OBJECTIVE To explore conditions and outcomes of a first delivery at term that might predict later preterm birth. DESIGN Population based, prospective register based study. SETTING Medical Birth Registry of Norway, 1999-2015. PARTICIPANTS 302 192 women giving birth (live or stillbirth) to a second singleton child between 1999 and 2015. MAIN OUTCOME MEASURES Main outcome was the relative risk of preterm delivery (<37 gestational weeks) in the birth after a term first birth with pregnancy complications: pre-eclampsia, placental abruption, stillbirth, neonatal death, and small for gestational age. RESULTS Women with any of the five complications at term showed a substantially increased risk of preterm delivery in the next pregnancy. The absolute risks for preterm delivery in a second pregnancy were 3.1% with none of the five term complications (8202/265 043), 6.1% after term pre-eclampsia (688/11 225), 7.3% after term placental abruption (41/562), 13.1% after term stillbirth (72/551), 10.0% after term neonatal death (22/219), and 6.7% after term small for gestational age (463/6939). The unadjusted relative risk for preterm birth after term pre-eclampsia was 2.0 (95% confidence interval 1.8 to 2.1), after term placental abruption was 2.3 (1.7 to 3.1), after term stillbirth was 4.2 (3.4 to 5.2), after term neonatal death was 3.2 (2.2 to 4.8), and after term small for gestational age was 2.2 (2.0 to 2.4). On average, the risk of preterm birth was increased 2.0-fold (1.9-fold to 2.1-fold) with one term complication in the first pregnancy, and 3.5-fold (2.9-fold to 4.2-fold) with two or more complications. The associations persisted after excluding recurrence of the specific complication in the second pregnancy. These links between term complications and preterm delivery were also seen in the reverse direction: preterm birth in the first pregnancy predicted complications in second pregnancies delivered at term. CONCLUSIONS Pre-eclampsia, placental abruption, stillbirth, neonatal death, or small for gestational age experienced in a first term pregnancy are associated with a substantially increased risk of subsequent preterm delivery. Term complications seem to share important underlying causes with preterm delivery that persist from pregnancy to pregnancy, perhaps related to a mother's predisposition to disorders of placental function.

中文翻译：

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足月并发症和随后的早产风险：基于登记的研究。


目的 探讨足月首次分娩的条件和结果，以预测以后的早产。设计 基于人群、前瞻性登记的研究。设置挪威医学出生登记处，1999-2015 年。参与者 302 192 名在 1999 年至 2015 年间生育第二个单胎的妇女（活产或死产）。 主要观察指标 主要观察指标是第一胎足月分娩后出现妊娠并发症的早产相对风险（<37 孕周） ：先兆子痫、胎盘早剥、死产、新生儿死亡和小于胎龄。结果 足月时患有五种并发症中任何一种的女性在下次怀孕时早产的风险显着增加。第二次妊娠的早产绝对风险为 3.1%，无五种足月并发症 (8202/265 043)，足月先兆子痫后为 6.1% (688/11 225)，足月胎盘早剥后为 7.3% (41/ 562），足月死产后 13.1%（72/551），足月新生儿死亡 10.0%（22/219），足月小于胎龄后 6.7%（463/6939）。足月先兆子痫后早产的未经调整相对风险为 2.0（95% 置信区间 1.8 至 2.1），足月胎盘早剥后为 2.3（1.7 至 3.1），足月死产后为 4.2（3.4 至 5.2），足月新生儿后死亡人数为 3.2（2.2 至 4.8），足月后小于胎龄儿为 2.2（2.0 至 2.4）。平均而言，第一次妊娠出现一种足月并发症时，早产风险会增加 2.0 倍（1.9 倍至 2.1 倍），而出现两种或两种以上并发症时，早产风险会增加 3.5 倍（2.9 倍至 4.2 倍）。在排除第二次妊娠中特定并发症的复发后，这种关联仍然存在。 足月并发症和早产之间的联系也存在相反的方向：第一次妊娠的早产预示着第二次妊娠足月分娩的并发症。结论 第一次足月妊娠中出现的先兆子痫、胎盘早剥、死产、新生儿死亡或小于胎龄与随后早产的风险显着增加相关。足月并发症似乎与早产有着共同的重要根本原因，并且从怀孕到怀孕持续存在，可能与母亲易患胎盘功能障碍有关。