Table 2.

The distribution of age at delivery in women with preexisting diabetes mellitus, undiagnosed diabetes mellitus, gestational diabetes mellitus (GDM) or without hyperglycemia in pregnancy (HIP) in Taiwan in 2008-2017.

	Preexisting diabetes			Undiagnosed diabetes			GDM			Without HIP		P value
Age at delivery	n	(%)	OR (95% CI)	n	(%)	OR (95% CI)	n	(%)	OR (95% CI)	n	(%)
<30 years old	3,303	(23.1)	1.00	1,156	(25.5)*	1.00	69,006	(26.8)*	1.00	579,677	(37.3)*†‡	<0.001
30-34 years old	5,565	(38.9)	1.57(1.50- 1.64)	1,739	(38.3)	1.40 (1.30-1.51)	109,078	(42.3)¥∮	1.47 (1.46-1.49)	622,353	(40.0)¥₤
35-39 years old	4,258	(29.8)	2.48 (2.37-2.60)	1,281	(28.2)	2.13 (1.97-2.31)	66,065	(25.6)αβ	1.84 (1.82-1.86)	301,438	(19.4)αβγ
≥40 years old	1,182	(8.3)	4.10 (3.83-4.38)	359	(7.9)	3.56 (3.16-4.01)	13,449	(5.2)§∥	2.23 (2.19-2.28)	50,602	(3.3)§∥¶
Total	14,308	(100.0)	P<0.0001	4,535	(100.0)	P<0.0001	257,598	(100.0)	P<0.0001	1,554,070	(100.0)

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

*p < 0.05 vs. preexisting diabetes mellitus in women <30 years old. †p < 0.05 vs. undiagnosed diabetes mellitus in women <30 years old. ‡p < 0.05 vs. GDM in women <30 years old.

¥p < 0.05 vs. preexisting diabetes mellitus in women 30-34 years old. ∮p < 0.05 vs. undiagnosed diabetes mellitus in women 30-34 years old.₤p < 0.05 vs. GDM in women 30-34 years old.

αp < 0.05 vs. preexisting diabetes mellitus in women 35-39 years old. βp < 0.05 vs. undiagnosed diabetes mellitus in women 35-39 years old.γp < 0.05 vs. GDM in women 35-39 years old.

§p < 0.05 vs. preexisting diabetes mellitus in women ≥40 years old. ∥p < 0.05 vs. undiagnosed diabetes mellitus in women ≥40 years old. ¶p < 0.05 vs. GDM in women ≥40 years old.