Increased risk of recurrence of pregnancies complicated by fetal neural tube defects in mothers receiving poor diets, and possible benefit of dietary counselling.

Abstract

Summary and conclusionsOne hundred and seventy-four women who had previously had a child with a neural-tube defect were assessed retrospectively on the quality of their diets during the first trimester of that pregnancy, between pregnancies, and during the first trimester of other pregnancies. They were then studied prospectively during the first trimester of 186 following pregnancies and the outcome of these was recorded. One hundred and three women (with 109 pregnancies) were given dietary counselling before the pregnancy, the remaining 71 (with 77 pregnancies) not being counselled. Seventyeight (72%) of the counselled women improved their diet compared with only nine (12%) of the uncounselled women. The difference was significant (p <0 001). There were three recurrences of neural-tube defects in the counselled women (3%) and five recurrences in the uncounselled (7%). Although this difference was not significant, the relative risk in the counselled group was reduced to less than half of that in the uncounselled group. All eight recurrences occurred in the 45 pregnancies in women taking poor diets (18%), whereas there were no recurrences in the 141 other pregnancies.This difference is significant (p <0 001).It is concluded that women receiving adequate diets have a lower incidence and recurrence of fetal neuraltube defects than women receiving poor diets and that dietary counselling may be effective in reducing the incidence of fetal neural-tube defects. IntroductionThe incidence of fetal neural-tube defects in all surveys carried out in the British Isles has consistently been greater in mothers in social classes 4 and 5 than in those in social classes 1 and 2,'-5 though more recently this difference has been less pronounced, possibly reflecting the general improvement in the standard of living.3 A relation undoubtedly exists between social class and maternal diet, with several studies showing that mothers in social classes 4 and 5 more often have a poor diet in early pregnancy and sometimes suffer from deficiencies of essential dietary constituents.6 With this in mind we undertook a study of the diet of women who had had pregnancies complicated by fetal neural-tube defects as part of a larger survey of the possible biochemical abnormalities during early pregnancy of women who were at increased risk of such pregnancies. We report here some of the findings of the dietary part of the study together with the effect of dietary counselling.

Reduced Risks of Neural Tube Defects and Orofacial Clefts With Higher Diet Quality

“…One small study suggested better diet quality based on food groups was protective against NTDs 27,28 . A more recent study suggested that better diet quality, using an index based on intake of several nutrients, was protective, independent of folic acid intake 29 .…”

Birth defects in Arkansas: Is folic acid fortification making a difference?

“…Specific birth defects were selected based upon information from published epidemiologic literature that supports or suggests an association with folic acid or multivitamins containing folic acid. These defects include NTDs (Laurence et al, 1980; Mulinare et al, 1988; Milunsky et al, 1989; MRC, 1991; Czeizel and Dudas, 1992; Werler et al, 1993; Khoury et al, 1996; Shaw et al, 1995b; Smithells, 1996; Berry et al, 1999), orofacial clefts (Shaw et al, 1995c; Tolarova and Harris, 1995; Werler et al, 1999); limb reduction defects (Shaw et al, 1995a; Yang et al, 1997; Werler et al, 1999), omphalocele (Botto et al, 2002), conotruncal heart defects (Shaw et al, 1995a; Czeizel, 1996; Botto et al, 1996; Botto et al, 2000), and Down syndrome (Barkai et al, 2003; Al‐Gazali et al, 2001; Hobbs et al, 2000; James et al, 1999). ARHMS' 6‐digit birth defect diagnosis codes, which are based on the CDC‐modified BPA/ICD9‐CM birth defect codes, were used to classify defect groups (Paulozzi, 1997).…”

“…Periconceptional supplementation with folic acid, or multivitamins containing folic acid, is associated with reduction in the occurrence and recurrence of NTDs (Laurence et al, 1980; Smithells et al, 1983; Mulinare et al, 1988; Milunsky et al, 1989; MRC 1991; Czeizel and Dudas, 1992; Werler et al, 1993; Khoury et al, 1996; Shaw et al, 1995b; Smithells, 1996; Berry et al, 1999). Epidemiologic evidence also supports a protective effect for some congenital heart defects (Shaw et al, 1995a; Czeizel, 1996; Botto et al, 1996; Botto et al, 2000), obstructive urinary tract defects (Czeizel and Dudas, 1992; Li et al, 1995; Czeizel, 1996; Werler et al, 1999), limb reduction defects (Shaw et al, 1995a; Yang et al, 1997; Werler et al, 1999), orofacial clefts (Shaw et al, 1995c; Tolarova and Harris, 1995; Werler et al, 1999), imperforate anus (Myers et al, 2001) and non‐syndromic omphalocele (Botto et al, 2002).…”

Guideline adaptation and implementation planning: a prospective observational study

“…The ADAPTE Collaboration recently published feedback from an on-line survey they conducted during the same period [10]. Survey participants could download the ADAPTE Manual and Toolkit but received no additional assistance; they did not necessarily engage in adaptation, and their activities were not monitored.…”