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Week 6
The baby is now known as an embryo. It is around 3 mm in length. By this stage, it is secreting special hormones that prevent the mother from having a menstrual period. -
Week 1
The first week is actually your period because the due date isn't calculated until the last day of your period. -
Week 2
Fertilization of your egg by the sperm will take place near the end of this week. -
Week 3
The cell (zygote) has divided into 16 cells. After two more days, the zygote has migrated from the fallopian tube to the uterus (womb). Seven days after conception, the zygote burrows itself into the plump uterine lining (endometrium). The zygote is now known as a blastocyst. -
Week 4
The developing baby is tinier than a grain of rice. The rapidly dividing cells are in the process of forming the various body systems, including the digestive system. -
Week 1
This first week is actually your menstrual period. Because your expected birth date (EDD or EDB) is calculated from the first day of your last period, this week counts as part of your 40-week pregnancy, even though your baby hasn’t been conceived yet. -
Week 2
Fertilization of your egg by the sperm will take place near the end of this week. -
Week 3
The cell (zygote) has divided into 16 cells. After two more days, the zygote has migrated from the fallopian tube to the uterus (womb). Seven days after conception, the zygote burrows itself into the plump uterine lining (endometrium). The zygote is now known as a blastocyst. -
Week 4
The developing baby is tinier than a grain of rice. The rapidly dividing cells are in the process of forming the various body systems, including the digestive system. -
Week 5
The evolving neural tube will eventually become the central nervous system (brain and spinal cord). -
Week 7
The heart is beating. The embryo has developed its placenta and amniotic sac. The placenta is burrowing into the uterine wall to access oxygen and nutrients from the mother’s bloodstream. -
Week 8
The embryo is now around 1.3 cm in length. The rapidly growing spinal cord looks like a tail. The head is disproportionately large. -
Week 9
The eyes, mouth and tongue are forming. The tiny muscles allow the embryo to start moving about. Blood cells are being made by the embryo’s liver. -
Week 10
The embryo is now known as a fetus and is about 2.5 cm in length. All of the bodily organs are formed. The hands and feet, which previously looked like nubs or paddles, are now evolving fingers and toes. The brain is active and has brain waves. -
Week 11
Teeth are budding inside the gums. The tiny heart is developing further. -
Week 12
The fingers and toes are recognizable but still stuck together with webs of skin. The first trimester combined screening test can be done around this time. This test checks for trisomy 18 and trisomy 21. -
Week 13
The fetus can swim about quite vigorously. It is now more than 7 cm in length. -
Week 16
The fetus is around 14 cm in length. Eyelashes and eyebrows have appeared, and the tongue has tastebuds. The second-trimester maternal serum screening will be offered at this time if the first-trimester test was not done (see week 12). -
Week 18-20
An ultrasound will be offered. This fetal morphology scan is to check for structural abnormalities, the position of the placenta, and multiple pregnancies. Interestingly, hiccoughs in the fetus can often be observed. -
Week 24
The fetus is around 33 cm in length. The fused eyelids now separate into upper and lower lids, enabling the baby to open and shut its eyes. The skin is covered in fine hair (lanugo) and protected by a layer of waxy secretion (vernix). The baby makes breathing movements with its lungs. -
Week 28
Your baby now weighs about 1 kg (1,000 g) or 2 lb 2oz (two pounds, two ounces) and measures about 25 cm (10 inches) from crown to rump. The crown-to-toe length is around 37 cm. The growing body has caught up with the large head and the baby now seems more in proportion. -
Week 32
The baby spends most of its time asleep. Its movements are strong and coordinated. It has probably assumed the ‘head down’ position by now, in preparation for birth. -
Week 36
The baby is around 46 cm in length. It has probably nestled its head into its mother’s pelvis, ready for birth. If it is born now, its chances for survival are excellent. The development of the lungs is rapid over the next few weeks. -
Week 40
The baby is around 51 cm in length and ready to be born. It is unknown exactly what causes the onset of labor. It is most likely a combination of physical, hormonal, and emotional factors between the mother and baby.