2.2 IODINE DEFICIENCY IN THE NEONATE

The availability of methods for neonatal screening in developed countries (Burrow, 1980) has led to their application in developing countries such as India and Zaire. In India observations on cord blood in iodine-deficient areas indicate as many as 4 percent of neonates with serum thyroxine levels below 3 mcg percent (Kochupillai et al., 1984). In Zaire up to 10 percent of neonates have been observed with low thyroxine levels (Ermans et al., 1980a). These frequencies should be compared with 0.02 percent in most developed countries with normal iodine nutrition (Burrow, 1980).

In a further study from Zaire, the effect of an injection of iodized oil on birth weight, perinatal and infant mortality, and development quotient was assessed by comparison with an untreated group (Thilly, 1981). The findings are shown in Table 5. They indicate substantial improvements in birth weight of infants, with reductions in perinatal and infant mortality and improvement in the development quotient. These findings indicate the necessity of iodine and normal thyroid function for general foetal development and neonatal health. Longer-term benefits evident in children up to the age of 10 to 12 years have been shown in controlled studies following injections of iodized oil before or during pregnancy (Connolly et al., 1979; Pharoah et al., 1984; Fierro-Benitez et al., 1986). These include improved psychomotor performance and improved school performance.

TABLE 4

CHILDREN BORN IN JIMI RIVER SUBDISTRICT (PAPUA NEW GUINEA)
TO TREATED AND UNTREATED MOTHERS FROM 1966

Treatment received by mother	Total no. of new births	No. of children examined	No. of deaths recorded	No. of endemic cretins
Iodized oil	498	412	66	7 (1)
Untreated	534	406	97	25 (2)

Source: Pharoah et al., 1971 See also Fig. 3

(1) Mothers of 6 already were pregnant when injected with oil
(2) Mothers of 5 already were pregnant when injected with saline solution

TABLE 5

EFFECT OF INJECTION OF IODIZED OIL GIVEN DURING PREGNANCY, IN ZAIRE

	Not treated		Treated
Birth weight (g.±)	2634 ± 552	(98)	2837 ± 542	(112)
Perinatal mortality per 1 000	188	(123)	98	(129)
Infant mortality per 1 000	250	(263)	167	(252)
Developmental quotient	104 ± 24	(66)	115 ± 16	(72)

Modified from Thilly, 1981
Sample size in brackets

All differences were significant (P<0.05).

Figure 2. The results of a controlled trial of iodized oil injection in the Jimi River district of the highlands of Papua New Guinea. Alternate mothers were given an injection of iodized oil and saline in September 1966. All newborn children were followed up for the next five years. Each dot represents a cretin child. The figure shows the disappearance of cretin children among births to mothers given iodized oil injections in comparison with their persistence in the untreated group. (Reproduced from Pharoah et al., 1971 with permission)