Effect of Zishen Yutai Pill on Live Birth Rates in Frozen-Thawed Embryo Transfer Cycles Among Women of Advanced Maternal Age (ZYPHFETAL): A Multicenter, Randomized, Double-Blind, Placebo-Controlled Trial

INTERVENTION: Intervention Group:Zishen Yutai Pill;Control group:Placebo; CONDITION: Advanced Maternal Age Infertility PRIMARY OUTCOME: Live Birth Rate; SECONDARY OUTCOME: Positive Pregnancy;Embryo Implantation Rate;Clinical Pregnancy;Pregnancy Loss Rate;Pregnancy‐induced hypertension;Gestational diabetes mellitus;Postpartum hemorrhage;Preterm birth rate (<37 gestational weeks at delivery);Neonatal birth weight;Incidence of Low Birth Weight Infants;Incidence of Small for Gestational Age (SGA);Macrosomia incidence;Large‐for‐gestational‐age (LGA) incidence;NICU admission rate;Incidence of congenital anomalies;Neonatal mortality; INCLUSION CRITERIA: (1) Age between 35 and 44 years old (inclusive of 35, exclusive of 44); (2) History of = 2 embryo transfer cycles, planning for FET; (3) At least one transferable cleavage‐stage embryo or blastocyst available.