Hormonal milieu in singleton pregnancy during the first trimester of gestation: comparison between spontaneous, in vitro fertilization and eggs donation pregnancies

Introduction: In pregnancies obtained by ART exogenous estrogens and progesterone need to be administered to ensure endometrial receptivity and to maintain pregnancy after embryo transfer. To our knowledge there are few data on estrogen and progesterone maternal blood levels either spontaneous and in ART pregnancies during the first trimester. The first aim of our study is to create 17β - Estradiol and Progesterone growth curves in spontaneous pregnancy and successively to compare them with those from autologous and oocyte donation pregnancies. Methods From November 2015 to June 2016 three groups of singleton pregnancies were studied: spontaneous, in vitro fertilization pregnancies with autologous oocytes (Autologous IVF) and oocyte donation (OD) pregnancies. Maternal hormonal venous concentrations were analyzed in our reference laboratory in 85 spontaneous, 23 homologous IVF from fresh cycles and 12 OD pregnancies between 4 and 13+6 weeks of gestations. Serum samples were processed and assayed for 17 β – estradiol and progesterone using the Electro Chemo Luminescence in Immunoassay (ECLIA – Elecsys/Cobas®) method. Results In spontaneous pregnancy, maternal venous 17β - estradiol and progesterone concentrations increase according to gestational age. There is a significant relation between progesterone growth and gestational age, with a concentration growths of 0.2ng/ml per day of gestation. 17β - Estradiol and progesterone are linked by a linear correlation expressed by the following formulation: Log (17β-estr) = 2,5933 + 0,0149 x progesterone and the correlation coefficient is equal 0.388. Comparing the different mode of conception, maternal serum concentration of 17β - Estradiol appears lower in OD donation than in spontaneous and autologous IVF pregnancy in any weeks of pregnancy (fig 1), while progesterone values are higher in autologous IVF pregnancy than in spontaneous and OD pregnancies (fig2). Conclusion Estrogen level are lower in OD pregnancy in the first trimester of pregnancy. Low estrogen level may enhance an efficient and early invasion of spiral artery by the trophoblast. In autologous IVF the higher progesterone concentration may suggest a revision of progesterone therapy after pick up. It is possible that the correlation between concentration of 17β – estradiol and progesterone could help in prescribing support therapy during the first weeks of pregnancy.