Supine hypotensive syndrome (SHS) is an issue in late pregnancy and has been well described for more than 6 decades.1 The maneuver of left uterine displacement (LUD) has been a standard care in labor and delivery suites as well as operating rooms to attempt solving SHS in the United States, no questions will be asked, and the written concept exists in every major textbook from obstetrics to anesthesia. However, it has not been a standard or a routine practice in other countries, perhaps in the majority population in the rest of the world as Zhao’s review2 has pointed out.
Now, questions become: “Is LUD really necessary?” “What are potential mechanisms behind SHS?” “Does it occur to every woman?” “What gestational week could SHS start?” “Do pregnant women know if they have SHS?” “Does it occur as soon as pregnant women lie flat?” “Why do some women present bradycardia even during hypotension?” “Should we trust the current methods to measure pregnant women’s blood pressure?” “How much should LUD be, too much, or too less?” “What consequences would it have if lying flat?” “How much does neuraxial labor analgesia affect SHS? What about neuraxial anesthesia or general anesthesia for cesarean deliveries? What about anesthesia complications such as high/total spinal?” “Is there any alternative way to manage this issue when parturients really need to lie supine, for example, during resuscitation of maternal cardiac arrest?”
Also, even in the United States, questions could still be asked: “How much do pregnant women know about SHS?” “How many of them are not actually lying on their backs?” “How much effort should health care providers make to reinforce the maneuver?”
Furthermore, in the era of evidence-based medical practice, “Is there any high level evidence to support or not support the LUD?” Or even, “Is it necessary for Level Ia evidence to guide our practice in this issue?”
We have questions after questions about SHS. It is not a current hot topic as we expected, but really worth to have a systematic review like this. It is a big clinical matter in our daily practice. In addition, it might become a potential hot topic after this review, especially in the anesthesia field.