Strengths and limitations
Our present work has some strength of note. Firstly, we adjusted more variables to ensure that the result was more reliable. Secondly, proper statistical methods and sensitivity analysis ensure structural stability. Thirdly, the study included solely ovulatory women to cleanly analyze the impact of both types of endometrial preparation. Last but not least, we only included women in the first cycle of FET, thus avoiding bias from multiple cycles.
Several limitations are associated with the present study warrant mention. Firstly, the type of endometrial preparation was chosen by the treating physician’s preference and this may introduce a potential bias. Secondly, this was a retrospective study and could not investigate other confounders, including exercises, nutritional supplements and diets. Thirdly, we could not compare the incidence of preeclampsia and placental dysfunction in pregnancies after NC and AC, since these data were not collected in our dataset.