To the top

Page Manager: Webmaster
Last update: 9/11/2012 3:13 PM

Tell a friend about this page
Print version

Neonatal and maternal out… - University of Gothenburg, Sweden Till startsida
To content Read more about how we use cookies on

Neonatal and maternal outcome after frozen embryo transfer: increased risks in programmed cycles.

Journal article
Authors Erica Ginström Ernstad
Ulla-Britt Wennerholm
Ali Khatibi
Max Petzold
Christina Bergh
Published in American journal of obstetrics and gynecology
Volume 221
Issue 2
Pages 126.e1-126.e18
ISSN 1097-6868
Publication year 2019
Published at Institute of Clinical Sciences, Department of Obstetrics and Gynecology
Institute of Medicine, Department of Public Health and Community Medicine, Health Metrics
Pages 126.e1-126.e18
Language en
Keywords Frozen embryo transfer, obstetric outcome, low birthweight, macrosomia, hypertensive disorders in pregnancy, postpartum bleedings
Subject categories Health Sciences


Frozen embryo transfer is associated with better perinatal outcome regarding preterm birth and low birth weight yet higher risk of large for gestational age and macrosomia compared to fresh transfer. Further, higher rates of hypertensive disorders in pregnancy are noted after frozen embryo transfer. Whether these differences are due to the protocol used in frozen cycles remains unknown.To analyze the obstetric outcome after frozen embryo transfer depending on protocol used. Comparison was also made for frozen vs. fresh transfer and for frozen transfer vs. spontaneous conception.A population-based retrospective registry study including all singletons born after frozen embryo transfer in Sweden from 2005 to 2015. The IVF register was cross-linked with the Medical Birth Register, the Register of Birth Defects, the National Patient Register, the Swedish Neonatal Quality Register and the Prescribed Drug Register. Singletons after FET were compared depending on the presence of a corpus luteum in the actual cycle. All frozen transfer singletons were also compared with fresh transfer and spontaneous conception singletons. Primary outcomes were preterm birth (<37 w), low birth weight (<2500 g), hypertensive disorders in pregnancy and postpartum hemorrhage (>1000 ml). Crude and adjusted odds ratio (AOR) with 95% confidence interval (CI) were calculated and adjustment made for relevant confounders.9726 singletons were born after frozen embryo transfer (natural cycles, n=6297, stimulated cycles, n=1983, programmed cycles, n=1446), 24,365 after fresh transfer and 1,127,566 after spontaneous conception. No significant differences were noticed for preterm birth and low birth weight between the different protocols used in frozen embryo transfer. Compared to natural and stimulated frozen cycles programmed frozen cycles were associated with a higher risk of hypertensive disorders in pregnancy (AOR 1.78, 95% CI, 1.43-2.21 and AOR 1.61; 1.22-2,10, respectively) and postpartum hemorrhage (AOR 2.63, 95% CI, 2.20-3.13 and AOR 2.87; 95% CI, 2.29-2.60, respectively). Moreover higher risks for postterm birth (AOR 1.59; 95% CI 1.27-2.01 and AOR 1.98; 95% CI 1.47-2.68) and macrosomia (AOR 1.62; 95% CI, 1.26-2.09 and AOR 1.40; 95% CI 1.03-1.90) were detected. There were no significant differences in any outcomes between stimulated and natural cycles. Frozen cycles in general compared to fresh cycles and compared to spontaneous conceptions showed neonatal and maternal outcomes in agreement with earlier studies.No significant difference could be seen regarding preterm birth and low birth weight between the different protocols. However, higher rates of hypertensive disorders in pregnancy, postpartum hemorrhage, postterm birth and macrosomia were detected in programmed cycles. Stimulated cycles had outcomes similar to natural cycles. These findings are important in view of the increasing use of frozen cycles and the new policy of freeze-all cycles in IVF. The results suggest a link between the absence of corpus luteum and adverse obstetric outcomes.

Page Manager: Webmaster|Last update: 9/11/2012

The University of Gothenburg uses cookies to provide you with the best possible user experience. By continuing on this website, you approve of our use of cookies.  What are cookies?