Study limitations:
This was a retrospective study, and therefore there was considerable variation in the timing of echocardiographic studies. However clinical practice would dictate timing to coincide with trimester. At our centre, it is a routine practice to obtain a baseline echocardiogram at the time of the referral and also a repeat echocardiogram during 2nd trimester in women with LVOTO/AS. This likely mitigates some of the issues surrounding potential selection bias. Secondly, our study had a very small number of women with moderate or greater LVOTO/AS. This may potentially explain why the event rates for obstetrical and fetal/neonatal outcomes were also low. Finally, we assessed only the longitudinal strain, without measuring the circumferential or the radial strain. However, we feel that the longitudinal strain is the most clinically relevant marker, and the other types of strain are less applicable in clinical practice.