Pregnancy Pregnancy Development Your Pregnancy Week by Week MORE IN Your Pregnancy Week by Week Overview First Trimester Week 1 Week 2 Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 Week 9 Week 10 Week 11 Week 12 Week 13 Second Trimester Week 14 Week 15 Week 16 Week 17 Week 18 Week 19 Week 20 Week 21 Week 22 Week 23 Week 24 Week 25 Week 26 Week 27 Third Trimester Week 28 Week 29 Week 30 Week 31 Week 32 Week 33 Week 34 Week 35 Week 36 Week 37 Week 38 Week 39 Week 40 Week 41 Week 42 Week 16 of Your Pregnancy Your fetus now measures the size of an avocado, and big things are happening to you both during week 16 of pregnancy. Read on to learn more. By Alexandra Frost Updated on November 1, 2023 Medically reviewed by Kiarra King, M.D. Trending Videos Close this video player Design By Alice Morgan / Illustration by Tara Anand At 16 weeks, you’re nearing the halfway point of your pregnancy. You are in your fourth month—and second trimester. Your body is changing at a fairly rapid pace, and your unborn baby is developing quickly. Their circulatory system is now functioning, pumping more than 25 quarts of blood each day! But you may also be experiencing some aches, pains, and (new or recurring) pregnancy symptoms…or not! One of the joys of pregnancy is that every one is different. Below are some commonly asked questions, doctor’s appointments, and developmental changes you and your unborn baby go through when you are 16 weeks pregnant. Pregnancy Week 16 Quick Facts At 16 weeks, you’re four months pregnantYou have 24 weeks until your due dateYou're in your second trimester Your Unborn Baby's Size at 16 Weeks While you probably won’t “see” your unborn baby for another few weeks—the 20-week anatomy ultrasound usually falls at, you guessed it, 20 weeks—at 16 weeks pregnant, the fetus measures approximately 4.57 inches and weighs about 3.53 ounces. Pregnancy Symptoms Week 16 The nausea and vomiting of pregnancy typically end by 16 weeks, although some people don't see relief until about 20 weeks or even later. Though your stomach may have settled—and nausea waned—there are other symptoms some pregnant people experience in week 16, including: Backache, joint pain, or nerve pain like carpel tunnel syndrome Dizziness Headaches Indigestion, acid reflux, constipation, or diarrhea Round ligament pain Urine leakage Vaginal discharge At week 16, with multiple weeks of the second trimester behind me, I was feeling better than at any point in my pregnancy, except for the pesky headaches that started at week 15. My energy was back, my nausea was low, and I was motivated to have a healthy and happy pregnancy, full of positivity, exercise, rainbows, and butterflies. In retrospect, this is when I should have been planning a nursery, not at 30 weeks. I did have increased back pain as the bump grew, and some other achy joints, making this a great week to pick a pregnancy pillow to get more rest at night. G. Thomas Ruiz, MD, an OB-GYN at MemorialCare Orange Coast Medical Center, says that low back pain and round ligament pain might cause issues during week 16 of your pregnancy. "The more babies you have, the earlier round ligament pain may start," he says. Dr. Ruiz recommends Tylenol (acetaminophen) for pain, Icy Hot on the ligaments such as the back—but not on the belly—and a maternity belt for support. 11 Pregnancy Symptoms You Shouldn't Ignore Developmental Milestones You’re probably wondering what changes are taking place with the fetus this week, and for good reason. Your unborn baby is developing rapidly, and week 16 is no exception! When you are 16 weeks pregnant, your unborn baby's urinary and circulatory systems begin to work—with the latter pumping more than 25 quarts of blood per day. (This will increase to 1,900 quarts by week 40 of pregnancy!) Their eyes and ears are settling in their final positions, and your unborn baby is getting some extra swimming room, in the form of increased amniotic fluid. They are also preparing for a growth spurt in the coming weeks. Design by Alice Morgan Prenatal Tests and Doctor's Appointments Between 15 and 20 weeks, a doctor, midwife, or health care provider might order a second-trimester screening test to look for abnormalities. They will review your testing options so you can make an informed decision about which tests are right for you. "Everything is optional," Dr. Ruiz explains. However, these screening tests can provide important medical information about your unborn baby. At 16 weeks, you might also be heading in for your final visit before the 20-week anatomy scan, if you visit your doctor, midwife, or health care provider every four weeks. Feel free to ask any questions you want ahead of that scan, which looks at all the baby's vital body parts and organs. Common Questions at This Pregnancy Stage What can I expect at my 20-week ultrasound? If you opt out of the second-trimester screening test, your provider will look for spinal and brain anomalies during this scan. "By ultrasound, you can see anencephaly, meningomyelocele (commonly known as open spina bifida), and abdominal wall defects,” says Dr. Ruiz. Other conditions may also be apparent. However, in most cases, the 20-week ultrasound, also known as the 20-week anatomy scan, is used to check routine things, like fetal measurements, the heartbeat, and the sex of your unborn baby, if that is something you want to know. You'll learn if your baby is on track developmentally when considering their due date calculation.Why am I peeing when I sneeze? While it may be embarrassing and even catch you off guard, leaking urine during pregnancy is fairly common, particularly in the second and third trimesters—when your expanding uterus can overwhelm your bladder. "If you are completely incontinent, that's one thing, but unfortunately a little leaking is pretty normal during pregnancy,” says Barbara Frank, MD, a faculty member at Harvard Medical School and an OB-GYN at Brookline Village OB-GYN in Boston. The leaking could also be due to a weak pelvic floor, adds Dr. Frank. "If you are leaking in early pregnancy, this may be due to laxity in muscles/pelvic floor that happens quickly when pregnant—especially in a subsequent pregnancy.” The good news is this issue usually resolves itself. In most cases, prenatal urine leaks cease after childbirth. However, there are things you can do to ease symptoms. "Talk to your doctor so you can learn how to do kegels,” suggests Dr. Frank. These perinatal exercises can strengthen your pelvic floor and help prevent leaks. If the issue continues after birth, pelvic floor therapy is an option and can be very beneficial. Is it safe to visit the dentist while pregnant? For many years, going to the dentist during pregnancy was falsely considered risky. However, visiting the dentist for preventative care and exams is safe and recommended during pregnancy, particularly as poor dental health can lead to serious complications, such as premature birth. Crowns, fillings, and other emergency procedures should also be done to reduce the risk of infection. That said, non-emergency and elective procedures should usually be postponed until after delivery. Pregnancy Ultrasounds Week by Week Things You Might Consider This Week You might have expected your fatigue and nausea to be much better by now like they are for most pregnant people. If you're still experiencing these symptoms, let your medical provider know. There are strategies that can help. Alyssa Keith, a first-time pregnant mom in Philadelphia, says, "I still experienced extreme fatigue and tiredness at 16 weeks. I asked my doctor about whether this was typical in the second trimester, and they recommended drinking a lot of water, exercising, increasing protein in my diet, and taking outdoor walks. Setting aside just a few minutes every day to get outside has made a huge difference in my energy levels." As for nausea, Shannon Tripp, a mom of five in Puerto Rico, experienced gastrointestinal issues through week 16 of pregnancy, longer than most pregnant people. Eating small, frequent meals and hydrating helped her cope with prolonged nausea until it went away for good. Which Medications Can I Take While Pregnant? Support You May Need This Week If those achy joints and round ligament pains are getting to you, enlist your partner (if you have one), family members, or friends to support you in taking time to rest, stretch, and take it easy. Trying Dr. Ruiz's recommendations such as Tylenol, Icy Hot, heat and ice, and stretching can make things easier, but so can others pitching in when you aren't feeling up to cooking, clearing, or running an errand. Changing positions, such as from standing to sitting, going for a walk, or taking a shower may also provide some relief. I struggled to ask for support this early in my first pregnancy, even as joint pain progressed, thinking I "should" have been able to handle it. But with each subsequent pregnancy, symptoms started earlier, and getting some help became a must. I had to step back and realize my limitations before I overdid it, a battle that started each day anew. Luckily, supporters really do want to help, and if you give them a job, they are usually happy to chip in. Head over to week 17 of pregnancy Was this page helpful? Thanks for your feedback! Tell us why! Other Submit Sources Parents uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Recasting Current Knowledge of Human Fetal Circulation: The Importance of Computational Models. J Cardiovasc Dev Dis. 2023. The World Health Organization Fetal Growth Charts: A Multinational Longitudinal Study of Ultrasound Biometric Measurements and Estimated Fetal Weight. PLoS Med. 2017. Emerging Progress in Nausea and Vomiting of Pregnancy and Hyperemesis Gravidarum: Challenges and Opportunities. Front Med (Lausanne). 2022. Physiology, Pregnancy. StatPearls. 2023. Critical Periods of Development. Mother to Baby: Fact Sheets. 2021. Knowledge and Experience of Women about Dental Services Utilization during Pregnancy: A Cross-Sectional Questionnaire Study. J Pharm Bioallied Sci. 2021. Morning Sickness: Nausea and Vomiting of Pregnancy. American College of Obstetricians and Gynecologists. 2021.