Table 3.

Cox regression results of second childbirth

Variable	Model 1	Model 2	Model 3
	Coefficient (SE)	Coefficient (SE)	Coefficient (SE)
Fertility intention
Intended number of children		0.615***	0.632***
		(0.107)	(0.109)
Presence of son preference (reference category: No)
Yes			−0.162+
			(0.091)
Individual characteristics
Age	−0.252**	−0.261**	−0.251*
	(0.098)	(0.097)	(0.098)
Age squared	0.006***	0.006***	0.006***
	(0.001)	(0.001)	(0.001)
Age at first childbirth	−0.188***	−0.187***	−0.187***
	(0.019)	(0.020)	(0.020)
Year of first childbirth (reference category: 2000 and after)
1980s and 1990s	−0.710***	−0.736***	−0.738***
	(0.147)	(0.148)	(0.147)
Hukou type (reference category: non-rural type)
Rural type	0.827***	0.812***	0.822***
	(0.123)	(0.124)	(0.124)
Education (reference category: elementary school and below)
Middle school	−0.311*	−0.145	−0.164
	(0.137)	(0.141)	(0.142)
High school/technical secondary school	−0.499**	−0.350+	−0.373*
	(0.175)	(0.179)	(0.180)
Junior college	−2.059***	−1.908***	−1.942***
	(0.374)	(0.376)	(0.377)
College and above	−3.355***	−3.337**	−3.372***
	(1.016)	(1.016)	(1.016)
Existing childbirth status
Gender of first child (reference category: Female)
Male	−0.718***	−0.678***	−0.658***
	(0.079)	(0.080)	(0.081)
Prior abortion (reference category: No)
Yes	−0.916***	−0.939***	−0.937***
	(0.215)	(0.215)	(0.215)
Family environment
Number of paternal siblings	0.086**	0.076**	0.073*
	(0.029)	(0.030)	(0.030)
Presence of parents-in-law (reference category: No)
Yes	3.614**	3.337**	3.384**
	(1.284)	(1.256)	(1.261)
Presence of parents-in-law * Age	−0.087**	−0.080**	−0.081**
	(0.032)	(0.031)	(0.031)
Regional factor
Region (reference category: Central Shaanxi)
Southern Shaanxi	−0.151	−0.202*	−0.197*
	(0.100)	(0.100)	(0.100)
Northern Shaanxi	0.746***	0.654***	0.727***
	(0.100)	(0.101)	(0.110)
Sample size	2,101	2,101	2,101
−2LL	871.57***	906.53***	909.71***

^***p<0.001;

^**p<0.01;

^*p<0.05;

+p<0.1