Good News about Morning Sickness

Dr. Koren is the founder and director of the Motherisk Program and professor of Paediatrics, Pharmacology, Pharmacy, and Medical Genetics at the University of Toronto. He is also the Richard and Jean Ivey Chair in Molecular Toxicology in the Schulich School of Medicine, at The University of Western Ontario, where he holds the rank of professor in Medicine and Paediatrics.


Nausea and vomiting of pregnancy (NVP) is often called “morning sickness” because for most women it peaks in the morning. But for many women symptoms persist all day, and for some continue throughout the entire pregnancy.

Morning sickness occurs in 80% of pregnancies, with symptoms typically peaking between 5 and 12 weeks’ gestation. Adverse effects include weight loss, weakness and poor quality of life. Motherisk counsels women to eat and drink (non-alcoholic beverages) in small amounts, avoid foods and beverages that cause irritation by taste or smell, and, if these steps are not effective, to use antiemetic medication. In Canada, the only approved antiemetic drug for use in pregnancy is Diclectin.

While NVP may have negative effects on mom , it is associated with favourable outcomes for baby, including reduced rates of miscarriage, stillbirth, preterm birth, intrauterine growth retardation, and congenital malformations. However, there is still much to learn about the effects of NVP on long-term child development, particularly intelligence and specific cognitive skills.

A recent Motherisk study used standardized tests to assess the development of children who were exposed before birth to maternal use of Diclectin, as well as the effect of their mothers’ NVP. Of the 92 women with NVP who participated in the study , 40 experienced NVP only during the first trimester, 29 during the second trimester, and 23 during the third trimester. Significantly more women in the Diclectin-treated group had longer-lasting NVP than women who chose not to treat their condition.

The children of the women in the “NVP-with-Diclectin” group scored significantly higher on measures of IQ, than children in the “no-Diclectin” and “no-NVP" groups. Children of mothers with NVP had significantly higher nonverbal intelligence scores (such as performance IQ) than children whose mothers did not have NVP; however, they had similar verbal intelligence scores as those of children whose mothers did not have NVP.

A possible cause for the improved performance of children whose mothers had severe NVP may be their exposure to higher levels of maternal hormones before birth.

The good news is that there may be a silver lining to your morning sickness suffering, and just as important, there are no adverse effects of Diclectin treatment for NVP.

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