Advanced maternal age and birth outcomes in pregnancies from donated gametes in 2007 − 2017, Sweden

Abstract Background Assisted reproductive technology (ART) has lowered the biological barriers to childbearing at older ages, but the role of maternal age in birth outcomes of pregnancies from donated gametes remains unclear. We examine the association between advanced maternal age and birth outcomes in first births among women conceiving through ART using either the couples’ own gametes, donated oocytes, or donated sperm. Methods We linked all live births in Sweden in 2007 − 2017 with information on ART from the National Registry for Assisted Reproduction (Q-IVF), and information on birth weight, low birth weight (<2,500g), preterm birth (<37 weeks), small for gestational age, and parental sociodemographic characteristics (e.g., education, country of origin, maternal smoking) from the medical birth register and the population registers. We restricted our analyses to first births that are more prone to adverse birth outcomes, as well as maternal ages 25 − 34, 35 − 39, and 40 and over due to our focus on advanced maternal age and rareness of ART at younger ages. Preliminary results We observed a clear maternal age gradient in naturally conceived pregnancies, with poorer birth outcomes among older first-time mothers. In contrast, maternal age made little difference for birth outcomes in ART pregnancies using own gametes. Among women aged over 40, birth outcomes of ART pregnancies using own gametes were similar or even better than in naturally conceived pregnancies. No consistent maternal age gradient could neither be observed in birth outcomes of pregnancies from donated oocytes or donated sperm, but the relatively small number of cases lends some uncertainty to the results. Conclusions Adjusted for multiple births and parental sociodemographic characteristics, the birth outcomes in ART pregnancies from own or donated gametes were overall similar or slightly poorer than in naturally conceived pregnancies but the risks were not elevated among women of advanced maternal age. Key messages • ART pregnancies using own or donated gametes have a slightly elevated risk of poorer birth outcomes. • In contrast to naturally conceived pregnancies, advanced maternal age does not predict poorer birth outcomes in ART pregnancies using own or donated gametes.