Saliva, hair, tears, and other biological materials obtained non-invasively for diagnosis in pregnancy: a literature review.

As medical technology evolves, clinicians are increasingly choosing relatively painless non-invasive methods of patientdiagnosis and treatment. There are two principles behind this: greater patient comfort and lower cost. Tears, hair, saliva,urine, and faeces can replace blood for diagnosis. The varied constituents in these biological materials can serve as biomarkersfor the detection of both local and systemic diseases. In this paper, we review a range of diagnostic techniques - allusing biological material obtained via non-invasive procedure - for detecting medical conditions in pregnant women.PubMed, Medline, Embase, and the Cochrane Library were searched from January 1996 until December 2018. Forty sevenstudies were included: thirty-five original articles, nine reviews and three meta-analysis.Analysis showed that saliva, hair, tears, and other biological material - obtained via non-invasive methods - may serveas clinically informative biomarkers. These biomarkers may be used for: toxicology, psychological studies, disease detection,biomonitoring, and drug abuse. The analysis of tears, hair, saliva, urine, and faeces is a safe, noninvasive and usefuldiagnostic tool within groups of pregnant women, but further investigation is necessary to fully realize the promise ofthese novel diagnostic tools.