The third trimester—your pregnancy's final 12 weeks—is when your body readies for labor and your baby prepares to arrive. During this time, your medical appointments increase, important screening tests happen, and you'll need to recognize the signs that labor is beginning.
Understanding what to expect, how to prepare physically and mentally, and when to seek help gives you confidence and control as you approach one of life's most transformative moments. Preparing for labor is not about eliminating uncertainty—labor's timing and course vary from person to person—but about knowing what's normal, recognizing warning signs, and having a clear plan for the decisions ahead. This guide walks through the medical milestones of the third trimester, the physical and practical steps you can take now, the signs that distinguish real labor from false alarms, and what to do when labor actually begins.
Table of Contents
- What's Happening in Your Third Trimester
- Group B Strep Screening and What It Means
- Recognizing True Labor and False Alarms
- Physical Preparation: Exercise and Movement During Late Pregnancy
- Creating a Birth Plan and Exploring Pain Management Options
- Packing Your Hospital Bag and Preparing to Leave
- Pre-Labor Signs and What They Mean
- Warning Signs That Require Immediate Attention
- Preparing Mentally and Building Your Support Team
- Final Checklist and Getting Ready
- Frequently Asked Questions
What's Happening in Your Third Trimester
The third trimester begins at 28 weeks of pregnancy and continues until delivery. During these 12 weeks, your baby shifts into the head-down position for birth and gains significant weight. Your body undergoes major changes: your belly expands, your center of gravity shifts, you may experience more back pain and fatigue, and your joints and ligaments loosen to prepare for labor.
These changes are normal and expected, even if they make daily life more uncomfortable. Your prenatal care schedule intensifies during the third trimester. According to ACOG guidance, you'll have appointments every 2 weeks from 28 to 36 weeks, then weekly from 36 weeks until delivery. At each visit, your provider checks your blood pressure, tests your urine, measures your belly, and listens to your baby's heart.
These frequent check-ins help catch complications early and track your baby's growth and position as you approach birth. Between 36 and 37 weeks, you'll have an important screening test for Group B Strep, a bacterium that can be present in the vagina or rectum without causing any symptoms. The CDC recommends this test via vaginal and rectal swabs, and if positive, you'll receive IV antibiotics during labor to prevent transmission to your baby. The bacteria do not infect or harm you; treatment is routine and highly effective at protecting your newborn.
You may also notice Braxton Hicks contractions becoming more frequent during the third trimester. These practice contractions feel like your belly tightening but are usually painless and irregular. They differ significantly from true labor contractions. During the third trimester, your baby also drops lower into your pelvis—a shift called lightening—that changes how you carry your belly and may ease breathing difficulties but increase pressure on your bladder and pelvis.
Group B Strep Screening and What It Means
Group B Strep (GBS) is a bacterium found in the vagina or rectum that does not cause infection in the pregnant person and typically has no symptoms. If present during delivery, however, GBS can pass to the baby during labor, potentially causing serious infection in the newborn.
Screening and treatment during labor prevent this transmission effectively and routinely. ACOG recommends testing between 36 and 37 weeks of pregnancy using swabs from the vagina and rectum. This simple test takes just a few minutes and is usually done at one of your routine prenatal appointments.
Your provider sends the swabs to a laboratory, and you'll receive results within a few days. If you do not have results by the time you go into labor, your provider may give antibiotics as a precaution. If your Group B Strep test is positive, it does not change your pregnancy or your ability to labor—it only means your healthcare team needs to manage your labor differently.
During active labor, you will receive intravenous (IV) penicillin, usually given every 4 hours, to reduce the risk of the bacteria reaching your baby. Penicillin is safe during pregnancy and labor; allergies are rare but should be reported to your provider so alternative antibiotics can be used if needed. Many people worry about a positive GBS result, but treatment is routine and highly effective.
You may continue your birth plan exactly as you envisioned—the IV antibiotic is simply one additional element. Your newborn will be monitored after birth to ensure no signs of infection develop, but most babies born to treated GBS-positive mothers never become infected. This is one of the most straightforward ways prenatal screening improves outcomes for both mother and baby.
Recognizing True Labor and False Alarms
One of the most common questions in the third trimester is whether contractions mean labor is beginning. Braxton Hicks contractions—false labor—often intensify near the end of pregnancy and can feel alarming if you are not expecting them. True labor contractions are different in pattern, intensity, and consistency, and recognizing the difference helps you avoid unnecessary trips to the hospital while ensuring you arrive when labor is actually active.
Braxton Hicks contractions are irregular, occurring at unpredictable intervals without a consistent pattern. They usually do not hurt; instead, your abdomen simply tightens and then relaxes. These contractions often stop when you change position—lying down, getting up, or moving around—and they do not increase in intensity. They are your uterus practicing, and while they can last through most of the third trimester, they do not lead to labor on their own.
True labor contractions occur at regular intervals of 2 to 5 minutes apart, last 60 to 90 seconds, and grow progressively stronger over time. Unlike Braxton Hicks, true labor contractions continue regardless of your position or activity; walking, resting, or changing positions does not make them stop. The pain or tightness usually starts in your lower back and radiates to the front of your abdomen, and each contraction builds in intensity rather than staying the same strength.
Contact your healthcare provider if you experience more than six contractions per hour that steadily increase in strength, as this pattern suggests active labor may be beginning. Your provider will ask about the timing, intensity, and any other signs like vaginal bleeding or fluid leakage. They may ask you to come in for an evaluation, where they will check your cervix and monitor your baby. Trust your instincts—if something feels different or concerning, it is always better to call and be evaluated.
Physical Preparation: Exercise and Movement During Late Pregnancy
Movement and exercise during the third trimester build strength and flexibility that directly benefit labor and delivery. ACOG recommends at least 150 minutes of moderate-intensity aerobic activity per week throughout pregnancy, including the third trimester, unless your provider has advised otherwise due to complications. This does not mean intense exercise; walking, swimming, stationary cycling, and prenatal yoga all count as moderate activity.
Walking is one of the simplest and most effective exercises for late pregnancy. A daily 30-minute walk—broken into shorter intervals if needed—strengthens your legs and cardiovascular system while keeping your joints mobile. Walking also engages your core and pelvis in the movement pattern used during labor, essentially rehearsing the mechanics your body will use to push your baby out.
Many providers recommend regular walking in the final weeks as a gentle way to encourage labor progression. Squatting, practiced regularly during the third trimester, improves pelvic floor flexibility and strengthens the muscles you use during labor and pushing. A supported squat—holding a countertop, partner, or resistance band—for 20 to 30 seconds, repeated several times, builds leg strength without strain.
Squatting also opens the pelvic outlet, which can aid labor progression and may reduce the need for certain interventions. Prenatal yoga classes often include squats and modified poses tailored for late pregnancy. Regular movement during pregnancy, particularly walking and squatting, encourages your baby into the ideal head-down position for birth and helps your baby descend into the pelvis as labor approaches. Conversely, prolonged sitting or lying down can leave your baby in a less favorable position.
Your healthcare provider can advise on specific exercises based on your pregnancy, fitness level, and any complications. The goal is not intense exercise but consistent, moderate activity that keeps your body strong and flexible.
Creating a Birth Plan and Exploring Pain Management Options
A birth plan is a written statement of your preferences for labor and delivery. It communicates to your healthcare team how you hope to experience labor, what kind of support matters to you, what pain management options you prefer, and any specific decisions you want to make ahead of time. A birth plan is not a guarantee—labor often changes direction—but it is a way to think through your values and preferences before labor begins, when clear thinking is easier.
Non-medical pain management options include massage, water therapy like a shower or tub, breathing exercises, music, and aromatherapy. Many people find that moving freely—walking, swaying, position changes—significantly reduces pain perception. A partner or support person trained in massage and counterpressure can provide immense comfort during contractions. Water, whether a shower or a laboring tub if your hospital has one, helps some people relax and manage discomfort, though water is not recommended for pain relief if you have complications.
Breathing techniques, practiced ahead of time, help you stay calm and focused during contractions. Simple techniques like breathing in through your nose for a count of four and out through your mouth for a count of six can interrupt pain cycles and give your mind something to focus on. Music that resonates with you—whether upbeat, calming, or spiritual—creates an emotional anchor during labor.
Aromatherapy using essential oils like lavender can promote relaxation, though hospital policies vary on what is allowed. If medical pain relief is important to you, discuss options with your provider during pregnancy. Options include nitrous oxide (laughing gas), epidural anesthesia, and IV pain medications, each with benefits and trade-offs. A written birth plan shared with your healthcare team before labor documents your preferences and allows your provider to support your choices. Many people find that flexibility helps: preparing to try non-medical options first, knowing medical options are available, and being ready to adapt if labor takes an unexpected turn.
Packing Your Hospital Bag and Preparing to Leave
By 36 weeks of pregnancy, prepare your hospital bag so you are ready if labor begins unexpectedly. Hospital bag preparation is straightforward and takes just an hour or two. Pack duplicates—one bag for the hospital and one backup at home—or keep the packed bag easily accessible in your car. Most hospitals send you home with hospital-provided items for the baby, so your focus should be on your comfort and practical items you'll need for the first days.
For yourself, pack loose, comfortable clothing in layers—think clothes you wore at six months pregnant rather than tight maternity wear. Include a comfortable robe or button-front shirt for easy nursing and skin-to-skin contact with your baby. Bring a few pairs of underwear you do not mind discarding, as labor can be messy. Pack toiletries (toothbrush, toothpaste, shampoo, hair ties), pajamas that open in front for easy nursing, a bathrobe, slippers with grip, and any comfort items like a favorite pillow with a colored pillowcase to distinguish it from hospital linens.
Pack copies of your identification, insurance cards, and hospital pre-registration paperwork, along with your medical history, medication list, and a copy of your birth plan. Include a notebook and pen for questions that arise after delivery. Bring phone chargers, headphones for music, and a camera if you want photos of labor or delivery.
Some people pack printed images of inspiring people or quotes to focus on during labor. For your partner or support person, they should have a small bag with snacks, water, a change of clothes, toiletries, and reading material or a tablet for downtime between active labor. Partners often find that having something to occupy their hands and mind helps them stay calm and present.
Confirm with your hospital in advance what items are permitted and what supplies they provide—policies vary. Store your bag in a visible, accessible location and remind your partner or support person where it is, so it can be grabbed quickly when labor begins.
Pre-Labor Signs and What They Mean
In the days or hours before labor begins, your body often sends signals. Lightening—when your baby drops lower into your pelvis—can occur weeks before labor or just days before, and you may notice your belly shape changes and your breathing feels easier. Lightening also increases pressure on your bladder, meaning more frequent urination, and may create a feeling of heaviness or pressure in your pelvis and thighs.
Some people do not notice lightening at all, especially if they have given birth before. Vaginal discharge often increases in the third trimester and may change texture and appearance as you near labor. Clear or slightly bloody vaginal discharge signals your cervix is preparing for birth, though the exact timing is unpredictable. You may also pass your mucus plug—a thick, gelatinous mass that has sealed your cervix during pregnancy—which can be clear, yellowish, or tinged with blood.
Passing the mucus plug means your cervix is beginning to dilate, but this can happen days or even weeks before actual labor. Some people experience a surge of energy in the final days before labor—an urge to organize, clean, or prepare—while others feel increasingly tired and want to rest. Both patterns are normal. A few people report loose stools in the hours before labor, as hormonal changes relax the entire digestive system.
Sleep may become harder as you find fewer comfortable positions and Braxton Hicks contractions intensify, waking you frequently. These pre-labor signs are frustrating because they do not pinpoint when labor will actually begin. Someone could pass their mucus plug and not go into labor for two weeks; another person might have no signs and wake up in active labor.
This unpredictability is maddening but completely normal. If you experience any vaginal bleeding, continuous severe pain, decreased fetal movement, or fever, contact your provider rather than waiting for other labor signs.
Warning Signs That Require Immediate Attention
Most pregnancies progress normally, but certain signs during the third trimester warrant urgent evaluation. If you experience signs of labor before 37 weeks—regular contractions paired with cervical change—contact your provider immediately, as this indicates preterm labor that needs prompt medical attention. Preterm labor needs evaluation to assess whether labor can be delayed or whether your baby will be delivered now.
Vaginal bleeding is another sign to report right away. Light spotting may be normal, especially after a cervical check, but heavy bleeding—more than a pad per hour—or bleeding paired with pain needs immediate evaluation to rule out serious complications. Do not assume any amount of bleeding is normal; if you are unsure, contact your provider or go to the emergency room without delay.
Continuous severe abdominal pain that does not ease with position changes or rest, or severe headache and vision changes, require immediate care, as these can indicate preeclampsia, a serious condition affecting blood pressure and organ function. Call your provider or go to the ER without delay if you experience persistent headache, visual disturbances, sudden swelling in your face or hands, or upper abdominal pain. Do not wait to see if symptoms pass.
Decreased fetal movement is a sign to take seriously. You know your baby's normal movement pattern—if you notice a significant drop in kicks, rolls, or movement, do not wait. Contact your provider or go to labor and delivery to have your baby monitored with a nonstress test. Trust your instincts: if something feels wrong, get evaluated rather than waiting to see if it resolves. Most times, everything is fine, but evaluation provides peace of mind and catches real problems early.
Preparing Mentally and Building Your Support Team
Preparing for labor is not just physical; it is mental and emotional too. Identify the people you want present during labor—your partner, a family member, a close friend, or a professional labor doula. Your support team should know your birth plan, understand your values around labor and pain management, and feel comfortable advocating for you if communication breaks down.
Many people find that having trained, calm support present significantly improves their labor experience and reduces anxiety. Consider taking a childbirth education class offered by your hospital or a private instructor. These classes cover pain management options, the stages of labor, what to expect from medical staff, and how your partner can support you effectively.
Classes vary in philosophy—some focus on natural birth, others present medical options neutrally—so research what approach resonates with you. Even if you take a class, questions will arise during labor; knowing you can ask your healthcare team at any moment reduces uncertainty. Discuss your medical history, any previous traumatic experiences, and your preferences with your healthcare provider well before labor.
If you have had previous trauma, sexual abuse, or a prior difficult birth, mentioning this helps your provider anticipate your needs and adjust their communication or care approach. Many hospitals now ask about this proactively and have protocols to support trauma-informed care. You do not need to share your full history but giving your provider context helps them care for you more thoughtfully.
Manage expectations: labor rarely goes exactly as planned, and that is okay. Pain is often more intense than people anticipate, and unexpected complications may require interventions you did not plan on. Instead of a rigid vision of labor, adopt flexible intentions: "I want to stay mobile during early labor, and if pain becomes intense, I will consider medical options." A birth plan that branches into options—if-then scenarios—helps you adapt without feeling like your plans have failed when the unexpected happens.
Final Checklist and Getting Ready
In the weeks before your due date, organize your important documents. Gather your identification, insurance card and group number, hospital pre-registration paperwork, and medical history summary including all medications and supplements you take. Make photocopies if your hospital will keep originals. Create a one-page summary of your birth plan and bring multiple copies—one for your labor room chart, one for your partner, and extras in case you meet multiple staff members.
Discuss logistics with your partner or support person. Who will drive you to the hospital? What is the fastest route, and have you practiced it? Who will be called when labor begins—parents, siblings, close friends? What kind of updates do you want shared during labor, and who has permission to share them? Clarify these decisions now rather than figuring them out mid-contraction.
Confirm that your support person has read your birth plan and knows your values. Check with your hospital about final pre-admission details. Confirm what to bring, where to check in when you arrive in labor, whether your hospital offers laboring tubs or showers, and what your hospital's policies are on continuous fetal monitoring, movement during labor, and eating and drinking.
Know the hospital phone number and where to go when you arrive in labor. Some hospitals have a separate entrance for labor and delivery; confirm you know which one. Two weeks before your due date, start daily practices that prepare your body and mind. Eat well, take your prenatal vitamins as directed, keep your hospital bag packed and accessible, and continue gentle exercise like walking.
Practice your breathing techniques and visualize labor going well, even as you acknowledge that uncertainty is part of the process. Review your birth plan one final time with your partner. Trust that you have prepared as well as you can, and that your healthcare team is ready to support you through whatever labor brings.
Frequently Asked Questions
When does the third trimester start, and how often will I see my doctor?
The third trimester begins at 28 weeks of pregnancy. You'll have prenatal appointments every 2 weeks from 28 to 36 weeks, then weekly until delivery, so your provider can monitor your health and your baby's development closely as labor approaches.
What is Group B Strep, and does a positive test mean something is wrong?
Group B Strep is a bacterium that can be present in your vagina or rectum without causing any symptoms. A positive test at 36-37 weeks means you'll receive IV antibiotics during labor to prevent transmission to your baby, which is highly effective and routine.
How can I tell the difference between Braxton Hicks contractions and true labor?
Braxton Hicks are irregular, painless, and stop with rest or position changes. True labor contractions occur 2-5 minutes apart, last 60-90 seconds, cause progressively stronger pain, and continue regardless of movement—call your provider if you have more than six per hour that steadily strengthen.
What exercises should I do during the third trimester to prepare for labor?
Aim for 150 minutes per week of moderate activity like walking, swimming, or prenatal yoga. Walking strengthens your legs and rehearses labor mechanics. Squatting improves pelvic flexibility and helps your baby into the head-down position. Movement also aids labor progression.
What should I pack in my hospital bag, and when?
Pack by 36 weeks: loose comfortable clothing, a robe, toiletries, phone chargers, copies of important documents and your birth plan, and comfort items. Your partner should bring snacks, a change of clothes, and entertainment. Ask your hospital what they provide for the baby.
What are signs that labor is about to begin?
Your baby may drop lower into your pelvis (lightening), increasing pressure on your bladder. Vaginal discharge may increase or change appearance. You might pass your mucus plug—a thick, gelatinous mass. These signs can happen weeks or days before labor; timing is unpredictable.
