Experiencing nausea in the third trimester can be an unexpected symptom, especially since it is most commonly associated with the early weeks of pregnancy. While first-trimester nausea is widely discussed, its return late in pregnancy is a frequent experience for many expectant mothers. This late-stage queasiness is often a normal physiological response to the significant changes happening as the body prepares for birth.
Understanding the Return of Nausea
The reappearance of nausea during the third trimester stems from mechanisms distinct from the initial hormonal surges of early pregnancy. The primary cause relates to the sheer size of the growing uterus, which exerts physical pressure on surrounding organs. As the baby grows, the uterus pushes upward on the stomach, limiting its capacity and slowing the digestive process.
This physical compression, coupled with hormonal effects, contributes to gastroesophageal reflux disease (GERD). High levels of the hormone progesterone cause the smooth muscles in the body to relax, including the lower esophageal sphincter. The relaxed sphincter and the physical pressure allow stomach acid to push upward more easily, leading to heartburn and nausea.
The slowing of the entire digestive tract, known as delayed gastric emptying, is also influenced by progesterone, which can keep food in the stomach for longer periods. This sluggish digestion contributes to feelings of fullness and subsequent nausea. Additionally, for some, nausea can be a subtle sign of pre-labor, as hormonal shifts begin to slow down the digestive system to conserve energy for delivery.
Effective Management Techniques
Several actionable strategies can help mitigate the discomfort of late-term nausea. Dietary modifications are often the first line of defense against third-trimester gastrointestinal distress. Instead of consuming three large meals, eating smaller portions more frequently throughout the day can prevent the stomach from becoming overly full and compressed.
It is beneficial to avoid foods that trigger acid reflux and slow digestion, such as spicy, fatty, or highly acidic items. To maintain hydration, sip fluids between meals rather than drinking large amounts during meals, as mixing solids and liquids can increase stomach fullness and acid reflux.
Positional adjustments, especially around mealtimes and sleep, can provide significant relief. Sitting upright while eating and remaining vertical for at least two to three hours afterward uses gravity to keep stomach contents down. When sleeping, elevating the head and shoulders using a wedge pillow or raising the head of the bed can reduce the backward flow of stomach acid.
For over-the-counter support, antacids containing calcium carbonate, such as Tums, are often considered safe for use in pregnancy. These neutralize stomach acid and provide a source of calcium. Vitamin B6 supplements (10 to 25 milligrams three to four times daily) can also help regulate brain chemicals that influence queasiness. All medication should be cleared with a healthcare provider before use.
Recognizing Serious Symptoms
While mild to moderate nausea is common, certain accompanying symptoms require immediate medical evaluation. Severe or persistent vomiting that prevents keeping liquids down for more than 12 to 24 hours poses a risk of dehydration. Signs of severe dehydration include dark urine, dizziness, a rapid heartbeat, and a lack of urination for eight hours or more.
A sudden onset of nausea in the third trimester can signal Preeclampsia or its severe variant, HELLP syndrome, which are serious hypertensive disorders of pregnancy. This is particularly concerning if the nausea is accompanied by new or severe headaches that do not respond to pain relievers. Watch for changes in vision, such as blurriness, seeing spots, or light sensitivity.
A sharp, intense pain in the upper right side of the abdomen, just under the ribs, is a specific warning sign of potential liver involvement with Preeclampsia or HELLP syndrome. Other urgent indicators include sudden, excessive swelling in the face and hands, or nausea accompanied by fever and severe abdominal pain. Any combination of these symptoms warrants an urgent call to your healthcare provider.