Vomiting in the Third Trimester

Pregnant woman in the bathroom

After dealing with morning sickness in early pregnancy, some women are surprised to experience vomiting in third trimester. Though most of the time from 27-40 weeks is spent getting ready for labor and delivery, vomiting can still sneak up on some moms-to-be. Many of the common causes for vomiting are related to stomach bugs and digestion problems, but a chronic upset tummy can also be a sign for serious pregnancy problems.

Reasons for Vomiting in Third Trimester

Some women think that vomiting in third trimester is simply an extension of the morning sickness they had in the first few months. This can sometimes be the case, especially if your morning sickness was present throughout the second trimester. Since shifts in hormone levels increase during the third trimester, it's possible to go several weeks with no vomiting to only have it return later.

If you had no morning sickness or vomiting during the first or second trimesters or if the vomiting comes on suddenly, however, it could be a sign of a serious complication. Anytime you experience unexpected vomiting during pregnancy, you should contact your physician. Pregnant women can dehydrate and lose vital nutrients quickly, so your doctor may want to run some blood tests to make sure everything is okay.

Some of the most common reasons for vomiting in third trimester include:

  • Labor: In addition to contractions and back pain, some women experience vomiting when they start labor. If the vomiting or nausea or accompanied by any of the other signs of labor, contact your doctor or midwife right away.
  • Stomach bugs: Vomiting in third trimester can be as simple as a case of food poisoning or your body's reaction to something unusual that you ate. It can also be a virus or a case of the flu. Since any of these can cause a sudden onset of vomiting and diarrhea, you can dehydrate very quickly. Make sure you are drinking a lot of water and keeping your doctor informed of how often you get sick, even if he has determined that there isn't a more serious cause for the vomiting.
  • Fetus size: As the fetus grows, there is simply not enough space in some women's abdomens. The growing uterus may push on the stomach, making it difficult for the mother to digest a large meal. This will often cause acid reflux and heartburn. Sometimes, especially after a large meal, a woman in her third trimester may experience burping and sudden vomiting. As long as this doesn't happen often, it is unlikely to be a problem.

Serious Complications

Preeclampsia, also known as hypertension in pregnancy or toxemia, is a serious condition that needs to be treated quickly. Vomiting is one of the main signs of preeclampsia and is often accompanied by headaches, visual changes, sudden weight gain, bloating, and high pressure. If not treated, preeclampsia can lead to seizures, coma, and even death of the mother or baby. Delivery of the baby is the most effective means of treating preeclampsia if the pregnancy is far enough along that it is safe to deliver. If preeclampsia occurs before the 36th week, the mom is usually admitted to the hospital, put on bed rest, and monitored closely until delivery is possible. Medications can be used to treat some of the symptoms of preeclampsia, but delivery is the only cure.


Just like during non-pregnant times, a woman may experience vomiting as a symptom of relatively minor health problems. But, any vomiting that happens more than once or gets worse from what you've experienced throughout your pregnancy needs to be evaluated immediately by your OB/Gyn. In rare cases, this can be one of the first signs of a serious health issue that needs to be addressed right away.

Vomiting in the Third Trimester