It must be very challenging for you to live under the fear that one day you may develop schizophrenia.
When explaining the causes and contributing factors of schizophrenia to patients, I would normally emphasize the following:
1. Stressful life events. These can be occupational stress, enlistment for military service, examination stress and relationship problems. Childbirth can be stressful for some individuals but you can certainly learn to better cope with it by planning for your pregnancy, enlisting your partner's support and be prepared for the challenges ahead.
2. Genetic factors. Yes, there is higher risk of developing schizophrenia if one's parent has schizophrenia. The risk is about 10% as compared with 1% for the general population. It is not 100% as the causation of schizophrenia is likely to be due to multiple factors.
3. A person's personality. Of importance will be whether that person has friends and is able to cope with challenging situations well.
In terms of age of onset, for males, schizophrenia usually starts in the early 20s. For females, it usually starts in the late 20s. As you are 37 and do not manifest any signs of the condition, the chances of you developing it will be considered relatively low.
It looks like you have concerns about childbirth. Are you worried about having a painful labour? It will be good to discuss this with your obstetrician. I hope your pregnancy is a planned one. Is your spouse supportive of the pregnancy?
Also, it is important to make arrangements regarding child care and make sure that you have sufficient sleep and rest. Becoming a parent is an important decision and oftentimes it creates many joyful moments. Cheers!