# Day 72: A very fast heart > Ten weeks and two days. The heart is beating very fast, and by the end of this week the embryo officially becomes a fetus. Today you ask when you might get to hear it. - Series: Your third month of pregnancy, day by day (https://chorevia.com/learn/pregnancy-month-3), day 72 of 280, 10 weeks + 2 days - Your baby this week: about the size of a small apricot; around 30 mm from head to bottom - Canonical URL: https://chorevia.com/learn/pregnancy-month-3/day-72 - Last reviewed: 2026-10-22 - Publisher: Chorevia (https://chorevia.com) - Cite as: Chorevia. "Day 72: A very fast heart." Last reviewed October 22, 2026. https://chorevia.com/learn/pregnancy-month-3/day-72 This guide is general education that summarizes published research and guidance from groups like the American Academy of Pediatrics, the CDC, and the WHO. It isn’t medical advice, and every child develops on their own timeline. Your pediatrician knows your child; if something feels wrong, call them. In an emergency, call 911. Ten weeks and two days. Somewhere inside you, a heart the size of almost nothing is beating very fast. This week it also gets a new name. ## Your baby Around 30mm from head to bottom, about the size of a small apricot, and the heart "beats very fast" ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/1st-trimester/week-10/)). The heart has had a regular rhythm since weeks 6 and 7, when it can be seen on a vaginal ultrasound ([MedlinePlus](https://medlineplus.gov/ency/article/002398.htm)). At the end of week 10 the embryo becomes a fetus, and fetal heart tones may be detected by Doppler ([MedlinePlus](https://medlineplus.gov/ency/article/002398.htm)). "May" is doing real work in that sentence; the NHS puts the midwife's handheld monitor at around 14 weeks ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/2nd-trimester/week-14/)). ## Your body This week's NHS list of common signs: tiredness, nausea, mood changes, breast soreness, headaches, dizziness, food cravings or aversions, and skin and hair changes ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/1st-trimester/week-10/)). If you've got most of them, you are on schedule. Your heart is working harder too. The NHS says higher blood volume can cause heat, sweating and dizziness, and that rest is important ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/1st-trimester/week-11/)). ## Try today ### The Doppler ask - **Time:** 5 minutes to write, then the visit 1. Add to your visit list: "Will you listen for the heartbeat at this visit?" 2. Under it: "When does the handheld monitor usually pick it up?" The NHS says a midwife may be able to hear it with a handheld monitor around 14 weeks ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/2nd-trimester/week-14/)). 3. Ask whether your partner can be in the room for it, and whether you can record the sound on your phone. 4. If the answer is "not yet", write down the visit they expect to hear it at, so the waiting has a date. **Make it work:** A quiet Doppler this early is not a verdict. MedlinePlus says heart tones "may" be detected at the end of week 10 ([MedlinePlus](https://medlineplus.gov/ency/article/002398.htm)). Ask what they'd do next, and let them answer. ## Watch for - **Normal:** dizziness, on this week's list of common signs ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/1st-trimester/week-10/)). **Call your provider today** for dizziness or fainting; it's on CDC's urgent list, which says to seek medical care immediately ([CDC](https://www.cdc.gov/hearher/maternal-warning-signs/index.html)). - **Normal:** tiredness and sore breasts ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/1st-trimester/week-10/)). **Go to the ER** for chest pain, a fast-beating heart or trouble breathing; CDC says these need medical care immediately ([CDC](https://www.cdc.gov/hearher/maternal-warning-signs/index.html)). - **Normal:** feeling hot and sweaty with the extra blood volume ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/1st-trimester/week-11/)). **Go to the ER** for symptoms of heat-related illness; pregnancy makes heat illness come on sooner, and CDC says to seek medical care immediately ([CDC](https://www.cdc.gov/heat-health/risk-factors/heat-and-pregnancy.html)). ## For you One number for the fridge: the baby's heart rate rose to about 170 beats a minute in weeks 9 and 10, against your own of about 80 to 85; babies' hearts are so small that they can't pump much blood, so they beat faster, which also helps keep the baby warm ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/3rd-trimester/week-28/)). It will slow to about 140 by week 28 and about 130 at birth ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/3rd-trimester/week-28/)). If you're the partner: ask to be in the room for the first time it's heard. It's a moment worth being there for. ## Sources - NHS. "Week 10." Week-by-week guide to pregnancy, Best Start in Life. https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/1st-trimester/week-10/ - MedlinePlus. "Fetal development." Medical Encyclopedia, National Library of Medicine. https://medlineplus.gov/ency/article/002398.htm - NHS. "Week 14." Week-by-week guide to pregnancy, Best Start in Life. https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/2nd-trimester/week-14/ - NHS. "Week 11." Week-by-week guide to pregnancy, Best Start in Life. https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/1st-trimester/week-11/ - Centers for Disease Control and Prevention. "Urgent Maternal Warning Signs and Symptoms." HEAR HER campaign, 2024. https://www.cdc.gov/hearher/maternal-warning-signs/index.html - Centers for Disease Control and Prevention. "Heat and Pregnancy." 2024. https://www.cdc.gov/heat-health/risk-factors/heat-and-pregnancy.html - NHS. "Week 28." Week-by-week guide to pregnancy, Best Start in Life. https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/3rd-trimester/week-28/