The decision to take anti-vomiting (antiemetic) medication during pregnancy is difficult.
However, the risks of dehydration & malnutrition due to HG are generally
much greater than the small possible risks of medications.
In a large, multicenter cohort study, there was no association between ondansetron exposure during pregnancy and increased risk of fetal death, spontaneous abortion, stillbirth, or major congenital malformations compared with exposure to other antiemetic drugs.
Taking Ondansetron (Zofran)
Since Ondansetron lasts about 4-6 hours, so it needs to be taken regularly to be effective. Stay ahead of symptoms. Take on a strict schedule, as prescribed for maximum effect. Set an alarm for both daytime and nighttime doses. Yes! Wake up to take it in the night.
Options that may be available: Tablets, Oral disintegrating tablets (ODT), Compounded cream, Subcutaneous infusion, IV infusion, and Liquid. Also consider options such as a transdermal patch (granisetron) and inserting ondansetron oral disintegrating tablets vaginally.
A daily stool softener like magnesium citrate or docusate (or both) is often needed while taking Ondansetron to prevent constipation. IV fluids and a bowel stimulant (enema) up to 3x a week might also be needed. For more bowel care recommendations, download our patient treatment guide (bowel care is section 4c).
Research finds minimal if any risk to mom and baby. At 8 weeks, the risk of major birth defects from medications is rare because the baby's organs are mostly developed. Risks taking medications during the usual range of dosing are low. Ondansetron/Zofran does not appear to have added risk if taken until delivery. Use with caution and consider an EKG if you have underlying heart issues or electrolyte deficiencies. If you are taking an antidepressant medication, please let your healthcare team know.
The American College of Obstetricians and Gynecologists recommends early treatment of nausea and vomiting of pregnancy to stop progression to hyperemesis gravidarum. We've compiled numerous studies and journal articles related to antiemetics and Hyperemesis Gravidarum >
Typical dosing for Ondansetron is as follows: 4 mg every 3-6 hours, 8 mg every 6 hours, maximum 32 mg/day. Always consult your healthcare provider before making any changes to your treatment plan or lifestyle. This information is for educational purposes only and does not constitute medical advice.
Kimber’s Rule of 2's: Wean over 2 weeks in 2nd+ trimester after 2+ weeks without symptoms. Important: When stopping any medication for HG, reduce the dose very slowly over 1-2 weeks. If symptoms worsen, you will likely need to go back up on your dose until you are feeling better and eating/drinking for 2+ weeks.
- Zofran/Ondansetron Quick Reference card
- Ondandestron Safety Statement
- HER Foundation HG Treatment Guide
- What Causes HG?
- Treatment Algorithm: The algorithm takes ACOG guidelines and recommended treatment options and puts them into a practical format.
- Zofran/Ondansetron Maternal Safety
- Zofran/Ondansetron Fetal Safety
Subcutaneous Infusion Site & Set-Up
A subcutaneous pump should be considered when multiple medication options and combinations are consistently taken on a schedule and are not tolerated or do not give adequate relief.
- Studies find more success with ondansetron pumps vs metoclopramide. (Klauser CK, Fox NS, Istwan N, Rhea D, Rebarber A, Desch C, Palmer B, Saltzman D AM J Perinatal. 2011 Oct; 28(9): 715-721 Epub 2011 Jun 10)
- Ask about trying less common medications on our Treatment
Algorithm before trying the pump. - Also consider options such as a transdermal patch
(granisetron) and ondansetron oral disintegrating tablets
vaginally. - Contact Optum OB Home Care for infusion services and Zofran/ondansetron or metoclopramide pumps (subcutaneous). They will help you get coverage with your insurance.
Ways to get more relief:
Ask for IV rehydration with electrolytes and vitamins when needed.
- If ondansetron pills are not tolerated, ask about taking the oral disintegrating tablets (ODT) vaginally with a drop of water or a compounded form (e.g. cream).
- Ask to switch from ondansetron to granisetron (pill, transdermal) or mirtazapine (pill, ODT), especially if you have headaches.
- Talk to your OB about additional medications to take such as an antihistamine, promethazine or metoclopramide, and steroids. See our online treatment guides.
- Discuss famotadine (Pepcid) to reduce acid. Change to
lansoprazole or pantoprazole for severe reflux. - Add vitamin B1 (thiamin). See hyperemesis.org/b1 for info.
Request IV fluids with vitamins be given regularly for a few days or weeks. - Ask about an infusion pump which offers a slow, continuous dose of medication and may be more effective. Ondansetron and metoclopramide can be given subcutaneously (see below) or intravenously (IV). Note there may be discomfort and significant expense with the subcutaneous pump.
- A syringe pump can also be used to infuse medication into a PICC line.
- REMEMBER: No medication(s) will resolve all nausea and vomiting immediately, and medication may be needed for months or until delivery.
HG Voices
"I wish my healthcare provided knew how much a difference hospital admissions, weekly IV hydration and a zofran pump made to treatment. I wish my healthcare provided knew my HG was not going to get better after the first trimester. It felt like every appointment I was told, just wait until 12 weeks... 24 weeks. It never got better and it took so long to a more permanent treatment plan in place."
Amaya
Tennessee, US
"I wish my healthcare provider knew about Zofran pumps and other alternatives. That sedation wasn't the only way to help me. I hope that more providers will have more knowledge of HG. I hope that one day there will be a cure. Having Hyperemesis Gravidarum did not just impact my physical health but my mental health. It made me feel as if I had gotten my "womanhood" stripped away from me."
Victoria
Kentucky, US
