Pyridoxine can be used alone  or in combination with other antiemetic’s (doxylamine succinate) in the treatment of NVPs.Systematic reviews of randomized and/or control trials reveals pyridoxine improves mild to moderate nausea with little effect on vomiting [1,16].Hence, used in combination with other antiemetics in the treatment of Hyperemesis Gravidarum.As a single agent the maximum dose in pregnancy is 200 mg/day; however, a cumulative dose up to 500 mg/day is found to be safe .
Pregnant women experience these symptoms mainly in the first trimester between 6 and 12 weeks of gestation, few of them continue till 20 weeks of gestation while in few others it continues throughout the pregnancy.
Nonetheless, given the widespread prevalence of nausea and vomiting, its adverse effects and effects on psychological conditions of pregnant women, it is necessary to be treated effectively and safely during embryonic and fetal developmental stages.
First trimester exposure is important to be assessed to monitor the teratogenic potential of the drug; however, randomized control trials are rarely conducted for pregnant women for ethical reasons.
Nausea; Pregnancy; Etiology; Embryonic and fetal developmental stages Various categories of pharmacological agents either singly or in combination are used in the treatment of NVPs.
There are five neurotransmitter sites mainly used in the treatment of nausea and vomiting; M1-muscarinic acetylcholine, D2-dopamine, H1-histamine, 5-HT3-hydroxytryptamine (serotonin), and neurokinin-1 (NK-1) receptor-substance P.