Τόμος 4 (1986) – Τεύχος 2 – Άρθρο 6 – Επιθεώρηση Κλινικής Φαρμακολογίας και Φαρμακοκινητικής-Ελληνική Έκδοση – Volume 4 (1986) – Issue 2 – Article 6 – Epitheorese Klinikes Farmakologias και Farmakokinetikes-Greek Edition

Iron and Pregnancy

PHARMAKON-PRESS

4: 51-60 (1986)

PHARMAKON-Press: Epitheorese Klin. Farmakol. Farmakokinet.

4: 51-60 (1986)

Ειδικότερα κατά την εγκυμοσύνη, η παρατη­ρούμενη ένδεια σιδήρου αποτελεί κοινό φαινόμενο, ακόμη και στις αναπτυγμένες βιομηχανικά χώρες. Στις κοινωνίες αυτές τα 20% περίπου των γυναικών με έμμηνο ρύση έχουν ένδεια ή μειωμένο σίδηρο. Η αντιμετώπιση της κατάστασης αυτής απαιτεί ιδιαίτερη προσοχή. τόσο για την ίδια την έγκυο όσο και για το έμβρυο.

Στο άρθρο αυτό επισκοπείται γενικά η εντόπιση, απορρόφηση, διανομή, μεταβολισμός, απέκκριση και φυσιολογική λειτουργία του σιδήρου στον οργανισμό, με ιδιαίτερη έμφαση στη χορήγηση συμπληρωμάτων σιδήρου κατά την εγκυμοσύνη.

The body contains about 45 mg of iron per kg of body weight. This iron is distributed in the body in four main forms: transport iron (bounded with transferrin), he­moglobin, storage iron (ferritin and haemoside­rin) and cellular tissue iron (component of oxi­dative enzyme systems). Iron enters the body usually as ferric ion in food. Only about 10 to 30% of the ingested iron is absorbed and the remaining is eliminated in the feces. Most absorption occurs in the stomach and duode­num. Absorption is also dependent on the form of iron; haeme iron has 20 to 40% absorption while non-haeme iron (grains and vegetables) has only 5% absorption. A number of factors influence the absorption of iron. Factors favo­ring the absorption include: tissue need, low pH (gastric HCI), vitamin C, calcium. The fol­lowing factors hinder iron absorption: tissue saturation, high pH, high phosphate, phytate and oxalate, malabsorption disorders. Iron ser­ves two major purposes in human metabolism: hemoglobin formation and cellular oxidation. Clinical abnormalities may result from either a deficiency (nutritional anemia, hemorragic ane­mia, pernicious anemia, postgastrectomy ane­mia, malabsorption anemia) or an excess of iron (hemosiderosis, hemochromatosis, accu­mulation associated with aplastic or hemolytic anemias). The recommended daily allowances are: adults 10 mg for men and 18 mg for women, infants 10 to 15 mg, children 15 mg, boys 18 mg. in pregnancy iron deficiency is common even in “developed countries”. During pregnancy the hemoglobin falls according the equation: hemoglobin,(g/100 ml) = 0.059x + 13.33, where x = weeks of gestation, due to the increase in maternal circulating blood volume estimated to be from 40 to 50%, or more with multiple births. The minimum acceptable levels of hemoglobin during pregnancy are: first tri­mester 12.5 g/100 ml, second trimester 11.5 to 12 g/100 ml, third trimester 11.0 to 11.5 g/100 ml. Iron is essential to the formation of hemoglobin. If law pre-conception stores are suspected, if there is a history of anemia, or if there is doubt concerning adequate dietary iron sources,iron supplementation is needed. Iron is also needed for fetal development, especially for storage of reserve in the liver; this is necessary because milk lacks iron. Adequate maternal iron stores also fortify the mother against the blood losses at delivery. The oral route of administration is preferable for iron supplements and that these could be ferrous gluconate or ferrous sulphate, rather than de­layed or sustained release preparations which are less effective. The hazards of parenteral administration of iron preclude administration via this route except where there is intoleran­ce to oral administration, malabsorption cau­sing failure of oral therapy or continued blee­ding enceeding, oral iron intake.

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