1. That is a misfortune and not a problem. In olden times, there were many rites of passage to be conducted before and during pregnancy (
Sanskara (rite of passage) - Wikipedia). Most people do just one or two now. These days we observe just one 'Samskara" (that is the correct spelling) and it is known as 'Godh Bharanā' (filling the lap). This is equivalent to what is mentioned in Wikipedia as 'Sīmāntonnayana'. The other rite is 'Jātakarma', after the birth of child. The later rites are performed even now.
2. and 3. Already answered, Bhagya, Ishwar Ichcha and Karmas of the previous lives.
4. A person has harmed some one in a previous life. The child is the harmed person who is allowed to take revenge. In one of the cases (as mentioned in stories by my grandfather) the person had cheated another of Rupees 20,000. A child was born and when the expenses for the child totalled Rupees 20,000, the child died. Moral of the story: Don't cheat anyone. You may have to repay it in a future life. Of course, as an atheist Hindu, I do not believe in the story.
5. In India, there are many children (or used to be). One miscarriage was not considered a calamity. People took it in their stride. As I said in my first post - get on with it. My sister lost her first born in six months (Sudden Infant Death Syndrome, SIDS). She mothered two children later. My grandmother lost her first daughter in infanthood then mothered my uncle and father.
6. Medicines if required or family support. Perhaps some rituals also in case of those who believe in them.
7. Health, psychological support.
8. They don't fear anything. It is a mishap which affected people have to take in their stride.
Are you disappointed that Hindus do not take recourse to Voudoo?