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Preventing recurrence of severe morning sicknessGideon Koren, MD, FRCPC  Caroline Maltepe

ABSTRACT

QUESTION  A recent Motherisk article showed that initiating antinauseants even before symptoms start couldprevent recurrence of severe morning sickness. In the study described, however, different physicians useddifferent drugs. How can one be sure which drugs work?

ANSWER  The study of 26 women who had had severe morning sickness during previous pregnancies showed

that using antiemetics before symptoms of morning sickness started appeared to prevent recurrence of severemorning sickness in subsequent pregnancies. Physicians in the United States used various antinauseant drugs.Physicians in Canada administered only one drug, the combination of doxylamine-pyridoxine (Diclectin®), to 12women. Subanalysis of these 12 women revealed that pre-emptive use of doxylamine-pyridoxine significantlydecreased the likelihood that severe morning sickness would recur.

RÉSUMÉ

QUESTION  Dans un récent article de Motherisk, on faisait valoir que l’amorce d’une thérapie aux médicamentsantinauséeux avant même l’apparition des symptômes pourrait prévenir la récurrence de nausées matinalessévères. Par contre, dans l’étude décrite, divers médecins utilisaient différents médicaments. Comment peut-onsavoir quel médicament fonctionne?

RÉPONSE  L’étude auprès de 26 femmes qui avaient souffert de nausées matinales sérieuses au cours degrossesses antérieures a démontré que le recours aux antiémétiques avant l’apparition des symptômesde nausées matinales semblait prévenir la survenance de nausées matinales sévères dans les grossessessubséquentes. Les médecins aux États-Unis avaient utilisé différents médicaments antinauséeux. Les médecinsau Canada avaient administré un seul et même médicament, la combinaison de doxylamine et de pyridoxine(Diclectin®) chez 12 femmes. Une sous-analyse réalisée chez ces 12 femmes a révélé que l’utilisation paranticipation de la doxylamine-pyridoxine réduisait considérablement la probabilité d’une réapparition desnausées matinales sévères.

We have recently documented that women who haveexperienced severe nausea and vomiting during pre-vious pregnancies benefit from pre-emptive antinauseanttreatment during their current pregnancies.1 Treatmentneeds to be started before symptoms appear.

Among the 26 women participating in the study,1 14were American patients who received various combi-nations of antihistamines or ondansetron as their phy-sicians preferred. The other 12 women were Canadianand were treated with 10 mg of pyridoxine combinedwith 10 mg of doxylamine (Diclectin®, a delayed-releaseproduct). All these 12 women had experienced severenausea and vomiting during their previous pregnancies.Pre-emptive therapy decreased the severity of their

symptoms significantly during their current pregnanciesto mild in 5 cases and moderate in 4 cases ( P  < .01). In

3 cases, severity remained the same. In their previouspregnancies, 8 of these women had had to be hospi-

talized for severe nausea and vomiting. In their cur-rent pregnancies, only 1 woman had to be hospitalized( P  < .01).

Among 12 matched controls who had had severenausea and vomiting during previous pregnancies andwho did not receive pre-emptive antinauseant therapy,only 1 woman had less severe symptoms during hercurrent pregnancy. Her nausea and vomiting improvedfrom severe to moderate.

The apparent effect of doxylamine-pyridoxine wasstronger than the effects of any other antiemetics withwhich the American women were treated. Results sug-

gest that pre-emptive antiemetic treatment can mod-ify the vicious circle of severe nausea and vomiting

Motherisk Update

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during pregnancy that causes many women to needhospitalization.

Motherisk is currently conducting a random-ized controlled tr ial comparing pre-emptivedoxylamine-pyridoxine therapy with the regular rec-ommended protocol (ie, starting medication only inresponse to symptoms) to corroborate the initial find-ings of our prospective observational study. Studypatients are women who are planning pregnancy orwho have just conceived who experienced severe nau-sea and vomiting during their previous pregnancies.

Competing interests

 Duchesnay, manufacturer of Diclectin® , partly sponsors the

 Motherisk NVP Healthline.

Reference1. Koren G, Maltepe C. Pre-emptive therapy for severe nausea and vomiting of preg-nancy and hyperemesis gravidarum. J Obstet Gynecol 2004;24:530-3.

Motherisk questions are prepared by the Motherisk Team  at the

Hospital for Sick Children in Toronto, Ont. Dr Koren is Director and

Ms Maltepe  is a member of the Motherisk Program. Dr Koren  is

supported by the Research Leadership for Better Pharmacotherapy

during Pregnancy and Lactation and, in part, by a grant from the

Canadian Institutes of Health Research. He holds the Ivey Chair

in Molecular Toxicology at the University of Western Ontario in

London.

Do you have questions about the effects of drugs, chemicals, radia-

tion, or infections in women who are pregnant or breastfeeding?

We invite you to submit them to the Motherisk Program by fax at

416 813-7562; they will be addressed in future Motherisk Updates.

Published Motherisk Updates are available on the College of Family

Physicians of Canada website (www.cfpc.ca ) and also on the

Motherisk website (www.motherisk.org).

Motherisk Update

1546  Canadian Family Physician •  Le Médecin de famille canadien   VOL 52: DECEMBER  • DÉCEMBRE 2006