Third Trimester of Pregnancy

Highlights

• The third trimester begins at the 27th week and lasts until birth.
• This stage involves significant physical and emotional changes.
• Common challenges include discomfort, sleep difficulties, and preparation for labor.
• Nutrition, medical monitoring, and emotional support are crucial.
• Proper planning reduces risks and improves maternal well-being.

In This Article

• Duration and key milestones of the third trimester
• Maternal changes and common symptoms
• Fetal development
• Possible complications and risk factors
• Nutrition and diet guidelines
• Recommended tests and medical monitoring
• Preparing for childbirth and hospital admission
• Vitamins and supplements
• Sexual health considerations
• Illnesses and safety precautions
• Tools and assistance for expectant parents

Overview of the Third Trimester

The third trimester is the final stage of pregnancy, beginning at week 27 and continuing until delivery, typically between weeks 40 and 42. This period is marked by rapid fetal growth and increasing maternal discomfort due to the enlarging uterus. Despite these challenges, the anticipation of meeting the baby often outweighs the difficulties.

Maternal Changes

By the last trimester, the uterus has grown considerably, displacing internal organs and limiting lung capacity, which often results in shortness of breath. Other common issues include:

• Limited mobility and difficulty dressing or walking due to abdominal size.
• Lower back pain and the so-called “duck-like” gait.
• Frequent insomnia, often caused by fetal activity at night.
• Emotional instability, anxiety, and fear of labor due to hormonal fluctuations.
• False contractions (Braxton Hicks), which may be confused with true labor.

Fetal Development

During this stage, the fetus undergoes rapid growth in weight and height.

• By week 27: approximately 24 cm in length and about 1000 g in weight.
• Organs such as the lungs, liver, and kidneys mature further.
• The nervous system develops rapidly; the fetus responds to light, sound, and touch.
• Hair, eyelashes, and nails appear, while tooth buds are covered with enamel.
• By 7 months, the fetus can recognize voices, hiccup, and actively move.

Potential Complications

• Preterm labor: Risk increases in the third trimester.
• Placental insufficiency: May cause developmental delays if untreated.
• Umbilical cord entanglement: In severe cases, may require cesarean delivery.
• Bleeding: Always requires urgent medical evaluation.
• Edema and leg cramps, frequent heartburn, or urinary leakage under pressure (e.g., coughing).
• Headaches, dizziness, gum bleeding, or anemia.

Nutrition in the Third Trimester

Proper nutrition remains essential. Contrary to myths, pregnant individuals do not need to “eat for two.” Instead, the focus should be on nutrient-rich foods:

• Lean meat and fish (sources of protein, iron, phosphorus, potassium, magnesium, and omega-3).
• Dairy products and eggs for calcium and protein.
• Whole grains such as oats, brown rice, and buckwheat for fiber and B vitamins.
• Fresh fruits and vegetables, preferably raw, as a source of vitamins.
• Nuts and dried fruits for healthy fats, vitamin E, and folic acid.

Foods and drinks to avoid include alcohol, carbonated beverages, processed juices, high-sugar foods, fried or fatty meals, and excessive salt.

Meals should be small and frequent to reduce nausea and heartburn. Limiting excess fluid intake may help prevent edema.

Recommended Tests and Screenings

• Urine analysis: to check for infection, glucose, or protein.
• Blood tests: to monitor for anemia and inflammation.
• Infectious disease screening: HIV, syphilis, hepatitis B and C before maternity leave.
• Ultrasound (31–33 weeks): evaluates placenta maturity, amniotic fluid, and organ development.
• Cardiotocography (CTG): monitors fetal heartbeat and movements.

Preparing for Birth

Expectant parents are advised to prepare hospital bags in advance. Essential items include medical documents, hygiene products, personal clothing, and newborn essentials such as clothes, diapers, wipes, and baby creams.

At home, preparations should include a crib, bedding, a changing table, a bath, and a baby first-aid kit.

Vitamins and Supplements

Continuation of prenatal vitamins is recommended, with a focus on:

• Iron: prevents maternal anemia and ensures oxygen delivery to the fetus.
• Calcium: supports bone and teeth formation.
• Magnesium: reduces muscle cramps.

Supplements may also be continued postpartum to support breastfeeding and maternal recovery.

Sexual Health

Sexual activity is not prohibited unless contraindicated by a physician. Comfort and safety should guide intimate relations. In some cases, intercourse close to the due date may stimulate labor.

Illnesses and Common Conditions

During this stage, even mild illnesses require caution. Self-medication is not advised; any treatment should be approved by a healthcare provider. Preventative measures include a balanced diet, adequate rest, avoiding crowds, and maintaining hygiene.

Tools and Assistance

• Pregnancy tracking apps for monitoring fetal growth, contractions, and appointments.
• Prenatal classes for childbirth preparation and parenting skills.
• Support groups and communities to reduce anxiety and share experiences.
• Comfort tools such as maternity pillows, compression stockings, and supportive belts to ease discomfort.
• Professional counseling or physiotherapy for pain management and stress reduction.

Conclusion

The third trimester is physically and emotionally demanding, but it also represents the final step toward welcoming a newborn. Balanced nutrition, regular medical monitoring, emotional support, and proper preparation for childbirth all contribute to a healthier and safer experience for both parent and child.