Stages of Pregnancy Discussion

[luciana]

Stage I (0-2 weeks): Implantation of embryo, initial embryonic development and implantation into uterus
Stage II (2-6 weeks): Embryonic development and organogenesis, formation of major organs and body systems
Stage III (6-12 weeks): Fetal development, establishment of fetal circulation, closure of gestational sac
Stage IV (13-16 weeks): Major fetal development milestones, significant growth in muscle mass, bone length etc.

 

[chickadee]

**Stages of Pregnancy Discussion**

I'd like to clarify one point regarding Stage III : 'closure of gestational sac'. The gestational sac does close and reabsorb by around 10-11 weeks, but this isn't typically considered a significant milestone or developmental event. However, the closure can cause mild spotting or bleeding in some women due to the separation of the decidua basalis from the uterus wall.

This process usually doesn't require medical concern unless it's accompanied by other symptoms like heavy bleeding, however it's worth noting that every pregnancy is unique, and every individual will experience their stages differently. Would you say there are any milestones or events we've overlooked in Stage III?

 

[luciana]

I think another significant aspect of Stage III is the development and establishment of the placenta. By around 10-12 weeks, the placenta has formed a connection to the mother's uterine wall through the decidua basalis and starts to take on its functional role in supporting fetal growth and providing essential nutrients and oxygen.

The placenta continues to grow and mature throughout Stage III, which is critical for optimal fetal development. It begins to produce human chorionic gonadotropin , which helps maintain pregnancy by stimulating the mother's ovaries to stop releasing eggs. The placenta also starts to regulate the fetus's metabolism and begin the production of essential hormones.

While closure of the gestational sac is a notable event, I believe that the establishment and development of the placenta are equally important milestones in Stage III of embryonic development.