Brussels IVF, UZ Brussel, Jette, Belgium.
Hum Reprod. 2024 Oct 1;39(10):2233-2239. doi: 10.1093/humrep/deae193.
Is there a difference in clinical pregnancy rates (CPRs) in good prognosis patients after single embryo transfer (SET) on Day 5, in case of stable culture at 36.6°C or 37.1°C?
CPR (with heartbeat at 7 weeks) after blastocyst transfer do not differ after culturing at 36.6°C or 37.1°C.
Since the beginning of IVF, embryo culture has been performed at 37.0°C; however, the optimal culture temperature remains unknown. Changes in incubator types have led to significant improvements in temperature control. Stable temperature control, i.e. with temperature differences of max. 0.1°C between chambers, is possible in some incubators. A previous prospective pilot study showed that embryo development on Day 5/6 was not affected when embryos were cultured at a stable temperature of 36.6°C or 37.1°C, but culture at 37.1°C resulted in an increased CPR when compared to culture at 36.6°C (74.2% vs 46.4%).
STUDY DESIGN, SIZE, DURATION: A prospective randomized controlled trial was performed in a tertiary fertility centre between February 2017 and November 26, 2022. A sample size of 89/89 patients with fresh single embryo transfer (SET) was required to achieve 80% power to detect a difference of 0.22 between group proportions (0.43-0.65) at a significance level of 0.05 using a two-sided z-test with continuity correction.
PARTICIPANTS/MATERIALS, SETTING, METHODS: Patients were recruited on the day of oocyte retrieval based on inclusion criteria with final randomization after denudation once six mature oocytes were present. The primary endpoint was CPR (heartbeat at 7 weeks); secondary endpoints were fertilization rate, blastocyst development, biochemical pregnancy rate, live birth rate (LBR), and cumulative live birth rate (CLBR).
A total of 304 patients were eligible for the study; of these 268 signed the consent, 234 (intention-to-treat) were randomized and 181 (per-protocol) received a SET on Day 5: 90 received culture at 36.6°C and 91 at 37.1°C. Patients were on average 32.4 ± 3.5 versus 32.5 ± 4.2 years old, respectively. No differences were observed in embryological outcomes per cycle between culture at 36.6°C versus 37.1°C: 12.0 ± 3.8 vs 12.1 ± 3.8 COCs retrieved (P = 0.88), 10.0 ± 3.1 versus 9.9 ± 2.9 mature oocytes inseminated (P = 0.68), with a maturation rate of 84.2% (901/1083) versus 83.5% (898/1104) (P = 0.87); and 8.0 ± 3.1 versus 7.9 ± 2.7 normally fertilized oocytes with a fertilization rate of 79.7% (720/901) vs 80.5% (718/898) (P = 0.96), respectively. On average 1.5 ± 1.7 versus 1.4 ± 1.9 (P = 0.25) and 1.1 ± 1.1 versus 0.9 ± 1.0 (P = 0.45) supernumerary blastocysts were vitrified on Day 5 and Day 6, respectively. The utilization rate per fertilized oocyte was 46.1% vs 41.5% (P = 0.14). A SET was performed for 181 patients, leading to a biochemical pregnancy rate of 72.2% (65/90) versus 62.7% (57/91) (P = 0.17), respectively. The CPR per fresh transfer cycle was 51.1% (46/90) versus 48.4% (44/91) [OR (95% CI) 1.11 (0.59-2.08), P = 0.710]. To date, a CLBR of 73.3% (66/90) versus 67.0% (61/91) (P = 0.354) has been observed, respectively. In each group, seven patients without live birth have remaining blastocysts frozen. The CPR for the intention-to-treat groups were 38.3% vs 38.6% [OR (95% CI) 0.98 (0.56-1.73), P = 0.967], respectively, for culture at 36.6°C versus 37.1°C.
LIMITATIONS, REASONS FOR CAUTION: Only selected patients with expected good prognosis were eligible for the study.
Embryos tend to tolerate small changes in temperature deviations during culture to the blastocyst stage, as demonstrated by their similar implantation potential at two slightly different temperatures.
STUDY FUNDING/COMPETING INTEREST(S): There is no funding or conflicts of interest to declare.
NCT03548532.
23 October 2017.
DATE OF FIRST PATIENT’S ENROLMENT: 10 November 2017.
在稳定培养至 36.6°C 或 37.1°C 的情况下，对于预后良好的患者，在第 5 天行单胚胎移植（SET）后，临床妊娠率（CPR）是否存在差异？
在囊胚移植后，胚胎培养至 36.6°C 或 37.1°C 时，心跳的 CPR 并无差异。
自 IVF 开始以来，胚胎培养一直在 37.0°C 下进行；然而，最佳培养温度仍不清楚。孵育箱类型的变化显著提高了温度控制水平。在一些孵育箱中，可以实现稳定的温度控制，即腔室之间的温差最大为 0.1°C。一项先前的前瞻性试点研究表明，当胚胎在稳定温度 36.6°C 或 37.1°C 下培养时，第 5/6 天的胚胎发育不受影响，但与 36.6°C 相比，37.1°C 培养时的 CPR 增加，差异有统计学意义（74.2% vs 46.4%）。
研究设计、规模、持续时间：2017 年 2 月至 2022 年 11 月 26 日，在一家三级生育中心进行了一项前瞻性随机对照试验。需要招募 89/89 例新鲜的单胚胎移植（SET）患者，以在 80%的效能下检测到组间比例（0.43-0.65）相差 0.22 的差异，在显著性水平为 0.05 时，使用具有连续性校正的双侧 z 检验。
参与者/材料、设置、方法：根据纳入标准，在卵母细胞回收当天招募患者，一旦出现 6 个成熟卵母细胞，在去核后进行最终随机分组。主要终点是 CPR（孕 7 周时的心跳）；次要终点是受精率、囊胚发育、生化妊娠率、活产率（LBR）和累积活产率（CLBR）。
共有 304 例患者符合研究条件；其中 268 例签署了同意书，234 例（意向治疗）随机分组，181 例（按方案）在第 5 天行 SET：90 例接受 36.6°C 培养，91 例接受 37.1°C 培养。患者的平均年龄为 32.4±3.5 岁和 32.5±4.2 岁。在每个培养温度下，每个周期的胚胎学结果均无差异：12.0±3.8 个 COCs 与 12.1±3.8 个 COCs 相比（P=0.88），10.0±3.1 个成熟卵母细胞与 9.9±2.9 个成熟卵母细胞相比（P=0.68），受精率为 84.2%（901/1083）与 83.5%（898/1104）（P=0.87）；8.0±3.1 个正常受精卵与 7.9±2.7 个正常受精卵相比（P=0.96），受精率为 79.7%（720/901）与 80.5%（718/898）相比。平均 1.5±1.7 个和 1.4±1.9 个（P=0.25）和 1.1±1.1 个和 0.9±1.0 个（P=0.45）超数囊胚分别在第 5 天和第 6 天冷冻。受精卵的利用率为 46.1%和 41.5%（P=0.14）。181 例患者进行了 SET，生化妊娠率分别为 62.7%（57/91）和 62.7%（57/91）（P=0.17）。每个新鲜移植周期的 CPR 分别为 51.1%（46/90）和 48.4%（44/91）[比值比（OR）（95%CI）1.11（0.59-2.08），P=0.710]。迄今为止，分别观察到 73.3%（66/90）和 67.0%（61/91）的累积活产率（P=0.354）。在每个组中，7 名未分娩的患者有剩余的冷冻胚胎。CPR 分别为 38.3%和 38.6%（OR（95%CI）0.98（0.56-1.73），P=0.967），分别在 36.6°C 和 37.1°C 培养。
局限性、谨慎的原因：仅选择预期预后良好的患者进行研究。
胚胎在培养至囊胚阶段时，对温度偏差的微小变化倾向于耐受，这从两个略微不同温度下相似的着床潜力中得到了证明。
研究资金/利益冲突：无资金或利益冲突声明。
NCT03548532。
2017 年 10 月 23 日。
2017 年 11 月 10 日。
