The development of your baby in the womb is a wonderful process. We have compiled a month-by-month timescale of pregnancy. But keep in mind that different pregnancies do develop at different rates. Also, bear in mind that the method doctors and midwives use to date your pregnancy means that you could be around 2 weeks out from this timescale (see below).
In this description, we have adopted the method that doctors use. For example, where we write ‘week 8’ we have counted this from the first day of your last period — your baby will usually only be 6 weeks old at this point.
How doctors date your pregnancy
The average pregnancy lasts for 38 weeks from the date you conceive (this is called conception). However, doctors usually date your pregnancy from the first day of your last menstrual period — that is the day your last period started. Using this method a pregnancy is said to last 40 weeks (280 days).
Your due date is usually calculated as 40 weeks from the first day of your last period. However, fertilisation of your egg by sperm happens a day or 2 after ovulation, which occurs in the middle of a 28-day cycle, and then it is a couple of days before the fertilised egg implants in the uterus, so for the first 2 weeks of the 40-week ‘pregnancy’ you are not actually pregnant at all.