BACKGROUND It is not known whether segmentation of an in vitro fertilisation (IVF) cycle, with freezing of all embryos prior to transfer, increases the chance of a live birth after all embryos are transferred. METHODS In a prospective study of UK Human Fertilisation and Embryology Authority data, we investigated the impact of segmentation, compared with initial fresh embryo followed by frozen embryo transfers, on live birth rate and perinatal outcomes. We used generalised linear models to assess the effect of segmentation in the whole cohort, with additional analyses within women who had experienced both segmentation and non-segmentation. We compared rates of live birth, low birthweight (LBW < 2.5 kg), preterm birth (< 37 weeks), macrosomia (> 4 kg), small for gestational age (SGA < 10th centile), and large for gestational age (LGA > 90th centile) for a given ovarian stimulation cycle accounting for all embryo transfers. RESULTS We assessed 202,968 women undergoing 337,148 ovarian stimulation cycles and 399,896 embryo transfer procedures. Live birth rates were similar in unadjusted analyses for segmented and non-segmented cycles (rate ratio 1.05, 95% CI 1.02-1.08) but lower in segmented cycles when adjusted for age, cycle number, cause of infertility, and ovarian response (rate ratio 0.80, 95% CI 0.78-0.83). Segmented cycles were associated with increased risk of macrosomia (adjusted risk ratio 1.72, 95% CI 1.55-1.92) and LGA (1.51, 1.38-1.66) but lower risk of LBW (0.71, 0.65-0.78) and SGA (0.64, 0.56-0.72). With adjustment for blastocyst/cleavage-stage embryo transfer in those with data on this (329,621 cycles), results were not notably changed. Similar results were observed comparing segmented to non-segmented within 3261 women who had both and when analyses were repeated excluding multiple embryo cycles and multiple pregnancies. When analyses were restricted to women with a single embryo transfer, the transfer of a frozen-thawed embryo in a segmented cycles was no longer associated with a lower risk of LBW (0.97, 0.71-1.33) or SGA (0.84, 0.61-1.15), but the risk of macrosomia (1.74, 1.39-2.20) and LGA (1.49, 1.20-1.86) persisted. When the analyses for perinatal outcomes were further restricted to solely frozen embryo transfers, there was no strong statistical evidence for associations. CONCLUSIONS Widespread application of segmentation and freezing of all embryos to unselected patient populations may be associated with lower cumulative live birth rates and should be restricted to those with a clinical indication.

中文翻译：

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与传统的新鲜和冷冻胚胎移植相比，冷冻所有胚胎时的活产率和围产期结局：一项针对体外受精周期为337,148的队列研究。

背景技术未知的是，体外受精（IVF）周期的分段（在转移之前将所有胚胎冷冻）是否增加了在所有胚胎转移之后的活产的机会。方法在对英国人类受精和胚胎学管理局的数据进行的前瞻性研究中，我们调查了分割，与最初的新鲜胚胎，随后的冷冻胚胎移植相比，对活产率和围产期结局的影响。我们使用广义线性模型评估了整个队列中的细分效果，并对经历了细分和非细分的女性进行了额外的分析。我们比较了活产，低出生体重（LBW <2.5千克），早产（<37周），巨大儿（> 4千克），胎龄小（SGA <10％），对于给定的卵巢刺激周期，其胎龄较大（LGA> 90％），这说明了所有胚胎的移植。结果我们评估了202,968名妇女，他们接受了337,148个卵巢刺激周期和399,896个胚胎移植程序。分段和非分段周期的未调整分析中的活产率相似（比率1.05，95％CI 1.02-1.08），但根据年龄，周期数，不育原因和卵巢反应（比率）进行校正后，分段周期的活产率较低0.80，95％CI 0.78-0.83）。分段的周期与巨大儿风险增加（校正风险比1.72，95％CI 1.55-1.92）和LGA（1.51，1.38-1.66）相关，但LBW（0.71，0.65-0.78）和SGA（0.64，0.56-）较低0.72）。在对具有此数据（329,621个周期）的那些中的胚泡/卵裂期胚胎移植进行调整后，结果发生了显着变化。在3261名同时进行分割和未分割的女性中进行分段和不分段的比较时，观察到了相似的结果，并且重复分析时排除了多个胚胎周期和多个怀孕。当分析仅限于单胚胎移植的女性时，在分段周期中冷冻融化的胚胎的移植不再具有较低的LBW（0.97，0.71-1.33）或SGA（0.84，0.61-1.15）风险。 ，但仍存在巨大儿（1.74，1.39-2.20）和LGA（1.49，1.20-1.86）的风险。当围产期结局的分析进一步仅限于冷冻胚胎移植时，则没有强有力的统计学证据显示相关性。