New follow-up of hydatidiform mole.

neural-tulbe defects. This is not a new suggestion."3 Of great relevance is the recent work of E. G. Knox on the possible relationship with anencephalus of more than a hundred different foodstuffs.22 Data on their consumption in England and Wales 'by yearly quarters in the years 1961-7 were correlated with quarterly anencephalus rates, with due allowance for gestation length. Far from confirming the potato hypothesis, a negative temporal correlation with old potatoes was found. The strongest associations were found with bread, cereals, ice cream, canned peas, and cured and canned meat products. Other correlations were evident with these meat products. Thus, those regions of England and Wales with the greatest intakes of cured meats had the highest anencephalus rates, while a drop in the sale of corned beef after the Aberdeen typhoid outbreak was followed six months later by the lowest anencephalus rates on record. In addition, the estimated intake of nitrite-cured meats over a nine-year period showed a remarkably close correlation with anencephalus rates. Interestingly, nitrates and nitrites used to cure meats are known to produce nitrosamines by bacterial digestive processes at least analogous to the curing process, and these are teratogenic in certain mammals.23 Knox is cautious in interpreting these results, but his conclusion that certain food additives and their associated processes deserve further investigation should be followed up. The case against the potato is far from compelling. Nevertheless, it has been argued that when a theory suggests a simple preventive measure against such major malformations the proper reaction is to apply the measure and test the theory in practice.3 Against this it can be said that strong dietary advice may encourage obsessive feelings and neurotic overconcern, not to mention guilt if the advice is not religiously followed. Most, however, would support on general grounds the statement by Sir Keith Joseph in the Commons that "it is always wise to discard any potatoes that are diseased, decayed or discoloured and to cut away any damaged portions."24 Until a trial or other appropriate work has provided more conclusive evidence, the theory can be explained to women with an affected child who are planning another pregnancy so that if they wish they can avoid potatoes completely until they become pregnant and the fetus is at least two months old.