The present study was primarily designed to accurately determine biventricular and biatrial myocardial function, assessed by two-dimensional speckle tracking echocardiography (2D-STE), in a prospective cohort of pregnant women aged ≥ 35 years, at the second trimester of pregnancy. Secondly, we aimed at investigating the main independent predictors of adverse maternal outcome (AMO) in the same study population. 80 consecutive pregnant women aged ≥ 35 years, 80 gestational week-matched (18.4 ± 1.6 vs 18.5 ± 1.8 weeks, p = 0.71) pregnant women aged < 35 years and 80 non-pregnant women aged ≥ 35 years without any comorbidity were included in this prospective study. All pregnant women underwent obstetric evaluation, modified Haller index (MHI) assessment and a conventional two-dimensional transthoracic echocardiography implemented with complete 2D-STE analysis of both ventricles and atria at the second trimester of pregnancy. AMO was defined as the occurrence of any of the following: gestational hypertension (GH) including preeclampsia; gestational diabetes mellitus (GDM); preterm delivery (PD); emergency caesarean section (ECS); postpartum haemorrhage (PPH); premature rupture of membranes (PROM); maternal death. Compared to younger pregnant women, pregnant women aged ≥ 35 years were more likely to be found with: (1) body mass index (BMI) ≥ 30 kg/m (37.5% of total); (2) significantly increased inflammatory markers; (3) significantly greater left ventricular mass index; (4) significantly impaired hemodynamics; (5) significantly reduced bi-atrial and bi-ventricular myocardial strain parameters, despite normal ejection fraction. A strong inverse correlation between second trimester BMI and left ventricular (LV)-global longitudinal strain (GLS) (r =  - 0.84) and between second trimester MHI and LV-GLS (r =  - 0.81) was demonstrated in pregnant women aged ≥ 35 years. GH, GDM, PD, ECS, PPH and PROM were detected in 15%, 12.5%, 10%, 8.7%, 8.7% and 7.5% of women, respectively. Age (OR 2.04, 95% CI 1.46-2.84), second trimester BMI (OR 2.40, 95% CI 1.64-3.51) and second trimester LV-GLS (OR 0.07, 95%C I 0.01-0.34) were independently associated with outcome. Age ≥ 37 years, BMI ≥ 30 kg/m and LV-GLS less negative than - 18% were the best cut-off values for predicting AMO. A LV-GLS less negative than - 18% allows to identify, among older pregnant women, those with an increased risk of AMO. Both intrinsic myocardial dysfunction and extrinsic compressive mechanical phenomena might affect global myocardial deformation during gestation.