What Is The Size of My Baby at 13 Weeks Pregnant?

13 weeks fetus

For most women, the first trimester can feel like utter hell, but the thirteenth week of pregnancy usually signals a break in the clouds—by the end of it, you will officially be in your second trimester, a time when the more unpleasant side effects of pregnancy begin to subside and your life becomes a little bit more enjoyable.  It’s not known as the easiest of the three trimesters for nothing!

At this point, your mini-me is still literally miniature, measuring about three inches in length.

Throughout the first trimester, your baby has largely resembled a bobblehead doll—huge noggin with a comparatively tiny body.

This is still the case, although by week 13, their proportions are starting to even out, making them look more like a human and less like an amorphous alien creature.

Your child even has the beginnings of eyebrows!

He or she also has fingerprints, but their skin is still translucent enough to be able to see their rapidly-growing veins and organs.


The thirteenth week marks a few major milestones for fetal development.

Skeletal system

Your child’s tiny skeletal system is continuously growing, as are their organs. Their bones are hardening and as their body continues to grow, organs begin to move into their proper places.

Development of vocal chords and lungs

All of the crying and screaming that will later wake you up and destroy your sleep schedule can be traced back to here.

At week 13, your baby’s vocal chords and lungs are beginning to develop. This is when they will take their first breaths, but it won’t be of oxygen. That’s supplied via the umbilical cord.

No, instead they will be inhaling amniotic fluid, which fits in an odd way, since they still resemble one of those aquatic creatures that live at the bottoms of oceans.

Sucking muscles

It won’t be long before their little mouth is tugging at your nipple, but right now, those sucking muscles in the cheeks are just now developing.

Testes and ovaries

If you’re having a baby girl, her ovaries are now home to about two million eggs. When she’s born, that number will have dropped by half to one million and will continue dropping as she ages. If you’re having a baby boy, their testes are now fully developed inside of their body


At the 13th week, the pancreas begins to produce insulin, which will regulate your child’s blood sugar levels throughout their life (unless they turn out to be diabetic).


Hooray! Your baby’s intestines are functioning and in their correct position within your child’s body.


It may be hard to believe, but though your baby is only about three inches long at this point, he or she is already incredibly active.

They can hiccup, kick, suck their thumb, yawn, and move their head, and by the thirteenth week you can probably even feel it!

Pregnancy books – that are worth buying:


Ina May’s Guide to Childbirth: gives expectant mothers comprehensive information on everything from the all-important mind-body connection to how to give birth without technological intervention. 


Mayo Clinic Guide to a Healthy Pregnancy: From Doctors Who Are Parents, Too! Hundreds of pages of helpful information parents can use. Features include week-by-week updates on baby’s growth. 


What to Expect When You’re Expecting:A completely revised and updated edition of America’s pregnancy bible, the longest-running New York Times bestseller ever. 


The second trimester is when you’ll be able to see your baby somewhat clearly on an ultrasound.

Their head will be identifiable, as will their appendages.

If your partner has seemed disinterested or not as involved or excited about the pregnancy as you would think they’d be, the thirteenth week ultrasound is a great time to bring them along to the appointment as they’ll be able to see, for the first time, their child looking like a human baby.

Symptoms of Pregnancy at 13 Weeks

Here’s what’s going on during your 13th week of pregnancy

Reduction of some uncomfortable side effects

Those nastier symptoms of pregnancy that have been making your life seem like a joyful (sarcasm) roller coaster ride of mood swings (complete with the vomiting  and dizziness that comes at the end of the ride) should be coming to an end and you’ll likely find that you feel less fatigued.

For the next few weeks, you may feel like you have more energy than you did pre-pregnancy. Make sure you enjoy it (and use it to your advantage) now, because in the latter stages of pregnancy, you’ll be back to feeling dead tired.

Other first trimester discomforts, such as headaches, bloating, and constipation, also usually start to fade by the 13th week.

However, there will be some unlucky women who do not experience a subsiding of these types of side effects. For some, nausea and fatigue, as well as the other unpleasant side effects mentioned above will continue for several months.

Pregnancy Journals For Recording Your Memories:


The Belly Book: A Nine-Month Journal for You and Your Growing Belly The first pregnancy journal devoted 100% to you and your belly, The book is organized by trimester and includes pages for “time-lapse” belly photos and ultrasound images, as well as prompts for writing about morning sickness, food cravings, maternity clothes and much more.


Bump to Birthday, Pregnancy & First Year Baby Journal : an award-winning journal / diary to help you hold onto memories of the growing bump, the birth & the first year with your baby


Studio Oh! Guided Pregnancy Journal, Bump for Joy! Bump for Joy is a wonderful way to create a unique keepsake of the most memorable moments of your pregnancy
Guided journal is arranged by trimester and contains thoughtful prompts, checklists and fill-in-the-blanks to help you plan for Baby’s arrival

Body pains

Your uterus grows up and out of your pelvic bones, relieving the pressure put on your bladder, but making you more likely to experience pain in your abdomen.

You’re also going to feel some ligament pain, which is caused by the stretching of the ligaments supporting your uterus.

This pain can be severe, but is common and normal. You can contact your healthcare provider if you want, but unless those pains come with blood or fluid loss, you probably don’t have anything to worry about.

If there is blood or fluid loss, this could be a sign that something is seriously wrong and you should contact your doctor or midwife immediately.

Breast tenderness may still be an issue as your breasts and mammary ducts continue to enlarge and colostrum, which causes sensitivity, is produced.

Vaginal discharge

I call it gross, but doctors call it leukorrhea, a thin and milky discharge that is usually either odorless or mild-smelling and which is caused by the increase in blood flow and the body’s estrogen production.

It’s nothing to worry about; in fact, it’s actually helpful. Leukorrhea maintains the vagina’s bacterial ecosystem and protects the birth canal from infection.

However, this doesn’t make it any less irritating and it can make a mess of your underwear, so if it really bothers you, use a panty liner, but do not douche.

Get a $35 Baby Basket for FREE

Step #1: Become an Amazon Prime Member
Step #2 Set up an Amazon Baby Registry
If someone purchase at least $10 in product from the registry, you’ll be eligible to get a baby box – $35 value- for free!
Quick Tip

Physical Changes at 13 Weeks

Breast changes

You may have already noticed that your areolas have been darkening—this is likely to continue as your pregnancy progresses.

Your veins will also be more pronounced (and not just in your breasts, actually) due to the increased blood flow.

Don’t worry, you won’t be striped blue forever; your veins will return to their normal size after you’ve given birth. Some women also develop what are called Montgomery’s tubercles, which are little bumps around the areolas. Don’t freak out—they are totally normal and harmless.

Your belly (and what’s going on inside of it)

By the 13th week, you may be starting to slightly show. Others may not be able to notice it, but you probably can, especially when you find that your jeans are becoming increasingly hard to button.

You probably don’t need to switch to maternity clothes yet (but if you haven’t gone shopping yet, now is the time to do so, since you’re not experiencing as many negative side effects and you’re not yet large enough to be described as “cumbersome”.), but wearing looser pants or skirts can alleviate a lot of discomfort.

Sex During Pregnancy

Sex. It’s what (probably) got you into this position in the first place.

Here’s how pregnancy will affect it.

Changes in sex drive

This is something that is going to differ for every woman and couple. Some women find that pregnancy gives them a voracious sexual appetite that turns them into temporary nymphomaniacs, while others will shut down the love-making machine and shudder at the idea of being touched.

Let’s be honest: it can be hard to feel sexy or in the mood when you’ve been puking or feeling like a bloated beached whale or are so tired that all you want to do is sleep. Plus, there’s the possible discharge, which may leave you feeling icky. Or you may not notice any changes at all.

Your partner’s sex drive may alter as well. Your larger breasts and growing belly may prove to be irresistible to them, leading them to want to constantly touch you.

Or they may lose their sex drive altogether. Or their desires and needs might not change at all. There’s honestly no way of knowing how either party’s sex drive will react to pregnancy.

Additionally, as your pregnancy progresses, you and your partner’s levels of sexual desire are likely to fluctuate. One month you may find yourself wanting sex constantly; a few months later, you may not want to be touched at all. Pregnancy is basically a biological roller coaster ride.

Sex during pregnancy

In the old days, women were warned to not have intercourse during pregnancy out of fear of harming the fetus.

Now we know that sex during pregnancy does not harm the tiny life blossoming inside of you. Know that it is extremely common for pregnant women to bleed during intercourse; as long as it is only spotting or small amounts of blood, it’s nothing to worry about, though you should tell your practitioner. However, during oral sex, your partner should not blow air into your vagina as this can cause an air bubble to block a blood vessel.

Diet and Exercise


If your morning sickness has been keeping you from eating, now that it has (probably) subsided, you’re likely feeling ravenous, causing the entire world to look like a giant buffet.

Control yourself. Remember that the whole “eating for two” thing doesn’t mean eating double the amount of food.

Ideally, you should only consume a few hundred calories more daily while pregnant, and even less than that if you are overweight. The slower your weight gain, the less stretch marks you’ll have, so work out your nutrition plan with your doctor. Some foods to avoid are:

  • Mercury-rich seafood
  • Lunch meats (unless you heat them up before consuming them)
  • Some herbal teas
  • Raw seafood (unfortunately, this includes sushi)
  • Undercooked meats
  • Raw eggs (If this is a change for you, why are you consuming raw eggs to begin with?)
  • Caffeine
  • Alcohol
  • Unwashed fruits and veggies
  • Unpasteurized foods

Instead, eat foods that are rich in vitamins and minerals and beware of the snack attack monster.

It’s helpful to keep a fruit or veggie tray around so that you have something healthy to munch on when you start craving food. It’ll help keep you away from things like potato chips and ice cream. One of the best types of fruit to incorporate into your diet are berries, since they are rich in anti-oxidants. They also make a great snack! You’ll also want to get plenty of lean protein in your diet.

Start Prenatal Vitamins Right Away


Garden of Life Vitamin Code Raw Prenatal Multivitamin, New Super Saver Pack 360-(Veggie-Caps) specifically formulated to meet the unique needs of women during pre-conception, pregnancy and lactation, providing the nourishment to support both mom and her developing baby.


SmartyPants Prenatal Complete Daily Gummy Vitamins: Gluten Free, Multivitamin, Folate (Methylfolate), Vitamin K2, Vitamin D3, Methyl B12, Biotin, Omega 3 DHA/EPA Fish Oil, 180 count (30 Day Supply) Chewable prenatal vitamin formulated with premium ingredients


One A Day Women’s Prenatal Multivitamin is a complete multivitamin that provides nutritional support in a two pill (one tablet, one liquid gel) formula for before, during and after pregnancy 


Exercise can really help you have a healthy pregnancy, and as long as it has been cleared by your doctor, it is safe to do so.

Swimming is one of the best exercises a pregnant woman can do because it is easy on the body and makes you feel lighter. Swimming is especially good during later stages of pregnancy, when your body is larger and heavier and your ankles are swollen.

Yoga is also a good exercise choice, as is walking and lifting light weights. You should avoid any exercises that require you to lay flat on your back; this is because the increased weight of your growing uterus pushes down, decreasing blood flow to your heart, which slows oxygen delivery to the baby and causes you to become lightheaded.


Real Food for Pregnancy: The Science and Wisdom of Optimal Prenatal Nutrition: you’ll get clear answers on what to eat and why, with research to back up every recommendation. Author and specialist in prenatal nutrition. 


Birth Wisdom Yoga Remedies & Journal:  The book prompts women to nourish themselves, and therefore their families, with simple but effective activities including writing prompts and yoga poses organized by trimester


Yeah Baby!: The Modern Mama’s Guide to Mastering Pregnancy, Having a Healthy Baby, and Bouncing Back Better Than Ever will change everything you think you know about pregnancy, arming you with the most cutting-edge information available,

Miscarriage Risk for the 13th Week

Miscarriages are most likely during the first 13 weeks of pregnancy, so you’ve almost made it through the most worrisome time.

There are a variety of possible causes of miscarriage during the early weeks of pregnancy, but usually, the reason for a miscarriage is not identifiable.

The most common culprit is a chromosomal abnormality, but other causes are drug use, malnutrition, radiation or toxin exposure, too much caffeine, smoking, problems with your hormones, trauma, age of the mother, and incorrect implantation of the egg into the uterine lining.

But you’re almost out of the woods. Stay strong and welcome to your second trimester, Mom!

13 weeks pregnant

Read this next:

14 weeks pregnant

Creative and Practical Nursery Storage Ideas

Infant Optics DXR-8 Video Baby Monitor Review



Fetal development – 13 weeks pregnant from http://www.babycentre.co.uk/13-weeks-pregnant

13 Weeks Pregnant from http://www.pregnancycorner.com/being-pregnant/pregnancy-week-by-week/13-weeks-pregnant.html

13 Weeks Pregnant: Symptoms, Tips, and More from http://www.healthline.com/health/pregnancy/13-weeks-pregnant#1

13 Weeks Pregnant from http://www.whattoexpect.com/pregnancy/week-by-week/week-13.aspx

Your Pregnancy Week by Week: Weeks 13-16 from http://www.webmd.com/baby/guide/your-pregnancy-week-by-week-weeks-13-16

The Best Sex Positions for Pregnant Women from http://www.fitpregnancy.com/pregnancy/sex-relationships/best-sex-positions-pregnant-women?page=2

Sex Positions for Pregnancy from http://www.babycentre.co.uk/l25017307/sex-positions-for-pregnancy

Miscarriage from http://americanpregnancy.org/pregnancy-complications/miscarriage/

Understanding miscarriage from http://www.babycentre.co.uk/a252/understanding-miscarriage

Leave a Comment

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.