Vomiting during pregnancy

By trimester

Weeks 1–13

1st trimester

Most vomiting starts here, often between weeks 4 and 9, peaking around weeks 7 to 12. Small, frequent sips of fluid and plain snacks usually keep things manageable at this stage. If vomiting first shows up after week 10, or you can't keep any fluids down for half a day, that's worth a same-day call rather than waiting for your next visit.

Weeks 14–27

2nd trimester

Vomiting usually eases by 12 to 16 weeks. If it's still frequent, getting worse, or starts fresh after a symptom-free stretch, mention it to your obstetric team instead of assuming it will fade on its own. A pattern that breaks this way is exactly the kind of thing worth a phone call.

Weeks 28–birth

3rd trimester

New or worsening vomiting this late in pregnancy is uncommon and deserves its own look, since third-trimester causes can differ from early pregnancy nausea. Skip the home remedies here and call your provider so they can check what's actually behind an upset stomach this late on.

What does the evidence show for vomiting?

• Throwing up sometimes in early pregnancy is common: nausea and vomiting affect roughly 8 in 10 pregnancies, so one queasy episode on its own usually isn't a red flag. 1
• Vomiting crosses into a more serious condition called hyperemesis gravidarum once it causes real weight loss and dehydration, which happens in up to about 3 in 100 pregnancies and can call for a hospital stay. 1
• Losing more than about 5% of your pre-pregnancy weight, along with a fast pulse, a dry mouth, or skin that's slow to bounce back when pinched, are the hands-on signs your care team checks for dehydration from vomiting. 2
• Vomiting that goes on long enough to cause a vitamin B1 (thiamine) shortage can, in rare cases, lead to confusion, odd eye movements, or trouble with balance, which are emergency signs and not something to wait out at home. 2
• A home urine ketone strip isn't a reliable way to judge how serious your vomiting is, since your provider is more likely to track your weight, hydration, and a short symptom questionnaire instead. 3

When should I call my provider about vomiting?

What separates ordinary pregnancy vomiting from hyperemesis gravidarum is measurable: weight loss of roughly 5 percent or more of prepregnancy weight, ketones in the urine, and electrolyte disturbance such as low potassium or low sodium. Dehydration shows as dizziness on standing, dry mucous membranes, decreased skin turgor, and slow capillary refill, and that combination is a same-day call rather than a reason to sip harder at home. Vomiting that first appears after 9 weeks of gestation should send your provider looking at other causes instead of straight to a stronger nausea plan. Confusion, unsteadiness, or unusual eye movements after prolonged vomiting can point to thiamine deficiency, and sudden severe chest or upper abdominal pain after retching can point to an esophageal tear: both are emergencies. None of these lists replace your own judgment: if this symptom worries you, that on its own is enough reason to check in with your healthcare provider.