Large for gestational age and macrosomia in singletons born after frozen/thawed embryo transfer (FET) in assisted reproductive technology (ART)

TY - JOUR

T1 - Large for gestational age and macrosomia in singletons born after frozen/thawed embryo transfer (FET) in assisted reproductive technology (ART)

AU - Berntsen, Sine

AU - Pinborg, Anja

N1 - © 2018 Wiley Periodicals, Inc.

PY - 2018/5/1

Y1 - 2018/5/1

N2 - Increase in success rates with frozen embryo transfer (FET) and reduced risk of ovarian hyperstimulation syndrome (OHSS) and multiple pregnancies has lead to a steady rise in FET. Further, FET is associated with lower risk of prematurity and low birth weight in singletons, when compared with fresh transfer. However, there is a growing concern of increased risk of large for gestational (LGA) and/or macrosomic children after FET. Macrosomic/LGA births have a higher risk of cesarean section, fetal hypoxia and stillbirth. Improvements in cryopreservation techniques indicate that FET is a trend expected to continue and a freeze-all policy has lately been introduced. With this review, we wished to evaluate the association between FET and LGA and/or macrosomia. We searched electronic databases on January 12, 2018. Ten studies on LGA and six studies on macrosomia were eligible for meta-analysis. We found that the risk of LGA in FET was increased 1.5-fold (AOR = 1.50 95% CI 1.44-1.57 p < 0.001) compared to fresh cycles and 1.3-fold (AOR = 1.31 95% CI 1.20-1.43 p < 0.001) compared to natural conception (NC). Similarly we found a 1.7-fold increased risk of macrosomia in FET compared to fresh transfer (AOR = 1.71 95% CI 1.59-1.83 p < 0.001) and a 1.4-fold increased risk compared to NC (AOR = 1.42 95% CI 1.17-1.71 p < 0.001). Whether the increased risk of LGA and macrosomia is associated with higher long-term health risks remains unknown. Future studies should explore epigenetics modifications in children born after FET and predictors of long-term diseases need to be examined further with longitudinal studies.

AB - Increase in success rates with frozen embryo transfer (FET) and reduced risk of ovarian hyperstimulation syndrome (OHSS) and multiple pregnancies has lead to a steady rise in FET. Further, FET is associated with lower risk of prematurity and low birth weight in singletons, when compared with fresh transfer. However, there is a growing concern of increased risk of large for gestational (LGA) and/or macrosomic children after FET. Macrosomic/LGA births have a higher risk of cesarean section, fetal hypoxia and stillbirth. Improvements in cryopreservation techniques indicate that FET is a trend expected to continue and a freeze-all policy has lately been introduced. With this review, we wished to evaluate the association between FET and LGA and/or macrosomia. We searched electronic databases on January 12, 2018. Ten studies on LGA and six studies on macrosomia were eligible for meta-analysis. We found that the risk of LGA in FET was increased 1.5-fold (AOR = 1.50 95% CI 1.44-1.57 p < 0.001) compared to fresh cycles and 1.3-fold (AOR = 1.31 95% CI 1.20-1.43 p < 0.001) compared to natural conception (NC). Similarly we found a 1.7-fold increased risk of macrosomia in FET compared to fresh transfer (AOR = 1.71 95% CI 1.59-1.83 p < 0.001) and a 1.4-fold increased risk compared to NC (AOR = 1.42 95% CI 1.17-1.71 p < 0.001). Whether the increased risk of LGA and macrosomia is associated with higher long-term health risks remains unknown. Future studies should explore epigenetics modifications in children born after FET and predictors of long-term diseases need to be examined further with longitudinal studies.

U2 - 10.1002/bdr2.1219

DO - 10.1002/bdr2.1219

M3 - Review

C2 - 29714057

SN - 0270-3211

VL - 110

SP - 630

EP - 643

JO - Birth Defects Research

JF - Birth Defects Research

IS - 8

ER -