Maternal Thyroid Function during the Second Half of Pregnancy and Child Neurodevelopment at 6, 12, 24, and 60 Months of Age

Table 4

Associations between maternal thyroid hormone levels during pregnancy (27 weeks’ gestation) and child neurodevelopment at 6, 12 and 24 months of age.

			Bayley scales		Preschool language scale
			Mental development index	Psychomotor development index	Auditory comprehension	Expressive comprehension	Total score
6 Months^1	Free T4	β	−3.14	−3.27	−2.03	1.65	−0.10
		(95% CI)	(−7.65, 1.36)	(−9.36, 2.82)	(−9.80, 5.75)	(−5.48, 8.79)	(−6.45, 6.25)
	Total T4	β	0.03	−0.06	−0.24	0.58	0.19
		(95% CI)	(−0.57, 0.62)	(−0.86, 0.74)	(−1.28, 0.80)	(−0.37, 1.53)	(−0.66, 1.05)
	TSH	β	0.85	1.46	1.51	0.24	1.06
		(95% CI)	(−0.49, 2.18)	(−0.33, 3.26)	(−0.81, 3.84)	(−1.91, 2.38)	(−0.87, 2.98)
12 Months^2	Free T4	β	−0.48	−6.40	4.39	1.26	3.45
		(95% CI)	(−6.22, 5.26)	(−13.89, 1.08)	(−3.56, 12.34)	(−7.20, 9.72)	(−4.76, 11.67)
	Total T4	β	−0.12	−0.45	0.33	−0.15	0.12
		(95% CI)	(−0.92, 0.68)	(−1.53, 0.63)	(−0.79, 1.46)	(−1.34, 1.04)	(−1.05, 1.28)
	TSH	β	1.71	0.10	2.92	0.46	1.91
		(95% CI)	(0.05, 3.37)*	(−2.16, 2.35)	(0.59, 5.25)*	(−2.04, 2.95)	(−0.51, 4.33)
24 Months^3	Free T4	β	−4.29	−2.67
		(95% CI)	(−11.60, 3.02)	(−8.95, 3.62)
	Total T4	β	−0.17	0.43
		(95% CI)	(−1.20, 0.85)	(−0.43, 1.30)
	TSH	β	0.33	−1.31
		(95% CI)	(−1.97, 2.63)	(−3.25, 0.63)

^∗𝑃<0.05.
¹Models adjusted for maternal age, employment status at enrollment and at the 6-months visit, country of birth, time lived in the US, Diet Quality Index, blood lead levels and delivery complications; child hospitalization before 6 months, season of assessment and psychometrician.
²Models adjusted for maternal age, employment status at enrollment and at the 6 months visit, country of birth, time lived in the US, Diet Quality Index, Kotelchuck Adequacy of Prenatal Care Utilization Index, blood lead levels, delivery complications and PPVT score; child age, preterm birth, hospitalization at 6 months and 1 year, family structure at 1 year; season, and language spoken at the time of assessment.
³Models adjusted for maternal age, income, employment status at enrollment, 6 months and 1 year, country of birth, Diet Quality Index, Kotelchuck Adequacy of Prenatal Care Utilization Index, blood lead levels, delivery complications, PPVT score; child hospitalization at 1 year; number of children in the home at 6 months, home density at 2 years, family structure at 1 year; season, psychometrician and language of assessment.
⁴Since TSH was expressed on a log₂ basis, β are equal to the change in neurodevelopmental outcomes for a doubling in TSH levels.