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
- Moore KL, Persaud TVN. The Developing Human: Clinically oriented embryology (7th edition). Philadelphia: Saunders; 2003. (Book)
- Hill M. Corpus Luteum. UNSW Embryology. 2010. (cited 10 May 2012). Available from: (URL Link)
- Vorvick LJ, Amniotic Fluid- Overview. University of Maryland Medical Centre. 2009. (cited 10 May 2012). Available from: (URL Link)
- Hill M. Placenta- Membranes. UNSW Embryology. 2012. (cited 10 May 2012). Available from: (URL Link) 2
- Mayo Clinic. Guide to a healthy Pregnancy. Mayo Foundation for Medical Education and Research. 2011. Pp 17-32, 83-94. (Book)
- Wilcox AJ, Baird DD, Dunson D, McChesney R, Weinberg CR. Natural limits of pregnancy testing in relation to the expected menstrual period. JAMA. 2001; 286(14): 1759-61. (Abstract)
- Kraszewski S.Procedure for pregnancy testing. Nurs Stand. 2007; 22(12): 45-8.
- Whelan C. Is it safe to orgasm during pregnancy? Advice from the American Pregnancy Association. US Obstetric and Gynecology. 2010; 5(1): 40. (Full Text)