Table 5. Factors associated with preterm delivery based on GEE model.

Patients’ characteristic	OR (95% CI)	P-value
Hypothyroidism alone	1.14 (0.996–1.3)	<0.0001
Diabetes mellitus alone	0.86 (0.58–1.28)	0.0567
Hypothyroidism and Diabetes Mellitus	1.86 (0.87–3.98)	0.4613
Age, years	1.02 (1.01–1.03)	0.1101
Parity, 2–5 deliveries vs. 1 delivery	0.42 (0.39–0.46)	<0.0001
Parity, >6 deliveries vs. 1 delivery	0.4 (0.35–0.46)	<0.0001
Infertility treatment	1.35 (1.13–1.61)	<0.0001
History of preterm delivery	1.75 (1.53–1.99)	0.0008
Infection of amniotic fluid	4.09 (3.37–4.97)	<0.0001
PPROM	5.37 (4.64–6.2)	<0.0001
Male gender	0.91 (0.85–0.97)	<0.0001
Chronic HTN	5.38 (4.66–6.2)	0.0049
>3 Spontaneous abortion	1.11 (0.91–1.35)	<0.0001

Notes.

GEE - Generalized estimating equations; PPROM – Preterm prelabor rupture of membranes; HTN – Hypertension.