Gestation is the duration of time in between conception and also birth once a baby grows and also develops within the mother"s womb. Due to the fact that it"s difficult to know specifically when conception occurs, gestational age is measured indigenous the first day that the mother"s critical menstrual cycle come the existing date. It is measure in weeks.

This means that during weeks 1 and 2 the pregnancy, a mrs is no yet pregnant. This is once her body is preparing for a baby. A normal gestation lasts almost everywhere from 37 come 42 weeks.

Week 1 come 2

The very first week of pregnant starts through the an initial day of a woman"s term period. She is not yet pregnant.During the end of the 2nd week, one egg is exit from an ovary. This is when you are most likely to conceive if you have actually unprotected intercourse.

Week 3

During intercourse, sperm enters the vagina ~ the guy ejaculates. The the strongest sperm will certainly travel with the cervix (the opened of the womb, or uterus), and also into the fallopian tubes.A solitary sperm and also the mother"s egg cell meet in the fallopian tube. Once the solitary sperm enters the egg, conception occurs. The merged sperm and also egg is called a zygote.The zygote contains every one of the genetic information (DNA) necessary to end up being a baby. Half the DNA comes from the mother"s egg and half from the father"s sperm.The zygote safety the next couple of days traveling under the fallopian tube. Throughout this time, that divides to form a round of cells dubbed a blastocyst.A blastocyst is consisted of of one inner team of cells through an external shell.The inner team of cell will end up being the embryo. The embryo is what will develop into your baby.The outer group of cell will end up being structures, dubbed membranes, i beg your pardon nourish and also protect the embryo.

Week 4

Once the blastocyst will the uterus, the buries itself in the uterine wall.At this point in the mother"s expression cycle, the lining of the uterus is thick with blood and ready to support a baby.The blastocyst rod tightly to the wall of the uterus and receives nourishment from the mother"s blood.

You are watching: The gestational age of the embryo is measured from when the sperm and egg unite.

Watch this video clip about:Cell division

Week 5

Week 5 is the begin of the "embryonic period." This is once all the baby"s significant systems and also structures develop.The embryo"s cell multiply and start to take it on particular functions. This is referred to as differentiation.Blood cells, kidney cells, and nerve cells all develop.The embryo grows rapidly, and also the baby"s exterior features start to form.Your baby"s brain, spinal cord, and heart start to develop.Baby"s gastrointestinal tract starts come form.It is during this time in the first trimester the the baby is most at threat for damage from points that may cause birth defects. This includes specific medicines, illegal drug use, hefty alcohol use, epidemic such as rubella, and also other factors.

Weeks 6 come 7

Arm and leg buds start to grow.Your baby"s mind forms into 5 different areas. Some cranial nerves space visible.Eyes and ears begin to form.Tissue grows that will become your baby"s spine and other bones.Baby"s heart continues to grow and also now beats at a constant rhythm. This have the right to be checked out by vaginal ultrasound.Blood pumps v the main vessels.

Week 8

Baby"s arms and legs have actually grown longer.Hands and also feet start to type and look like little paddles.Your baby"s mind continues come grow.The lungs start to form.

Week 9

Nipples and also hair follicles form.Arms grow and also elbows develop.Baby"s toes can be seen.All baby"s essential organs have started to grow.

Week 10

Your baby"s eyelids are an ext developed and begin come close.The external ears begin to take it shape.Baby"s facial attributes become an ext distinct.The intestines rotate.At the end of the 10th main of pregnancy, your baby is no longer an embryo. The is now a fetus, the stage of advance up till birth.

Weeks 11 come 14

Your baby"s eyelids close and will no reopen until around the 28th week.Baby"s challenge is well-formed.Limbs room long and also thin.Nails appear on the fingers and toes.Genitals appear.Baby"s liver is making red blood cells.The head is very huge -- about half of baby"s size.Your small one have the right to now make a fist.Tooth buds show up for the baby teeth.

Weeks 15 come 18

At this stage, baby"s skin is almost transparent.Fine hair called lanugo creates on baby"s head.Muscle tissue and bones store developing, and bones come to be harder.Baby begins to move and also stretch.The liver and pancreas produce secretions.Your small one currently makes suck motions.

Weeks 19 to 21

Your baby deserve to hear.The infant is more active and continues to move and also float around.The mother may feel a fluttering in the reduced abdomen. This is referred to as quickening, when mom deserve to feel baby"s very first movements.By the finish of this time, baby deserve to swallow.

Week 22

Lanugo hair consists baby"s whole body.Meconium, baby"s very first bowel movement, is do in the intestinal tract.Eyebrows and also lashes appear.The infant is an ext active with increased muscle development.The mother have the right to feel the baby moving.Baby"s heartbeat deserve to be heard v a stethoscope.Nails flourish to the finish of baby"s fingers.

Weeks 23 to 25

Bone marrow begins to do blood cells.The lower airways of the baby"s lungs develop.Your baby starts to store fat.

Week 26

Eyebrows and eyelashes room well-formed.All components of baby"s eyes space developed.Your baby might startle in solution to loud noises.Footprints and fingerprints space forming.Air sacs type in baby"s lungs, yet lungs room still not all set to work outside the womb.

Weeks 27 to 30

Baby"s mind grows rapidly.The nervous mechanism is developed enough to control some human body functions.Your baby"s eyelids have the right to open and close.The respiratory system, when immature, produces surfactant. This substance helps the air bag fill with air.

Weeks 31 come 34

Your infant grows quickly and also gains a the majority of fat.Rhythmic breathing occurs, however baby"s lungs space not completely mature.Baby"s skeletal are totally developed, however are quiet soft.Your baby"s body begins storing iron, calcium, and phosphorus.

Weeks 35 to 37

Baby weighs about 5 1/2 pounds (2.5 kilograms).Your infant keeps acquiring weight, but will most likely not obtain much longer.The skin is not as wrinkled as fat creates under the skin.Baby has definite resting patterns.Your little one"s heart and blood vessels are complete.Muscles and also bones are completely developed.

See more: Proponents Of The Notion Of A &Quot;Political Business Cycle&Quot; Suggest That

Week 38 to 40

Lanugo is gone except for top top the top arms and shoulders.Fingernails might extend beyond fingertips.Small breast sprout are existing on both sexes.Head hair is currently coarse and also thicker.In her 40th week of pregnancy, it has been 38 weeks since conception, and also your baby can be born any day now.