Robitussin is what my doctor recommended when I recently had a cold but he said as long as it isn't DM because it causes u to get drowsy and it's too much for the baby but as long as it's any other Robitussin you will be fine ...I got over my cold in no time ...good luck and of your still skeptical just call your doctor and he'll let u know that Robitussin is perfectly safe
I have the same problem im 28+4 days so I called L&D and they said it will be fine to take Robitussin. I took the cough-chest congestion and I feel a lot better. Good luck