Learn what your body is doing week-by-week from fertilization to birth.
Conception—this is typically 2 weeks past the first day of your last period. The egg and sperm most often unite in the Fallopian tube to form a single cell called a zygote. In this tiny cell is all the information needed to determine the baby's features, including sex, and hair and eye color.
This life is now called an embryo and it's cells are continuously dividing as it travels down the fallopian tube to the uterus. The lining of the uterus is preparing to receive the embryo.
WEEK 1 (FROM FERTILIZATION)
The embryo implants on about day 6. Hormones are now triggered to nurute the pregnancy and prevent monthly periods.
A pregnancy test can now be taken to measure hCG, the pregnancy hormone, and tell her she is pregnant. The embryo is completely attached and draws nourishment from the mother.
The heart is the first organ to function and the first signs of brain development are evident. The foundation for every organ system is established and beginning to develop.
Eyes are developing. Arm and leg buds are now visible. A beating heart can be seen on an ultrasound scan.
The embryo measure 1/3 of an inch long and he or she is making its own blood. Depending on gender, the testicales or ovaries are beginning to form.
Elbows and fingers can be seen. Lungs are beginning to develop. Taste buds and tooth buds are forming, as well as eyelids.
Developing ears and nose are visible. There is pigment in the retina. Bones in the arms are beginning to calcify and harden.
The embryo is now known as a fetus and he or she can yawn and suck. Each minute the brain produces almost 250,000 new neurons! For the first time in development the brain can make the muscles move on purpose. Upper and lower portions of arms and legs are clearly seen, as well as fingers and toes. A baby boy begins to produce testosterone.
The fetus is nearly 2 inches long and the kidneys are already producing urine. During the next several weeks the baby's body will grow rapidly, increasing in weight 30x and tripling in length.
Now 3 1/2 inches long, the fetus is coordinated to find thumb and suck it. Fingernails and toenails are beginning to grow, and baby can swallow and urinate.
FIRST TRIMESTER FETAL DEVELOPMENT VIDEO
The heart is pumping between 110 and 180x per minute and pumps about 6 gallons of blood a day! Gender may now be able to be seen on an ultrasound. If baby is a girl, millions of eggs are forming in her ovaries.
The fetus is now about 7 ounces. The skeleton is hardening and calcifying and is visible on an ultrasound. Reflexes such as blinking and frowning are now developing. The baby also has its own unique fingerprints and footprints. Gender differences have been observed during this time of development. Females move their jaws more often than males.
Mother is beginning to "show." The fetus is now about 10 inches long from head-to-heel and weighs 11 ounces. The baby has unique waking and sleeping patterns, and even has a favorite position to sleep in.
If baby is a male, his testicles are beginning to descend from the abdomen to the scrotum. Hair is visible on the head and body. From now until 32 weeks, the baby feels pain more intensely than at any other time in development.
The baby now weighs approximately 1 1/2 pounds and inhales amniotic fluid in preparation for breathing. Ears are developed to the point where the baby recognizes the mother's voice, breathing, and heartbeat. Rapid eye movements began about a week ago, an activity associated with dreaming. Premature babies have been born and survived at this stage and beyond.
The baby weighs almost 2 pounds and reacts to sounds outside of the mother's body. Eyes can respond to light, and the permanent teeth buds are apparent in the gums. Eyelashes and eyebrows are formed, and hair on the head is growing longer.
SECOND TRIMESTER FETAL DEVELOPMENT VIDEO
The baby is approximately 15 inches long. With support of intensive care, a baby born at this stage is capable of breathing air. The brain can regulate body temperature. Skin is becoming smooth as the baby gains weight.
The baby is now 17 inches long and weighs 4 1/2 pounds. By this stage of development, the eyes are wide open!
WEEK 37-40 (approximately 40 weeks from LMP)
The baby is now 20 inches long and may weigh 7-9 pounds. He or she has a plump body and firm grasp. The baby is now considered full-term and is typically head down in the mother's pelvis awaiting birth.
Only 5% of babies are actually born on their due date. On average with first-time mothers, babies are born 8 days past their original due date.