Study protocol: a multi-center, double-blind, randomized, 6-month, placebo-controlled trial to investigate the effect of supplementing hormone therapy FET cycles with Gushen'antai pills on the outcomes of in vitro fertilization.

Background: Infertility is a widespread global challenge. Currently, the most effective treatment strategy for infertility is in vitro fertilization (IVF), which is an assisted reproductive technique (ART). The use of IVF for assisted pregnancy dates back to the last 41 years when the first IVF baby was born. During IVF, many oocytes are obtained in an IVF cycle, and more than one embryo is formed. Subsequently, frozen-thawed embryo transfer (FET) is increasingly being used in IVF cycles for women in whom a fresh embryo transfer fails to result in a pregnancy, or in those who return for a second baby. However, the pregnancy success rates following FET treatment cycles are reportedly lower than in fresh embryo transfers. Therefore, recent related studies are increasing determining mechanisms of improving the sustained pregnancy rate of FET and reducing the rate of early abortion. The Gushen'antai pill (GSATP), which contains a mixture of 10 herbs, has been widely used in traditional Chinese medicine (TCM) as a pharmacological option to prevent miscarriage. However, randomized controlled trials (RCT) have never been conducted to provide high-level clinical evidence on the clinical efficacy of GSATP. The objective of this study is to investigate the effect of GSATP of hormone therapy (HT) FET cycles on pregnancy rate.

Methods: A total of 300 subjects aged between 18 and 40 years which prepared for HT cycle FET will be enrolled in the study. The patients were from five different hospitals, with 60 patients from each hospital. Patients were randomly divided into two groups, and medication was started on the day of endometrial transformation. After FET 28 days, B-ultrasound was done to determine whether to continue the medication. Baseline assessments were carried out before the trial and outcomes were collected 4, 6, 8, 10, and 12 weeks of each gestational cycle.

Discussion: Differences in ongoing pregnancy rate, clinical pregnancy rate, implantation rate, and threatened abortion rate between the two groups will be statistically analyzed. We can finally have an objective evaluation of the efficacy of the traditional Chinese medicine Gushen'antai pills.

Trial Registration: ChiCTR1900026737 . Registered October 20, 2019.