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Nausea and vomiting in early pregnancy

In early pregnancy nausea affects up to 85% of women, and vomiting 50%. It doesn't happen just in the morning, nor in the first few weeks and months of pregnancy. Pregnant women lose time off work, and/or fail to deal with everyday activities. So treatments are important, and a recent Cochrane review gives us some answers about efficacy.


This is a Cochrane review, so searching was exhaustive. Treatments tested for were different anti-histamine medicines, Pyridoxine (vitamin B6), the combination medicine Debendox, and P6 acupressure.


There were three treatments with at least two trials, not all of which would be considered as properly randomised. Results were in many forms, but extractable as dichotomous outcomes was success judged as the absence of persistent nausea. For individual trials, the results are shown in the L'Abbé plot, and the pooled information is in the Table.

Summary of studies for treatment of nausea and vomiting in early pregnancy
Treatment Number of studies Number of patients NNT (95%CI)
P6 acupressure 2 396 4.5 (3.2 to 7.8)
Debendox 3 240 4.4 (2.9 to 9.1)
Pyridoxine 2 392 47 (8.6 to no benefit)

P6 acupressure in two studies showed 52% of patients with control having a success, compared with 75% with P6 acupressure. The NNT was 4.5 (3.2 to 7.5).

Debendox in three studies showed 49% of patients with control having a success, compared with 72% with Debendox. The NNT was 4.4 (2.9 to 9.1).

Pyridoxine in two studies showed 63% of patients with control having a success, compared with 65% with Pyridoxine. The NNT was 47 (8.6 to no benefit).


Pyridoxine doesn't seem to work, and Debendox was withdrawn because of fears (probably incorrect) of teratogenicity. That leaves P6 acupressure as the one treatment available with some evidence of efficacy.

While there is more in the review than abstracted here, including some comments on adverse effects like drowsiness, the overwhelming feeling on reading it is how little evidence there seems to be for this important condition. Most of the 650,000 or so women delivering every year would appreciate more help. But the bottom line is that the success rate with control was consistently about 50% or so. Mostly the problem goes away.

Many thanks to the authors for sending original data to allow calculation of NNTs and the L'Abbé plot.


  1. D Jewell, G Young. Treatments for nausea and vomiting in early pregnancy. Cochrane Library 1998, 3rd issue. Date of most recent amendment 16 April 1998.

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