Your baby's the size of a lime at week 12 of pregnancy

What to Expect During Week Twelve of Pregnancy

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Three months or 12 weeks of pregnancy down, and you’re about to bid trimester one goodbye! Time zoomed by – how do you feel? If you need a refresher on everything that’s happened since conception, go back to weeks one to eleven.

Your twelve-week fetus is essentially fully formed, with all systems (and body parts) go. While there’s still significant maturing left before their arrival, your baby is getting larger and stronger by the week.

The second trimester is ahead, a highlight phase of pregnancy absent from many troubling symptoms. You’re energised, regaining bladder control, and feeling somewhat normal again.

What’s to come? Stick with us and find out. We provide detailed, weekly updates on your little bean and pregnancy, answering your questions about the baby’s size, weird symptoms, unusual body changes, and more.

At a Glance: Week Twelve of Pregnancy

  • It’s the last week of the first trimester – reflect on your pregnancy journey thus far.
  • Your baby’s the size of a lime, measuring between 6 to 6.5 centimetres, and still has a ton of growing to accomplish. But, for all intents and purposes, is fully formed.
  • The placenta is working diligently to keep your baby fed and protected. It also doubles as a waste-disposal service that filters and removes fetal urine and more from the womb.
  • While your symptoms might still be up and down, you might feel a marked improvement compared to previous weeks.
  • This week, consider taking a few proactive steps. Think how you’ll tell work about your pregnancy and outline a budget for the future – the costs of parenthood add up.

Week Twelve Pregnancy Overview

As the placenta starts working this week, you may experience positive changes. Symptoms like breast tenderness or frequent urination might start to decrease or even vanish for a while now that the placenta is in charge of hormone production and other roles.

While it might be a relief to feel better, many will return. Our advice? Take advantage of this short, symptom-free time!

Exiting the first trimester, you can breathe a sigh of relief, knowing that you’ll feel better soon and the risk of miscarriage declines. Once you hear that fetal heartbeat during your ultrasound, the journey to having a child may feel more real than ever.

Baby Size and Latest Developments for Week Twelve of Pregnancy

At 12 weeks, your fetus has doubled in size and is fully formed, with body parts and systems in place. But while your little one is developing quickly, they’ve got far to go before becoming a healthy newborn.

Here’s what’s unfolding in the womb this week.

  • Measuring 6 to 6.5 centimetres, your baby’s about the size of a lime.
  • Vocal cords are gradually forming, hinting at future cries, noise, gurgling, first laughs, giggles and words.
  • Your tiny tot’s bone marrow is creating white cells for protection against germs and illness. Inevitably, your baby will get sick later in life, but a robust immune system means they’ll recover quickly.
  • Wonder what your baby’s skin looks like? It’s translucent, revealing an intricate network of veins at work underneath. It soon becomes less opaque, with pigment setting in later.
  • An ultrasound this week may demonstrate a strong heartbeat as fetal cardiac activity continues to develop. A handheld instrument called a doppler should pick up a fast-paced thumping, likened to a galloping horse because it’s loud and fast. We will just say, though, that the effectiveness of home Doppler’s does need more research!
  • Bones, like the skeleton, skull and long bones, are hardening to provide shape, protect vital organs from external forces and facilitate movement.
  • The reproductive, urinary and circulatory systems are finishing up.

Because every pregnancy is unique, the above description generalises fetal development. Variations in the timing of milestones can occur.

Body Changes For Week Twelve of Pregnancy

With the final weeks of the first trimester finally arriving, you might notice a few positive effects.

Vomiting less? Experiencing a vestige of an appetite? Have renewed energy and the motivation to enjoy life? You should start getting back into the swing of things as some soul-destroying ailments disappear.

While the ending or lessening of some symptoms offers much-needed relief, your body continues to physically change in both wondrous and unpleasant ways.

Mammas-to-be, here’s a range of unwanted pregnancy symptoms to expect as you reach week twelve.

It’s important to note that all pregnancies are unique.  The timing and experiences of pregnancy symptoms may vary. 

1. A Growing Uterus

The urge to frequently urinate slows down as your uterus grows upwards and out of the pelvis. Unfortunately, this relief on your bladder is a short-lived gain. As the uterus grows, it will push down on the bladder, reducing its ability to hold urine.

2. A Growing Belly or a Small or Invisible Bump

Many women might start to look pregnant by week twelve, but not everyone does. As we’ve explained in earlier articles, body type, prior pregnancy and other factors can affect a pregnancy bump’s first appearance and size.

3.  Skin Changes

In our week 11 article, we spoke about the skin changes linked to the downsides of pregnancy glow. What other skin afflictions should you know about?

Melasma is a skin disorder commonly experienced during pregnancy. Sometimes referred to as the “mask of pregnancy”, dark patches of skin appear across the upper lip, nose, forehead and cheekbones in the shape of a mask.

While melasma ends after pregnancy, we’ve included some helpful tips for prevention and treatment.

4. Dark, Vertical Stomach Line

For non-pregnant women, a faint, barely noticeable line runs from the stomach to the pubic area.

But when you fall pregnant, hormonal changes darken this line. Called the linea nigra – Latin for black line – its exact function isn’t known, although some theorise that it protects the unborn fetus against UV rays or is a visual marker that guides a newborn toward the breast.

Regardless of these theories, linea nigras are commonly experienced. And although they’re more likely to appear later in pregnancy, the linea nigra might become visible early.

Like several other body changes, this line fades after pregnancy ends.

5. Thick, Vaginal Discharge

Thought you wouldn’t have to think about pads or panty liners as a pregnant mother-to-be? Think again. Pregnancy discharge might have you reaching for sanitary towels.

However, having discharge during pregnancy is normal, but its colour and consistency matter. White and mild-smelling mucous is considered healthy, but if it’s green and odorous, it could be a sign of an infection that requires treatment.

6. Dizzy Spells

You might feel faint or experience dizzy spells as progesterone widens your blood vessels, increasing the blood flow reaching your baby. With lots of blood channelled to the unborn fetus, the mother might not receive an adequate supply, sometimes resulting in low blood pressure and episodes of dizziness.

This decreased blood flow could impact you negatively. Speak to your doctor or midwife if you’re experiencing abnormal dizziness or fainting frequently.

7. Symptoms You Won’t Have or Not Experience as Much

  • Morning Sickness and Food Aversions: As you begin to feel less nauseous, you might be able to tolerate different foods you couldn’t stomach earlier during pregnancy.
  • Sore Boobs: Breast sensitivity and pain could lessen around this time as hormones start to stablise.
  • Fatigue: While you might have some of your energy back, continue to prioritise rest. Unfortunately, this symptom is only being paused – it tends to reemerge.

Week Twelve of Pregnancy Tips and Tricks

As the first trimester comes to an end, there are things you should think about. Add the below to your growing to-do list.

1. Tell Work You’re Pregnant

talk to work about maternity leave during week 12 of pregnancy.

You might keep your work and home life separate as a professional. But pregnancy is an unavoidable subject that you’ll need to bring up, especially since you’re entitled to take maternity leave and have rights. Do you want to know more about maternity leave? Take a look here.

Even if you’re not ready to tell work, put it on the agenda for later.

2.  Enjoy Time With Friends, Family And Loved Ones

tell friends by week twelve of pregnancy

If you’ve been hibernating all through trimester one, you might feel well enough to go out to dinner, have coffee and see friends! You could also be in the mood to plan a romantic date with your partner – there’s no time like the present!

3. Get Physical

Libido and pregnancy – it’s a mixed bag! Some women feel frisky and eager for romance, while others are too tired and sick to even consider sex.

But, hey, if you’re in the mood, why not get physical with your partner? It won’t hurt the baby!

4. Start A Budget

How many nappies do you need during the newborn phase? Whatever number you’re thinking, the reality is higher. According to the NHS, newborn infants need changing nearly twelve times a day! Lots of money will go towards the nappy fund, that’s for sure!

Of course, nappies are only one of many baby products you’ll need to stock up on, with the cost of baby gear quickly adding up. As crazy as it may sound because your baby isn’t here yet, you’ll also need to consider childcare if you return to work.

Sit down with your partner to discuss your finances and start a budget. Talking about money and the future is a sensitive but necessary conversation. Raising children is expensive – see how you can shed some expenses and save for the future. We love this budget planner if you think you need a helping hand!

5. Maternity Wear

Do you spend a lot of time squeezing your new body into too-small clothes? It could be time for a slight wardrobe adjustment. Select a few key pieces, like stretchy jeans and flowy dresses, that comfortably accommodate your sprouting bumpy. Another budget-friendly option is to borrow old maternity wear from friends and family.

If this isn’t your first pregnancy, bring your old pregnancy clothes out of retirement and use them again!

6. Skincare

There are a few simple ways to beat skin conditions like melasma that are commonly experienced during pregnancy.

  • Limit your exposure to harmful UV rays, as direct sunlight may cause further damage! When you’re outside, stay in the shade and avoid tanning. If you exercise outdoors, enjoy workouts in the mornings and evenings when you’re less likely to burn.
  • Use gentle skin products (fragrance-free, sensitive-skincare brands, etc) over aggravating face cleansers, serums and lotions.
  • Apply an SPF 30 (or higher) sunblock generously and protect your face with a wide-brim, floppy hat.

Do I need an Ultrasound for Week 12 of Pregnancy?

Week Twelve is the ideal time for an ultrasound. A 12-week-old fetus is developed enough to be viewed clearly on a monitor. And with all the major organs and vital structures fully formed, a healthcare provider can conduct comprehensive health checks and provide valuable information on the fetus.

In addition, with cardiac activity ramping up this week, the fetal heartbeat is likely audible at a 12-week ultrasound. But pregnancies are different; the heartbeat may be heard earlier or later.

You might have screenings scheduled that check for specific conditions. Although nerve-wracking, they are essential to check your baby’s wellbeing.

Fun Facts for Pregnancy Week Twelve

Crying baby

  • In Japan, pregnant women receive badges they can pin to their bags to let others know they’re pregnant. This pregnancy badge can be beneficial to use on public transport where fellow commuters might offer up their seats. 

Week Twelve of Pregnancy Checklist

  • You’ve reached the end of the first trimester – it’s time to celebrate!
  • Feel better? Plan to see friends and go on dates.
  • In the mood? Pregnancy sex is not just safe but recommended! 
  • Think about the future – plan a baby budget and maternity leave.
  • Skin acting up? Up the ante on your skincare. 
  •  Stay tuned for week 13 to learn more about the second trimester!


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I'm the person who wrote this

Julie Y

Hi! I’m Julie, one of the Admin over here at The Baby Edition!

I extensively studied Children whilst completing my Degree in Psychology, with much of my research being based on the Development of Twins! Since then, I have continued to work with vulnerable families, and raised a child of my own in the Meantime!

Even to this day, I’m constantly researching Topics relating to Parenting, and love sharing what I have learned with our wonderful Readers!

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