There are a few sentences which are awfully similar to an article on the PBGS website. Are you sure you only used textbooks as your references?

For example:

You wrote: Thus, supplementary iron therapy is needed for all pregnant mothers from 16 weeks onwards.

This is taken from the PBGS website:

Supplementary nutritional therapy with iron is needed for all pregnant women from 16 to 20 weeks onwards.

That was not a 100% similar but as you didn't quote the original source, it can be considered as an act of plagiarism. You also wrote: The patient should wear loose but comfortable garments. High heel shoes should better be avoided in advanced pregnancy when the center of balance alters.

This is taken from the PBGS website:

You should wear loose but comfortable garments. High heel shoes should better be avoided in advanced pregnancy when the center of balance alters.

In this case, the sentences were not quoted, so it is a plagiarised sentence. You should know the importance of not simply copy-pasting from the original source. Give some credit to the original author and consider writing a point in your own word. If you really need to copy-paste some sentences, make it as a quoted text and put the source's link.