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Factors that predispose to
premature delivery
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Preterm birth is defined
as the birth of a fetus after 20 weeks
and before completing 37 weeks of
gestation (normal is 40 weeks),
considering the time elapsed since the
first day of last menstrual period. In
general the rate of premature birth
varies between approximately 5 and 15%
of all births.
Mild is considered premature if born
between weeks 32 and 36 of pregnancy,
very premature at birth between weeks 28
and 32 of gestation, extreme prematurity
at birth before 28 weeks' gestation and
births occurring before 20 weeks are
considered as abortions.
A number of factors have been associated
with increased risk of preterm delivery,
which can be divided into socio-economic
status, medical history and obstetric
habits during pregnancy and pregnancy
complications.
The low socioeconomic status, both as a
race (those of African descent are twice
as likely for preterm delivery than
white women), age (the highest
percentage in women under 20 years and
over 35 years), nutritional status: low
nutritional represented by a low
prepregnancy weight and underweight
increased during pregnancy are risk
factors for preterm delivery both to
intrauterine growth retardation.
Also a history of previous preterm birth
is an increased risk in subsequent
pregnancies. The risk increases further
with each preterm delivery and decreases
with each pregnancy that comes to term.
A history of previous abortions are
related especially when it has occurred
in the second quarter and there is a
high risk of prematurity.
Cervical incompetence may be congenital
or acquired secondary to dilation of the
cervix or cervical conization, but their
relationship to preterm birth is not
very clear.
Uterine malformations
also cause premature delivery. The
overall incidence is 4% for septate
uterus and 80% for bicornuate uterus.
Fibroids are also major causes of
premature birth.
Habits during pregnancy are also factors
that can cause premature delivery, so
that work activities that result in
significant psychological stress as well
as those which determine an important
physical activity, give rise to
increased risk for preterm delivery (PP)
and also in fetal intrauterine growth
retardation.
Cigarette smoking increases the risk of
PP in relation to the number of
cigarettes smoked, also happens to
adverse life situations; cocaine use
during pregnancy is associated with risk
of P. P. 25%.
Complications of pregnancy urine is
infection by bacteria and presence of
symptoms, which may coincide with an
underlying kidney disease or development
of acute renal infection as a
complication.
Endotoxins of certain germs can launch a
birth, as severe preeclampsia, diabetes,
hyperthyroidism, heart disease,
gestational cholestasis, hepatitis and
anemia.
Abdominal surgery performed during the
last six months of pregnancy can cause
DB
Pregnancies obtained by assisted
reproductive techniques has a high rate
of prematurity (approximately 27%) due
to the high frequency of multiple
pregnancies (twins, triplets, etc..),
Which ranges between 30 and 50%.
The presence of amniotic fluid in
abundance is also a risk factor, like
congenital anomalies such as
anencephaly, absent kidney, central
nervous system abnormalities.
Hemorrhages before birth are also
covered at this point: whether they are
caused by the presence of placenta
previa or abruption of the placenta, is
associated with an increased risk of
preterm delivery. Infections, several
mechanisms can cause the appearance of a
PP, so that the infection inside the
uterus has been responsible for PP up to
25%. The invasion of the lower genital
tract by various microorganisms such as
chlamydia trachomatis, ureaplasma
urealiticum, group B Streptococcus,
Gardnerella vaginalis, Trichomonas
vaginalis, and so on. have been
associated with outbreaks of P.P.
