Month 4, A Baby's Development

By: Clara Kelly, Peyton Cavnar, and Katherine Moore

The Baby

By month 4 (or week 16) the baby is in the second trimester. It is in the fetus stage. The fetus is 5 inches long from the baby’s head to the baby’s bottom. It weighs about 3.5 ounces. At this stage, fat begins to form underneath the skin. The fetus is covered with a protective soft down to regulate its temperature. The baby’s lungs have started to develop because of the process of inhaling and exhaling small quantities of amniotic fluid. The facial muscles of the baby also start to develop so facial expressions like frowning and squinting are able to be performed. This is when the baby also starts to form eyebrows and eyelashes. The buds on the side of the baby’s head start to form ears. This means he/she can hear you talk! For social development, the baby can hear you (as mentioned above) and if you touch your stomach, the baby will try to move away! The baby moves, kicks, sleeps, wakes, swallows, and passes urine. The baby is also covered with little hairs called lanugo. Since the baby is in early development, it has a low cognitive development. Sadly, if the baby were delivered now, there would only be a small chance it would survive. 25 percent of these babies would have disabilities. As you can see below, there is a picture of an avocado. This means at month 4, the baby is the size of an avocado.
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At month 4, the mom will feel butterflies in the lower abdomen. This normal sensation is called quickening. By now, the mom should switch to looser clothing because of the growing of the abdomen. This is the time when you have to accept you are having a baby. The baby is too developed to have abortion. The hormones have settled and morning sickness is gone. The mom may get heartburn. At month 4, the mom's waistline starts to disappear. By now, the mom needs to get regular checkups and get prenatal vitamins.

Dangerous Signs- If you start and continue to bleed heavily, it could be a sign of an ectopic pregnancy!

The mom's abdomen might be tender to the touch, but this is normal. The mom's skin may darken and stretch marks may appear on the abdomen and breasts. The mom's breasts may begin to produce colostrum. The mom might also have increased vaginal discharge. The mom's diet depends in the 4 month period on what vitamins she lacks and the baby needs. It is normal for the mom's gums to bleed and for her to have a congested nose.

Key Terms

colostrum-The thin yellowish fluid secreted by the mammary glands at the time of parturition that is rich in antibodies and minerals, and precedes the production of true milk. Also called fore-milk.

ectopic pregnancy- A pregnancy in which the fetus develops outside the uterus, typically in a Fallopian tube.

prenatal vitamins-Prenatal vitamins are vitamin and mineral supplements intended to be taken before and during pregnancy.

trimester-a period of three months, especially as a division of the duration of pregnancy.

fetus-An unborn offspring of a mammal, in particular an unborn human baby more than eight weeks after conception.

amniotic fluid-The protective liquid contained by the amniotic sac of a pregnant female.

lanugo- Fine, soft hair, especially that which covers the body and limbs of a human fetus or newborn.