Preterm Labor Prof. Ryszard Czajka Chair and Department of Obstetrics and Perinatology

PRETERM BIRTH PTB PRETERM LABOR PTL PRETERM DELIVERY PTD PREMATURITY LOW-BIRTH WEIGHT PREMATURE NEWBORN DYSTROPHIC NEWBORN

Preterm Labor is defined as the presence of regular uterine contractions, occuring with a frequency of 10 minutes or less between 23 and 37 weeks gestation, with each contraction lasting at least 30 seconds

This uterine activity is accompanied by cervical effacement, cervical dilation and/or descent of the fetus into pelvis

However, variations of this definition are commonly used, so it is often difficult to know when a patient is really in PTL. This present a problem because treatment appears to be more effective when initiated early in the course of PTL; waiting for cervical changes to occur to establish a definitive diagnosis may limit successful therapy.

Symptoms and Signs of Preterm Labor Menstrual – like cramps Low, dull backache Abdominal pressure Abdominal cramping (with or without diarrhoea) Increase or change in vaginal discharge (mucus, watery, light bloody, discharge) Uterine contractions, often painless

Many preterm births are the result of deliberate intervention for a variety of pregnancy complication and hence have unavoidable perinatal complications. A major cause of preterm birth, however is PTL. Many preterm births are the result of deliberate intervention for a variety of pregnancy complication and hence have unavoidable perinatal complications. A major cause of preterm birth, however is PTL.

Because PTB is the most common cause of perinatal morbidity and mortality, its prevention and treatment are major concerns in obstetric care Because PTB is the most common cause of perinatal morbidity and mortality, its prevention and treatment are major concerns in obstetric care

The consequences of PTL and PTB occur with increasing severity and frequency the earlier the gestational age of the newborn

Besides perinatal death in the very young fetus, common complications of PTL include – –Respiratory Distress Syndrome (RDS, hyaline membrane disease) – –Intraventricular hemorrhage – –Necrotizing enterocolitis – –Sepsis – –Seizures

Long-term morbidity associated with PTL and delivery includes – –Bronchopulmonary dysplasia – –Developmental abnormalities

The significant impact of PTB is best summarized by this fact: The 10% of the babies born prematurely account for more than 50% of all perinatal morbidity and mortality in the United States.

In the consideration of the consequences of PTD, it is important to seperate the concepts of low-birth weight and prematurity

Prematuriy reflects gestational age, whereas low-birth weight is based on the single parameter of weight, usually 2500g or less

For example, a growth- restricted fetus (IUGR) of a hypertensive patient may weight well under 2500g at 40 weeks gestation

Such an infant is a low-birth weight infant but not preterm and will suffer the consequences associated with low- birth weight and maternal hypertension, but not of premature birth

Likewise, an infant of a diabetic mother may by delivered before term, weigh in excess of 2500g, and still have the significant perinatal morbidities of PTB.

Factors Associated with Preterm Labor Dehydration Premature rupture of membranes (PROM) Incompetent cervix – –Primary – –Secondary to surgery (e.g. cone biopsy of cervix)

Factors Associated with Preterm Labor Infections – –Urinary – – Cervical – –Bacterial vaginosis – –Intra amniotic

Factors Associated with Preterm Labor Placental abnormalities Abruptio placentae Placenta previa Maternal smoking (strong implications) Substance abuse Iatrogenic: induction of labor

Factors Associated with Preterm Labor Excessive uterine enlargement: Hydramnios Multiple gestation Uterine distortion – –Leyomyomas – –Septate uterus, uterine didelphis and other anomalies

Risk factors of premature labor Medical factors Social factors Demographic factors Environmental factors

Risk factors of premature labor Medical factors - medical history (preterm labor, spontaneous and induced abortion, previous steelbirths) - medical factors variable arising during pregnancy a) uterine bleeding b) multiple pregnancy c) placenta previae d) preeclampsia e) urinal infections d) vaginal infections

Risk factors of premature labor - maternal diseases a) diabetes mellitus b) epilepsia c) hypertension d) EPH – gesthosis (PIH) e) Urinary disease f) Uterine malformation g) Myoma uterine h) Incompetence cervix i) Fetal malformation j) Pathology of placenta k) Infections

Risk factors of premature labor Social factors – –low socioeconomic status smoking Demographic factors -Young (below 18) and old (over 35) maternal age -Multiparity Unmarried status Environmental factors - physical factors (radiation, jonization, termical factors, magnetism), vibration, noisy, chemical factors

Risk factors of premature labor Psychogenic factors Psychogenic factors - - family or own diseases - death of family member - stressful of life events - stressful with husband and parents - stressful with unmarried status - bad of residence - work/fatigue - anxiety - past of obstetrical history - arising symptoms of premature labor - insufficient of obstetrical care

Prevention of Preterm Delivery In Europe premature birth remains primary cause of neonatal morbidity and mortality. Early identification of high risk pregnancies through various screening methods as well as specific markers for preterm delivery is crucial.

Prevention of Preterm Delivery Ascending infections play an important role in the pathogenesis of preterm delivery, and thus have to receive adequate diagnostic attention. Ascending infections play an important role in the pathogenesis of preterm delivery, and thus have to receive adequate diagnostic attention. In the scope “step-by-step concept” of markers, the vaginal pH is most easily measured. Vaginal pH is an important indicator of abnormalities of vaginal flora and predisposition to ascending infections. In the scope “step-by-step concept” of markers, the vaginal pH is most easily measured. Vaginal pH is an important indicator of abnormalities of vaginal flora and predisposition to ascending infections. Trichomonas and bacterial vaginosis can be detected in native sample; Trichomonas and bacterial vaginosis can be detected in native sample; If other infections are suspected, vaginal bacteriology is to be carried out. If other infections are suspected, vaginal bacteriology is to be carried out. According to recent publications, specific pathogens are closely are closely associated with preterm delivery According to recent publications, specific pathogens are closely are closely associated with preterm delivery –(syphilis, gonorrhea, bacterial vaginosis), –whereas correlation of preterm delivery with other pathogens (beta-Streptococcus, Ureaplasma, Mycoplasma, Chlamydia, Trichomonas) is still disputed.

Prevention of Preterm Delivery Fibronectin is also a predictive factor for imminent preterm delivery. Fibronectin is also a predictive factor for imminent preterm delivery. Elevated CRP values may indicate beginning infection Elevated CRP values may indicate beginning infection

Prevention of Preterm Delivery Pathogenesis of Preterm Delivery Vaginal pH Vaginal Wet Smear Cultures - beta Streptococcus - Ureaplasma urealyticum - Mycoplasma hominis - Chlamydia Trachomatis - Trichomonas vaginalis - Gardnella vaginalis Cervical – Vaginal Oncofetal Fibronectin C-Reactive Protein

Evaluation of a patient in suspected preterm labor Once a patient describes symptoms ans signs suggestive of PTL, evaluation should be prompt External elctronic fetal monitoring Abdominal palpation by experienced personnel The status of the cervix should be determined by visualization with speculum or gentle digital examination

Evaluation of a patient in suspected preterm labor Serial digital examination Serial digital examination Ultrasound examination Ultrasound examination –Gestational age –AFI –Placental location –Cervix dilation

Evaluation of a patient in suspected preterm labor Urinalysis Investigation of clinical or subclinical infection: – –White blood cells – –CRP – –Bacteriological culture

Risk of preterm delivery, according to Creasy (1980)

Preterm birth risk score (According to Papiernik)

Agents Used in Treating Preterm Labor  - adrenergic agents (phenoterol) Magnesium sulfate Calcium channels blockers (werapamil) Oxytocin receptor blockers (tractocile)

Administration of Magnesium Sulfate for Preterm Labor g MgSO4 are mixed in ml of D5W and infused over minutes as a loading dose g MgSO4 are mixed in 1000 ml of D5W, providing an MgSO4 concentration of 1 g MgSO4 in 25 ml of solution Using a piggyback infusion via an infusion pump, the physician usually begins infusion at 2g/hr (50ml/hr) and increases it in 0,5 g/hr increments as needed.