Only 13 weeks ago you may have been wrestling with the news that you were pregnant — and now look at you! You’ve probably had some challenging experiences and even had to deal with a few tricky spots, but here you are at the second trimester! By week 13, your little baby has become very busy indeed, and you’ve also got lots going on.

By week 13, your baby has become the size of a pea pod. The baby is constantly growing. Now, he/she is more than 2.8 in (7 cm) from the top of his/her head to the coccyx. The eyelids are completely closed; he/she will be able to open The head-to-body proportion is changing: now, the head is 1/3 of the total length. The fingertips are marked with fingerprint patterns. The baby is able to put the thumb in the mouth, trying to suck it.

Join Flo as we take you through the major stages of week 13 of pregnancy:

Your baby at week 13 of pregnancy

As you’ll recall from our coverage of the earlier stages of pregnancy, in the weeks leading up to this point your little one has been growing in size and developing at a rapid pace. This will continue in the next phase of your pregnancy. The fetal head is still disproportionately large compared to the rest of the body, but this is gradually starting to even out.

By now, you’ll have noticed changes in your own body, too. Your uterus will have increased substantially in size and now fills your pelvis. If nausea in the morning or at any other time of day has put you off your food, you might be feeling well enough now to enjoy your meals — and maybe put on a little weight!

How big is your baby at 13 weeks pregnant?

Your baby now weighs 25g and is around the size of a pea-pod! It might not seem like much, but only 5 weeks ago it was the size of a blueberry.

Pregnancy week 13 fetal development

Considering how rapidly your baby has been developing over the last few months, it’s no surprise that he or she has come so far! The eyes are moving into position and the wrists and ankles are already well formed. On top of this, the baby’s body is growing significantly and this means that it won’t be long until the head and the body no longer appear so mismatched in size.

By this stage in the pregnancy, a girl’s ovaries and a boy’s testes are fully developed internally — and on the outside, the genitalia are in the process of forming. For a while now, the fetus has had a pronounced swelling between the legs and this is now undergoing rapid development into what will ultimately become the penis of a male or the clitoris of a female.

How big is a baby at week 13 of pregnancy?

Your body at week 13 of pregnancy

At 13 weeks, your uterus is now much larger and fills your pelvis. As it’s grown, the uterus has risen into your abdominal cavity. 

If you’ve been avoiding meals and snacking like you’re on a picnic because of morning sickness, you might find now that your nausea is easing and your appetite returning. Time to indulge those cravings!

13 weeks pregnant belly

As your uterus has grown in size and started to fill your pelvis, it has also risen into your abdominal cavity (resulting in the typical smooth oval that you may be able to feel). 

And this has another consequence: if for the last few months you’ve been urinating more than usual, it’s because your uterus has been putting pressure on your bladder and this should start to ease as the uterus moves further up your body.

13 weeks pregnant symptoms

One of the most significant developments for an expecting woman at this stage is the typical relief from nausea that occurs at around 13 or 14 weeks. Up to this point, your queasiness is likely to have hampered your appetite and put you off your usual diet — for this reason, it’s not uncommon for many women to only gain a little weight until the second trimester of pregnancy.

But around now you’ll start to feel yourself again — just a very pregnant version of yourself! At the very least, nausea and tiredness of morning sickness (which can occur at any time of day) will start to wear off. As your appetite returns, feel free to indulge in the things you’ve been avoiding all this time — but try to maintain a healthy, balanced diet nonetheless.

Another change that many women notice is an increased libido. It may be the result of either the increased blood flow to your genital area or the activity of your pregnancy hormones. Whatever the reason, if you’re feeling frisky then you might want to share it with your partner — unless a health professional has told you otherwise, you can safely remain sexually active for the full duration of your pregnancy.

13 weeks pregnant ultrasound: do you need it?

In most countries, the first scan of a pregnant woman takes place between weeks 8 and 14. It’s usually followed by another scan at 18-21 weeks. 

You should also be aware that screening tests for a number of serious developmental disorders (including Down’s syndrome) are available to you at this stage. Your healthcare provider has probably already mentioned these this to you and put things into motion, but if not feel free to flag it up and ask what arrangements need to be made.

 girl eating a hamburger and chocolate sitting on the couch.

13 weeks pregnant lifestyle

Your pregnancy may be a challenging time for you, but do your best to follow a healthy lifestyle. This will provide the best support for you and your baby until delivery. Your diet should contain a wide variety of foods from all the recommended food groups, including a mixture of fresh fruit and vegetables whenever possible. You should also aim to drink between eight and 10 8-ounce glasses of water (from all sources) a day unless your doctor says otherwise.

Try not to fixate on the old idea of ‘eating for two’ — in reality you only need around 300 to 350 extra calories per day to provide for your baby. 

Sex at week 13 of pregnancy

Unless your doctor has told you otherwise, your sex life can continue as normal throughout pregnancy.

What to expect at 13 weeks pregnant — checklist

Here’s your week 13 pregnancy checklist:

  • Care to share…?

Different couples work differently together: some partners become very involved in pregnancy from the get-go, while others are more reticent. Whatever the case, week 13 is a great opportunity to try to involve your partner more in your and your baby’s experiences. Why not suggest to your partner that he join you at your next checkup? It’s a chance for him to hear the baby’s heartbeat and catch up on what’s been going on.

  • And while you’re being intimate with your partner…

Many women experience heightened sex drive in the early part of the second trimester — there’s lots of blood flowing to your pelvis and your hormones are raging. If this makes you feel like being intimate with your partner, then let them know about it! Some couples can feel a little disconnected over the course of a pregnancy, so try to take advantage of the opportunity to restore your bond. Unless your health practitioner has told you otherwise, sex is safe for you and your partner throughout pregnancy.

  • Remember to be cautious about urinary tract infections (UTIs)

Now that your uterus is expanding into your abdomen, it will put less pressure on your bladder — and this will mean fewer bathroom breaks. Stay alert to any sign of a UTI (particularly pain when urinating). UTIs do occur when pregnant and should be treated promptly to reduce the risk of kidney infection.

https://www.webmd.com/baby/guide/your-pregnancy-week-by-week-weeks-13-16#1
https://www.nhs.uk/conditions/pregnancy-and-baby/13-weeks-pregnant/
https://www.nhs.uk/start4life/pregnancy/week-by-week/2nd-trimester/week-thirteen/

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