Fetal development. What is fetal hypoxia?

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Diagnosis “pre-natal fetal hypoxia” always causes anxiety in future moms. They have quite regular questions: what is this condition, which are its after-effects and is it possible to prevent it?

Fetal development

is a complex of changes in fetal development, happening due to low
supply of oxygen. This is not an independent disease, but an effect of various
pathologic processes, happening in mother`s organism, fetus and placenta.
What are dangers of hypoxia?
Oxygen deprivation
leads to disorder of organism activity, change of metabolic processes. In
different terms of pregnancy oxygen deprivation has different
after-effects for fetus. On early terms it leads to appearance of congenital abnormalities,
late development of embryo. On late terms of pregnancy oxygen deprivation
leads to growth inhibition of fetus, its central nervous system damage,
reduces adaptive capabilities of a newborn.
We should say that fetal organism has good compensatory abilities, necessary to
support necessary level of blood circulation. This is reached
due to increase of cardiac rate up to 150-160 beats per minute, special fetal hemoglobin structure, which catches and keeps oxygen better, than adults` hemoglobin does. Decrease of arterialization leads to changes of metabolic processes in fetus. All its organs and systems
start working with bigger activity. Fetus strives to provide vital parts with
blood (brain, kidneys, heart), and intestinal hypoxia takes place this time, and,
as a result, meconiorrhea.
However, unfortunately, resources of these compensatory abilities are limited, and
while long negative influence this protection weakens. And, first of all,
nervous system suffers, as now it is admitted that nerve tissue is one of most
oxygen-dependent tissues, and, as a result, it is most sensitive to damaging
effect of hypoxia, so it becomes the first object of oxygen deficit
pathologic effect.
Fetal development. Hypoxia
slows down ripening of brain structures in embryo since already 6-11 weeks of
development, causes disorders of structure and functioning of vessels, slows
down ripening of blood-brain barrier. This barrier represents a protective
mechanism of central nervous system - system of brain capillaries, and any its
damages threaten normal functioning of brain.
Small hypoxia usually has no influence on a future baby health. Serious hypoxia is
accompanied with ischemia (areas with deficit of blood circulation) and necroses
(areas of fulguration) in different organs, what leads to irreversible effects.
During post-natal period neurological disorders in a baby, born from pregnancy,
which passed under hypoxia conditions, are varied in wide range: from
functional disorders to serious disorders of psychic development.
Why hypoxia appears?
Factors, contributing to development of hypoxia are numerous. First of all, these are
mother`s diseases. Anemia is among them - it means lowering of hemoglobin.
While anemia general function of red corpuscles is broken - oxygen delivery
to tissues of organism.
If a future mother has heart diseases, myocard diseases, and chronic lung diseases,
then under the conditions of increased load on these organs, circulatory inefficiency appears, microcirculation in tissues is broken, and hypoxia and disorders in work of a system
“mother-placenta-fetus” are developed.
Respiratory tract diseases (bronchial allergy, chronic bronchitis etc) also
affect passing of pregnancy negatively. They become a reason of respiratory distress,
which causes hypoxia of woman`s organs and tissues and, as a result, fetus.
Kidney diseases, diabetes also can cause lowering of fetal hypoxia.
Other reasons of hypoxia are disorders of fetal-placental blood circulation what happens
while retarded birth, threat of premature birth, pathology of placenta and
umbilical cord, anomalies of labor activity, other complications of pregnancy
and delivery.
Fetal diseases also can lead to hypoxia: rhesus hemolytic disease, pre-natal
infection, congenital abnormalities, long head compression
during delivery. As you can see, there`re many reasons.

You can suspect of fetal hypoxia by yourself, observing changes of fetal moving
activity. In initial stage you can notice restless behavior of fetus, acceleration
and intensification of fetal movements. While long or progressive
hypoxia weakening of fetal movements takes place. This requires immediate reference to a doctor and usage of additional methods of investigation, such as cardiotocography and Doppler ultrasonography, investigation of amniotic fluid,
laboratory diagnostics. Retardation of fetal growth is a sign of hypoxia.
Fetal development. Cardiotocography
is one of modern high-informative methods of fetal condition diagnostics during
pregnancy with usage of monitoring device. Estimation of condition is
carried out basing on fetal cardiac rate analysis and its moving activity. Such
investigation is especially important during delivery. Doctors receive 2 diagrams:
one shows fetal cardiac rate, other - its moving activity. Uterine contractions
are registered at the same time. After doctors estimate the way heart beat
changes depending on movements or birth pangs, they can detect a baby`s
condition. This research is carried out in the third trimester of pregnancy
since 32 weeks.
While delivery defect of fetal heart activity is a general criterion of hypoxia,
that`s why fetal cardiotocography is widely used while delivery.
Doppler ultrasonography - is one of ultrasound investigation methods,
allowing investigating character and blooding velocity in placental
vessels and umbilical cord, which defects lead to development of hypoxia.
Ultrasound investigation is also important
for diagnostics of hypoxia. As pre-natal development of fetus since the moment
of implantation up to delivery passes in aquatic environment (amniotic fluid), solution, volume and color of amniotic fluid are very important while diagnosis
of fetal pathologic conditions. Almost all mentioned parameters can be detected
with help of ultrasound investigation.
As a rule, amniotic fluid remains homogeneous during
long time. Since 28th week, you can see fine mixture in amniotic fluid while ultrasound
investigation. Fine mixture is not a sign of fetal vital functions defects.
Small particles represent cast-off coverlet epithelium and elements of fetal vernix caseosa - in the end of 5th month of pregnancy (20 weeks) oil-bags start excreting a fatty matter, which is
mixed with furfur and forms vernix caseosa, covering fetal skin with a
thin coat. This vernix caseosa prevents fetal skin from destructive
influence of amniotic fluid. However, ultrasound investigation cannot estimate condition and solution of amniotic fluid, peculiar for hypoxia, in full measure.
Marked changes of amniotic fluid volume have practical meaning. Both marked hypamnion and fetal hydrops are signs of trouble.
Fetal development. Amnioscopy
- is examination of lower pole of fetal bladder with help of endoscopic instrument,
inserted in cervical canal. Doctors use amnioscopy to estimate fetal
condition while suspicion of retarded birth, chronic and acute fetal
hypoxia, rhesus-factor, anamnesis record (habitual non-carrying of
pregnancy, spontaneous abortions, acute gestational toxicosis, premature
birth). Doctors detect fetal condition basing on color, clarity, quantity of
amniotic fluid, vernix caseosa look, presence of meconium and some other
signs. Amnioscopy has a range of contra-indications, such as show (suspicion of placenta previa), coleitis, cervicitis and other infections of genital tracts, threat of termination of pregnancy. Complications while amnioscopy (premature discharge of amniotic fluid and development of labor, bleeding, infection) can happen very seldom.  Color of amniotic fluid, which is also an indicator of fetal condition in uterus, is
detected, as a rule, during dilating stage of labor, after discharge of amniotic fluid.
If pregnancy is passing normally, amniotic fluid is colorless and almost clear.
Coloration of amniotic fluid in green with meconium is one of signs of fetal
If doctors suspect chronic fetal hypoxia (toxicosis, extragenital
diseases and others), they hospitalize pregnant woman or send her to a diagnostic and treatment center to investigate fetal condition, discover reason of hypoxia. Measures, directed to improvement of uterine-placental blood circulation and normalization of fetal metabolic processes, can be carried out under outpatient observation.
Gymnastics against hypoxia

If there`re no contra-indications, pregnant women can be prescribed
aqua-gymnastics in combination with a complex of breathing exercises. During
breathing gymnastics relaxation of uterine tone and whole organism takes place,
fetal oxygen uptake is increased. Addition of aqua-gymnastics contributes
to better relaxation of uterine tone, intensification of metabolic processes in
mother`s and fetal organism, fetal oxygen uptake. As a result of all
measures, reduction of fetal hypoxia signs takes place.
Rest is important for pregnant with chronic fetal hypoxia. Confinement to bed
contributes to improvement of uterine blood supply. Treatment of general
disease, which caused hypoxia development, is important. Therapy, directed to
improvement of fetal oxygen uptake and normalization of metabolic
processes is also carried out. This therapy should be complex. With help of
medicines doctors try to achieve:
vasodilatation of uterine- and fetal-placental
departments of placenta (Aminophylline, No-spa);
relaxation of uterine muscular system (Gynipral,
normalization of blood flow property in a system
“mother-placenta-fetus” (Trental, Actovegin).

Besides, preparations, normalizing metabolic
processes, are also necessary (mixtures of amino acids, proteins), contributing
to stabilization of structural-functional qualities of cell membranes (Essenciale,
Chophytol), increasing immunity of fetal brain and tissues against hypoxia.

If complex therapy brings no effect and fetal condition on term of
pregnancy after 28 weeks worsens, question about urgent delivery through Cesarean
is decided.

If pregnancy was passing under the conditions of chronic fetal hypoxia,
doctors use cardiotocography during delivery, as this increases chances to
detect acute hypoxia and allows efficient solution of question about further
tactics of delivery.

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