O-146 Oocyte donation does not increase live birth rates in young women suffering from recurrent pregnancy loss
Authors: Miguel-Escalada I , Almansa-Ordoñez A , Santaló J , Blázquez A , Vassena R , Tiscornia G , Popovic M , Rodriguez A 
Published: June 2023

Abstract

Study question
Does oocyte donation improve reproductive outcomes in recurrent pregnancy loss (RPL) patients?

Summary answer
Oocyte donation increases live birth and reduces miscarriage rates in RPL women older than 35, but it does not improve reproductive outcomes in younger patients.

What is known already
Recurrent pregnancy loss (RPL) is defined as 2 or more pregnancy losses prior to 20-24 weeks of gestation and has an incidence of approximately 1 to 2% in couples trying to conceive. Known risk factors for RPL are embryo aneuploidy, advanced maternal age (AMA), previous miscarriages, uterine abnormalities, parental chromosomal abnormalities, antiphospholipid syndrome, endocrine factors, such as thyroid function or obesity, and thrombophilia. However, 50-70% of patients suffering from RPL do not present any known risk factor, making the management of idiopathic RPL patients particularly challenging for ART clinicians.

Study design, size, duration
This is a cohort retrospective study involving 2 centers. Charts from 18,273 women undergoing IVF treatment between 2011 and 2020 were reviewed. A total of 912 patients (5%) met the definition of RPL and were classified into study groups based on their age and oocyte origin: ≤35 years old receiving oocyte donation (n = 39) or using their own oocytes (n = 35), and AMA women using donor eggs (n = 716) or their own (n = 122).

Participants/materials, setting, methods
Demographic variables analysed included known risk factors, number of transferred embryos, day of embryo transfer (3 vs 5) and sperm origin (partner/donor). Differences in biochemical, clinical, ongoing pregnancy, miscarriage and live birth rates were assessed by Pearson’s Chi-squared or Fisher’s exact test. P-values &lt;0.05 were considered significant.

Main results and the role of chance
RPL patients had 2.77±1.27 pregnancy losses overall (2.76±1.37 in women ≤35 and 2.77±1.26 in patients &gt;35). Most RPL patients (91.9%) were of AMA. Other RPL-associated risk factors, including uterine malformations, previous pregnancy losses, chromosomal abnormalities and thrombophilia were identified in 207/912 patients (22.7%). Interestingly, these were more frequent in patients &lt;35 (37.8% vs 21%, p = 0.001). Young RPL women presented higher rates of karyotype abnormalities than older patients (17.6% vs 3.8%, p &lt; 1x10-04), while showing a similar incidence of uterine abnormalities (14.9% vs 12.9%, p &gt; 0.63) and thrombophilia (4.1% vs 4.7%, p &gt; 0.81).
RPL patients &gt;35 preferentially underwent oocyte donation (85.4% vs 52.7%, p &lt; 1x10-04), which led to significantly higher biochemical (52.5% vs 17.1%, p &lt; 1x10-04), clinical (42.4% vs. 8.5% p &lt; 1x10-04), ongoing pregnancy (37.9% vs 5.1%, p &lt; 1x10-04), live birth (32% vs 4%, p &lt; 1x10-04) and lower miscarriage rates (10.5% vs 40%, p = 0.0186) than in autologous cycles. In contrast, RPL patients &lt;35 had similar reproductive outcomes: biochemical (41% vs. 52.9), clinical (28.2% vs. 37.1%), ongoing pregnancy (25.6% vs 29.4%), live birth (25.6% vs 26.4%) and miscarriage rates (9% vs 23%), regardless of oocyte origin (donated vs own, p &gt; 0.05 for all cases). Importantly, this was also true for a small subgroup of idiopathic young RPL patients (n = 13).

Limitations, reasons for caution
The main limitation of this study is its retrospective nature, which does not allow for full elucidation of all potential confounders. The number of young RPL patients undergoing oocyte donation may be too low to draw significant conclusions.

Wider implications of the findings
RPL can be resolved in AMA patients by using donor oocytes, which points to key roles of oocyte quality and aneuploidy underlying RPL aetiology. However, RPL is not ameliorated by oocyte donation in young women, suggesting an endometrial/systemic origin and highlighting the need to further study mechanisms driving this disorder.

Trial registration number
Not applicable