Date: June 11th, 2019

Reference: Huybrechts et al. Association of Maternal First-Trimester Ondansetron Use With Cardiac Malformations and Oral Clefts in Offspring. JAMA Dec 2018.

Guest Skeptic: Dr. Nick Papalia completed his MD at Western University. He is currently completing an Obstetrics and Gynecology residency at the University of Calgary.

Case: A 24-year-old woman G2T1P1A0L1 who presents with nausea and vomiting of pregnancy at nine weeks gestational age. She has stopped her iron pills, taken ginger, used acupressure, tried vitamin B6 with doxylamine and dimenhydrinate. She is frustrated nothing is working and wants to try something else. Her friend got little wafers that dissolved under her tongue (ondansetron). She is worried because her google search said it could cause a birth defect like a cleft lip.

Background: Many women suffer from nausea and vomiting when pregnant. These symptoms can become clinically significant in over 30% of woman. Hyperemesis gravidarum is the most common reason for hospitalization in early pregnancy and impacts a small percentage of these pregnancies.

The Society of Obstetricians and Gynecologists of Canada (SOGC) published a guideline for the management of nausea and vomiting of pregnancy in 2016 (Campbell et al 2016). They make 13 recommendations:

* Women experiencing nausea and vomiting of pregnancy may discontinue iron-containing prenatal vitamins during the first trimester and substitute them with folic acid or adult or children’s vitamins low in iron. (II-2A)

* Women should be counselled to eat whatever pregnancy-safe food appeals to them and lifestyle changes should be liberally encouraged. (III-C)

* Ginger may be beneficial in ameliorating the symptoms of nausea and vomiting of pregnancy. (I-A)

* Acupressure may help some women in the management of nausea and vomiting of pregnancy. (I-B)

* Mindfulness-based cognitive therapy as an adjunct to pyridoxine therapy may be beneficial. (I-B)

* Pyridoxine monotherapy or doxylamine/pyridoxine combination therapy is recommended as first line in treating nausea and vom- iting of pregnancy due to their efficacy and safety. (I-A)

* Women with high risk for nausea and vomiting of pregnancy may benefit from preemptive doxylamine/pyridoxine treatment at the onset of pregnancy. (I-A)

* H1 receptor antagonists should be considered in the management of acute or chronic episodes of nausea and vomiting of pregnancy. (I-A)

* Metoclopramide can be safely used as an adjuvant therapy for the management of nausea and vomiting of pregnancy. (II-2B)

* Phenothiazines are safe and effective as an adjunctive therapy for severe nausea and vomiting of pregnancy. (I-A)

* Despite potential safety concerns of ondansetron use in pregnancy, ondansetron can be used as an adjunctive therapy for the management of severe nausea and vomiting of pregnancy when other antiemetic combinations have failed. (II-1C)

* Corticosteroids should be avoided during the first trimester because of possible increased risk of oral clefting and should be restricted to refractory cases. (I-B)

* When nausea and vomiting of pregnancy is refractory to initial pharmacotherapy, investigation of other potential causes should be undertaken. (III-A)

The primary literature used to support the acupressure recommendation is very weak. A review by Roscoe and Matteson 2002 showed conflicting results from seven methodologically flawed trials. The conclusion was that acupressure might (might not) be beneficial.

The American College of Obstetricians and Gynecologists (AGOC) has published a practice Bulletin (