Nausea in Pregnancy

About 50% of women have nausea and vomiting in early pregnancy and about 75% experience nausea alone.  In about 35% of women, the nausea and vomiting associated with pregnancy is significant enough to result in lost work time, dehydration and other potential medical complications.  In most patients, the onset of nausea is within 4 weeks after the last menstrual period and the problem typically peaks at 9 weeks of gestation.  By the end of the first trimester, 60% of cases are resolved and 91% are resolved by 20 weeks.  We used to call nausea and vomiting with pregnancy “morning sickness”.  However, this condition can occur anytime during the day and so the term “morning sickness” is a bit of a misnomer. 

The cause of nausea and vomiting in pregnancy is unknown.  Nausea and vomiting in pregnancy correlates with levels of a hormone called human chorionic gonadotropin (HCG).  It is also theorized that vitamin B6 deficiency may contributed to nausea and vomiting in pregnancy.  Vitamin B6 can mitigate the nauseating effect of estrogen and is thought to have a role in the synthesis of serotonin, dopamine, norepinephrine and gamma-amino butyric acid of GABA.  GABA deficiency might induce nausea and vomiting.

The effects of nausea and vomiting in pregnancy can range from just mild irritation to severe debilitation and can pose threats to the mother and child.  Infants of mothers who have lost weight in early pregnancy have lower mean birth weights and lower percentile weights for gestational age and they are more likely to be in the less than 10th percentile of birth weights.

The treatment of nausea and vomiting in pregnancy is usually follows a straight forward progression.  The pharmacological treatment algorithm recommended by the American College of Obstetricians and Gynecologists is found in figure 1.  Personally, I prefer “non-drug” approaches to wellness whenever possible including acupressure, using ginger and correcting any vitamin deficiency, especially B vitamin deficiencies.  If those fail, then the patient has no choice but to seek pharmacological relief.

Acupressure:  Studies have shown that application of pressure to the inner wrists (more technically the P6 or Neiguan site) can relieve nausea and vomiting.  This type of pressure can be easily applied with a Sea Band ® wrist bracelet.  Some scientific studies question the validity of pressure point therapy for nausea and vomiting in pregnancy, but this treatment has absolutely no potential for adverse effects and is therefore something that should be considered for the treatment of all forms of nausea.

Ginger:  Ginger is well known to relieve nausea and vomiting and is recommended by the American College of Obstetrics and Gynecology.  Ginger comes in many forms from ginger ale to candied ginger.  One component of ginger has been found to inhibit serotonin type 3 receptors in a manner similar to Zofran®.  This mechanism may explain why it works so well for the treatment of nausea and vomiting.  Keystone Pharmacy compounds 200mg ginger lollipops to help quell nausea.  They have a very strong taste of ginger, but are basically free from side effects and should be considered as an option all forms of nausea.  These lollipops do require a physician’s prescription because they are compounded, but we have found almost universal acceptance by physicians when the request for the lollipops is made.

Vitamin B6 (Pyridoxine):  Randomized, placebo controlled studies have found pyridoxine to be effective in treating nausea and vomiting.  Doses of 10-25mg every 8 hours are required.  Again, this is a therapy with relative few side effects.  It is also over the counter, so it can be tried very early on, at the first sign of nausea.

Doxylamine:  Doxylamine is also known as Unisom®.  The combination of 10mg of both doxylamine and pyridoxine in a delayed release capsules have been approved by the FDA to treat nausea and vomiting in pregnancy.  This combination product is known as Diclegis and costs about $6/tablet.  One could closely approximate the effects of Diclegis by taking 10mg of pyridoxine with ½ of an over the counter Unisom®.   Of course, doxylamine can cause marked drowsiness (remember, it IS Unisom®), so be careful if you have to drive or perform dangerous tasks.

Other options:  If the above options fail, other options including the use of Phenergan, Dramamine, Zofran or Reglan.  The progression to these agents will be very quick if the above therapies do not work.  In the event that nausea and vomiting persist for more than a day or so, consult your physician very early on to ensure dehydration and other complications to not ensure.
by Dr David J2013_08_30_14_38_340001 Miller, RPh, PhD, FIACP

Gastroenterology Clan North Am. 2011 June; 40(2): 309–vii.

doe:  10.1016/j.gtc.2011.03.009

PMCID: PMC3676933


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