Birth, before 37 completed weeks, the 259th day of pregnancy (WHO 1993)
Independent definition of intrauterine growth
Limit of viability: 25 weeks
Before 37 completed weeks: painful contractile activity of the uterus (≥ 2/10 minutes) + modification of the cervix → leads to premature delivery if untreated appropriate (membranes intact)
The seriousness of a Threatened preterm labor (TPL) can be appreciated and quantified with a follow-up of the evolution by an index (sometimes called score or index) comprising four rated parameters each from zero to four points.
The values retained are:
Index ≤ 3: Slight threat.
Index ≥ 4 and ≤ 5: Moderate threat.
Index ≥ 6: Severe threat.
Most important prematurity (22-27 W): 10%
Intermediate prematurity (28-31 W): 10%
The most frequent prematurity (80%) is the least serious (32-37 W)
Infectious: are favored by the immaturity of the immune system.
Lungs: Hyaline Membrane Disease, a consequence of insufficient synthesis of surfactant, may cause respiratory distress
Digestive, neurological, ophthalmological
Growth delay compensated around 8 years
Less good school performance on average: attention disorders, hyperactivity, disorders behavior and social relationships
Uterine causes
Congenital uterine abnormalities: uterine hypotrophy, double uterus
Acquired uterine abnormalities: fibroids
cervico-isthmic open bite:
Congenital
Acquired: traumatic cervical injury
Diagnosis: Hegar 8 in the premenstrual phase
Processing: strapping
Genital infections: viral, bacterial or parasitic, vaginitis, cervicitis, chorioamnionitis
Other pelvic pathologies: uterine trauma by intraoperative injury
Ovary causes
Fetus: multiple pregnancy, fetal malformations, fetal infection (sepsis, chorioamnionitis)
Placenta: Placenta previa, retro-placental hematoma, placentitis/chorio-amnionitis
Membranes: premature rupture of membranes (10-15% of pregnancies)
Amniotic fluid: polyhydramnios, amniotic infection
General causes: vascular-renal syndromes, diabetes with polyhydramnios, infections (pyelonephritis, asymptomatic bacteriuria, listeriosis; viral hepatitis, malaria, toxoplasmosis, cytomegalovirus, periodontitis)
< 37 weeks: painful or tender uterine contractions, blood loss.
Vaginal examination: cervix: length < 1 cm, internal orifice dilation > 1 cm
Abdominal palpation
Cardiotocogram
Vaginal ultrasound: length of the endocervical canal < 30 mm (normal 42 mm), orifice internal > 1 cm, prolapse of the membranes in the endocervix, thickness of the lower segment <0.6cm
Baumgarten score: ≤ 3: mild (TPL), 4-5: moderate (TPL), ≥ 6: severe (TPL)
Detection of causes before pregnancy: surgical treatment of uterine malformations,
cerclage, anti-infective treatments, treatment of vascular-renal syndromes
Relaxation