Time passes quickly, and you have entered the twelfth week of your pregnancy. In this exciting period, your baby rapidly develops, and your body changes accordingly. You increasingly feel pregnant. When you go to the doctor for a check-up, you have thousands of questions on your mind: “I wonder how much my baby has grown?” “Is he developing normally?” “Am I healthy enough for this pregnancy?” “When will my baby bump become visible?” To eliminate these question marks from your mind, we have collected all important information about the twelfth week of pregnancy.
Your Baby at Twelve Weeks
Every week of pregnancy is very important, and your baby has entered a phase of even faster development compared to a week ago. The twelfth week is one of the most important periods in your baby’s growth in your womb. Let’s examine what you need to know about a twelve-week-old foetus.
How Big is Your Baby at Twelve Weeks?
Whenever you have your check-up, you undoubtedly wonder, “How much has my baby grown?” As development continues at full speed, your baby’s length and weight increase equally quickly. Your baby now has approximately the size of a plum.
You can find the average foetal length and weight in the table below. These values are averages and may vary from baby to baby due to differences in the moment of fertilisation, which cannot exactly be determined. If fertilisation occurred later than expected, your baby’s values might be lower. Only your doctor can tell you whether there is cause for concern or not.
| Gestational Age | Weight | Length |
| 12th week | 8-14 g | 4-6 cm |
Development of the Organ Systems and New Skills
In the twelfth week of pregnancy, your baby enters the foetal period, a period of rapid organ development.
- The Nervous System
While brain development continues rapidly, the cerebellum starts to form. This part of the brain allows the muscles to work regularly, and your baby now moves slowly. Although his movements are reflexive, they respond to brain signals as the muscles develop. When you press your tummy, your baby will feel it and act reactively, but you cannot feel these movements yet.
- The Circulatory System
As of this week, the placenta begins to fulfil its duty. The umbilical cord has started functioning, providing blood circulation between the mother and baby. Although your baby has been producing urine since its kidneys began to work, most waste materials reach the placenta through the umbilical cord. They are then transported to the mother’s blood. Thus, body waste does not affect the valuable amniotic fluid your baby is in.
When your doctor listens to your baby’s heartbeat during the ultrasound, you may be surprised by how fast it beats. A baby’s heart rate is about 120-160 beats per minute.
- The Digestive System
In twelve weeks of pregnancy, your baby’s organs gradually find their place and start working. The kidneys continue to develop. In addition, meconium begins to form this week. This is your baby’s first poo. It will be expelled within 24 hours after birth if all goes well.
- The Respiratory System
As your baby’s swallowing reflex develops, he starts swallowing amniotic fluid. This stimulates lung development and the respiratory system and prepares your baby for breathing. Your baby has also begun to hiccup.
- The Musculoskeletal System
As your baby’s organs have almost completed their development, at twelve weeks, the baby spends most of his energy on physical growth. Your baby also moves more as his muscles and skeletal system develop. As of this week, your baby may turn upside down in the womb, kick, stretch backwards and do somersaults.
- The Urinary System
The kidneys started working in the previous weeks. The baby swallows amniotic fluid, passes it through the kidneys, and delivers it back to the placenta in the form of urine. In this way, he gradually practices peeing.
- The Reproductive System
A question that greatly interests most expectant mothers is the gender of their baby. So, can the sex of a twelve-week-old baby be determined? The genital organs started to develop in the seventh week and now take their specific female or male characteristics. However, this cannot be seen on ultrasound yet. It takes a little more patience to find out your baby’s gender.
- The Endocrine and Immune System
During the twelfth week of pregnancy, the immune system starts to develop. The bones start producing white blood cells, the cornerstones of the immune system. In addition, your baby’s pancreas begins to make the hormone insulin.
Your Baby’s Movements at Twelve Weeks
From the moment you find out you are pregnant, you eagerly await the day when you will feel your baby’s kicks and movements. In the twelfth week, he starts wiggling, curling his fingers, and even opening and closing his hands. Unfortunately, it is still too early to feel this. He first needs to grow a little more.
A Twelve-Week-Old Foetus’s Sense Organs
The brain controls the sense organs, which develop parallel with the brain. Let’s examine the developments and changes in the sense organs in the twelfth week of pregnancy together.
- The Eyes and the Sense of Sight
The eyes continue developing, but technically, their structure is sufficiently advanced to allow for eyesight. The eyelids have also fully developed but will remain closed until approximately 26 weeks. The eyes are approaching their final location on the face, so when looked at from the side, the foetus now has a human appearance.
- The Ears and the Sense of Hearing
The development of the ears, the hearing organs, accelerated in the previous week. This week, the ears become more apparent, and you may be able to see them on ultrasound.
- The Skin and the Sense of Touch
The sense of touch was the first to become operational. The skin is transparent, and soft hairs appear on its surface. The nails also start to grow. You will need to cut these long, soft nails after birth. So, remember to add baby nail clippers to your baby-items list.
- The Tongue and the Sense of Taste
When swallowing the amniotic fluid, your baby can taste the liquid. He opens and closes his mouth, and the swallowing reflex works well now. His vocal cords also take shape this week. Get ready to hear his first postpartum cry!
How Many Months is Your baby at Twelve Weeks?
Pregnancy is a period of nine months and ten days, corresponding to forty weeks. Although we are used to expressing this period in months, your doctor will talk about weeks. This may confuse you. So, how can you convert the number of weeks into months? Let’s calculate this together:
1 week = 7 days, 1 month = 30 days
12 weeks = 12×7 = 84
84/30 = 2 months 24 days
At twelve weeks, you are in the third month of pregnancy. You will have to wait another few weeks to enter the second trimester of pregnancy.
Your Body at Twelve Weeks of Pregnancy
As your baby changes, so do you, both physically and mentally. Let’s look at the changes you may experience at twelve weeks of pregnancy.
- Weight gain
The most obvious physical change during pregnancy is weight gain. By the twelfth week of pregnancy, you will have gained about 2−2.5 kilograms. If you were overweight before your pregnancy, you must pay extra attention to your weight gain, as it will accelerate in the second trimester. Try to keep it under control for the first three months. By week twelve, you usually gain weight on the sides of your abdomen, hips, and legs.
- The expansion of your uterus
This week, your uterus will reach the size of a large grapefruit. This may cause some muscle pain in that area from time to time. Your expanded uterus also puts pressure on your bladder. This pressure, however, decreases as the uterus moves further into the abdominal cavity.
- Heartburn
Reflux and heartburn are quite common at twelve weeks. This burning, sour sensation may be felt in your oesophagus, from your sternum (breastbone) to your throat. Especially when you lie on your back, the complaints increase, as stomach acid may come up all the way into your mouth. If you suffered from this condition before pregnancy, this will probably increase during pregnancy. Ask your doctor for advice.
- Belly expansion
With the enlargement of your uterus, your lower abdomen becomes more pronounced. You will finally start seeing a small baby bump.
- Vaginal discharge
Pre-pregnancy, you may have had some odourless, or slightly odorous, milk-like discharge in your underwear from time to time. During pregnancy, this discharge may increase due to the increased oestrogen levels and blood flow in the vaginal area.
If you experience unusual discharge that looks different, you should immediately contact your doctor. If the discharge is pink or brown in colour, it may signal that something is wrong with your pregnancy. If a burning sensation and itching accompany the discharge, it may indicate that you have a fungal or bacterial infection, which also needs medical attention during pregnancy.
- Dry or oily skin
While some expectant mothers say that their skin improves with pregnancy, some also have problems such as acne and blemishes. You may also notice that freckles and moles get darker. This all depends on your skin type and hormonal changes. These changes are normal, so there is no need to worry. However, if they bother you, you can ask your doctor for a safe skin solution that will not harm you and your baby.
Suggestions to Minimise Troublesome Pregnancy Symptoms
While leaving some of the most difficult days of pregnancy behind, some twelfth-week pregnancy symptoms may bother you. Here are some easy and comforting tips to minimise these annoying pregnancy symptoms.
- Paying attention to what you eat is important to avoid heartburn and reflux. Avoid bitter and sour foods, coffee, and chocolate. Also, change your sleeping position. Instead of lying flat, use cushions to raise your head and chest to prevent stomach acid from coming up to your throat.
- Always remember to chew well to facilitate digestion and prevent heartburn.
- To keep your weight under control and prevent heartburn, eating easily digestible foods and dividing large meals into smaller, more regular ones may help.
- As morning sickness reduces, your appetite may increase. However, instead of eating for two, you should consume nutritious foods that benefit you and your baby. Opt for protein-rich foods such as chicken, fish, and meat, and add fibre-rich foods such as rye, oats, barley, and legumes to your diet.
- During the twelfth week of pregnancy, your breasts continue to grow. If you experience pain in your nipples, you can apply nipple cream for a short time until you find relief. You will be able to use this after birth as well.
How Much Weight Should You Gain?
Excess weight gain during the first trimester is undesirable as your baby weighs only 8−14 grams and continues to grow fast. It is best to gain no more than 2−2.5 kilograms between the start of pregnancy and the twelfth week. Over the next few weeks, your baby’s mass will quickly increase, and your weight gain will also accelerate.
Nutritional Recommendations at Twelve Weeks of Pregnancy
Your baby grows and develops. For this, he uses the nutrients he receives through the placenta. What you eat and drink is more important than ever.
- When you suffer from heartburn or reflux, you should choose easily digestible foods to spare your stomach. Avoid bitter and sour foods, caffeine, and chocolate.
- If you continue to suffer from constipation, adding extra fibres to your diet will be beneficial.
- As your baby uses your nutritional stores, you should consume calcium-rich foods and milk products. You can add kefir, milk, yoghurt, and cheese to your diet as snacks or side dishes.
- While sweet and fatty foods may give you a feeling of satisfaction, fruits and vegetables are more beneficial for a healthy and balanced diet.
- Remember to consume plenty of fluids. Drinking at least eight glasses of water is important to prevent constipation and support your body in getting rid of toxins.
Exercise Recommendations at Twelve Months
Pregnancy shouldn’t get in the way of exercising or being active. On the contrary, light exercise will help you to control your weight gain. You also need strong muscles for birth and after. However, as of this week, you may feel out of breath and tired more quickly. This is because your body needs more oxygen than before. Therefore, be careful while exercising. Make sure to rest and take small breaks regularly. Ideal twelve-week pregnancy activities are light-paced walking, Pregnancy Pilates, and yoga.
Twelve-Weeks-Pregnancy Checklist
- You should test for certain common foetal abnormalities, such as Trisomy 21, commonly known as Down Syndrome. You can have the nuchal translucency test between the eleventh and fourteenth week of pregnancy. This test consists of an ultrasound and blood analysis and detects. However, it cannot provide you with a definitive diagnosis. If there are any doubts, your doctor will be able to give you the best advice.
- You can start creating a shopping list for you and your baby. It is a lot of fun deciding what to buy for your baby with your partner. For certain items, you also need to research whether you need them or which brand is best, so starting early is key.
- Knowing what to expect in the coming period and reading up on pregnancy, birth, and baby care will help you feel more confident.
