31 Weeks pregnant: Baby development, symptoms & signs

Your body at Week 31

Nesting

Have you woken up in the morning and suddenly felt the need to clean the entire house or tackle that organizational project you’ve been avoiding? This might be your brain telling  you to nest! 

Nesting is not only for birds - many animals including humans have important instincts during reproduction to prepare for the arrival of their young. The instinct to nest can come at any time during pregnancy, but tends to be most common in the final trimester. Nesting includes not just preparing your space, or home, for the baby’s arrival, but can also include changes to your social behavior and patterns. While nesting is completely normal, it is important to avoid any chores that involve heavy lifting or the use of certain chemicals like bleach and oven cleaner [1].

Finally, it is important to remember that not everyone will experience  nesting. Like almost everything else in pregnancy, each journey is different and unique.

Nothing to wear

Everyone’s body changes differently during pregnancy too — some women might show late, others might look extremely pregnant before the first trimester is done. At this stage, you might be growing tired of maternity clothes or feel like nothing fits. With only weeks to go, it makes sense not to want to invest money in completely new clothes. Or it might be time to splurge on that new outfit that will help make you feel great in these final weeks. It is important for you to feel comfortable and do what is best for you.

If you’re looking for a cost-effective  refresh, consider diving into the closets of partners, friends or family. Investing in a pair or two of comfortable maternity leggings to pair with oversized t-shirts or button up shirts (worn open with a tank top or closed). Thrift stores, consignment sales, and outlets are also great places to snatch up larger sized clothing for less.

Your baby’s development at 31 weeks

During the seventh month of pregnancy, your baby is continuing to grow and gain more fat as they prepare to enter the world. At 31 weeks your baby can breathe rhythmically, but they will not be able to breathe on their own for 4-5 more weeks [2, 3]. Your baby is also beginning to store important minerals like iron, calcium, and phosphorus [2]. Iron is crucial for developing and sustaining healthy levels of cells in your baby’s blood, like erythrocytes, which carry oxygen from your baby’s lungs through its body [4]. Calcium and phosphorus are both important for growing and maintaining bone tissue [4].

At week 31, your baby is as big as a cabbage. They are about 15-16.5 inches (39-42 cm) long and typically weigh between 3.5 to 4 pounds (1.6-1.8 kilograms) [5].

Pregnancy symptoms during week 31

Braxton Hicks contractions

Braxton Hicks contractions, also known sometimes as “practice contractions”, usually occur in the second half of pregnancy. Unlike labor contractions, Braxton Hicks contractions are irregular and infrequent. While labor contractions will get stronger, and come at regular intervals, Braxton Hicks contractions can last anywhere from 30 seconds to 2 minutes, and seem to come randomly [6]. Like labor contractions, Braxton Hicks contractions will feel like the muscles in your uterus are tightening and then releasing, and they can be relatively painless or quite strong.

Though they can be startling, or scary, Braxton Hicks contractions are your body’s way of preparing for labor. You can even use Braxton Hicks contractions to practice breathing exercises or other methods of self-help pain relief that you plan to use during labor [7]. 

Leaky breasts

You might notice yellow or orange staining inside your bra cups, or even liquid coming out of your bra. Believe it or not, that is actually breastmilk, more specifically colostrum, pre-milk, or fore-milk. Colostrum is thicker than regular breastmilk, because it is higher in protein, minerals, antioxidants, and antibodies [8]. It is designed by your body specifically for your newborn’s first few days to help prevent infection and even works as a laxative to help your baby poo for the first time [8].

You can use nursing pads or cotton rounds inside your bra to help absorb any leakage. If you aren’t leaking, do not worry, your breasts are still likely producing colostrum.

Pregnancy brain

So-called pregnancy brain, or pregnancy brain fog, refers to verbal, memory, cognitive, and learning deficiencies that accompany pregnancy, particularly late pregnancy [9]. Studies have suggested that hydrocortisone and sex hormones that are present during pregnancy can affect both learning and memory abilities, as well as general cognitive function [9]. Research has also found that the brain’s gray matter, the part of the brain responsible for cognition and processing information around us, actually shrinks during pregnancy.  Doctors have attributed this to the brain’s preparing itself to acquire the new cognitive functions required to nurture and raise a baby [9]. It seems shocking, and can certainly feel disconcerting, but brain fog during pregnancy is actually your brain’s way of getting ready to have a baby.

Tips in week 31

• Consider finding a course on infant first aid and CPR: Knowing what to do in the unlikely event of a medical emergency can help you stay calm and confident when you bring your baby home. 
• Find a car seat: If you have a car, or plan to use taxis or the vehicles of friends and family, it is important to purchase an infant-safe car seat. Depending on where you give birth, your hospital or health center might require you to have a car seat to take your baby home. They can sometimes be tricky to install, so be sure to follow the manufacturer’s instructions. In some cases, police or fire stations are happy to help you install infant car seats in your vehicle.
• Begin thinking about managing labor: Labor contractions last between 30 to 70 seconds and can vary in strength and pain depending on the position of the baby, your stage in labor, and the shape of your hips and pelvis. Depending on how you give birth, and how long it takes, various pain relief methods are available to you. It is a good idea to familiarize yourself with the different options and discuss with your doctor or midwife what might be best for you. It is important to remember that while birth can be unpredictable, you can prepare by getting to know your options when it comes to the different ways to manage labor pain [5].
• Take time to stretch: Stretching is great for circulation and relaxation. Try the butterfly stretch to gently open your pelvis and stretch out your inner thighs and lower back. Sit on the floor, a bolster pillow or folded blanket with your knees bent and open towards the floor and the bottoms of your feet touching. Depending on the openness of your hips and how intensely you would like to stretch, your feet can be closer or further from your body. With a straight back, lean forward gently until you feel a stretch in your outer thighs. Hold for a few breaths and then release. Check out our guide on exercise during pregnancy for more prenatal workout ideas.

Following your pregnancy with Natural Cycles

As the first FDA Cleared birth control app, Natural Cycles is a hormone-free and non-invasive way to track your menstrual cycle and take charge of your fertility. But did you know the app also has tools for planning and monitoring pregnancy and navigating postpartum life? Use NC° Follow Pregnancy during your pregnancy to learn week-by-week about the physical and emotional changes going on in your body and learn more about how your baby is developing. After your baby is born, NC° Postpartum is a great tool for learning about recovering from childbirth.