Does a hCG booster improve outcomes with natural frozen embryo transfer?

This study investigated if human chorionic gonadotrophin (hCG) improves pregnancy outcomes after frozen embryo transfer (FET). They found that hCG treatment may improve ongoing pregnancy rates (OPR) after FET.

Assisted reproduction (AR) involves a number of steps. Eggs are harvested from the woman. In vitro fertilization (IVF) is typically used to produce a fertilized embryo. Embryos can then be transferred to the uterus (ET). Embryos can also be frozen and transferred at another time (FET).

The uterus must be prepared before FET. One way of doing this is by taking drugs that stimulate hormone levels. These include estrogen (E) and progesterone (P). Some patients may not need hormone replacement. Endogenous (naturally secreted into the body) hormone levels may be at the right level for ET. This is called natural FET (nFET). Improving pregnancy outcomes is important in fertility treatment. Human chorionic gonadotrophin (hCG) is another important fertility hormone. hCG can stimulate E and P levels. Some studies suggest that hCG could improve pregnancy outcomes after FET. It is unclear if hCG improves pregnancy outcomes after nFET.

This study included 529 nFET cycles. Patients were divided into two groups. Group A received a dose of hCG. Group B did not. The main outcome of this study was the ongoing pregnancy rate (OPR). Other pregnancy outcomes evaluated included first-trimester loss (FTL) and biochemical pregnancy rate (BPR; pregnancy confirmed by laboratory tests).

OPR was significantly higher in the hCG treatment group (69.9%) versus the control group (57.4%). hCG treatment was associated with a 71.7% increase in the chance of achieving a pregnancy. This effect was seen in all embryo quality categories. FLT was not significantly different between the groups. BPR was also similar between the groups. 

The authors concluded that hCG treatment may improve OPR after FET.

The number of cycles in this study was low. Patients also underwent screening for genetic abnormalities. This is a common cause of failed pregnancy. More controlled studies are needed. 

If you have any concerns regarding infertility please consult with your doctor.