BRD2 and Bjornstad syndrome: The incidence of PTD was higher if there was one of the following factors: (a) female age ≥ 35, (b) female BMI > 24 kg/m2, (c) smoking, (d) high baseline FSH, (e) secondary infertility, (f) uterine factors, (g) cervical factors, (h) ovulatory factors, (i) EMT ≤7 mm, (j) two embryo transferred, (k) blastocyst transfer, (l) FET, (m) non-high quality embryo transfer, (n) two gestational sacs, (o) obstetric complications (PP, PA, GDMHDP, and PROM), and (p) a male fetus (Table 2).