During the second trimester of pregnancy, most women can expect see some of their early pregnancy symptoms taper off—including nausea and fatigue—as hormone levels that have been surging generally start to level off. Months four through six are often the most exciting and enjoyable stage of pregnancy, as the pregnancy starts to “show” and you can feel and even see your growing child through ultrasound.
But as that baby keeps on growing, the third trimester can bring a return of some of the discomforts that expectant mothers experienced at the beginning of pregnancy—though for different reasons, the dreaded pregnancy nausea in the third trimester. Some of the lucky ones who dodged those symptoms at the start may also develop the nausea and vomiting later in their pregnancy instead.
The most likely reason for a return or increase of nausea in the late weeks of pregnancy is simply increased internal pressure and competition for space in the abdominal cavity as the fetus grows. The stomach and entire digestive tract are increasingly stressed physically as the fetus grows larger. As the uterus expands and presses against the stomach, there is less room to accommodate food, so it’s even more important not to overload the stomach with large meals. Production of stomach acid tends to increase, leading to heartburn and acid reflux, both of which contribute to nausea and vomiting.
Some women also maintain an unusually high level of hCG throughout a pregnancy, and this can also cause nausea and vomiting through the entire term.
For most women, late-term nausea and vomiting can be managed in the same ways as early morning sickness: smaller meals, plenty of liquids, vitamin B6 and dietary remedies like ginger and eating dry crackers, bananas, rice, applesauce and toast. Motion sickness treatments like acupressure wristbands may help as well.
However, if vomiting becomes severe and persistent, preventing the mother from keeping down any food or liquids, more aggressive treatment may be called for. Particularly for women who did not have nausea and vomiting early in the pregnancy, later occurrences can be signs of more serious conditions, such as hyperemesis gravidarum, acute fatty liver of pregnancy, or HELLP syndrome.
Hyperemesis gravidarum is basically a very acute or extreme form of morning sickness that can result in severe dehydration and malnutrition. It affects about 1 to 3 percent of pregnant women. Women with twins or multiple embryos have an increased likelihood of developing hyperemesis gravidarum, probably because they have elevated concentrations of hCG. It can be treated with bed rest, anti-emetic drugs, acupressure and intravenous fluids.
Acute fatty liver of pregnancy is even rarer, affecting only a tiny percentage of women (one out of seven- to sixteen-thousand), but it is dangerous enough that medical experts advise that it should be at least considered and ruled out for any woman who develops third trimester nausea, vomiting or pain in the upper abdomen. Undiagnosed cases can lead to death in up to 75 percent of cases for both mother and child. Acute fatty liver of pregnancy tends to appear at about the 35-week point.
HELLP (Hemolytic anemia, Elevated Liver enzymes and Low Platelet count) Syndrome is another potentially serious complication in late pregnancy, associated with preeclampsia. Symptoms also include upper abdominal pain, nausea and vomiting. HELLP occurs in only 0.2-0.6% of all pregnancies.
Fortunately, both HELLP and acute fatty liver of pregnancy are very rare, but if there is any suspicion they may be the cause of a woman’s late term nausea and vomiting, they should be seen by specialists with experience in liver disease and high-risk obstetrics.