In our pregnancy week by week direct, you can discover out what to anticipate when you’re 4 week pregnant.
At 4 weeks into your pregnancy journey
The fertilized egg embarks on its journey through the fallopian tube towards the uterus, where it will eventually implant itself into the endometrium. This implantation process typically spans from 3 to 10 days.
During this time, you may experience what's known as implantation bleeding, which is characterized by light spotting, usually pinkish-brown in hue. This bleeding might occur intermittently over a couple of days and is generally not accompanied by blood clots. If you have concerns, it's advisable to consult your GP.
Some women may also notice mild cramping around the time of implantation.
At this early stage, you may not yet detect significant changes in your body, but as the week progresses, the absence of your period might prompt thoughts about pregnancy.
Regarding the development of the embryo at four weeks
- The ectoderm, which will give rise to the nervous system, brain, hair, and skin.
- The endoderm, responsible for developing the gut and various internal organs.
- The mesoderm, which will eventually transform into the skeleton, blood systems, and muscles.
The outer portion of the blastocyst divides into two parts:
- Chorionic villi, tiny projections that extend into the endometrium, ultimately evolving into the placenta.
- The inner part, which forms the amniotic sac.
In terms of multiple pregnancies, identical twins occur when a single sperm fertilizes an egg, leading to the division of the fertilized egg into two embryos. These twins share identical genetic makeup and are typically of the same sex.