Table 3.
Maternal folate concentrationa/deficiencyb during pregnancy and offspring head size at 20 weeks of gestation, prenatal head growth and postnatal head growthc
| Head circumference size (SDS) | ||||||
|---|---|---|---|---|---|---|
| Basicd | Adjusted for covariatese | |||||
| SDSf | Bg (95 % CI) | P | SDSf | Bg (95 % CI) | P | |
| Head size (intercept (SDS) at 20 weeks gestation) and folate concentration (n = 5832 (99.4 %), 11,323 observations) | ||||||
| Mean folateh,i | −0.055 | Reference | 0.074 | Reference | ||
| Folate (per SD)j | −0.021 | 0.034 (0.007; 0.061) | 0.01 | 0.081 | 0.007 (−0.022; 0.037) | 0.63 |
| Normal folatei | −0.051 | Reference | 0.077 | Reference | ||
| Folate-deficient | −0.100 | −0.049 (−0.148; 0.049) | 0.32 | 0.110 | 0.033 (−0.068; 0.134) | 0.52 |
| Head circumference growth (SDS) | ||||||
|---|---|---|---|---|---|---|
| Basicd | Adjusted for covariatese | |||||
| Bk (95 % CI) | P | Bk (95 % CI) | P | |||
| Period of head growth and folate concentration | ||||||
| Second and third trimester (n = 5832 (99.4 %), 11,323 observations) | ||||||
| Folate (per SD)h,i | 0.006 (0.003; 0.009) | <0.001 | 0.004 (0.001; 0.007) | 0.01 | ||
| Folate-deficient | −0.013 (−0.023; −0.002) | 0.02 | −0.007 (−0.018; 0.004) | 0.19 | ||
| Birth through 6 years (n = 5515 (94.0 %), 29,976 observations) | ||||||
| Folate (per SD)h,i | −0.000 (−0.000; 0.000) | 0.28 | −0.000 (−0.000; 0.000) | 0.66 | ||
| Folate-deficient | 0.000 (−0.000; 0.001) | 0.06 | 0.000 (−0.000; 0.000) | 0.29 | ||
SDS standard deviation score
aFolate concentration in standard deviation scores
bFolate deficiency was defined as a folate concentration < 7 nmol/L. Subjects without folate deficiency comprised the reference group ‘normal folate’
cGender and gestational age-adjusted foetal and child head circumference standard deviation scores
dModel 1: adjusted for gestational age at venipuncture
eModel 2: model 1, additionally adjusted for maternal age, ethnicity, education, income, parity, BMI, psychopathology, smoking and alcohol consumption during pregnancy and the interactions between gestational age and: maternal smoking, ethnicity and education
fValues represent offspring head size in SDS at 20 weeks of gestation (intercept) per type of folate concentration from mixed model regression analyses
gValues represent Β (95 % CI) for the difference in offspring head size (intercept) for each type of folate concentration compared with its reference (‘mean folate’ or ‘normal folate’) from mixed model regression analyses
hMean folate concentration: 0 SDS ≡ 17.4 nmol/L
iReference group of primiparae women who never smoked or drank alcohol during pregnancy, with mean age of 29.8 years and mean BMI of 24.5 at enrolment, Dutch national origin, higher education, family income > € 2000/month and median Global Severity Index score of 0.17 in mid-pregnancy
jStandard deviation folate concentration: 8.8 nmol/L
kValues represent Β (95 % CI) for the interaction between maternal folate concentration/deficiency and gestational age (in weeks) from mixed model regression analyses, i.e. the difference in head circumference growth (in SDS) per week for each SD increase in folate concentration/between children of mothers with and without folate deficiency