Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy.
Infertility Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.
Acta Obstet Gynecol Scand. 2024 Jan;103(1):121-128. doi: 10.1111/aogs.14685. Epub 2023 Oct 9.
Evidence on the role of medically assisted reproduction (MAR) in achieving the desired number of children is very limited. The aim of the current investigation was to assess the probability and the mode of conception of a second live birth according to the mode of conception of the first one.
This historical cohort study was based on administrative data from regional healthcare databases. Women hospitalized for childbirth in Lombardy between January 1, 2007 and December 31, 2017 were identified. The probability of a second live birth up to 2021 was estimated using the Kaplan-Meier method. We calculated this probability according to the mode of conception of the first birth, and the analysis was also performed in strata of maternal age at first birth. Cox proportional hazards models were fitted to estimate the hazard ratio (HR) and 95% confidence interval (CI) of the association between mode of conception at first live birth and the probability of having a second live birth. Mothers were right-censored if they moved out of the region, died, or did not have a second live birth by the end of follow-up.
We identified 431 333 women who had their first live birth after a natural conception and 16 837 who had their first live birth after MAR. The probability of having a second live birth was 58.6% and 32.1%, respectively in the two groups (HR = 0.68, 95% CI: 0.66-0.70). Considering solely women who naturally conceived their first live birth, the probability to have a second child with MAR was 1.1% and to have a second child naturally 59.3%. The corresponding values were 11.5% and 25.2% in the group of women with a first MAR-mediated live birth.
In our cohort, one woman out of 10 having a first MAR-mediated live birth underwent MAR programs again. Considering women who had a first natural live birth, this proportion was drastically reduced. In the field of MAR, more attention should be given to the capacity of a couple to achieve the number of desired children.
关于医学辅助生殖（MAR）在实现期望孩子数量方面的作用的证据非常有限。本研究的目的是根据第一胎的受孕方式评估第二胎活产的受孕概率和方式。
这是一项基于区域医疗保健数据库的行政数据的历史性队列研究。确定了 2007 年 1 月 1 日至 2017 年 12 月 31 日期间在伦巴第因分娩住院的妇女。使用 Kaplan-Meier 方法估计截至 2021 年的第二胎活产概率。我们根据第一胎的受孕方式计算了这一概率，并在第一胎生育时产妇年龄的分层中进行了分析。拟合 Cox 比例风险模型以估计第一胎活产的受孕方式与第二胎活产概率之间的关联的风险比（HR）和 95%置信区间（CI）。如果母亲在随访结束前搬离该地区、死亡或未生育第二胎，则对其进行右删失。
我们确定了 431333 名第一胎自然受孕的女性和 16837 名第一胎 MAR 受孕的女性。两组的第二胎活产概率分别为 58.6%和 32.1%（HR=0.68，95%CI：0.66-0.70）。仅考虑第一胎自然受孕的女性，MAR 受孕的第二胎概率为 1.1%，自然受孕的第二胎概率为 59.3%。第一胎 MAR 介导的活产的女性相应的数值分别为 11.5%和 25.2%。
在我们的队列中，每 10 名接受第一胎 MAR 介导的活产的女性中就有 1 名接受了再次 MAR 方案。考虑到第一胎自然活产的女性，这一比例大大降低。在 MAR 领域，应该更加关注夫妇实现期望孩子数量的能力。
