Maternal Left Lateral Position in Fetal Growth Restriction

The goal of this clinical trial is to learn if maternal left-lateral positioning in pregnancy works to treat fetal growth restriction. This study will also help us learn about the effects of left-lateral positioning on maternal metabolomics, maternal mental health, fetal cardiac function, and delivery outcomes. The main questions it aims to answer are: * Does maternal left-lateral position in a pregnancy with fetal growth restriction improve the baby's growth? * How are maternal metabolomics, delivery outcomes, maternal mental health, and fetal cardiac function impacted by maternal left-lateral position? Researchers will compare the intervention group to pregnancies with fetal growth restriction that receive standard of care (without left-lateral positioning) to see if left-lateral position improves fetal biometry in fetal growth restriction. Participants will: * Practice left-lateral position every day for 4 hours (cumulatively) with 10-mins stretching after every hour of left-lateral position, or continue to receive standard of care * Visit the clinic once after 4 weeks for a follow-up research visit, and at the time of delivery Tracking of the physical activity and adherence to left-lateral position at home in intervention group A will be done through a fitbit (smart watch) given during enrollment. A fitbit will also be given to participants in intervention group B, receiving standard of care, to monitor their physical activity trends at home.