An interesting development this week is that, Till the 13th week, Inside the uterus, it was the yolk sac which was producing the red blood cells and white blood cells for the fetus, from the 13th week onwards the yolk sac ceases to exit and the liver of the fetus takes over the function of producing RBC and WBC for the fetus. Please see above at the picture. You will notice the yolk sac surrounds the embryo. 

What will a pregnant lady in her fourth-month feel?

Some pregnant women hardly gain any weight during the first three months because of nausea and vomiting. But after 3 months they tend to develop a good appetite and may begin to gain weight. So, if you are one of them, who have not gained much weight because of nausea and vomiting in the first three months, don't worry, you may start gaining weight henceforth. But, make sure you are eating healthy and nutritious food.

Tests to be done this month

Doctor visits will be focused on making sure your baby is growing normally and that you are healthy. Your doctor will take several measurements, listen for baby’s heart, and perhaps do an ultrasound. If you are at risk for birth defects, your doctor may want you to have an amniocentesis test. Read more about amniocentesis here-

Warning Signs this month

Any fever more than 101 degrees Fahrenheit is a cause for concern. It could be due to an underlying infection. Please see your doctor immediately.