From scans and check ups to morning sickness and backache - there's a whole lot of things to think about when you get to 15 weeks of pregnancy.
Here's a round up of everything you need to know...
4 weeks pregnant: SymptomsYou knew about the morning sickness, the backache, even the heartburn, but a blocked nose? Feeling stuffed up may be one of the lesser known side-effects of pregnancy, but nearly a third of pregnant women experience a blocked up nose during pregnancy. Known as pregnancy rhinitis, it is caused by a rise in oestrogen and an increased blood flow. Nosebleeds are another nuisance which are caused as your increased blood flow put pressure on the vessels in your nose, causing them to break. To stem the flow of a nose bleed stay sitting and firmly pinch the soft part of your nose just above your nostrils for about 10 minutes. Both symptoms often start early in the second trimester and can continue throughout the rest of your pregnancy. Try setting up a humidifier in the bedroom as this can help with a blocked up-nose.
4 weeks pregnant: Fetal development
Your baby is around 10.1 cm long and weighs around 70 grams (the weight of a large egg). Your baby's body is now growing at a faster rate and they're starting to look more in proportion. Hair and eyebrows are also beginning to grow and your baby may even be able to suck its thumb.
A baby's sweet tooth starts in the womb. The things you eat and drink flavour your amniotic fluid and stimulate your baby's tiny taste buds. Studies have shown that a foetus's swallowing increases when surrounded by sweet tastes and decreases with bitter and sour tastes. Unborn babies have even been seen to express their displeasure with a frown!
4 weeks pregnant: The changes you should makeYou may have the Quadruple Test this week. This is a blood test used to screen for Down's Syndrome and Spina Bifida.
If you have chosen to be screened for abnormalities and a diagnostic test has been recommended then this is the earliest point at which an amniocentesis could be carried out. An Amniocentesis is not a routine antenatal test. You will only be offered an amniocentesis if you are identified as having a high risk of carrying a baby with fetal abnormalities such as Downs Syndrome.
Unlike antenatal screening tests, an amniocentesis is an invasive test. A fine needle is passed through your abdomen and guided via ultrasound into your uterus in order to collect a small sample of amniotic fluid. The fluid sample contains cells from the baby which can be grown in culture in a laboratory and used to look at the baby's chromosomes.
There are two main tests that can be done to look at the baby's chromosomes. The first is called a rapid test. It can look for the chromosome disorders Down's syndrome, Edward's syndrome and Patau's syndrome. Results from this usually take three days. The second test is called a full karyotype which looks at all the baby's chromosomes. This process can take up to three weeks.
There are some risks though. Approximately one out of every 150 women who has an amniocentesis will have a miscarriage.
If you're anxious about giving birth or would just like to learn relaxation and breathing techniques to reduce fear and increase confidence in labour then you may want to consider hypnobirthing, a technique widely reported to have been used by the Duchess of Cambridge during the birth of Prince George.