May 26, 2020
Getting the news that you are pregnant can be thrilling, shocking or both.
The Pregnancy Timeline was developed as a week by week guide to pregnancy which takes in how the baby develops and changes to the mother’s body.
| WEEKS | CHANGES |
| 1 – 4 | Fertilization occurs and a ball of quickly multiplying cells embeds itself in the lining of the uterus. |
| 5 | The mass of cells is developing fast and becomes an embryo. For many women the first sign of pregnancy is a missed period. |
| 6 | The embryo officially becomes a fetus. It is about the size of a baked bean and its spine and nervous system begin to form. |
| 7 | The baby’s heart is beginning to develop. Morning sickness and other side effects of early pregnancy may occur. |
| 8 | It is quite common to have a first scan at this stage if the woman has had a previous miscarriage or bleeding. |
| 9 | The fetus is about 5 cm long with its head tucked onto its chest. It has most of its major organs and eyes and ears are developing. |
| 10 | A scan at 10-13 weeks is recommended to determine and confirm the date of the pregnancy. |
| 11 | The umbilical cord is fully formed providing nourishment and removing waste products. The fetus looks fully human now. |
| 12 | By this week the threat of miscarriage is much reduced. Many women announce their pregnancy to friends and colleagues. |
| 13 | The woman’s uterus is becoming larger and is starting to rise out of the pelvis. The fetus can move its head quite easily. |
| 14 | Third of the way through. The average pregnancy lasts 266 days or 280 days from the first day of last period. |
| 15 | Screening for Downs syndrome is offered about now. A simple blood test is carried out first, then further tests may be offered. |
| 16 | The fetus now has toes and fingers, nails, eyebrows and eyelashes. It is also covered with downy hair. |
| 17 | The fetus can hear noises from the outside world. By this stage the mother is visibly pregnant and the uterus is rising. |
| 18 | By this stage the fetus is about 11 cm long and is moving around a lot probably enough to be felt. |
| 19 | By the end of this week the fetus is 20 cm long and weighs about 300g. Milk teeth have formed in the gums. |
| 20 | Half way through pregnancy, now all mothers are offered a scan. The fetus develops a waxy coating called vernix. |
| 21 | The mother may feel short of breath as her uterus pushes against her diaphragm leaving less space for the lungs. |
| 22 | Senses develop taste buds have started to form on the tongue and the fetus starts to feel touch. |
| 23 | The skeleton continues to develop and bones that form the skull begin to harden but not fully. |
| 24 | Antenatal checkup and scan to check the baby’s position. A baby born this early does sometimes survive. |
| 25 | All organs are now in place and the rest of the pregnancy is for growth. Preeclampsia is a risk from here onwards. |
| 26 | The fetus skin is gradually becoming more opaque than transparent. |
| 27 | The fetus measures about 34cm and weighs about 800g. |
| 28 | Routine checkup to test for preeclampsia. Women with Rhesus negative blood will also be tested for antibodies. |
| 29 | Some women develop restless leg syndrome in their third trimester. |
| 30 | Braxton Hicks contractions may begin around now. They are practice contractions which don’t usually hurt. |
| 31 | The fetus can see now and can tell light from dark. |
| 32 | Another antenatal appointment. The fetus is about 42 cm and weighs 2.2 kg. A baby born now has a good chance of survival. |
| 33 | From now the baby should become settled in a head downwards position. |
| 34 | The mother may find it more difficult to eat full meals as the expanded uterus presses on her stomach. |
| 35 | If the mother has been told she may need a planned caesarean, now is a good time to discuss it further. |
| 36 | The baby’s head may engage in the pelvis any time now. |
| 37 | The baby’s lungs are practically mature now and it can survive unaided. The final weeks in the womb are to put on weight. |
| 38 | Babies born from this week onward are not considered early. |
| 39 | Another antenatal appointment. The mother has reached her full size and weight by now. |
| 40 | In theory the baby should be born this week. The mother’s cervix prepares for the birth by softening. |
| 41 | First babies are often up to a week late but if there are signs of distress to mother or child the birth will be induced. |
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