Maternal cognitive function during pregnancy in relation to hypo‐ and hyperthyroxinemia

Abstract

Objective:To assess a possible relationship between maternal cognitive dysfunction during pregnancy and hypothyroxinemia, adjusted for major confounders.Background: Thyroid dysfunction in general is associated with cognitive dysfunction.Cognitive dysfunction is common during pregnancy.Design: Prospective follow-up study from 12 to 32 weeks of pregnancy. Participants: 2082 healthy pregnant women.Measurements: Cognitive function, depression and sleeping problems were assessed by self-report questionnaires at 12, 22 and 32 weeks of gestation, higher scores reflecting more symptoms. FT4, TSH and TPO-Ab were assessed at 12 weeks of gestation.Definitions: healthy (euthyroxinemia) control group: FT4 within 10-90th percentiles, without elevated TPO-Ab titres and TSH within first trimester-specific reference range (0.23-4.0 mU/L). Hypothyroxinemia: FT4 <2.5th percentile with TSH within first trimester-specific reference range. Poor cognitive function: a score >1 SD > mean on the cognitive function scale.Results: A total of 54 women showed hypothyroxinemia and 1476 women had euthyroxinemia. At 12 weeks, multiple logistic regression showed that poor cognitive function was independently related to hypothyroxinemia: OR: 2.9 (95% CI: 1.6-5.4), adjusted for depression (OR: 3.1; 95% CI: 2.7-4.6) and sleeping problems (OR: 2.8, 95% CI: 1.9-3.9). TPO-Ab + women with hypothyroxinemia had the highest levels of cognitive dysfunction. Other cut-offs of hypothyroxinemia (<5th or <10th percentile with normal TSH) showed similar results. GLM-ANOVA showed that throughout pregnancy women with hypothyroxinemia at 12 weeks had significantly higher cognitive dysfunction scores compared with the healthy controls: F = 12.1, P = .001. Conclusions:Women with hypothyroxinemia during early gestation are at risk for poor cognitive function throughout gestation, adjusted for depression and sleeping problems. K E Y W O R D Scognitive function, hypothyroxinemia, pregnancy, thyroid | 825 POP et al.

Method-dependent variation in TSH and FT4 reference intervals in pregnancy: A systematic review

“…Nineteen studies excluded women with antibodies to either thyroid peroxidase (TPOAb) or thyroglobulin (TgAb), 13,14,17–20,22,31,33,34,36,39,41,44,45,47,51,52,55 while 24 studies did not measure TgAbs and excluded women with positive TPOAb only. 15,16,21,23–25,27–30,32,35,37,38,40,42,43,46,48–50,53,54 The median age of patients ranged from 24 to 35 years with TSH and FT4 reference intervals determined during the first, second and third trimesters in 42, 28 and 26 studies, respectively. Studies that presented data separately for patients with different ethnicities and with multiple assay methods are presented separately.…”

Neuroendocrine Aspects of Pregnancy and Postpartum Depression

“…Women with hyperthyroxinemia showed less (but not significantly) cognitive dysfunction compared with the TPO-Ab-negative control group. Finally, within the hypothyroxinemic subgroups of women, those with elevated titres of TPO-Ab showed the poorest cognitive function (2).…”

“…Exposure to high levels of maternal stress during pregnancy has the potential to adversely impact maternal mental and physical health as well as fetal development (1). Women with hypothyroxinemia during early gestation are at risk for poor cognitive function throughout gestation, adjusted for depression and sleeping problems (2).…”

Does foetal gender influence maternal thyroid parameters in pregnancy?

“…In a review paper, TAI was not an important etiologic factor for the development of IH (39). However, in a recent Dutch study, the prevalence of elevated TPOAb was twice as high in women with IH (taking all FT4 cut-offs into account), compared with that in euthyroid women (40). The role of iron deficiency needs to be investigated further in this context since it might link TAI and lower FT4 levels (1).…”