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Week 12 of Pregnancy: All You Need to Know

Baby Development|Body and Life Changes|Your Doctor Visits|Health and Safety
Week 12 of Pregnancy: All You Need to Know

Baby Development

Week 12 of pregnancy baby development marks the end of the first trimester. The fetus’ organ systems have almost completed forming and will now continue to grow and function as the pregnancy progresses. The baby’s growth and development is accelerating considerably; by the last month of this trimester, the baby’s size would have already doubled.

Size-wise, the baby now measures roughly three inches long and weighs about 1 ounce. A baby bump may or may not be obvious yet, however, the womb is expanding to accommodate the rapidly growing fetus.

Due to increased hormone activity, external sex organs should now start appearing. In week 11, the fetus’ fingers and toes lost their webbed characteristics and became individual digits. This week, the baby is focusing on growing its fingernails. The eyes will position themselves nearer to one another this week and its kidneys can begin producing urine.

At week 12 of pregnancy baby development, they are developing complex reflexes, like sucking and swallowing. Spontaneous movement is also one thing that expectant mother can begin to look forward to this week.

Other developments during week 12 of pregnancy baby development:

  • Head and neck

The head constitutes half the fetus’ body size, while the salivary glands begin functioning.

  • Heartbeat

The heartbeat can be detected as early as week 10, should now be audible using an external Doppler scan.

  • Abdomen

Abdominal organs are now formed. These include the spleen, intestines, and liver.

  • Pelvis

Sex organs are already formed.

  • Limbs

The baby’s arms are now proportional and they now have hands that are becoming increasingly functional. Their legs, however, are still short.

  • Skin

The baby’s muscular and nervous system continues to mature. Skin and nails develop, and scattered rudiments of hair appear

Other changes include hormone production, thanks to the thyroid and pancreas glands.

Body and Life Changes

How is my body changing?

During week 12 of one’s pregnancy progression, an expectant mother may still experience symptoms that appeared in the earlier weeks of the first trimester. Some new symptoms may appear: weight gain, melasma (otherwise known as chloasma or skin pigmentation), darker areolas around the nipple and tender or sore breasts.

Skin pigmentation

Hormones are now being continuously produced in a pregnant woman’s body, causing all types of changes. One such change is skin pigmentation. After childbirth, these dark spots may lighten and ultimately disappear.

Breast changes

While in week 11, a pregnant woman’s breasts enlarge and become sore, week 12 affects the areolar area of the breast. One’s areolas are most likely to get darker during this stage of pregnancy. Breast tenderness or soreness may still present well into the second trimester.

Tips for relief

Recommended for breast changes during week 12 of pregnancy baby development is a support bra in the correct or enlarged size. Pregnant women who experience discomfort in their chest can try applying ice packs while lying down. Small silicone-filled breast soothing products can also be helpful.

What should I be concerned about?

A pregnant woman may start feeling the need to wear loose-fit clothing or maternity clothes around week 12 of pregnancy baby development.

Other symptoms may also include dizziness, changes in sex drive (an increase, in particular, thanks to increased estrogen production and energy), frequent urination, fatigue, excess saliva, bloating or gas, heightened sense of smell, occasional headaches and an increase in vaginal discharge.

It must be noted that there is a higher risk of a urinary tract infection (UTI) during pregnancy. It is important to monitor one’s symptoms if you suspect an infection. If so, speak to your doctor or a healthcare professional regarding treatment.

As the risk of miscarriage drops greatly this week, many women choose this time to make their pregnancy announcements. Plans for the period leading up to one’s maternity leave should start being made if they have not been made already. Speak to your employer about a possible shift in schedule or responsibilities as you near your due date, in order for you to get adequate rest.

The Philippines has the Expanded Maternity Leave Act which, among many other perks, extends the paid maternity leave period from 60 to 105 days regardless of how many previous pregnancies the woman has had, how the woman gave birth, or if the woman was married or not.

More than that, the law states that single mothers who qualify under the Solo Parents’ Act can get an additional 15-day paid leave. All new mothers also have the option to extend their leave for 30 more days but without pay.

Your Doctor Visits

What should I tell my doctor?

As your pregnancy is ending its first three months, an expectant mother’s prenatal appointments will vary widely.

Your OB will also discuss your questions and concerns with you. It is also good practice to keep a pregnancy journal in which to write down questions to bring up during your doctor visits.

What tests should I know about?

In week 12 of pregnancy baby development (and in later prenatal visits thereafter), your OB will do the following:

  • Check blood pressure
  • Measure weight increase
  • Determine “fundal height” — the developing fetus’ growth — by measuring the mother’s abdomen
  • Check the baby’s heartbeat and heart rate
  • Check hands and feet for swelling
  • Do tests to check sugar and protein levels
  • An ultrasound scan

Health and Safety

What should I know about being healthy and safe while pregnant?

During week 12 of pregnancy baby development, attention to diet is essential. Pregnant women typically gain weight, but a proper diet will ensure that you will not gain too much. Neglecting this aspect of your pregnancy may result in complications such as gestational diabetes, high blood pressure, as well as physical ailments like back pain and leg pain.

However, eating must not be actively avoided. Continue eating a balanced diet consisting of fruits, vegetables, lean proteins and complex carbohydrates. Junk food is strongly discouraged. Snacks like yogurt, dried fruit, and others which contain protein, calcium and minerals are encouraged.

Wearing sunscreen with SPF 15 or higher is recommended when going outside, in order to stave off skin pigmentation.

Week 12 of pregnancy is also an appropriate time to start doing Kegel exercises. These strengthen the muscles of the bladder, uterus and bowels. Through Kegels, you can learn how to relax and control your vaginal muscles to prepare for labor and childbirth. They are also recommended postpartum to heal the perineal tissues, strengthen the pelvic floor muscles, restore health of these muscles and increase urinary control.

It is also good to start simple stretching exercises, like head, neck and ankle rotations. Speak to your doctor about what exercise routines are right for you.


Due Date Calculator

Use this calculator to find your due date. This is just an estimate – not a guarantee! Most women, but not all, will deliver their babies within a week before or after this date range.

Cycle Length

28 days

Hello Health Group does not provide medical advice, diagnosis or treatment.

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Written by Louise Nichole Logarta Updated Jun 30, 2021
Medically reviewed by Jobelle Ann Dela Cruz Bigalbal, M.D.