Early serum β-human chorionic gonadotropin in pregnancies after in vitro fertilization: contribution of treatment variables and prediction of long-term pregnancy outcome  Shay Porat, M.D., Stephan Savchev, M.D., Yuval Bdolah, M.D., Arye Hurwitz, M.D., Ronit Haimov-Kochman, M.D.  Fertility and Sterility  Volume 88, Issue 1, Pages 82-89 (July 2007) DOI: 10.1016/j.fertnstert.2006.11.116 Copyright © 2007 American Society for Reproductive Medicine Terms and Conditions

FIGURE 1 Pregnancy success shows linear correlation with initial βhCG level 13 days after ET with a coefficient of the linear model of 1.0668 (P<.0001). βhCG quartiles: first quartile: 0–62 mIU/mL (n = 134), second quartile: 63–141 mIU/mL (n = 134), third quartile: 142–297 mIU/mL (n = 132), fourth quartile: 298–3,047 mIU/mL (n = 133). The odds ratio was 2.906 for each increase in the βhCG quartile. Porat. Low initial ahCG in IVF cycles. Fertil Steril 2007. Fertility and Sterility 2007 88, 82-89DOI: (10.1016/j.fertnstert.2006.11.116) Copyright © 2007 American Society for Reproductive Medicine Terms and Conditions

FIGURE 2 Pregnancy success rate is correlated with early embryonic developmental delay both in the study group and the control group. The difference in days between calculated embryonic age and actual embryonic age as derived from measured CRL is represented in the x-axis. Porat. Low initial ahCG in IVF cycles. Fertil Steril 2007. Fertility and Sterility 2007 88, 82-89DOI: (10.1016/j.fertnstert.2006.11.116) Copyright © 2007 American Society for Reproductive Medicine Terms and Conditions

FIGURE 3 Comparison of preterm deliveries rate in study and control groups. P values are shown. Porat. Low initial ahCG in IVF cycles. Fertil Steril 2007. Fertility and Sterility 2007 88, 82-89DOI: (10.1016/j.fertnstert.2006.11.116) Copyright © 2007 American Society for Reproductive Medicine Terms and Conditions