm birth Spontaneous preterm birth

causes of preterm labour1 Idiopathic :70%

2.Medical and obstetric causes:
Preeclampsia. Placenta previa abruptio placentae. Multiple birth . Polyhydramnia Fetal anomaly Fetal death. Previous second trimester abortion or induced abortion.
Uterine causes : anomaly, fibroid . Cervical incompetence Trauma or surgery Immunological disorder as antiphospholipid Ab syndrome DES exposure

3.Genetic factors:

Genetic factor may have a role since PTL runs in families and there is tendency for recurrence in subsequent pregnancy, and have different incidence in different races.

4.Infection:

Chorioaminionitis : local infection following abnormal bacterial vaginal colonization (bacterial vaginosis) cause local release of prostaglandin and stimulate uterine contractions Systemic infection ; as pyelonephritis is also implicated in preterm labour ,TORCH.

5.Lifestyle factors :

Age less than 20 years. Poor nutrition. Poor weight gain during pregnancy. Low maternal pre-natal weight gain . Poverty. Smoking. Short stature. Psychological stress.


Risk and complications of PTL:

Fetal risk :

1.The risk of underlying fetal condition e.g. :- congenital infection or anomalies 2.Fetal intrapartum hypoxia and birth trauma

Early neonatal risk of: Difficulty in maintaining body temperature. Difficulties in oral feeding. Increased risk of infection. Lung immaturity proportionate to the gestational age Congestive heart failure (PDA). Liver immaturity and sever neonatal jaundice with increased neurotoxic effects of unconjucated bilirubin. Intracranial haemorrhage. Necrotizing enterocolitis.

Prediction Screening for PTL

1.Past obstetric history
If woman has a single previous PTL increases the risk of PTL 4times when compared –ve such history

2. Bacterial vaginosis

Is abnormality of normal vaginal flora characterized by a reduced numbers of lactobacilli, higher PH& increased numbers of potential pathogens:- Gardenerella vaginalis ,bacteriodes ,Eschersia coli . Thereis double risk of preterm delivery

3. Ultrasound measurement of cervical length

Normal cervix measures about 35 mm Either serial measuring of cervical length in 2nd &early 3rd trimester Or single measurement of cervical length at 18 -22 w At any gestational age there is relationship between cervical length &the risk of PTL


4.Fetal fibronectin (FFN) testing. Fetal fibronectin (fFN) is glue-like protein binding the choriodecidual membranes . Rarely seen in the cervicovaginal secretion between 23-34 weeks . release of fFN indicate disruption of the choriodecidual interface which can be caused by preterm labour ,infection , stress ,or haemorrhage .

Prevention of preterm delivery:

Life style modification coupled with optimal management can reduce the incidence of preterm delivery (stop smoking , adequate nutrition). 2.Cervical cerculage : prophylactic cerculage in asymptomatic patient with short cervix diagnosed by ultrasound or patient with history suggestive of cervical incompetence.

3.Progesterone: progesterone has many cellular functions which maintain pregnancy and it’s withdrawal is a prerequisite for labour.4.non-steroidal anti-inflamatory drugs NSAIDs may be benificial 5.Screening and treatment of bacterial vaginosis early in pregnant who are high risk.

Management of preterm labour:

History : - proper estimation of the gestational age with the regard of the previous ultrasonic assessment to confirm that the baby is preterm. -symptoms of PTL/PROM: -Abdominal pain : not necessarily regular . -Backache. -Leaking liquor . -Vaginal discharge/Vaginal bleeding. - Underlying condition predispose to PTL: medical (UTI ,gastroenteritis), obstetric (APH , previous PTL) or fetal (anomaly ,death)

Examination : General : to exclude maternal disease as systemic infection , dehydration , hypertention . Abdominal examination: -exclude underlying abdominal pathology as appendicitis, pyelonephritis . -obstetric examination : palpable uterine contraction, fundal height , lie , presentation , fetal heart. Pelvic examination : to exclude cervical dilatation and effacement, rupture of the membrane, infection , bleeding.

Investigation :

GUE (mid stream) HVS. blood culture is indicated if pyrexia more than 38.5. C-reactive protein and ESR in cases of rupture of membrane. Abdominal ultrasound.

Treatment:

Initial treatment : - Bed rest in lateral decubitus. - external cardiotocographic monitoring . - tocolysis. - steroid administration.



Tocolytic drugs
Beta- adrenergic agonists. Mg sulphate . NSAIDs. Ca channel blockers. Glyceryl trinitrate. Oxytocin antagonists.

2.Antenatal corticosteroid:

Betamethasone and dexamethasone 24 mg divided in 2-4 doses improve neonatal outcome by reducing respiratory distress syndrome , intraventricular haemorrhage , necrotising enterocolitis.

Management of preterm delivery : If labour become established certain point are differs from delivery of term pregnancy: Continuous CTG monitoring (more risk of fetal distress ). Delivery of the fetus in their sac is better or to delay rupture of the membrane as late as possible in labour to protect the fragile fetus from birth trauma. caesarean section indicated in preterm breech presentation ,preterm twin or higher order multiple pregnancy . classical C.S. may be indicated in extreme prematurity. Assisted delivery to shorten the second stage of labour by forceps not ventouse to reduce the risk of I.C.trauma.