Association between levothyroxine supplementation for hypothyroidism in late pregnancy and risk of prematurity: a population-based cohort study

Table 3 Associations between levothyroxine dosage variation after the 14th weeks’ gestation and risk of prematurity

	N	Crude RR		Adjusted RR
Exposure	N = 6543^a	RR^b	95% CI^b	RR^c,b	95% CI^b	p -value
Levothyroxine dosage variation
No change	4173 (63.8%)	1.00	—	1.00	—
Increased	2370 (36.2%)	0.87	0.72, 1.06	0.84	0.67, 1.05	0.13

^a n (%)
^b RR, risk ratio; CI, confidence interval
^cAdjusted for: maternal age at LMP, welfare recipient, urban dweller, chronic hypertension, chronic diabetes, depression and anxiety, other psychiatric disorders, asthma, epilepsy, emergency visit and/or hospitalization, endocrinologist visits, general practitioner visits, other specialist visits, tobacco dependence, alcohol dependence, other drug dependence, obesity, preeclampsia or eclampsia, gestational hypertension, gestational diabetes, placenta previa, placental abruption, prenatal care by obstetrician/gynecologist, pregnancy 12 months before LMP, folic acid supplementation 6 months before LMP until end of first trimester

ISSN: 1741-7015