Placental volume and uterine artery doppler evaluation at 11 + 0 to 13 + 6 weeks of gestation in pregnancies conceived with in vitro fertilization: comparison between autologous and donor oocyte recipients

OBJECTIVE:To compare uterine artery pulsatility index (PI) and three dimensional(3D) placental volume values in first trimester pregnancies conceived naturally or through in-vitro fertilization (IVF) technique using either autologous or donor oocytes and to relate these measurements with pre-eclampsia (PE) development. METHODS: Uterine artery PI and placental volume were measured in 416 IVF pregnancies (307 women with autologous and 109 with donor oocytes) and in 498 spontaneously conceived pregnancies at 11 + 0-13 + 6 weeks of gestation. We recruited nulliparous women with singleton pregnancies. The measured mean uterine artery PI and placental volume values were converted to multiples of the expected normal median (MoM) adjusted for gestational age. MoM values of IVF pregnancies were compared with the naturally conceived group and related to PE development. RESULTS: No differences were found in uterine artery PI MoM between groups. Placental volume was significantly reduced in IVF pregnancies (K =169.3; p≤0.0001). Among IVF pregnancies significantly lower placental volume values were found in the donor oocytes recipients when compared to the autologous subgroup (z=3.89: p < 0.001). In IVF pregnancies developing PE lower values of placental volume were evidenced with respect to the normotensive ones (donor oocytes U=6.8; p = 0.009; autologous oocytes U = 5.1; p = 0.023) while no differences were found for uterine artery PI values. Multivariate logistic regression analysis demonstrated that placental volume is an independent predictor of PE (OR 1.97 (1.33-2.27)) as well as donor IVF (OR 2.24 (1.5-2.83)), while autologus IVF does not result significant in the model. CONCLUSIONS: First-trimester placental volume, as assessed by 3D ultrasound, is reduced in IVF pregnancies and this reduction is more marked in donor oocytes recipients. The relative decrease of placental volume found in IVF pregnancies that developed PE suggests an etiological mechanism different from uterine perfusion in such patients.