Table 2.

Association between universal two-child policy and early-term birth when adjusting for maternal and newborn’s characteristics (n=28 966)

Adjusting variables	Adjusted RR (95% CI)	P value
Crude*	1.19 (1.15 to 1.23)	<0.0001
Maternal age	1.17 (1.13 to 1.22)	<0.0001
Previous uterine scars	1.18 (1.14 to 1.22)	<0.0001
Parity	1.19 (1.15 to 1.24)	<0.0001
Maternal age +previous uterine scars+parity	1.17 (1.13 to 1.21)	<0.0001
Maternal age +previous uterine scars+parity+precursors for delivery	1.18 (1.14 to 1.23)	<0.0001
Maternal age +previous uterine scars+parity+precursors for delivery +the other maternal and newborn characteristics†	1.18 (1.14 to 1.22)	<0.0001

*Not adjusted for any variables.

†The other maternal and newborn characteristics were shown in online supplemental eTable 1.

RR, relative risk.