Ovarian hyperstimulation syndrome after assisted reproductive technologies: trends, predictors, and pregnancy outcomes

The rate of ovarian hyperstimulation syndrome (OHSS) has decreased steadily since 2006. Large oocyte yield and ovulatory disorder are important risk factors for OHSS. Adverse pregnancy outcomes are associated with OHSS.

VOLUME 114, ISSUE 3, P567-578


David A. Schirmer III, M.D., Aniket D. Kulkarni, M.B.B.S, M.P.H., Yujia Zhang, Ph.D., Jennifer F. Kawwass, M.D., Sheree L. Boulet, Dr.P.H., M.P.H., Dmitry M. Kissin, M.D., M.P.H.



To assess trends, predictors, and perinatal outcomes of ovarian hyperstimulation syndrome (OHSS) associated with in vitro fertilization (IVF) cycles in the United States.


Retrospective cohort study using National Assisted Reproductive Technology Surveillance System (NASS) data.


Not applicable.


Fresh autologous and embryo-banking cycles performed from 2000 to 2015.



Main Outcome Measure(s)

OHSS, first-trimester loss, second-trimester loss, stillbirth, low birth weight, and preterm delivery.


The proportion of IVF cycles complicated by OHSS increased from 10.0 to 14.3 cases per 1,000 from 2000 to 2006, and decreased to 5.3 per 1,000 from 2006 to 2015. The risk of OHSS was highest for cycles with more than 30 oocytes retrieved (adjusted risk ratio [aRR] 3.85). OHSS was associated with a diagnosis of ovulatory disorder (aRR 2.61), tubal factor (aRR 1.14), uterine factor (aRR 1.17) and cycles resulting in pregnancy (aRR 3.12). In singleton pregnancies, OHSS was associated with increased risk of low birth weight (aRR 1.29) and preterm delivery (aRR 1.32). In twin pregnancies, OHSS was associated with an increased risk of second-trimester loss (aRR 1.81), low birth weight (aRR 1.06), and preterm delivery (aRR 1.16).


Modifiable predictive factors for OHSS include number of oocytes retrieved, pregnancy following fresh embryo transfer, and the type of medication used for pituitary suppression during controlled ovarian hyperstimulation. Patients affected by OHSS had a higher risk of preterm delivery and low birth weight. Clinicians should take measures to reduce the risk of OHSS whenever possible.

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