Definition of Prematurity
ubetween the 22nd gestational week (> 154 days p.m.) and 37 completed weeks (< 259 days p.m.)ÞThis roughly correspondends to a birth weight 500 – 2,500 g
Note: menstrual dating may be inaccurate in up to 20%
gestation should be estimated on the best clinical way including ultrasound
Much epidemiological work uses birthweight as a standard:
llow birthweight (< 2501 g)
lvery low birthweight (< 1501 g)
lextremely low birthweight (< 1000 g) *
* WHO recommendation: registration of all births over 500 g
What is the Problem in Prematurity?
Mortality
uneonates with birth weights of less than 2,500 g comprise
up to 80% of perinatal mortality in developed nations
ua child with birth weight < 1,500 g has 200-fold increased
risk of death compared to a child weighing over 2,500 g
last 20 years: marked increase in survival
of infants < 1500 g:
luse of corticosteroids
lregionalization of perinatal care
limproved methods of mechanical ventilation
lavailability of exogenous surfactant
limproved nutritional therapy
Morbidity
urespiratory distress syndrome (RDS) /
bronchopulmonary dysplasia (BPD)
uintracranial hemorrhage, periventricular leucomalacia
(® cerebral palsy)
Note: 50 % of all major neurologic handicaps in
children result from premature births
upersistent patent ductus arteriosus
uhypothermia, hypoglycemia, apnea, bradycardia
uincreased risk of infection
Prematurity and its consequences
remain a major health problem!
The key to a successful management is a well-
structured and comprehensive set of guidelines:
l diagnosis
l therapy
l delivery
Epidemiology
Major Preterm Labor Risks:
relative risk
uprior preterm birth 6 – 8
uprior preterm birth < 28 weeks 10
umultiple gestations 6 – 8
ulow socioeconomic status 2 – 2.5
The strongest predictor of preterm birth
is previous preterm birth!
The more preterm the first birth,
the less likely the subsequent pregnancy
is go to term.
Modifiable Nonmodifiable
– poor maternal weight gain – extremes of age (<17 or >40 years)
– physically demanding work – history of uterine abnormality
– smoking – placenta previa
– anemia – low prepregnancy weight
– bacteruria
– bacterial vaginosis
– maternal systemic infections
(e.g., pyelonephritis)
Four major categories
uPPROM (preterm premature rupture of mambranes)
uuncomplicated spontaneous preterm delivery
uelective preterm delivery for severe maternal or fetal
medical conditions (e.g., alloimmunisation, IUGR)
ucomplicated emergency delivery (e.g., placenta previa,
abruptio placenta.
Prediction of Preterm Delivery/ Diagnostics
Assessment of risk of preterm delivery should be
a formal part of each antenatal visit.
concentrate on identification of modifiable risk factors:
– life style, stress, working pattern
– weight, smoking, drugs
– urinary and vaginal infection
uuse key non-modifiable demographic, past reproductive
history and current pregnancy risk factors to consider
secondary screening by ultrasound or biochemistry
