OBJECTIVE:

To assess the predictive value for clinical pregnancy outcome of β-hCG level at 13 d after embryo transfer.

METHODS:

Retrospective study of IVF clinical pregnancies diagnosed at 6 weeks. We calculated the value of β-hCG level at 13 d after embryo transfer to predict live births.

RESULTS:

We analyzed 177 IVF cycles between 2009 and 2014 (50 singleton births, 50 twin births, 27 sets with a vanishing twin, 43 first trimester singleton pregnancy loss and seven first trimester total twin pregnancy loss). Singleton pregnancies with a β-hCG concentration <85 mIU/mL had an 89% risk of having a first trimester loss whereas a concentration >386 mU/mL had a 91% chance of a live birth. Twin pregnancies with a concentration <207 mIU/mL had only a 33% chance of delivering twins and a 55% risk of having a vanishing twin; whereas a level >768 mIU/mL was associated with a 81% chance of live twin birth and a low risk (19%) of having a vanishing twin. Age, type and duration of infertility, body mass index (BMI) and number of fertilized oocytes did not affect these calculations.

CONCLUSIONS:

β-hCG level at 13 d after embryo transfer might predict outcomes in clinical singleton and twin pregnancies following IVF.