Pregnancy outcomes in bridal pregnancy and post-marital pregnancy, according to maternal age groups.

PTB, preterm birth; VPTB, very preterm birth; LBW, low birth weight; VLBW, very low birth weight; OR, odds ratio.
1Bridal pregnancy is defined as childbirth before 5 months of marriage.
2Post-marital pregnancy is defined as childbirth between 10 and 24 months of marriage.
3Calculated using the χ2 test.
4Adjusted for birthplace, sex, paternal age, paternal and maternal employment, and paternal and maternal education level.

PTB即早产（preterm birth），VPTB即极早产（very preterm birth），LBW即低出生体重儿（low birth weight），VLBW即极低出生体重儿（very low birth weight），OR即比值比（odds ratio）。
1. 新婚妊娠（bridal pregnancy）定义为结婚前5个月内分娩。
2. 婚后妊娠（post-marital pregnancy）定义为结婚后10至24个月内分娩。
3. 相关指标经χ²检验（卡方检验）计算得出。
4. 已对以下混杂因素进行校正：出生地、婴儿性别、父亲年龄、父母职业及父母受教育程度。