{"id":85130,"date":"2025-12-15T22:33:38","date_gmt":"2025-12-15T21:33:38","guid":{"rendered":"https:\/\/heloa.app\/?p=85130"},"modified":"2025-12-15T22:33:38","modified_gmt":"2025-12-15T21:33:38","slug":"third-trimester-week-by-week","status":"publish","type":"post","link":"https:\/\/heloa.app\/en\/blog\/pregnancy\/childbirth\/third-trimester-week-by-week","title":{"rendered":"Third trimester: week-by-week timeline and what to expect"},"content":{"rendered":"<p>The <strong>third trimester<\/strong> can feel like a countdown with a body that has its own agenda: heavier breathing on the stairs, reflux at the worst possible moment, and a baby who seems to host nightly dance rehearsals. Parents often ask the same questions\u2014how to read fetal movement, what \u201cnormal\u201d swelling looks like, when Braxton Hicks becomes labor, and which symptoms should trigger a call. The <strong>third trimester<\/strong> also brings more follow-up, more decisions, and, sometimes, more mental load.<\/p> <p>Expect a week-by-week sense of direction, clear explanations of medical terms, and practical ways to stay comfortable and safe.<\/p> <h2 id=\"thirdtrimesterbasicsdatesduedatelanguageandterm\">Third trimester basics: dates, due date language, and \u201cterm\u201d<\/h2> <p>The <strong>third trimester<\/strong> usually starts at <strong>28 weeks of gestational age<\/strong> and lasts until birth. Gestational age (GA) is counted from the first day of the last menstrual period.<\/p> <p>Your <strong>estimated due date (EDD)<\/strong> is an estimate around 40 weeks GA, not a deadline. Many healthy births happen between <strong>38 and 42 weeks<\/strong>.<\/p> <p>\u201c<strong>Viability<\/strong>\u201d refers to a baby\u2019s chance of survival outside the uterus with neonatal intensive care. In many settings, it\u2019s discussed around <strong>24 weeks GA<\/strong>, with outcomes improving after 28 weeks as lung and brain maturation accelerates.<\/p> <p>Term definitions:<\/p> <ul> <li><strong>Early term<\/strong>: 37+0 to 38+6<\/li> <li><strong>Full term<\/strong>: 39+0 to 40+6<\/li> <li><strong>Late term<\/strong>: 41+0 to 41+6<\/li> <li><strong>Post-term<\/strong>: 42+0 and beyond<\/li> <\/ul> <h2 id=\"thirdtrimestertimelinewhatoftenchangesbystage\">Third trimester timeline: what often changes by stage<\/h2> <p>Every pregnancy differs, but the <strong>third trimester<\/strong> often follows a recognizable rhythm.<\/p> <h3 id=\"weeks2831earlythirdtrimester\">Weeks 28\u201331: early third trimester<\/h3> <p>Baby growth ramps up. <strong>Subcutaneous fat<\/strong> increases, and the lungs raise <strong>surfactant<\/strong> production (it helps keep tiny air sacs open after birth).<\/p> <p>Many parents notice:<\/p> <ul> <li><strong>Braxton Hicks<\/strong> tightenings (often irregular, easing with rest or hydration)<\/li> <li>Heartburn and slower digestion (progesterone relaxes smooth muscle)<\/li> <li>Back discomfort and posture changes<\/li> <li>Sleep fragmentation<\/li> <\/ul> <p>A common topic here: vaccines such as <strong>Tdap<\/strong> (often offered between 27\u201336 weeks, depending on local protocols).<\/p> <h3 id=\"weeks3234crowdeduterusweeks\">Weeks 32\u201334: \u201ccrowded uterus\u201d weeks<\/h3> <p>Movements may feel stronger but less acrobatic\u2014more rolls and stretches, fewer flips. Many babies begin spending more time head-down, although position can still change.<\/p> <p>Depending on your care pathway, an ultrasound around this period may check fetal growth estimate and <strong>growth curves<\/strong>, placenta location, <strong>amniotic fluid<\/strong> (AFI or deepest pocket), and presentation.<\/p> <h3 id=\"weeks3537keytestsandpositionchecks\">Weeks 35\u201337: key tests and position checks<\/h3> <p>This is a common window for the <strong>GBS<\/strong> swab. If positive, antibiotics during labor lower the risk of early newborn infection.<\/p> <p>Appointments often become more frequent. Braxton Hicks can intensify\u2014annoying, sometimes painful, yet typically irregular.<\/p> <h3 id=\"weeks3740earlytermtoanydaynow\">Weeks 37\u201340+: early term to \u201cany day now\u201d<\/h3> <p>From 37 weeks, pregnancy is considered term. Engagement (baby settling deeper into the pelvis) may increase pelvic pressure and urinary frequency.<\/p> <p>Past the due date, clinicians may propose <strong>NST\/BPP<\/strong> and fluid checks, then discuss induction timing.<\/p> <h2 id=\"babydevelopmentinthethirdtrimester\">Baby development in the third trimester<\/h2> <p>The <strong>third trimester<\/strong> is a phase of rapid refinement.<\/p> <h3 id=\"growthandbodyfat\">Growth and body fat<\/h3> <p>A large share of fetal weight gain happens now. Ultrasound weight estimates use head\/abdominal measurements and femur length. Helpful, yes\u2014perfect, no.<\/p> <h3 id=\"brainandnervoussystemmyelination\">Brain and nervous system: myelination<\/h3> <p>Brain growth accelerates. <strong>Myelination<\/strong> (insulating nerve pathways) supports feeding coordination, reflexes, and sleep\u2013wake rhythms.<\/p> <h3 id=\"lungssurfactantandpracticebreathing\">Lungs: surfactant and practice breathing<\/h3> <p>Surfactant rises, and \u201cpractice breathing\u201d movements occur in amniotic fluid. Earlier births may need respiratory support, later <strong>third trimester<\/strong> births generally come with more lung readiness.<\/p> <h3 id=\"passiveimmunityiggtransfer\">Passive immunity: IgG transfer<\/h3> <p>Maternal <strong>IgG antibodies<\/strong> cross the placenta increasingly late in pregnancy, offering temporary newborn protection\u2014especially when vaccination boosts antibody levels.<\/p> <h3 id=\"skinvernixandlanugo\">Skin: vernix and lanugo<\/h3> <p><strong>Vernix caseosa<\/strong> protects the skin. <strong>Lanugo<\/strong> (fine hair) usually thins toward term. Increasing fat also improves temperature regulation.<\/p> <h3 id=\"amnioticfluid\">Amniotic fluid<\/h3> <p>Too little (<strong>oligohydramnios<\/strong>) or too much (<strong>polyhydramnios<\/strong>) may lead to closer monitoring.<\/p> <h3 id=\"positionheaddownbreechengagement\">Position: head-down, breech, engagement<\/h3> <p>Many babies settle into <strong>cephalic presentation<\/strong> (head-down) during the <strong>third trimester<\/strong>. If breech persists near term, <strong>ECV<\/strong> (external cephalic version) around 36\u201337 weeks may be discussed.<\/p> <h2 id=\"fetalmovementinthethirdtrimesterpatternscountswhentocall\">Fetal movement in the third trimester: patterns, counts, when to call<\/h2> <p>Space decreases, but movement should remain present and familiar.<\/p> <h3 id=\"whatmovementcanfeellikenow\">What movement can feel like now<\/h3> <p>In the <strong>third trimester<\/strong>, expect fewer flips and more strong rolls, stretches, and kicks. Quiet periods can be fetal sleep.<\/p> <h3 id=\"kickcountsasimplemethod\">Kick counts: a simple method<\/h3> <p>A common approach is <strong>10 movements in 2 hours<\/strong>:<\/p> <ul> <li>Choose a time your baby is usually active<\/li> <li>Lie on your side or sit quietly<\/li> <li>Count distinct movements<\/li> <\/ul> <h3 id=\"decreasedfetalmovement\">Decreased fetal movement<\/h3> <p>Call promptly if you notice a persistent drop from your baby\u2019s usual pattern.<\/p> <p>You may be offered:<\/p> <ul> <li><strong>NST<\/strong><\/li> <li><strong>BPP<\/strong><\/li> <li>Ultrasound assessment of growth, fluid, placenta, and position<\/li> <\/ul> <h2 id=\"commonthirdtrimestersymptomscausesandwhatcanhelp\">Common third trimester symptoms: causes and what can help<\/h2> <p>Late pregnancy symptoms often come from pressure, hormones, and circulation changes.<\/p> <h3 id=\"fatigueandirondeficiencyanemia\">Fatigue (and iron deficiency anemia)<\/h3> <p>Interrupted sleep and increased demands can drain you. Sometimes <strong>iron deficiency anemia<\/strong> contributes, blood tests can guide supplementation.<\/p> <h3 id=\"shortnessofbreath\">Shortness of breath<\/h3> <p>The diaphragm has less room. Upright posture, pacing activity, and side-sleeping help.<\/p> <p>Seek urgent care for chest pain, fainting, or sudden severe breathlessness.<\/p> <h3 id=\"heartburn\">Heartburn<\/h3> <p>Progesterone relaxes the lower esophageal sphincter, the uterus adds pressure. Try smaller meals, staying upright after eating, and elevating the upper body at night. Ask about pregnancy-compatible antacids (for example <strong>calcium carbonate<\/strong>).<\/p> <h3 id=\"pelvicpressureandbackpubicpain\">Pelvic pressure and back\/pubic pain<\/h3> <p>As the baby descends, heaviness and pelvic pulling sensations can appear. Support belts (when advised), heat\/cold packs, supportive shoes, and prenatal physiotherapy can help. Avoid NSAIDs unless your clinician approves.<\/p> <h3 id=\"swellingandheavylegs\">Swelling and heavy legs<\/h3> <p>Mild <strong>edema<\/strong> in ankles\/feet is common in the <strong>third trimester<\/strong>. Walking, leg elevation, and compression stockings (if advised) may help.<\/p> <p>Urgent assessment is needed for sudden face\/hand swelling, severe headache, vision changes, or one-sided leg swelling with redness\/pain.<\/p> <h3 id=\"constipationhemorrhoidsurinarychanges\">Constipation, hemorrhoids, urinary changes<\/h3> <p>Fiber, fluids, and gentle movement are first-line for constipation. Sitz baths and clinician-approved topical care can soothe hemorrhoids. Burning with urination or fever can suggest a UTI.<\/p> <h3 id=\"handtinglingcarpaltunnel\">Hand tingling (carpal tunnel)<\/h3> <p>Fluid shifts can cause <strong>carpal tunnel syndrome<\/strong> symptoms. Wrist splints and sleep positioning may help.<\/p> <h3 id=\"sleepandemotions\">Sleep and emotions<\/h3> <p>Side-sleeping, pillow support, a cool room, and a calmer routine can improve sleep. If anxiety becomes intrusive or mood drops sharply, bring it up quickly\u2014support exists.<\/p> <h2 id=\"prenatalcareinthethirdtrimestervisitstestsandmonitoring\">Prenatal care in the third trimester: visits, tests, and monitoring<\/h2> <p>Many schedules move from every two weeks to weekly near term.<\/p> <p>Common checks:<\/p> <ul> <li>Blood pressure<\/li> <li>Weight trends<\/li> <li>Urine testing when used<\/li> <li>Symptom review<\/li> <li>Fetal heart rate (often <strong>110\u2013160 bpm<\/strong>)<\/li> <\/ul> <h3 id=\"growthchecks\">Growth checks<\/h3> <p>Fundal height usually tracks roughly with weeks of pregnancy. If measurements are off, ultrasound can review growth, fluid, placenta, and position.<\/p> <h3 id=\"keyscreenings\">Key screenings<\/h3> <ul> <li>Glucose testing follow-up if gestational diabetes is diagnosed<\/li> <li><strong>GBS<\/strong> swab (often 35\u201337 weeks)<\/li> <li>CBC for anemia (often hemoglobin &lt;11 g\/dL in the <strong>third trimester<\/strong>)<\/li> <li><strong>RhIG<\/strong> around 28 weeks if you are Rh-negative and not sensitized<\/li> <\/ul> <h3 id=\"extramonitoring\">Extra monitoring<\/h3> <p>Depending on risk factors, clinicians may use:<\/p> <ul> <li><strong>NST<\/strong><\/li> <li><strong>BPP<\/strong><\/li> <li><strong>Umbilical artery Doppler<\/strong> when placental insufficiency is suspected<\/li> <\/ul> <h2 id=\"vaccinesinlatepregnancy\">Vaccines in late pregnancy<\/h2> <p>Vaccines can protect the pregnant person and support newborn protection via <strong>transplacental IgG<\/strong>.<\/p> <p>Depending on local guidance, options may include:<\/p> <ul> <li><strong>Tdap<\/strong> (often 27\u201336 weeks)<\/li> <li>Flu vaccine (inactivated)<\/li> <li>COVID-19 vaccination\/boosters<\/li> <li>Maternal RSV vaccine (in some settings)<\/li> <\/ul> <h2 id=\"skinchangesitchingandrashes\">Skin changes: itching and rashes<\/h2> <p>Dryness and stretching can itch. Moisturizers and cool compresses help.<\/p> <p>Call promptly if itching is intense and widespread\u2014especially on <strong>palms and soles<\/strong>, worse at night, or paired with dark urine or yellowing of eyes\/skin. This can suggest intrahepatic cholestasis of pregnancy and needs blood tests (including bile acids).<\/p> <h2 id=\"warningsignsinthethirdtrimesterwhentoseekurgentcare\">Warning signs in the third trimester: when to seek urgent care<\/h2> <p>Contact your maternity unit urgently for:<\/p> <ul> <li>Vaginal bleeding or clots<\/li> <li>Suspected rupture of membranes (gush or persistent leak)<\/li> <li>Regular painful contractions before 37 weeks<\/li> <li><strong>Decreased fetal movement<\/strong><\/li> <li>Severe headache, vision changes, right upper abdominal pain<\/li> <li>Sudden swelling of face\/hands<\/li> <li>Fever or chills<\/li> <li>One-sided leg swelling\/redness\/pain<\/li> <li>Chest pain, fainting, severe breathlessness<\/li> <\/ul> <h2 id=\"laborsignswhenitsbecomingreal\">Labor signs: when it\u2019s becoming \u201creal\u201d<\/h2> <p>Braxton Hicks are often irregular and may ease with rest, warmth, hydration, or position changes. True labor tends to become regular, closer together, longer, stronger\u2014and it changes the cervix.<\/p> <p>Time contractions from the start of one to the start of the next. Many units reference <strong>5-1-1<\/strong>, but follow your local instructions.<\/p> <p>If your water breaks, note time, amount, color, odor, and fetal movement pattern, then contact your unit.<\/p> <h2 id=\"preparingforbirthinthethirdtrimester\">Preparing for birth in the third trimester<\/h2> <p>The <strong>third trimester<\/strong> is when planning becomes practical.<\/p> <ul> <li>Keep birth preferences short and flexible, including pain relief options such as <strong>epidural anesthesia<\/strong>.<\/li> <li>Induction may be proposed for post-term pregnancy, ruptured membranes without labor, hypertensive disorders, diabetes-related concerns, or fetal growth issues.<\/li> <li>If breech persists, <strong>ECV<\/strong> may be discussed around 36\u201337 weeks.<\/li> <li>Many parents pack a bag between 32\u201336 weeks and confirm transport and childcare.<\/li> <\/ul> <h2 id=\"toremember\">To remember<\/h2> <ul> <li>The <strong>third trimester<\/strong> runs from week 28 to birth, \u201cterm\u201d ranges guide monitoring.<\/li> <li>Baby gains fat, matures brain and lungs, and receives increasing <strong>IgG antibodies<\/strong>.<\/li> <li>In the <strong>third trimester<\/strong>, movement may feel different, but it should remain present, reduced movement is a good reason to call.<\/li> <li>Warning signs (bleeding, leaking fluid, fever, severe headache\/vision changes, sudden swelling, preterm labor signs) deserve prompt medical attention.<\/li> <\/ul> <p>Professionals can help you sort what\u2019s expected from what needs evaluation. You can also download the <a href=\"https:\/\/app.adjust.com\/1g586ft8\" target=\"_blank\" rel=\"noopener\">Heloa app<\/a> for personalized guidance and free child health questionnaires.<\/p> <h2 id=\"questionsparentsask\">Questions Parents Ask<\/h2> <h3 id=\"isitsafetotravelorflyinthethirdtrimester\">Is it safe to travel (or fly) in the third trimester?<\/h3> <p>For many pregnancies, travel can still be possible in the third trimester\u2014especially earlier on. Comfort often becomes the main challenge: more bathroom breaks, swelling, reflux, and fatigue are common, and long sitting can make legs feel heavy. You can consider frequent walking breaks, good hydration, and compression stockings if your clinician agrees. Because airlines and care teams may have their own cut-offs (often around 36 weeks, sometimes earlier for multiples or higher-risk pregnancies), it\u2019s a good idea to ask what applies to your situation and destination. If you have complications (bleeding, high blood pressure, preterm contractions, placenta issues), travel may be discouraged\u2014no guilt, just a safety call.<\/p> <h3 id=\"issexsafeinthethirdtrimester\">Is sex safe in the third trimester?<\/h3> <p>Most of the time, yes\u2014sex is generally safe in late pregnancy if your pregnancy is uncomplicated. It can even help some parents feel more connected and relaxed. Mild cramping or Braxton Hicks after orgasm can happen and usually settles with rest and fluids\u2014reassuringly common. It\u2019s worth contacting your maternity team for personalized advice if there\u2019s vaginal bleeding, leaking fluid, placenta previa, or a history\/risk of preterm labor, as pelvic rest may be recommended in those cases.<\/p> <h3 id=\"howmuchweightgainisnormalinthethirdtrimester\">How much weight gain is \u201cnormal\u201d in the third trimester?<\/h3> <p>There isn\u2019t one perfect number. Weight changes depend on your pre-pregnancy BMI, fluid retention, baby\u2019s growth, and even timing of swelling. Slow, steady gain is common, and sudden jumps can sometimes be just water. If you notice rapid swelling plus symptoms like headache or vision changes, it\u2019s important to check in promptly.<\/p> <p><img decoding=\"async\" src=\"https:\/\/heloa.app\/wp-content\/uploads\/2025\/02\/3eme-trimestre-de-grossesse-anky-lau-A-2N_gSJ7wA-unsplash.jpg\" width=\"628\" alt=\"\"><\/p> <p>Further reading:<\/p> <ul> <li>3rd trimester pregnancy: What to expect \u2014 https:\/\/www.mayoclinic.org\/healthy-lifestyle\/pregnancy-week-by-week\/in-depth\/pregnancy\/art-20046767<\/li> <li>28 weeks pregnant guide &#8211; Best Start in Life \u2014 https:\/\/www.nhs.uk\/best-start-in-life\/pregnancy\/week-by-week-guide-to-pregnancy\/3rd-trimester\/week-28\/<\/li> <li>The Third Trimester \u2014 https:\/\/www.hopkinsmedicine.org\/health\/wellness-and-prevention\/the-third-trimester<\/li> <\/ul>","protected":false},"excerpt":{"rendered":"<p>A clear third trimester week-by-week guide: baby changes, common symptoms, kick counts, tests, and when to call. Feel more ready\u2014read now.<\/p>\n","protected":false},"author":4,"featured_media":11627,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_kad_blocks_custom_css":"","_kad_blocks_head_custom_js":"","_kad_blocks_body_custom_js":"","_kad_blocks_footer_custom_js":"","_kad_post_transparent":"","_kad_post_title":"","_kad_post_layout":"","_kad_post_sidebar_id":"","_kad_post_content_style":"","_kad_post_vertical_padding":"","_kad_post_feature":"","_kad_post_feature_position":"","_kad_post_header":false,"_kad_post_footer":false,"_kad_post_classname":"","rank_math_title":"","rank_math_description":"","rank_math_focus_keyword":"","rank_math_primary_category":null,"ilj_linkdefinition":["third trimester","the third trimester","third trimester pregnancy","third trimester {-1} weeks","third trimester timeline","third trimester symptoms","third trimester week{-1}by{-1}week","third trimester guide","third trimester overview","third trimester changes","third trimester baby{-1}movement","third trimester kick{-1}counts","third trimester tests","third trimester appointments","third trimester care","third trimester advice","third trimester tips","late pregnancy {-2} third trimester","third trimester stage","third trimester period"],"footnotes":""},"categories":[860,858],"tags":[],"class_list":["post-85130","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-childbirth","category-pregnancy-en"],"acf":{"prestation_table":"","technical_table":"","nom_professionnel":"","numero_telephone":"","convention_cas":"","contrat_acces_aux_soins":"","sesam_vitale":"","coordonnees":"","adresse":"","profession":"","numero_rpps":"","profession_description":"","commune":"","departement":"","prenom":"","origine":"","date_fete":"","signification_etymologie":"","histoire_origine_prenom":"","personne_celebre":"","age_moyen":"","prenoms_derives":"","prenoms_composes":"","naissances_2024":"","genre":"","prenoms_taxonomy":"","region_stats":"","evolution_naissances":""},"taxonomy_info":{"category":[{"value":860,"label":"Childbirth"},{"value":858,"label":"Pregnancy"}]},"featured_image_src_large":["https:\/\/heloa.app\/wp-content\/uploads\/2025\/02\/3eme-trimestre-de-grossesse-getty-images-J3KIjoInIYw-unsplash.jpg",628,407,false],"author_info":{"display_name":"Heloa","author_link":"https:\/\/heloa.app\/en\/author\/expert-heloa"},"comment_info":0,"category_info":[{"term_id":860,"name":"Childbirth","slug":"childbirth","term_group":0,"term_taxonomy_id":860,"taxonomy":"category","description":"","parent":858,"count":38,"filter":"raw","cat_ID":860,"category_count":38,"category_description":"","cat_name":"Childbirth","category_nicename":"childbirth","category_parent":858},{"term_id":858,"name":"Pregnancy","slug":"pregnancy-en","term_group":0,"term_taxonomy_id":858,"taxonomy":"category","description":"","parent":0,"count":231,"filter":"raw","cat_ID":858,"category_count":231,"category_description":"","cat_name":"Pregnancy","category_nicename":"pregnancy-en","category_parent":0}],"tag_info":false,"_links":{"self":[{"href":"https:\/\/heloa.app\/en\/wp-json\/wp\/v2\/posts\/85130","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/heloa.app\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/heloa.app\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/heloa.app\/en\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/heloa.app\/en\/wp-json\/wp\/v2\/comments?post=85130"}],"version-history":[{"count":2,"href":"https:\/\/heloa.app\/en\/wp-json\/wp\/v2\/posts\/85130\/revisions"}],"predecessor-version":[{"id":85134,"href":"https:\/\/heloa.app\/en\/wp-json\/wp\/v2\/posts\/85130\/revisions\/85134"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/heloa.app\/en\/wp-json\/wp\/v2\/media\/11627"}],"wp:attachment":[{"href":"https:\/\/heloa.app\/en\/wp-json\/wp\/v2\/media?parent=85130"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/heloa.app\/en\/wp-json\/wp\/v2\/categories?post=85130"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/heloa.app\/en\/wp-json\/wp\/v2\/tags?post=85130"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}