Mater Research Institute, University of Queensland, Brisbane, Queensland, Australia; Mater Mothers' Hospital, Brisbane, Queensland, Australia.
Torus Research, Brisbane, Australia.
Am J Obstet Gynecol. 2021 Oct;225(4):415.e1-415.e9. doi: 10.1016/j.ajog.2021.04.219. Epub 2021 Apr 20.
Small-for-gestational-age infants are at a substantially increased risk of perinatal complications, but the risk of recurrent small-for-gestational-age is not well known, particularly because there are many demographic and obstetrical factors that interact and modify this risk. We investigated the relationship between previous small-for-gestational-age births and the risk of recurrence at term in a large Australian cohort.
We aimed to identify key demographic and obstetrical variables that influence the risk of recurrence of a small-for-gestational-age infant at term. The primary outcome measure was the odds of recurrence of small-for-gestational-age in subsequent pregnancies up to a maximum of 4 consecutive term births.
This was a retrospective analysis of women who had more than 1 consecutive nonanomalous, singleton, term live births between July 1997 and September 2018 at the Mater Mother's Hospital in Brisbane, Australia. Women with multiple pregnancy, preterm birth, or major congenital malformations were excluded. Small-for-gestational-age was defined as birthweight at the <10th centile. We calculated the odds of recurrence depending on the number of previous small-for-gestational-age infants and if only the preceding infant was small-for-gestational-age. The study population was dichotomized into small-for-gestational-age and non-small-for-gestational-age for each consecutive pregnancy. Univariate analyses compared baseline demographic and obstetrical characteristics followed by logistic regression modeling to determine the odds of recurrence in the second, third, and fourth pregnancies.
The final study comprised 24,819 women. The proportion of women who had a small-for-gestational-age infant in their first pregnancy was 9.4%, whereas the proportion of women who had a small-for-gestational-age infant in their second, third, and fourth pregnancies after the birth of a previous small-for-gestational-age infant were 20.5% (479 of 2338), 24.6% (63 of 256), and 30.4% (14 of 46), respectively. Regardless of parity, the odds of recurrence increased if the preceding infant was small-for-gestational-age. The odds of recurrence increased markedly if there was more than 1 previous small-for-gestational-age infant. In women with 3 previous small-for-gestational-age infants, the adjusted odds of another small-for-gestational-age infant were 66.00 (95% confidence interval, 11.35-383.76). Maternal age, body mass index, ethnicity, and smoking were significant risk factors for recurrent small-for-gestational-age. However, maternal diabetes mellitus or hypertension, either in a previous or current pregnancy, did not influence the risk of recurrence.
The risk of recurrence in a subsequent pregnancy increased if there was a previous small-for-gestational-age birth. Women with consecutive small-for-gestational-age infants were at the highest risk of recurrence. Our results highlight that women with a previous small-for-gestational-age infant are at a substantial risk of another small infant and need to be counseled and monitored appropriately.
小于胎龄儿（SGA）的围产期并发症风险显著增加，但 SGA 复发的风险尚不清楚，特别是因为有许多人口统计学和产科因素相互作用并改变了这种风险。我们在一个大型澳大利亚队列中研究了既往 SGA 分娩与足月时 SGA 复发风险之间的关系。
我们旨在确定影响足月时 SGA 复发风险的关键人口统计学和产科变量。主要结局指标是随后妊娠中 SGA 复发的比值比（OR），最多可随访至连续 4 次足月分娩。
这是一项对 1997 年 7 月至 2018 年 9 月在澳大利亚布里斯班 Mater Mother's 医院连续有 1 次以上非多胎、单胎、足月活产的女性进行的回顾性分析。排除多胎妊娠、早产或重大先天性畸形的女性。SGA 定义为出生体重位于第 10 百分位数以下。我们根据既往 SGA 婴儿的数量以及仅前一个婴儿是否为 SGA 来计算复发的 OR。对于每个连续妊娠，研究人群均分为 SGA 和非 SGA。单变量分析比较了基线人口统计学和产科特征，然后进行逻辑回归模型分析，以确定第二、第三和第四次妊娠中复发的 OR。
最终研究纳入了 24819 名女性。在第一次妊娠中，SGA 婴儿的比例为 9.4%，而在前一次 SGA 婴儿出生后，第二次、第三次和第四次妊娠中 SGA 婴儿的比例分别为 20.5%（479/2338）、24.6%（63/256）和 30.4%（14/46）。无论产次如何，如果前一个婴儿是 SGA，复发的 OR 都会增加。如果有多个既往 SGA 婴儿，复发的可能性会显著增加。在前 3 次妊娠中均有 SGA 婴儿的女性中，再次发生 SGA 婴儿的调整 OR 为 66.00（95%置信区间，11.35-383.76）。产妇年龄、体重指数、种族和吸烟是 SGA 复发的显著危险因素。然而，既往或当前妊娠中存在糖尿病或高血压均不会影响复发的风险。
如果有既往 SGA 分娩，随后妊娠中复发的风险会增加。连续出现 SGA 婴儿的女性复发风险最高。我们的结果表明，有既往 SGA 婴儿的女性再次出现小婴儿的风险很大，需要进行适当的咨询和监测。
