Third Trimester Nausea

late-pregnancy-symptoms-of-laborThird trimester refers to weeks 27-40 of pregnancy. That’s to say, you will expect to welcome a new life in only a couple of weeks. For a few of you with nausea during the third trimester, this is still one of the tough times of your pregnancy. Just like fatigue, vomiting, diarrhea, dizziness, and hot flashes, nausea is also one of common third trimester symptoms. In fact, nausea may be more common than you think.

If it is a less serious case, it is often considered normal and generally does not need to be treated. However, in severe cases please talk with your gynecologist about your unpleasant queasy feeling. To sum up, third trimester nausea causes and corresponding countermeasures are as follows.

Decreased gastrointestinal motility

Since nausea in late pregnancy has some relationship to the decreased gastrointestinal motility, along with reduced stomach capacity due to the rise of the bottom of uterus, it’s perhaps not surprising to see third trimester nausea. For that reason, eating very little food or sometimes nothing, let alone eating hearty meals, will lead to an upset stomach. If that’s the case, it is always good to eat more frequent, smaller meals.

Pressure of the growing uterus

This, in essence, is similar to the above-mentioned one. As you may know, signs and symptoms of pregnancy vary in each individual pregnant woman. In general, your digestive system will react strongly in the first trimester and then the reaction will be gradually gone over time. If a pregnant woman experiences nausea in third trimester, growing baby bump can be one of possible causes. This is easy to understand since digestive system abnormalities will occur because of the growing fetus pressing against the stomach. Generally, this problem will be eased to some extent by spreading out your meals into 5 or 6 small ones throughout the day. If it is difficult to endure, it is recommended not to be nervous and visit an obstetrician if necessary.

Hormone fluctuation and morning sickness

So far the cause of nausea and vomiting of pregnancy (NVP) still remain unknown. According to existing research, it might be mainly related to hormone imbalance and mental illness. In early pregnancy, about six weeks after conception, increased human chorionic gonadotropin (hCG), decreased gastric acid secretion and delayed emptying of the stomach will cause dizziness, fatigue, loss of appetite, aversions to greasy food or cravings for sour flavors, and so on. As one of common symptoms in the first trimester, typically morning sickness needs no special treatment. So, when does morning sickness start and stop? It should be noted that it varies from expectant mother to expectant mother. In other words, some may experience it earlier, but other individuals late. More than that, NVP can be seen throughout the whole process.

Acid reflux

Sometimes also known as GERD and acid reflux or reflux, heartburn refers to a burning sensation in your chest during an episode of acid reflux. During pregnancy pregnant women tend to experience a variety of gastrointestinal symptoms, which include vomiting, nausea, constipation, tasting sour liquid or regurgitated food at the back of the mouth, and the like. So, there are more than about 50% of pregnant women suffering from heartburn. Usually heartburn occurs in the mid and late stages of pregnancy and in most cases this symptom will be gone after the labor.

Multiple factors can cause heartburn in pregnant women. In general, the decreased esophageal sphincter pressure and a baby growing in the womb will contribute to the increasing pressure on the stomach, which results in the reflux of acidic gastric contents and thus the heartburn.

And heartburn tends to get worse with bending, sitting, or lying down. And its incidence will increase as the number of weeks of pregnancy. In addition, if you’ve had heartburn or even you have been pregnant before, you will have an increased risk of this symptom during pregnancy. When it comes to gastroesophageal reflux disease (GERD), it can be diagnosed by the clinical history and symptoms. If you suspect you have ulcers, esophageal stricture, bleeding, or other complications, an endoscopic examination is extremely necessary.


Nausea probably means nothing when it appears by itself in the third trimester of pregnancy. However, this symptom can be a signal that the baby is ready for birth in some individuals, especially when combined with other signs of labor approaching, such as fairly frequent contractions, pelvic pressure, increased vaginal discharge, pelvic pressure, and so on. In this case, you have to contact your obstetrician in no time.

Acute fatty liver of pregnancy (AFLP)

It is normal that women feel nauseous during early pregnancy. However, morning sickness in the third trimester of pregnancy can be a warning of hepatic lipidosis of pregnancy, especially when persistent nausea combines with vomiting, fatigue, abdominal pain and other discomfort. Compared with other common diseases, AFLP is a very rare, potentially fatal complication. Once AFLP has been diagnosed the pregnancy will need to be terminated as soon as possible no matter regardless of the severity. This is because this disease progresses rapidly without treatment, and eventually leads to death due to severe liver dysfunction based multi-organ failure.


Preeclampsia is a disease peculiar to pregnant women. It generally occurs after 24 weeks of pregnancy in about 5 percent of all pregnant women. Preeclampsia is characterized by hypertension and kidney damage, or accompanied by symptoms of proteinuria and edema in some patients. In severe cases, patients may also suffer from headaches, blurred vision, upper abdominal pain and other symptoms. If left untreated, it may also cause generalized convulsions, coma, heart and kidney failure, and even maternal death. So, pregnant women with preeclampsia should pay more attention to their daily dietary intake since a healthy diet can largely reduce the risk of preeclampsia.

Since pregnancy-induced hypertension is complex and changeful, the purpose of monitoring and assessment is to understand the severity and progress and then give timely, reasonable treatment.

In summary, when third trimester nausea occurs you should consider 3 major different likely scenarios – the digestive tract diseases, growing baby bump, and liver problems. So, it is recommended to check and rule out these 3 mentioned possibilities. Generally, you can be assured if AFLP and preeclampsia have been ruled out. So, routine tests in the third trimester of pregnancy are really important.

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