FRIDAY, Jan. 30, 2026 (HealthDay News) -- A natural ovulation regimen for endometrial preparation is as effective as a programmed regimen for achieving a healthy live birth after frozen embryo transfer among ovulatory women, according to a study published online Jan. 21 in The BMJ.
Daimin Wei, M.D., Ph.D., from Shandong University, Jinan, in China, and colleagues compared a natural ovulation regimen before frozen embryo transfer to a programmed regimen in a multicenter randomized clinical trial. A total of 4,376 ovulatory women, aged 20 to 40 years, planning to undergo a frozen single blastocyst transfer were randomly assigned to receive a natural ovulation regimen or a programmed regimen of hormone replacement for endometrial preparation (2,185 and 2,191, respectively).
The researchers found that in the intention-to-treat analysis, 41.6 and 40.6 percent of those in the natural ovulation regimen group and the programmed regimen group, respectively, achieved a healthy live birth (relative ratio, 1.03; 95 percent confidence interval [CI], 0.96 to 1.10). Among patients who achieved clinical pregnancy, the risk for preeclampsia was lower in the natural ovulation regimen group than in the programmed regimen group (2.9 versus 4.6 percent; relative ratio, 0.63; 95 percent CI, 0.43 to 0.94). The natural ovulation regimen group also had significantly lower incidence rates of early pregnancy loss, placental accreta spectrum, caesarean section, and postpartum hemorrhage. No between-group differences were seen for birth weight or neonatal complications. The natural ovulation group had a higher rate of cycle cancellation (16.2 versus 11.5 percent).
"The findings of this trial may serve as a model for other preconception intervention trials to prevent maternal morbidity and mortality," the authors write.
One author disclosed ties to the biotechnology industry.