Rallis Anthia, Tremellen Kelton
Department of Obstetrics and Gynaecolgy, Women's and Children's Hospital, North Adelaide, South Australia, Australia.
Aust N Z J Obstet Gynaecol. 2013 Apr;53(2):165-9. doi: 10.1111/ajo.12063.
Preterm delivery rates are significantly higher for IVF-conceived pregnancies compared with naturally conceived pregnancies, even following adjustment for relevant confounding factors. Furthermore, preterm delivery is reportedly more common in pregnancies from fresh embryo, rather than frozen-thawed embryo transfer (FET), suggesting that the controlled ovarian hyperstimulation (COH) environment may initiate preterm labour.
As prior studies have confirmed a positive correlation between the numbers of corpora lutea generated during COH and serum relaxin levels, a reported trigger for cervical remodelling and preterm labour, the aim of this study was to examine the hypothesis that preterm delivery rates will therefore be lower in mono-follicular FET cycles compared to multi-follicular COH/IVF cycles (primary hypothesis). Our secondary hypothesis was that COH/IVF cycles yielding higher numbers of oocytes will be associated with higher rates of preterm birth and subsequent lower birth weight than those producing lower numbers of oocytes.
Retrospective review of 702 singleton pregnancies resulting from IVF treatment (COH/IVF and FET) during the years 2008-2009 at a single private IVF centre in Adelaide, South Australia.
There was no significant difference in rates of preterm labour between women undergoing COH with fresh embryo transfers compared with frozen embryo transfers (FETs), (11.59 vs 10%, P = 0.6011), nor was there any difference in the median gestation at delivery (39.4 vs 39.1 weeks, respectively, P = 0.1538). The rate of preterm delivery in both the fresh and frozen embryo transfer cohorts was higher than that observed in the general obstetric population (6.76%). A weak but marginally statistically significant correlation was observed between the number of oocytes retrieved following COH and gestation at delivery (r = 0.089, P = 0.048).
While a woman's response to COH was weakly negatively correlated with gestation at delivery, this relationship was not of major clinical importance as the rate of preterm delivery and the median gestation at delivery were not significantly different between pregnancies resulting from fresh or FETs in our study cohort.
与自然受孕的妊娠相比，体外受精（IVF）受孕的早产率显著更高，即便对相关混杂因素进行了校正。此外，据报道，新鲜胚胎妊娠的早产比冻融胚胎移植（FET）更为常见，这表明控制性卵巢过度刺激（COH）环境可能引发早产。
由于既往研究已证实COH期间产生的黄体数量与血清松弛素水平之间存在正相关，而血清松弛素据报道是宫颈重塑和早产的触发因素，本研究的目的是检验以下假设：因此，与多卵泡COH/IVF周期相比，单卵泡FET周期的早产率会更低（主要假设）。我们的次要假设是，产生较多卵母细胞的COH/IVF周期与较高的早产率及随后较低的出生体重相关，而产生较少卵母细胞的周期则不然。
对2008年至2009年期间在南澳大利亚阿德莱德一家私立IVF中心接受IVF治疗（COH/IVF和FET）的702例单胎妊娠进行回顾性分析。
接受新鲜胚胎移植的COH女性与接受冻融胚胎移植（FET）的女性相比，早产率无显著差异（分别为11.59%和10%，P = 0.6011），分娩时的中位孕周也无差异（分别为39.4周和39.1周，P = 0.1538）。新鲜胚胎移植组和冻融胚胎移植组的早产率均高于普通产科人群（6.76%）。COH后获取的卵母细胞数量与分娩孕周之间存在微弱但具有边缘统计学意义的相关性（r = 0.089，P = 0.048）。
虽然女性对COH的反应与分娩孕周呈微弱负相关，但在我们的研究队列中，新鲜胚胎或FET妊娠的早产率和分娩时的中位孕周并无显著差异，因此这种关系在临床上并不重要。
