Health outcomes for Massachusetts infants after fresh versus frozen embryo transfer

This study demonstrates that compared with infants conceived from fresh embryo transfer, those born by frozen embryo transfer have higher birth weight but increased odds of infectious disease, respiratory, and neurologic abnormalities.

Volume 112, Issue 5, Pages 900–907


Sunah S. Hwang, M.D., M.P.H., Dmitry Dukhovny, M.D., M.P.H., Daksha Gopal, M.P.H., Howard Cabral, Ph.D., Hafsatou Diop, M.D., M.P.H., Charles C. Coddington, M.D., Judy E. Stern, Ph.D.



To compare neonatal health outcomes after fresh versus frozen ET (FET).


Retrospective analysis of a population-based database of linked clinically assisted reproductive technology (ART) data with state vital records. Multivariable logistic regression was used to model the association between deliveries from fresh versus FET and adverse health outcomes, controlling for maternal characteristics.


Not applicable.


Live-born singleton infants born to Massachusetts women who conceived by fresh or FET after ART using autologous oocytes between July 1, 2004, and December 31, 2013.



Main Outcome Measure(s)

Preterm birth, low birth weight, neonatal mortality, birth defects, organ system conditions.


Compared with infants conceived from fresh embryos, those born to mothers who underwent FET were less likely to be small for gestational age (adjusted odds ratio [AOR] = 0.56; 95% confidence interval [CI], 0.44–0.70) and low birth weight (AOR = 0.72; 95% CI, 0.59–0.88) but more likely to be large for gestational age (AOR = 1.47; 95% CI, 1.26–1.70) and to experience greater odds of infectious disease (AOR = 1.46; 95% CI, 1.03–2.06), respiratory (AOR = 1.23; 95% CI, 1.07–1.41), and neurologic (AOR = 1.32; 95% CI, 1.04–1.68) conditions. There were no statistically significant differences in preterm birth, neonatal mortality, birth defects, cardiovascular, hematologic, and gastrointestinal/feeding conditions, and for infants ≥ 35 weeks, no statistically significant differences in prolonged hospital stay (>3 days for vaginal delivery, >5 days for cesarean).


Compared with infants conceived from fresh ET, those born by FET have higher birth weight but increased odds of infectious disease, hematologic, respiratory, and neurologic abnormalities. These risks should be considered when making decisions on fresh versus FET.

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Go to the profile of fabienne Pessione
over 2 years ago


Some remarks on details :

- I do not find the appendix 1

-the legend of table 3 : "adjusted for...polycystic ovarian syndrome" is not exact, because POS were excluded

- the link of reference 23 is not correct

- the year of reference 12 is 2019 not 2012

The paper is very interesting, I read it very carefully ! Thank you