Age-period-cohort effects in pre-existing and pregnancy-associated diseases amongst primiparous women

Table 2 Contribution of temporal trends in pre-existing and gestational comorbidities on perinatal outcomes

Perinatal outcome	Rate per 100 births		Relative change (2004 vs. 2014)
Perinatal outcome	2004 (n = 1,121,535)	2014 (n = 1,244,642)	Rate difference (95% CI)	Rate ratio (95% CI)	Percent change
Small for gestational age
Crude Adjusted for demographic variables^a Adjusted for demographic variables^a and comorbidities^b Incremental effect of comorbidities^b	113.35 110.59 101.26	123.65 124.77 124.95	10.30 (9.48–11.13) 14.18 (13.36–15.01) 23.69 (22.88–24.50)	1.09 (1.08–1.10) 1.13 (1.12–1.14) 1.23 (1.22–1.25) 0.10 (0.10–0.11)	9.09 12.83 23.40 10.57
Large for gestational age
Crude Adjusted for demographic variables^a Adjusted for demographic variables^a and comorbidities^b Incremental effect of comorbidities^b	71.47 72.68 78.74	72.02 71.46 71.82	0.54 (− 0.12, 1.20) − 1.23 (− 1.89, − 0.57) − 6.92 (− 7.60, − 6.25)	1.01 (1.00–1.02) 0.98 (0.97–0.99) 0.91 (0.90–0.93) − 0.07 (− 0.07, − 0.06)	0.76 − 1.69 − 8.79 − 7.10
Preterm birth
Crude Adjusted for demographic variables^a Adjusted for demographic variables^a and comorbidities^b Incremental effect of comorbidities^b	86.47 83.80 84.72	89.06 88.70 88.46	2.59 (1.87–3.31) 4.90 (4.18–5.62) 3.73 (3.02–4.45)	1.01 (1.02–1.04) 1.06 (1.05–1.07) 1.04 (1.03–1.06) − 0.02 (− 0.02, − 0.01)	2.99 5.85 4.41 − 1.44

^aDemographic variables include maternal age, maternal race, maternal education, marital status, smoking status, and gestational weight gain
^bComorbidities include chronic hypertension, pregnancy associated hypertension, eclampsia, pre-existing diabetes, and gestational diabetes

ISSN: 2042-6410