Division of Obstetrics and Gynaecology, Akershus University Hospital, Lørenskog, 1478, Norway.
Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
Eur J Epidemiol. 2024 Aug;39(8):905-914. doi: 10.1007/s10654-024-01148-y. Epub 2024 Aug 24.
We studied mean changes in birthweight from the first to the second delivery according to length of the inter-pregnancy interval. We also studied recurrence risk of low birthweight, preterm birth and perinatal death. We followed all women in Norway from their first to their second singleton delivery at gestational week 22 or beyond during the years 1970-2019, a total of 654 100 women. Data were obtained from the Medical Birth Registry of Norway. Mean birthweight increased from the first to the second delivery, and the increase was highest in pregnancies conceived < 6 months after the first delivery; adjusted mean birthweight increase 227 g (g) (95% CI; 219-236 g), 90 g higher than in pregnancies conceived 6-11 months after the first delivery (137 g (95% CI; 130-144 g)). After exclusion of women with a first stillbirth, the mean increase in birthweight at inter-pregnancy interval < 6 months was attenuated (152 g, 95% CI; 143-160 g), but remained higher than at longer inter-pregnancy intervals. This finding was particularly prominent in women > 35 years (218 g, 95% CI; 139 -298 g). In women with a first live born infant weighing < 2500 g, mean birthweight increased by around 1000 g to the second delivery, and the increase was most prominent at < 6 months inter-pregnancy interval. We found increased recurrence risk of preterm birth at inter-pregnancy interval < 6 months, but no increased recurrence risk of low birthweight, small for gestational age infant or perinatal death. In conclusion, we found the highest mean increase in birthweight when the inter-pregnancy interval was short. Our results do not generally discourage short pregnancy intervals.
我们根据两次妊娠间隔的长短，研究了从第一次分娩到第二次分娩时的体重均值变化。我们还研究了低出生体重、早产和围产儿死亡的复发风险。我们对所有于 1970 年至 2019 年间在妊娠 22 周或以上时初次分娩的单胎挪威女性，进行了随访，共涉及 654100 名女性。数据来源于挪威医学出生登记处。从第一次分娩到第二次分娩，出生体重均值呈上升趋势，且在距第一次分娩不到 6 个月怀孕的孕妇中增长幅度最大；调整后的平均出生体重增加 227g（95%CI：219-236g），比距第一次分娩 6-11 个月怀孕的孕妇高 90g（137g（95%CI：130-144g））。排除首次死胎后，在间隔不到 6 个月的妊娠中，出生体重的均值增加幅度有所减弱（152g，95%CI：143-160g），但仍高于较长的妊娠间隔。这一发现在年龄超过 35 岁的女性中尤为明显（218g，95%CI：139-298g）。在首次分娩的活产婴儿体重<2500g 的女性中，第二次分娩的出生体重平均增加了约 1000g，且在间隔不到 6 个月的妊娠中增长幅度最为显著。我们发现，在间隔不到 6 个月的妊娠中，早产的复发风险增加，但低出生体重、小于胎龄儿或围产儿死亡的复发风险没有增加。总之，我们发现当两次妊娠间隔较短时，出生体重的均值增长幅度最大。我们的研究结果通常不会劝阻缩短妊娠间隔。
