Table 3.

Prevalence of preexisting diabetes mellitus, undiagnosed diabetes mellitus and gestational diabetes mellitus (GDM) in different age groups by year in Taiwan in 2008-2017*.

	2008	2009	2010	2011	2012	2013	2014	2015	2016	2017	P for trend
Preexisting diabetes (%)
<30 years old	0.37	0.49	0.50	0.44	0.53	0.55	0.58	0.52	0.56	0.59	0.004
30-34 years old	0.55	0.75	0.78	0.73	0.71	0.81	0.82	0.80	0.78	0.80	0.032
≥35 years old	1.00	1.19	1.22	1.24	1.17	1.17	1.31	1.28	1.39	1.25	0.015
Undiagnosed diabetes (%)
<30 years old	0.16	0.13	0.14	0.12	0.14	0.15	0.16	0.24	0.24	0.34	0.006
30-34 years old	0.22	0.21	0.19	0.16	0.22	0.23	0.22	0.24	0.32	0.36	0.010
≥35 years old	0.34	0.34	0.35	0.34	0.37	0.34	0.36	0.35	0.41	0.47	0.015
GDM (%)
<30 years old	8.89	9.77	10.04	10.42	10.63	11.07	11.76	12.47	10.87	10.65	0.016
30-34 years old	12.87	14.12	14.47	14.95	14.66	15.03	15.51	16.24	14.94	14.38	0.053
≥35 years old	15.49	16.25	17.24	18.19	18.30	18.90	18.78	19.39	18.19	18.24	0.009

Preexisting diabetes mellitus, diabetes diagnosed before pregnancy; undiagnosed diabetes, diabetes mellitus first detected in early pregnancy, before 20 weeks of gestation.

*Prevalence was calculated by using the number of women with the indicated disease in the age group in the year as the numerator and the number of all pregnant women in the age group in the year as the denominator.