There is an expanding body of evidence for the correlation between maternal glucose intolerance (gestational diabetes) and an increased risk of offspring developing schizophrenia.
Van Lieshout and Voruganti (2008) concluded that the offspring of mothers who experienced diabetes are 7x more likely to develop schizophrenia compared with offspring whose mothers experienced glucose tolerance (no prolonged spikes in blood sugar) during pregnancy. The authors contributed three associations of diabetes with enabling the development of schizophrenia: hypoxia, oxidative stress, and increased inflammation of the brain in the womb.
A study by Wegelius et al. (2011) sampled 1051 offspring from 315 Finish families. They found that the offspring of diabetic mothers had a 2-fold increased susceptibility to developing schizophrenia.
Also, a study by Kandhal and Miller (2013) reviewed variables significant to schizophrenia and found several common risk factors such as gestational diabetes and high birth weights.
Kandhal, P. & Miller, B. J. (2013). Shared early life risk factors for schizophrenia and diabetes. Minerva Psichiatrica, 54, 3, 197-210.
Van Lieshout, R. J. & Voruganti, L. P. (2008). Diabetes mellitus during pregnancy and increased risk of schizophrenia in offspring: A review of the evidence and putative mechanisms. Journal of Psychiatry and Neuroscience, 33, 5.
Wegelius, A., Tuulio-Henriksson, A., Pankakoski, M., Haukka, J., Lehto, U., Paunio, T., Lönnqvist, J., & Suvisaari, J. (2011). An association between high birth weight and schizophrenia in a Finnish schizophrenia family study sample. Psychiatry Research, 190, 2/3, 181-186.
My grandmother is not alive to tell me whether or not she had diabetes in pregnancy, was overweight, or how big my father was at birth. I do know that growing up she was always attempting to lose weight and control sugar cravings. (Which makes me think she could have had uncontrolled blood sugar while pregnant… also her pregnancy was in 1951-1952).
As a nurse, I know that LGA babies are at risk for increased birth trauma, low blood sugar, jaundice, and too thick blood (not able to pump well) w/ too little oxygen going to tissues. In addition to these factors, babies of diabetic mothers are at risk for too little calcium (affects muscles/ heart rate), respiratory distress syndrome (lungs don’t mature enough), and congenital birth defects.
I also know that my mother had diabetes when she was pregnant with me. I was 10 lbs and 2 oz at birth. I was considered large for gestation (LGA). As a young child into my teenage years, I was very overweight. I also had asthma and was a pretty sickly kid. I slimmed down after becoming physically active and eating with nutrition in mind. (I’m also pretty concerned with developing schizophrenia like my father). Now, I am hyper-focused on living a healthy lifestyle. However, even with being much slimmer, my A1c is still on the higher side. (A1c is the long-term marker for how well your body controls blood sugar). -and so are my triglycerides. This makes me a bit concerned for developing gestational diabetes while pregnant, and along with my genetic factors giving my offspring a higher risk for SZ.