The twelfth week of pregnancy marks the end of the first trimester. Many mothers find the second trimester easier than the first, as severe morning sickness eases.

It's too early to feel a kick or see a baby bump, but this week brings many other interesting changes for mother and baby. This is also the time to make some important decisions.

First Trimester Screening

Between 11 and 13 weeks, many doctors perform a maternal blood test and ultrasound. These tests can show the first signs of disorders like a heart defect or Down syndrome. A positive result doesn't necessarily mean that the baby will have a specific condition, only that there is a higher risk. Doctors and midwives can offer support and advice based on the results.

Many mothers are understandably nervous about these screenings. The risk of the antenatal screening itself is relatively low, but parents can make their own decisions about which tests they want and how to use the information.

Ultrasound exam 7postman / Getty Images


All Major Organs Are Formed

Photographs of the fetus at twelve weeks show tiny legs, arms, a head, and the beginnings of ears. The baby is typically only about 2.5 inches long, but their heart, kidneys, brain, and other organs are all there. These systems will continue to develop throughout the pregnancy. At 12 weeks, the fetus cannot feel pain and cannot live outside the uterus.

pregnant woman showing 12 Weeks x-ray ultrasound scan of baby


The Fetus Begins to Move

Between 10 and 12 weeks, the fetus makes their first movements. The fetus is not yet conscious, so these motions are not the deliberate kicks and stretches of an older baby in the womb. Instead, movement is random, and the motions are too small for the mother to feel.

They are, however, the earliest precursors to every movement this new person will make throughout their life.

husband holding belly of his pregnant wife making symbol heart hands Serhii Sobolevskyi / Getty Images


The Risk of Miscarriage Decreases

Roughly 25% of pregnancies end in the first four weeks. This is usually before someone even knows they are pregnant, but the risk remains higher throughout the first trimester.

More than 80% of miscarriages occur within the first 12 weeks of pregnancy. While there is still a risk after this point, many parents find that twelve weeks is where they begin to feel comfortable publicly announcing their pregnancy.

couple videocall to announce pregnancy


Mothers May Feel Much Better

While every pregnancy is different, many mothers report that the intense fatigue and nausea of the first trimester starts to ease up at twelve weeks. This can be a huge relief. Food may become more appealing, as the mother becomes hungrier and has stronger cravings.

Mothers don't have to eat more than usual, as the baby gets proper nourishment from their regular diet, but they should have plenty of high-quality, nutritious food.

Pregnant Woman Eating Healthy Breakfast And Listening To Music On Bed Oscar Wong / Getty Images


Stomach Cramps Are Common

For some hopeful mothers, unexpected cramps are a frightening sign. In the absence of bleeding, however, this is likely a pregnancy symptom. Constipation is fairly common at twelve weeks. Gas and stretching as the uterus gets bigger can also cause cramps that may feel similar to period pains.

If the pain is persistent or severe, or if the mother notices blood, they should consult their doctor or midwife.

woman having stomach cramps 5432action / Getty Images


New Pregnancy Symptoms Start Appearing

The second trimester is generally less uncomfortable than the first and third, but there are a few symptoms to expect. Breasts grow bigger and might feel sore. Hair starts becoming thicker and shinier. Cravings intensify. Headaches, mood swings, bloating, and nausea could persist from early pregnancy.

Some mothers also report that their vaginal discharge is thicker and milkier in color. Spotting is not unusual, but mothers should still consult their doctor if there is blood in their discharge.

woman with her hands on her tummy and head in pain PixelsEffect / Getty Images


The Fetus' Eyelids Fuse Shut

One interesting quirk of pregnancy is that fetuses cannot open their eyes until the fifth month. Twelve weeks in, the eyelids fuse together, keeping the eyes shut until they are fully formed. This is important for ocular development. Eyelids protect the delicate surface of the eye and provide a structure for the developing visual system.

pregnant woman using laptop


Sex Organs Start to Develop

Internal sex organs, like the prostate and ovaries, start to take shape at twelve weeks. Genitals also begin to form. Roughly 2% of babies are intersex and may develop unusual combinations of sexual characteristics.

Some special tests can even determine sex at this stage, though they aren't typically done unless the parents and doctor are worried about sex-specific genetic conditions.

Couple holding pink and blue color card for baby gender Prostock-Studio / Getty Images


Mothers Can Start on a Birth Plan

The birth plan doesn't have to be fully decided, but twelve weeks is a good time for the mother to start thinking about where and how she'd like to give birth. Options include at home, a birthing center, or a local hospital.

In addition to the parents' preferences, cost may be a factor in where a mother can reasonably give birth, as well as local resources and the health of the pregnancy.

couple discussing holding laptop and paperworks Oscar Wong / Getty Images


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