Pregnancy Week by Week

Many of us think of pregnancy as lasting nine months, but a pregnancy is measured from the time of the woman’s last menstrual cycle. For this reason, a pregnancy usually lasts about ten months. These ten months are divided into three trimesters. Each trimester lasts about 13 weeks.

Receiving an ultrasound is the most accurate way to confirm a pregnancy and to determine how far along the pregnancy may be. If you believe you might be pregnant, Women’s Resource Center provides free pregnancy testing and ultrasound services.

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What Happens during the First Month? 

First Trimester Begins
Week 1 – Last Menstrual Period Week 2 – Conception (sperm fertilizes egg)
Week 3 – Embryo attaches to the uterus
Week 4 – Nerves, brain and spinal cord begin to develop

What Happens during the Second Month?

Week 5 – Heart begins to beat
Week 6 – Eyes, arms, legs, lungs, and stomach begin to form
Week 7 – Hands and feet are forming
Week 8 – Upper lip, teeth, fingers and ears begin to form

What Happens during the Third Month?

Week 9 – Toes and genitals are forming
Week 10 – Baby has permanent fingerprints
Week 11 – 
Baby starts to produce urine
Week 12 – Fingernails are forming

What Happens During the Fourth Month?

Second Trimester Begins
Week 13 – 
Baby flexes and kicks
Week 14 – 
Gender can often be determined by ultrasound
Week 15 – 
Skin begins to form
Week 16 – 
Facial expressions are possible

What Happens During the Fifth Month?

Week 17 – Fat accumulates
Week 18 – Baby begins to hear
Week 19 – 
Lanugo (tiny downy hair) covers baby’s skin
Week 20 – 
The halfway point

What Happens During the Sixth Month?

Week 21 – Nourishment evolves
Week 22 – Taste buds develop
Week 23 – Lungs prepare for life outside the womb
Week 24 – Sense of balance develops[/DDET]

What Happens During the Seventh Month?

Week 25 – Eyebrows & eyelashes are usually developing
Week 26 – Eyes remain closed
Week 27 – Baby continues to grow
Week 28 – Baby’s eyes open

What Happens During the Eighth Month?

Third Trimester Begins
Week 29 – Movement is more forceful
Week 30 – Baby packs on pounds
Week 31 – Reproductive development continues
Week 32 – Downy hair falls off

What Happens During the Ninth Month?

Week 33 – Baby detects light
Week 34 – Protective coating gets thicker
Week 35 – Rapid growth continues
Week 36 – Baby can suck

What Happens During the Tenth Month?

Week 37 – Baby is full-term
Week 38– Organ function continues to improve
Week 39 – Placenta provides antibodies
Week 40 – Your due date arrives