Developmental Changes in the Second Trimester

By Published On: August 5th, 2021

First of all, congrats! The second trimester of pregnancy is a welcomed mile marker for a few reasons: You’re likely to see a decrease in undesirable pregnancy symptoms like morning sickness and extreme fatigue, and your chance of miscarriage drastically drops to between 1-5 percent—a true sigh of relief. While you may feel less of the icky symptoms that come with a positive pregnancy test, there are still exciting things happening in baby’s watery world and ways you can best support his fetal development.

Changes for Mom

The second trimester includes weeks 13 through 28. Often referred to as the “honeymoon phase of pregnancy,” moms usually feel less pregnant and more like themselves as certain pregnancy hormones like estrogen adjust and human chorionic gonadotropin (hCG) lowers. Renewed energy makes it an ideal time to tackle the nursery and set up a registry, both of which can be more taxing than you’d think. The weight of your uterus probably hasn’t become bothersome at this point either, so picking back your exercise routine is a great goal for the time being.

As good as it sounds, know you may still deal with first trimester pests (like constipation) and encounter new symptoms and challenges in the upcoming weeks. According to the Mayo Clinic, these common physical and emotional markers are on the horizon:

Body Changes

Expanding Breasts and Belly

You may finally catch your baby bump showing in the mirror soon as your uterus expands for growth. Your chest may feel heavier and fuller, and you may notice a production in colostrum, the first milk for feeding your baby. This is totally normal and nothing to stress about. Break out your nursing pads early if you notice leakage; you can also express colostrum later in the third trimester to save for your newborn, which can be especially helpful if they have a stay in the NICU or have trouble latching early on.

Braxton Hicks Contractions

These practice contractions manifest in abdominal tightening sensations that come and go. They are typically uncomfortable and not painful, and should dissipate after changing positions or drinking cold water. If they become more regular or increase in intensity, call your healthcare provider to assess if you’re in labor.

Aches and Pains

The stretching of your ligaments can cause abdominal pain that rounds the belly or may be felt in the pelvic area on one or both sides. These jabbing pains can be sharp; gentle stretching of the hip reflex or using a belly band can help.

Moms-to-be also may suffer from leg cramps. Also known as charley horses, these painful involuntary muscle contractions are usually felt in the calf or foot and can strike during the day or at night. If you feel the start of a spasm, try to flex the foot, as it can stop the cramp from spreading. Muscle stretches, adequate magnesium and calcium, and good hydration also keep them at bay.

Skin Changes

Stretch marks may develop as your skin expands with your growing bod. Your stomach, breasts, hips, buttocks and other parts of the body can develop these marks.

Additionally, pregnancy increases melanin production, which may result in a dark line on your stomach called the linea nigra, as well as brown patches on the face known as melasma. These patches usually fade after birth, but know that sun exposure exacerbates the issue, so keep the sunscreen handy and buy yourself a wide-brimmed hat.


This burning sensation in the chest can make sleep impossible for moms. Avoid eating a large meal before bedtime, and steer clear of these common food offenders: greasy/fatty foods, spicy foods, garlic, onions and caffeine, to name a few.

Weight Gain

There’s no one-size-fits-all approach to weight gain during pregnancy, and your particular situation is affected by your prepregnancy weight, number of babies you’re carrying and any potential risk factors that may be present.

While steady weight gain is more important in the second and third trimester to keep up with baby’s rapid growth, your doctor can best evaluate the number on the scale and make adjustments as needed.

Emotional Changes

Anxiety About Labor and Delivery

As you begin to prep for parenthood, you may also stress about bringing baby earthside. Use this time to find a birth class or online course to start walking through what to expect and ways to minimize fears. (You may consider additional content surrounding breastfeeding, infant CPR, first aid and parenting.) It’s also a good idea to take a tour of your hospital or birth center, pending this option is available. By learning as much as you can ahead of time and adopting a plan for mental and emotional relaxation (as much as possible, anyway), you’ll have adequate time to practice before the big day.

Finding Care for Your Child

If you’re heading back to work at some point, know your maternity leave policy and establish a course of action with your employer or HR department. You also need to consider a pediatrician and daycare or nanny service earlier in pregnancy. Not all offices will be accepting new patients, and certain childcare facilities have extensive waitlists. Give yourself time and options to sift through, so you feel comfortable with what’s ahead.

Mixed Feelings About Your Changing Body

Of course you love your baby, but that doesn’t mean you have to love the feeling or the external changes of pregnancy. Know your thoughts of uncertainty and resistance are totally OK. Many moms have been there, and you’re definitely not the last. If it’s something that occupies your mind too often for our comfort or prevents you from participating in everyday activities, bring it up with your doctor. (Tip: Some OB offices and birth centers host online mom and parent groups to bring a community together to walk through the life-changing experience of pregnancy. Ask if your provider has connections to a group as an option for support.)

Changes for Baby

Baby’s development in the second trimester is amazing! Not only will the placenta be fully formed between 18-20 weeks, but your tiny bean’s growth equals stronger movements, meaning you should be able to feel baby move sometime soon. He can also hear your voice, making any prenatal story times even more meaningful. What’s more, you’ll be able to confirm his or her gender at the 20-week anatomy scan, if you wish to find out.

Speaking of anatomy, one of the most noticeable changes in your babe-to-be this trimester is their appearance. Key features take the stage and begin to transform your tiny sprout from blob-like to full-on baby. According to the American Pregnancy Association, the formation of the following attributes are underway:

  • A fine, soft hair called lanugo begins to appear on the skin, beginning with the head.

  • Tiny fingerprints will establish, cementing your wee one’s uniqueness forever. By mid-trimester your baby will also have bitty fingernails.
  • All the components of the eyes are developing, including eyebrows and eyelashes.
  • Vernix caseosa (the pasty white substance seen at birth) starts to cover the skin to protect it from amniotic fluid. (FYI: A mom’s fluid levels continue to rise until about 36 weeks’ gestation to keep a fetus well cushioned. As baby grows, so does his supply.)

  • The skin becomes less and less transparent and fat starts to add padding to your little one’s frame.

  • Organs such as the liver and pancreas are almost complete and able to function.
  • Your little dreamer has developed waking and sleeping cycles, and as you may eventually notice at bedtime, they’re often opposite of your own.
  • The nervous system and brain formations are full steam ahead.

Your baby’s weight gain is another exciting factor, as he will grow from a mere 4 ounces to a whopping 2.25 pounds! He will also reach approximately 14 inches in length.

How to Care for Baby’s Development

Along with continuing to take your vitamin and maintaining prenatal care with your provider, there are ways to best foster the growth and developmental stages of your baby during the second trimester.

1| Eat for brain health. Fish that’s high in omega-3 fatty acids like DHA may boost brain power. (A fish-oil supplement works, too.) Also aim to eat produce rich with antioxidants, such as dark leafy greens, papaya, blueberries and tomatoes, as well as plenty of protein for building cells and making needed hormones.

2| Eat for a stabilized blood sugar level. Sometime between weeks 24 and 28 you’ll have a glucose screening to determine your risk of developing gestational diabetes. Adopting a balanced diet of protein, fiber, healthy fats and complex carbohydrates will help keep your blood sugar stable and decrease spikes that come from sugar.

While you do not need to modify your diet specifically for the glucose test, this method of eating keeps your energy up and can help prevent excess weight gain, as well as avoid you or your baby gaining too much too quickly. Larger babies weighing 8.13 pounds or more at birth are diagnosed with macrosomia, which can come with birth complications that are best avoided.

3| Hydrate with water. Drinking enough H2O is connected to a myriad of benefits in pregnancy and beyond. It’s good for you, good for baby and good for the postpartum period of recovery and breastfeeding. Bonus: Keeping hydrated reduces edema, or pregnancy swelling, because your body doesn’t store as much water in its tissues.

4| Go to the dentist. It’s a lesser known fact that poor dental hygiene is linked to premature birth. Keep your teeth and gums healthy by treating your regular checkup with the same attention you do prenatal visits and continue to prioritize your oral health.

5| Exercise for 30 minutes daily. Getting your heart rate up for half an hour every day is recommended for a healthy pregnancy. It shouldn’t be overly strenuous or leave you feeling breathless; a brisk walk is a great option, as is swimming and prenatal yoga for staying gentle on your aching joints. This is also a good time to modify core exercises to avoid lying flat on your back and putting too much pressure on your abdomen.

By Lauren Lisle