Mucinex in week 4 of pregnancy before taking pregnancy test

Patient: I took 3 Mucinex before knowing I was pregnant. I was 4 weeks at the time. What is the chance of harm to the embryo?

Symptoms: Pregnancy

Doctor: Hi,Thanks for the query.I understand your concern.Mucinex contains guaifenesin.It belongs to category C drug in pregnancy.Means animal studies have shown some possible side effects on fetus but sufficient human studies are lacking.So, if you decided to continue the pregnancy regular antenatal checkups and ultrasound examinations are mandatory.Ultrasound examination at 11 to 12 weeks, TIFFA (Targeted imaging for fetal anomalies) between 18 to 20 weeks and quadruple blood test at the same gestational age helps in ruling out possible anomalies to some extent.Take care.