Association between blastocyst morphology and maternal first trimester serum markers in ongoing pregnancies obtained after single fresh blastocyst transfer.

Objective: Is there an association between blastocyst morphology and maternal first trimester serum markers in In Vitro Fertilization (IVF) pregnancies obtained after fresh single blastocyst transfer?

Study Design: This bi-centric retrospective study was conducted between January 2012 and August 2018. We included 122 women aged from 18 to 43 years-old, whose pregnancy progressed at least beyond 13 weeks after a single blastocyst transfer and who participated in the first trimester combined screening test. Day 5 and day 6 blastocysts were evaluated according to Gardner and Schoolcraft classification. Patients were classified into three groups according to blastocysts morphological quality: excellent (≥ 3AA), good (3-6AB, 3-6BA, B2), and medium to poor (3-6BB, 3-6AC, 3-6CA, B1, 3-6CB, 3-6BC). First trimester serum markers were measured in maternal blood between 9 and 11 + 6 gestational weeks. Univariate and multivariate analyses were performed.

Results: Female body mass index, smoking status, type of infertility, geographical origin, anti-mullerian hormone level, ovarian stimulation characteristics, pregnancy outcomes and obstetrical complications were comparable between the three groups. Patient's age was not distributed evenly across groups, with women in group "Medium to Poor" appearing to be slightly younger than in other groups. There were no significant differences in mean first trimester serum markers between the three groups (PAPP-A: excellent: 1.23 ± 0.59 MoM; good: 1.45 ± 0.71 MoM; medium to poor: 1.22 ± 0.52 MoM; p = 0,20; free beta-HCG: excellent: 1.66 ± 1.38 MoM; good: 1.19 ± 0.76 MoM; medium to poor: 1.81 ± 1.34 MoM; p = 0,12). No significant difference was found either between mean first trimester serum markers and inner cell mass morphology (PAPP-A: grade A: 1.23 ± 0.58 MoM; grade B: 1.26 ± 0.60 MoM; medium to poor: 1.64 ± 0.87 MoM; p = 0,67 ; free beta-HCG: grade A: 1.66 ± 1.36 MoM; grade B: 1.52 ± 1.10 MoM; medium to poor: 1.57 ± 0.39 MoM p = 0,60), trophectoderm cells morphology (PAPP-A: grade A: 1.25 ± 0.63 MoM; grade B: 1.26 ± 0.51 MoM; medium to poor: not comparable; p = 0,66; free beta-HCG: grade A: 1.60 ± 1.34 MoM; grade B: 1.69 ± 1.14 MoM; medium to poor: not comparable; p = 0,25), or blastocoel expansion (PAPP-A: B1: 1.08 ± 0.51MoM; B2: 1.57 ± 0.70 MoM; B3: 1.26 ± 0.61 MoM; B4: 1.28 ± 0.62 MoM; B5: 1.04 ± 0.38 MoM; p = 0,22; free beta-HCG: B1: 2.01 ± 1.88 MoM; B2: 1.07 ± 0.49 MoM; B3: 1.43 ± 0.87 MoM; B4: 1.68 ± 1.28 MoM ; B5: 1.82 ± 2.03 MoM; p = 0,48). After adjustment on potential confounding factors (female age, type of gonadotropin, parity, number of oocytes retrieved and occurrence of ovarian hyperstimulation syndrome), we did not observe any association between PAPP-A or free beta-HCG levels and blastocyst morphology.

Conclusion: Our study concluded that first trimester serum markers were not associated with blastocyst morphological characteristics. Although this needs further confirmation, this suggests that blastocyst morphology would not have an impact on placentation. Therefore, these findings are reassuring for couples undergoing IVF and blastocyst transfer.