4 weeks pregnant

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The second week of your baby’s growth begins at the start of the fourth week of pregnancy, or 22 days after the beginning of your last menstrual bleeding.

If you’ve been trying to get pregnant, you’re probably wondering whether or not you’re pregnant at this stage. Although you should wait until you’re 5 weeks pregnant to take a hCG pregnancy test, you may notice some signs of early pregnancy in week 4 of pregnancy. These may include fatigue due to your increased pregnancy heart rate, sore breasts and mood changes. Your placenta begins functioning and producing the pregnancy hormone human chorionic gonadotropin (hCG) which can be detected with a blood or urine test this week. Find out more about pregnancy symptoms which occur before a woman even knows she’s pregnant. Changes for mum this week

Your baby is still less than a millimetre in length but fetal development is occurring rapidly. This week the final stages of embryo implantation occur and the placenta which will nourish your baby for the rest of your pregnancy forms and begins producing hCG. The amniotic fluid is also formed this week. Find out more about the changes for growing babies in the fourth week of pregnancy.

Changes for baby this week

If you’ve been trying to get pregnant you probably can’t wait to take a pregnancy test. Although you may already be producing the pregnancy hormone hCG, it’s best to wait at least 5 weeks since the start of your last period before taking a pregnancy test. However, it’s never too early to start preparing your body for pregnancy and in week 4 you should be getting your pregnancy diet in shape and starting pregnancy exercise if you haven’t already. It’s too late to get pregnant this cycle if you haven’t already, but you can continue having sex without harming your baby if you are pregnant. Pregnancy health and lifestyle information this week


A quick summary of the changes to mum’s body, the baby to be, medical appointments and lifestyle information for both mum and dad.

Key points this week

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Date Created: June 25, 2012 Date Modified: July 3, 2018