METHODS: This retrospective cohort study of 9,867 twin pregnancies in Western Australia from 1980-2015. Relative Risks (RRs) were estimated for the interval prior to the pregnancy (IPI) as the exposure and after the pregnancy as a negative control exposure for preterm birth (< 37 weeks), early preterm birth (< 34 weeks), small for gestational age (SGA: < 10th percentile of birth weight by sex and gestational age) and low birth weight (LBW: birthweight < 2,500 g).
RESULTS: Relative to IPIs of 18-23 months, IPIs of < 6 months were associated with a higher risk of early preterm birth (aRR 1.41, 95% CI 1.08-1.83) and LBW for at least one twin (aRR 1.16, 95% CI 1.06-1.28). IPIs of 6-11 months were associated with a higher risk of SGA (aRR 1.24, 95% CI 1.01-1.54) and LBW for at least one twin (aRR 1.09, 95% CI 1.01-1.19). IPIs of 60-119 months and ≥ 120 months were associated with an increased risk of preterm birth (RR 1.12, 95% CI 1.03-1.22; and (aRR 1.25, 95% CI 1.10-1.41, respectively), and LBW for at least one twin (aRR 1.17, 95% CI 1.08-1.28; and aRR 1.20, 95% CI 1.05-1.36, respectively). IPIs of ≥ 120 months were also associated with an increased risk of early preterm birth (aRR 1.42, 95% CI 1.01-2.00). After negative control analysis, IPIs ≥ 120 months remained associated with early preterm birth and LBW.
CONCLUSIONS: Evidence for adverse associations with twin birth outcomes was strongest for long IPIs.
方法:这项对1980-2015年西澳大利亚9,867例双胎妊娠的回顾性队列研究。相对风险(RRs)估计为怀孕前的间隔(IPI)作为暴露和怀孕后作为早产的阴性对照暴露(<37周),早产(<34周),小于胎龄(SGA:按性别和胎龄划分的出生体重<10百分位数)和低出生体重(LBW:出生体重<2,500g)。
结果:相对于18-23个月的IPI,<6个月的IPI与较高的早期早产风险(aRR1.41,95%CI1.08-1.83)和至少一个双胞胎的LBW(aRR1.16,95%CI1.06-1.28)相关。6-11个月的IPI与至少一个双胞胎的SGA(aRR1.24,95%CI1.01-1.54)和LBW的高风险相关(aRR1.09,95%CI1.01-1.19)。60-119个月和≥120个月的IPI与早产风险增加相关(RR1.12,95%CI1.03-1.22;和(RR分别为1.25,95%CI1.10-1.41),至少一个双胞胎的LBW(分别为aRR1.17,95%CI1.08-1.28;和aRR1.20,95%CI1.05-1.36)。≥120个月的IPI也与早期早产风险增加相关(aRR1.42,95%CI1.01-2.00)。阴性对照分析后,IPIs≥120个月与早期早产和LBW相关。
结论:长期IPI与双胎分娩结局不良相关的证据最强。