Week 27 of Your Pregnancy

Pregnancy Week by Week: Week 27

Verywell / Bailey Mariner 

At 27 weeks pregnant, your baby is busy building new neural connections in the brain and practicing the muscle movements needed for breathing after birth. Meanwhile, you're in the final week of your second trimester.

27 Weeks Pregnant Is How Many Months? 6 months and 3 weeks

Which Trimester? Second trimester

How Many Weeks to Go? 13 weeks

Your Baby's Development at 27 Weeks

At 27 weeks pregnant, a baby is a little more than 9 1/2 inches (24.4 centimeters) from the top of their head to the bottom of their buttocks (known as the crown-rump length), and the baby's height is over 13 1/2 inches (34.7 centimeters) from the top of the head to the heel (crown-heel length). This week, your baby weighs over 36 ounces or 2 1/4 pounds (1,039 grams).

At 27 weeks pregnant, your baby is about the length of a baby botle brush
Verywell / Bailey Mariner 

Brain

Your baby’s brain is now more active than ever. The neurons and synapses (where the brain cells meet) are forming and making a system of complex connections throughout the areas of the brain.

Lungs

Your baby's lungs are continuing to mature and prepare to breathe after birth. The tiny air sacs in the lungs (called alveoli) are expanding to help your baby take in and exchange air after birth; meanwhile, the cells of the lungs are making the small amount of surfactant necessary to keep the alveoli from collapsing.

Your baby is also taking "practice breaths" of amniotic fluid—a practice that is an important part of their lung development. Your baby is spending about 10% to 20% of their time doing practice breaths.

Survival Outside the Womb

Babies born at 27 weeks are considered extremely premature and require a high level of care. However, research has found that up to 90% of babies born at 27 weeks will survive with extra support in the NICU.

Explore a few of your baby's week 27 milestones in this interactive experience.

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Your Common Symptoms This Week

Turning the corner into your third trimester typically comes with a whole new set of symptoms and pregnancy-related discomforts. This week you might notice significant breast growth and hemorrhoids as pregnancy-related hormones continue to affect your body systems (including digestion) and you continue to steadily gain weight.

Breast Growth

Healthy weight gain is a necessary part of pregnancy. Some of the added weight is a result of your growing baby, placenta, amniotic fluid, and uterus. All the extra blood your body is producing and retained water also plays a part in weight gain. Perhaps not surprisingly, your breasts also account for some added pregnancy weight.

Normally, breast size is determined by the amount of fat tissue in the breast. When you're pregnant, it's the milk-making tissue that is growing in preparation for your baby. This growth changes the size and weight of your breasts.

Hemorrhoids

Hemorrhoids are very common at this stage of pregnancy affecting between 25% to 35% of people who are pregnant. Straining during bowel movements caused by constipation (another common symptom in pregnancy) along with the increased downward pressure caused by your growing uterus can lead to swollen veins in your rectum. Hemorrhoids can burn, itch, and bleed. They can also make it painful to move your bowels.

Self-Care Tips

Breast changes and hemorrhoids are among the pregnancy-related symptoms that are also a common part of the postpartum experience. Learning how to deal with them while you are still pregnant will not only help you feel more comfortable now, but the knowledge may serve you well in the coming weeks.

Dealing With Larger Breasts

Some people who are pregnant only experience small changes in their breast size during but others experience big changes. Larger, heavier breasts can be uncomfortable and lead to back pain, especially if your pre-pregnancy bras aren't up to supporting the additional weight. To help reduce discomfort, you can:

  • Make sure you have a comfortable, supportive bra that fits your changing shape.
  • Opt for wider, padded bra straps, which can better distribute the weight and relieve shoulder discomfort.
  • Try sleeping in a comfortable sports-type bra if you find you're uncomfortable at night in bed.
  • Talk to your doctor if you have any concerns about your breast changes.

Dealing With Hemorrhoids

As your pregnancy progresses and your belly gets bigger and heavier, hemorrhoids might become an issue. Here are some ways to help ease your discomfort:

  • Avoid standing for long stretches.
  • Consume plenty of healthy fiber, such as whole wheat, flax, fruit with skins, vegetables, brown rice, and lentils, to aid regularity.
  • Drink plenty of water to keep your digestive tract moving and stools soft.
  • Don’t strain while on the toilet (constipation-related straining can actually cause hemorrhoids).
  • Exercise regularly to help move waste through your intestines.
  • Take a sitz bath with warm or cool water; you can use a sitz bath product that fits directly over your toilet or simply fill your bathtub with several inches of water.
  • Talk to your doctor about a safe stool softener and a cream to relieve itching and pain.

Your Week 27 Checklist

  • Eat healthy meals including foods high in fiber.
  • Drink plenty of healthy fluids.
  • Find a comfortable, supportive bra.
  • Add fiber- and magnesium-rich foods to your grocery list.
  • Start car seat research.

Advice for Partners

Most hospitals require that parents have a properly installed, infant-appropriate car seat before taking their newborn home. Your pregnant partner may already have their eye on a car seat or travel system, but if not, this is one must-have baby item you can take the lead on. Before helping choose one:

  • Familiarize yourself with all current car seat safety guidelines from the American Academy of Pediatrics (AAP).
  • Note that experts recommend that babies and toddlers ride rear-facing for as long as possible; both infant-only and convertible car seats will offer this option, but different products and brands will have different height and weight limitations in rear-facing positions.
  • Think twice before opting for second-hand; Consumer Reports advises that it’s best to avoid buying a used car seat since it can be difficult to determine crash history, expiration dates, and recalls.
  • Check out the U.S. Department of Transportation’s Ease-of-Use Guide, which may help you determine what car seat is best for your family.
  • Plan to get help with installation. Consider reaching out to a child passenger safety technician (CPST) who can ensure your seat is properly installed. Your local police or health department may also offer this service.

At Your Doctor’s Office

The CDC recommends that all pregnant women get the whooping cough vaccine (Tdap) between 27 and 36 weeks of each pregnancy. Because babies cannot be vaccinated against whooping cough (also called pertussis) until they are 2 months old, it’s important that you pass the antibodies to your baby before birth by getting the Tdap yourself.

It takes time to make and pass the antibodies to the baby. To maximize your antibody response, it’s best to get the shot as close to 27 weeks as possible. The vaccine is safe for both you and your baby.

The most common side effects of the vaccine include:

  • Pain, redness, or swelling at the injection site
  • Body aches
  • Tiredness
  • Fever

Once you are vaccinated, you won't contract whooping cough and risk passing it to your baby, and through your immunity, your baby will be better protected against it from outside sources. However, other people who are not vaccinated can still pass this serious illness to your baby. It's important that your partner and anyone else who will be close to your baby is vaccinated as well.

Upcoming Doctor’s Visits

Your next routine prenatal visit will likely be around week 28 (next week).

Upcoming tests may include:

  • A blood test for Rh antibodies next week
  • Testing for high-risk pregnancies after week 32

Recommended Products

Even if you plan to hunker down at home during the newborn period, a safe car seat is a must-have for taking your baby home from the hospital or birth center after birth and to and from pediatrician visits (of which there will be many in the first year).

Choosing the best car seat for your family's lifestyle requires lots of research. To help cut through the clutter, brush up on current safety guidelines, and seek recommendations from trusted family, friends, and expert sources.

Special Considerations

Starting around week 20, your provider likely began measuring the size of your uterus (known as the fundal height), which helps track your baby's growth. If your provider notes that your uterus feels or measures smaller than it expected during a prenatal exam, they may call for an ultrasound to check in on baby's growth.

Intrauterine Growth Restriction

Intrauterine growth restriction (IUGR) means that a baby is not growing as expected. Other than a smaller-than-expected fundal height or ultrasound measurement, you may not have any signs that indicate IUGR.

IUGR has many causes, including factors relating to the mother's health, the baby's health, or a problem with the pregnancy such as issues with the placenta. Substance use such as smoking and drug and alcohol use can also lead to growth issues. To treat this condition, your doctor will try to determine and treat the cause. Treatment may also include:

  • More frequent monitoring
  • Ultrasounds
  • Special testing for high-risk pregnancy such as a non-stress test, contraction test, and biophysical profile
  • Bedrest
  • Hospital treatment with IV nutrition and other medication

A Word From Verywell

Next week marks the first week of your third trimester and the start of more frequent prenatal visits with your doctor or midwife, which means you'll have more opportunities to check-in and ask questions. Take this time to continue to develop your relationship with your provider so you can feel confident going into this final phase of pregnancy and getting ready to meet your baby.

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  1. Oyer CE, Sung CJ, Friedman R, et al. Reference values for valve circumferences and ventricular wall thicknesses of fetal and neonatal hearts. Pediatr Dev Pathol. 2004;7(5):499-505. doi:10.1007/s10024-004-1117-6

  2. Kiserud T, Piaggio G, Carroli G, et al. The World Health Organization Fetal Growth Charts: A multinational longitudinal study of ultrasound biometric measurements and estimated fetal weight. PLoS Med. 2017;14(3):e1002284. doi:10.1371/journal.pmed.1002220

  3. Jakab A, Schwartz E, Kasprian G, et al. Fetal functional imaging portrays heterogeneous development of emerging human brain networks. Front Hum Neurosci. 2014;8:852. doi:10.3389/fnhum.2014.00852

  4. Schittny JC. Development of the lungCell Tissue Res. 2017;367(3):427-444. doi:10.1007/s00441-016-2545-0

  5. Gleason CA, Juul SE. Avery's diseases of the newborn e-book. Elsevier Health Sciences; 2017.

  6. Anderson JG, Baer RJ, Partridge JC, et al. Survival and major morbidity of extremely preterm infants: A population-based study. Pediatrics. 2016;138(1). doi:10.1542/peds.2015-4434

  7. March of Dimes. Weight Gain During Pregnancy. Updated January 2019.

  8. Żelaźniewicz A, Pawłowski B. Maternal breast volume in pregnancy and lactation capacity. Am J Phys Anthropol. 2019;168(1):180-189. doi:10.1002/ajpa.23734

  9. Staroselsky A, Nava-Ocampo AA, Vohra S, Koren G. Hemorrhoids in pregnancy. Can Fam Physician. 2008 Feb;54(2):189-90. PMID:18272631

  10. Avsar AF, Keskin HL. Haemorrhoids during pregnancy. J Obstet Gynaecol. 2010;30(3):231-7. doi:10.3109/01443610903439242

  11. Lohsiriwat V. Treatment of hemorrhoids: A coloproctologist's viewWorld J Gastroenterol. 2015;21(31):9245–9252. doi:10.3748/wjg.v21.i31.9245

  12. Durbin DR, Hoffman BD. Child passenger safety. Pediatrics. 2018;142(5). doi:10.1542/peds.2018-2460

  13. Consumer Reports. Are Secondhand Car Seats Safe?. January 28, 2017.

  14. Centers for Disease Control and Prevention. Get the Whooping Cough Vaccine During Each Pregnancy. National Center for Immunization and Respiratory Diseases. Updated June 29, 2017.

  15. Centers for Disease Control and Prevention. Whooping Cough Vaccines are Safe but Side Effects Can Occur. National Center for Immunization and Respiratory Diseases. Updated June 29, 2017.

  16. American College of Obstetricians and Gynecologists. Practice Bulletin No. 181: Prevention of Rh D Alloimmunization. Obstet Gynecol. 2017;130(2):e57-e70

  17. American College of Obstetricians and Gynecologists. Practice Bulletin No. 145. Antepartum fetal surveillanceObstet Gynecol. 2014;124:182-92. doi:10.1097/01.AOG.0000451759.90082.7b

  18. Sharma D, Shastri S, Sharma P. Intrauterine growth restriction: Antenatal and postnatal aspects. Clin Med Insights Pediatr. 2016;10:67 doi.org/10.4137/CMPed.S40070