Your Guide to Becoming a Mother | Fit Pregnancy

Your Guide to Becoming a Mother

Get your baby off to a safe start.


What’s going on>>All systems and organs continue to grow and develop; genitals distinctly male or female.

12 weeks

Size>>3 1/2–4 inches long (about the size of a baseball); weighs almost 1 oz.

Looks like>>Ears and eyes have moved to their final positions.

What’s going on>> All systems and organs continue to grow and develop; cartilage being transformed into bone.

13-14 weeks

Size>>4–4 1/2 inches long; 1 3/4–2 3/4 oz. (about the size of a softball)

Looks like>>Blood vessels are visible through skin; fine hair (lanugo) covers body.

What’s going on>>Bones are hardening; fetus can smell, taste and swallow; may suck its thumb.

17-19 weeks

Size>>5 1/4–7 1/4 inches long;

7–10 1/2 ounces (about the

size of a large banana)

Looks like>>Fetus begins

to put on fat.

What’s going on>>Fetus begins swallowing more

amniotic fluid, which helps digestive system develop;

is able to hear; pregnancy is half over.

23-25 weeks

Size>>8 3/4–10 3/4 inches long;

1 1/2–3 pounds (about the size of a cantaloupe)

Looks like>>Eyebrows, eyelashes and hair on head are present; fetus looks plumper.

What’s going on>>Has sleep/wake cycles; if born now, has a chance of surviving; at about 24 weeks, appears

to recognize parents’ voices.

29-33 weeks

Size>>11 3/4–13 1/4 inches long (20 1/4 inches including legs);  3 1/2–5 1/2 pounds (about the size of a basketball)

Looks like>>Fetus is chubbier, more babylike.

What’s going on>>Fetus makes purposeful movements to get comfortable; lungs (among last organs to develop fully) continue maturing.

34-38 weeks

Size>>20 3/4–21 1/2 inches long; 6–7 1/2 pounds (about the size of a medium watermelon!)

Looks like>>Fetus is bigger and very newborn-like.

What’s going on>>In 97 percent of pregnancies, fetus begins to move into delivery position; by week 37, lungs

are developed; by week 38,

is ready to be born.

A GLOSSARY of terms Zygote stage: the first week after fertilization Blastocyst stage: weeks 1–2 after fertilization Embryonic stage: weeks 2–8 after fertilization Fetal stage: weeks 9–38


Here’s what kind of action to expect from within, and when:

((First heartbeat)) Your baby’s heart starts beating a few weeks after conception, but you’ll have to wait until about the 12th week of pregnancy to hear it.

((First kicks, aka quickening)) You’ll feel these anywhere from 16 to 20 weeks of pregnancy, depending on the fetus’ size, activity level and other factors.


Most Popular in pregnancy