He defined HG based on the symptoms, vomiting exceeding three times a day with significant ketonurea or weight loss more than or equal to 5% of pre pregnancy weight, electrolytic imbalance or fluid depletion, and onset occurs at 4 to 8 weeks of pregnancy till 14 to 16 weeks.
Nausea and vomiting in pregnancy is of multifarious etiology (fluctuating levels of progesterone, estrogens, Thyroid Stimulating Hormone (TSH), slow peristaltic movement of Gastrointestinal (GI) tract); however, the exact mechanism remains still unclear.
First-generation antihistamines, which include diphenydramine (Benadryl) and clemastine (Tavist) cause more severe side effects (such as drowsiness) than most newer second-generation antihistamines.
For this reason, second-generation antihistamines are generally preferred and recommended over first-generation antihistamines.
Also available are quick-dissolving tablets, which are marketed as being faster to get into one's circulatory system, but require special handling to avoid degrading in the package.
Patients with severe hepatic (liver) disorders may need to start with a lower dose.
In Part 3 of our 7-part Drugs in Pregnancy series, we pick up a tissue in sympathy with the many women who suffer more-frequent colds and coughs over the 9 months of pregnancy.