My child will be healthy?
Filiberto Di Prospero M.D.
(Maternal and Children Department , 62012 Civitanova Marche, Italy)

THE WORRY

Every woman in the beginning and during the gestation has this doubt: my child will be healthy? Some times the anxiety of the reproductive success, to have in arm an absolutely healthy child can be such strong to damage psychologically the future mother and  the couple life to.

It is necessary for first  to consider  that a healthy child is not only the result of a correct cromosomal pattern but also of a  "healthy" pregnancy in a woman therefore in good conditions. Also we could say that to a healthy baby we should think about a lot of time before programming a pregnancy.

To maintain a normal weight, to follow a normal diet and  physical  activity, to avoid the smoke and avoid sexual transmitted infections, to carry out regular gynaecological  examinations and screenings,  they are all "trickiness" that any woman in reproductive age should take.

THE FIRST STEP.....

Very important is the reproductive consueling  before the conception  and  the  first obstetrical visit. The general healty status (the pregnancy and the delivery will constitute a strong engagement for the maternal organism),  the reproductive apparatus evaluation (esclusion of malformative pathologies either congenital or acquired), the genetic risk analysis they are all fundamental moments.

The doctor will give you also useful informations about dietary, hygiene and sexual attivity. The Doctor will help you to individualize behaviors that require a ready correction (ie smoke, drugs and alcohol's consumption).

For example, only few women know that a small dose of the vitamin folic acid (4 mg to the dì) in the preceding period and during the first weeks of gestation is effective to reduce neural tube defects (spina bifida).

THE AGE PROBLEM

The strong social changes of these last decades,  the new social role of the woman and economical factors ave delayed the reproductive moment. Today it is very frequent to ave a marriage after the age 30 and to conceive between the 35 and the 40 years.
The choice of a reproduction that we could define "late" (when happens particularly after the age of 35) produces two type of problems: some pathologies in pregnancy and during the delivery (ie  spontaneous miscarriage and premature delivery, dynamic distocies);  the increase of the  fetal pathology that may be  cromosomal  (Down Syndrome) and not cromosomal ( iposviluppo.......).

As you ca see in the table the Down Syndrome's risk and other cromosomal fetal malformations  increases with advance in the maternal age. Note that the greatest increase happens after the 36 years. From this evidence most Scientific Societies and Health Organizations recommend to perform a rouitne villocentesis or precox amniocentesis in women 36 y.o. or older. The progress of the medicine in general and the progress of the obstetric assistance particularly  allows to ave today a more easier management of the problems in this pregnat population.

At the same time large progresses were done in the diagnoses and screening of some fetal malformations  in  pregnat women aged <36 y.o.
This pregnat population can be considered no at risck for genetic problems of the fetus but it's not completely immune from this patology. Then, it's important to individualize the genetic problems in this populations to.

 
SCREENING AND  DIAGNOSTIC TESTS

We talk now about the different tests for thef screening and diagnosis of fetal anomalies.

Screening tests: exams  performed without risks and at low costs in a large population for  individualize the subjects to submit at more careful tests. They was normally employed in a population not at risk or at very low risck: in this populations a genetic fetal malformative event is rare.

Diagnostic tests: tests performed  in a selected populations (ie positive to the screening tests) or at risk (pregnat women >36 y.o.)  These tests are able to be talora also invasive, have an diagnostic accuracy (capacity to individualize the fetal malformation) very high and their cost is certainly superior to the screening tests.

In a pregnant woman before age 36, not at  risk for  hereditary diseases it's recommended the use of a screening test. 

TRIPLE-TEST is one of the first and more important test of screening. It it is performed between the 15 and 17 weeks of amenorrea; it is based on the computerized analysis of four elements: the maternal age and three fetus origin serum markers. It individualizes 70% of the Trisomia 21 (Down Syndrome) but also  Edwards Syndrome and Spina Bifida.  The positive patients to the test  should perform the amniocentesis for a definitive diagnosis. Caution: this test is  not reliable in twin pregnancy and maternal diabetes.

DOUBLE-TEST has the advantage to be performed more early between the 11^ and the 14^ weeks. The result depends from the analysis of the maternal age compared to the assay of two maternal ormones. In positive women is recommended shoul perform villocentesis.

GENETIC ULTRASONOGRAPHY
Ultrasound screening is based on the observation that fetuses with  cromosomal abnormalities show some  tipical anatomical  features that can be recognized by ultrasonography of the first quarter of the gestation.
Nucal translucency: most fetuses affected by cromosomal anomalies have a transitory accumulation of liquid in the subcutaneous layers of the neck between 10 and 14 weeks; if the thickness of this zone is > 3 mm the probability of comosomal anomalies is 75%. In these cases is advisable to proceed therefore immediately to a villocentesis and if this is negative is recommended to repeat a careful observation of the fetus by an ecography  of second^ level between the 20 and the 22 week.
Nasal bone architecture: in the november 2001 a group of researchers of the King' s College Hospital of London proposed a further ecographyc marker useful to individualize affected embryos from Syndrome of Down, the study of the nasal bone. Most fetuses affected by Down Syndrome has not nasal bone.

The DOUBLE TEST AND GENETIC ULTRASONOGRAPHY are frequently associated.

In pregnant women at risk for age > 36 or  positive in the screening tests or with ereditary problems, it's legitimate to proceed with invasive diagnostic tests whose have a high diagnostic accuracy. 

The CHORIONIC VILLUS SAMPLING is a little sampling of the villi; it's a technology of more recent acquisition. It comes carried out between the 10 and the 12 week and is indicated for the study of the fetal cromosomal map and some enzimatic defects. At this time have a risk of miscarriage aroud  0,5%.

 The AMNIOCENTESIS is undoubtedly the invasive metod for prenatal diagnosis more used in the world. It is directed mainly to the cromosomal evaluation of the fetus. Easy to perform, it has a very low risk of miscarriage (0,2-0,3%). It is carried out between 15 and 16  weeks and consists in the aspiration of about 10-15 ml of amniotic liquid.

The CORDOCENTESIS consists in the withdrawal of a small quantity of fetal blood (1-3ml) from the umbilical cord. It allows to perform different investigations as  citogenetic, biochemical,  immunological, infective.