Note for use of this pregnancy calendar: A pregnancy usually lasts 38 weeks from conception, or 40 weeks from the start of your last menstrual period (LMP). If you are counting from the date of conception, just add two weeks to use this calendar. For example, if you conceived two weeks ago, you are in week 4 by the usual method.
The length of the developing baby is measured from the crown of the head to the bottom of the baby's rump, this is referred to as the CRL measurement
the sperm and the egg both contribute 23 chromosomes for a total of 46
immediately after fertilization the egg begins to divide, from 1 cell to 2, 2 to 4, 4 to 8, and so on
around 4 days after fertilization the developing baby enters the uterus from the fallopian tube
implantation of the rapidly developing cells into the uterine lining usually occurs about 6 days after conception
hCG (human chorionic gonadotropin) is produced by the embryo and it is this hormone that is detected by home pregnancy tests 2 weeks or so after conception
there are generally few or no signs of pregnancy during this week, although there may be some bleeding or spotting after implantation occurs
the cells are still dividing, but they are also moving and changing to create the amniotic sac, the yolk sac, the beginnings of the umbilical cord, and of course, the baby itself
depending on the sensitivity of the pregnancy test, you may get a positive result on or after 11 days post-conception
while the baby is still just a tiny speck, your hormones are already changing to sustain your pregnancy
some women experience breast tenderness, water retention, or constipation even at this early stage
Week 5
no menstrual period this week - time for a home pregnancy test!
now your baby is 1.5mm long (or 6/100ths of an inch)
the baby's brain and spinal cord just begin to form
it's especially important to avoid alcohol during the first formative months of your pregnancy, this is the time when all the organs are being formed and when alcohol and drugs have the greatest effect on your baby
Sources for fetal development information include: The Developing Human by Moore and Persaud, how life begins by Christopher Vaughan, and Your Pregnancy Week-by-Week by Glade B. Curtis
This internet site provides information of a general nature and is designed for educational purposes only. If you have any concerns about your health or that of your child, you should always consult with a physician or other healthcare professional.