Medication & Treatments
None of the information provided on this website is meant to suggest any medical course of action. Instead the information is intended to inform and to raise awareness so that these issues can be discussed by / with qualified Healthcare Professionals with their patients. The responsibility for any medical treatment rests with the prescriber.
There are many reasons for considering Nausea and Vomiting in Pregnancy (NVP) to be a condition caused by hormones, cytokines (locally acting hormones) or prostaglandins, substances produced by the early placenta. These include: the very high incidence of the condition (about 70-80% of pregnant women have NVP and and between 1 in 100 and 1 in 150 for Hyperemesis Gravidarum), the average start day, which is concentrated around 39 days from the 1st day of the last menstrual period (LMP), or in 13% of women occurring, to their surprise, before their first missed period; the variation of NVP from pregnancy to pregnancy in the same woman; and the fact that NVP is an unusual type of nausea, in that it is often improved by eating (see "Literature Review" sections 1 - 8 inclusive). These facts suggest a physiological, rather than a psychological, cause for the condition. The hormone Human Chorionic Gonadotrophin (hCG), has been related to the condition by some research workers (see "What Causes Pregnancy Sickness by Gadsby, R" and for more information see "Causes") Further investigation into the hormones, cytokines and prostaglandins related to the production of hCG or the effects of this hormone are required. This under-researched and under-funded condition lacks resources for further investigation in the UK at present.
Safe & Effective Treatments
The most important feature of any treatment for nausea and vomiting in pregnancy are:-
- Does it work (efficacy)?
- Does it do any harm to the developing foetus (safety)?
- Does it have significant side effects on the mother to be?
An evidence based clinical guideline for the treatment of nausea and vomiting in pregnancy has recently been published. It provides an excellent summary of the evidence for the efficacy and safety of various treatments and gives a treatment algorithm. (Reference at bottom of page)
Early recognition and management of NVP could have a profound effect on women’s health and quality of life during pregnancy, as well as a financial impact on the healthcare system
Antihistamine with Vitamin B6 
Doxylamine is an antihistamine that has been shown to be effective in treating nausea and vomiting in pregnancy. In combination with pyridoxine (Vitamin B6) it was called Bendectin which has been shown to be effective in at least 3 randomised controlled trials. Although Bendectin had been used by 33 million pregnant ladies it was withdrawn by its manufacturer in the early 1980’s because of exhaustive defence costs against liability suits for foetal defects. Eventually all these legal cases against Bendectin, which went to court, were unsuccessful. Doxylamine and pyridoxine are now among the very few therapies that are classed as having no risk to the foetus. As no credible evidence of human or animal teratogenesis or other undesirable effects existed, a Canadian company began to make a generic form of doxylamine – pyridoxine in delayed release form (Diclectin) in 1984. This has been prescribed for the treatment of nausea and vomiting of pregnancy in Canada since then. The evidence based guidelines (approved by the Society of Obstetricians and Gynaecologists of Canada) state that Diclectin should be the initial treatment of choice since it has the greatest evidence to support its efficacy and safety.
A recent study by Matepe and Koren (2013) found that for women who have suffered HG in a previous pregnancy, early use of this treatment, prior to onset on symptoms can significantly reduce the impact the severity of the condition and is superior to starting treatment only when symptoms have started. The full text article is available here.
Diclectin is very difficult and expensive to import into the UK and therefore not currently very feasible. Cyclizine or Promethazine combined with B6 is the closest combination available at the moment.
A wide body of evidence suggests that H1 receptor antagonist antihistamines have no human teratogenic potential. Pooled data from 7 randomised controlled trials indicate that these antihistamines are effective in the treatment of NVP.  Some of the H1 receptor antagonist antihistamines that are available in the UK include Promethazine (Avomine) and Cyclizine (Valoid) These antihistamines can cause drowsiness and should not be taken without medical advice.
Pyridoxone (Vitamin B6)
It has been shown to be effective in helping NVP in 2 randomised controlled trials against placebo (one trial at 30mgs / daily, the other at 75mgs / daily). A retrospective cohort study concluded that pyridoxine monotherapy had no increased risk for major malformations. There are no apparent side effects.
Prospective and retrospective cohort studies, case-control, and record linkage studies of patients with exposure to various and multiple phenothiazines have failed to demonstrate an increased risk of major malformations. Significant therapeutic effect on NVP was demonstrated in 3 randomised controlled trials in severe NVP.  One of the phenothiazines available in the UK is prochlorperazine (Stemetil). Side effects include drowsiness, restlessness and occasional extra pyramidal effects. These are prescription only medications.
There is only limited information on its safety in pregnancy, although the little that has been published is reassuring. There are a very limited number of studies that indicate the effectiveness of metoclopramide in the treatment of NVP.  Side effects include drowsiness, restlessness and occasionally extra pyramidal effects. This is a prescription only medication.
This is a powerful anti sickness tablet used to treat people who have severe sickness when being treated with chemotherapy for cancer.
There are a few studies published in the world literature of it being used to treat severe hyperemesis gravidarum when other therapies have failed.
One fairly small observational study in around 170 pregnancies in which the Mums had taken ondansetron showed no increase in foetal abnormalities.  A recent study of 1,849 women exposed to ondansetron found no increased risk of adverse fetal outcomes. 
There may be a small increased risk of oral clefting associated with the use of corticosteroids and many authorities say that they should not be used to treat NVP in the first 12 weeks of pregnancy. There is emerging data on the effectiveness of corticosteroids to treat severe and persistent NVP. Corticosteroids need to be given under medical supervision and assessment.
Dr Roy Taylor from Newcastle University published a paper in 2009 regarding the use of Steroids as the treatment of choice in severe Hyperemesis Gravidarum. for the full reference and summary please see our resources page.
Non-pharmacological remedies - Ginger
The conclusion from 6 randomised controlled trials with a total of 675 participants was that ginger extract at 1000 mgs per day may be effective treatment for NVP. However the small number of patients in these studies allocated to receive ginger (n=303) may have been insufficient to properly test the safety of ginger with regards to pregnancy outcome. Ginger is a non regulated food product and most preparations available are of variable purity and composition so dose is uncertain. Side effects include heartburn and thromboxane synthetase inhibition i.e. inhibits platelet aggregation.
Acupuncture and Acupressure
Stimulation of the P6 point, located three fingers breadth above the wrist, has been used for many years to treat nausea from a variety of causes. Trials of a non-blinded randomised nature have shown a decrease of persisting nausea by at least 50%. Bands worn at the wrist (e.g. Sea Bands) that apply pressure may be a simple way of stimulating the P6 point. There are no theoretical concerns about the safety of acupressure in pregnancy.
1. ARSENAULT M-Y LANE C.A.
The management of Nausea and Vomiting of Pregnancy
J Obstet Gynaecol Canada (2002) 24; 817 - 823
2. MAZZOTTA P, MAGEE L.A.
A risk benefit assessement of pharmacological treatments for nausea and vomiting of pregnancy.
Drugs 2000 59 (4) 782-800
3. EINATSON A, MALTEPE C, NAVIOZ Y, KENNEDY D, TAN MP, KOREN G. The safety of ondansetron for nausea and vomiting of pregnancy: a prospective comparative study. BJOG 2004 Sep;111(9):940-3
4. Pasternak, B., H. Svanstrom, et al. (2013). Ondansetron in pregnancy and risk of adverse fetal outcomes. N Engl J Med 368(9): 814-23.