Congratulations, it’s the last week of your first trimester! You may start to feel your energy return to pre-pregnancy levels. Many, though not all, women experience little, if any, fatigue and nausea at this point in the pregnancy. You may also take fewer trips to the bathroom as your uterus shifts up and forward, away from the bladder. But don't get too comfortable — by the third trimester, the baby and uterus will be big enough that they will be pressing on the bladder, sending you back to frequent bathroom runs.
What Is Happening To Your Body
You may find yourself getting headaches or feeling lightheaded. This is from your increase in blood volume. Remember to take caution and not stand up too quickly.
Pregnancy can cause changes in the skin. Many women develop a dark line from the belly button downward; this is known as a linea nigra. Your face may take on a “glowing” appearance. Increased blood volume and hormones work together to increase oil gland secretion, the combination of which leads to a “pregnancy glow.”
You may also start developing dark patches on the face and neck, known as melasma, or the "pregnancy mask." This discoloration will disappear or lighten significantly once your pregnancy is over.
Starting this week, your doctor may offer you a nuchal translucency test which checks for Down syndrome in your baby.
What Is Happening To Your Baby
Your baby is now approximately 2.5 to 2.8 inches (6.4 to 7 cm) long from crown to rump, or roughly the size of a large plum. At this point, your baby should weigh about 0.3 to 0.5 ounces (8.5 to 14.2 grams).
At week 12, your baby is fully formed. Though its brain and organs will continue to grow and develop, it has all the necessary pieces. However, it wouldn’t be able to survive outside of the womb yet. Your baby’s brain will continue to grow from this point on but will maintain its current shape. The pituitary gland, located at the base of your baby's brain, is also beginning to produce hormones this week.
Your baby has also started developing nerves and a spinal cord which allows him or her to feel some types of pain. Fingers and toes have separated and hair and nails are starting to form.
Your baby’s vocal cords also form this week. In addition, the kidneys begin to function as the baby starts swallowing amniotic fluid and passing it out as urine. Your baby’s digestive tract is also strengthening.
Most importantly, your baby’s heart is beginning to pump several quarts of blood daily. This can be heard with the aid of a doppler (a special listening device). The heartbeat will be very fast, like the clicking of horse hooves.
The external genitalia have also developed and will begin showing signs of either the male or female sex. Though your health care provider may guess the gender, there is still a lot of uncertainty.
Ultrasound images courtesy of GE Healthcare
The clinical images and information presented in this application represent normal fetal growth during a typical pregnancy. The images and information are to be used for educational purposes only and not for diagnostic purposes. Please consult a licensed physician regarding any specific questions pertaining to your pregnancy.