MeSH Browser

MeSH Heading: Pregnancy Trimester, First
Tree Number(s): G08.686.707.408
Unique ID: D011261
RDF Unique Identifier: http://id.nlm.nih.gov/mesh/D011261
Annotation: human only
Scope Note: The beginning third of a human PREGNANCY, from the first day of the last normal menstrual period (MENSTRUATION) through the completion of 14 weeks (98 days) of gestation.
Entry Version: PREGN TRIMESTER FIRST
Entry Term(s): Early Placental Phase; Pregnancy, First Trimester; Trimester, First
Previous Indexing: Gestational Age (1968-1974); Pregnancy (1966-1974); Time Factors (1967-1974)
Public MeSH Note: 76; was PREGNANCY, FIRST TRIMESTER 1975
Online Note: use PREGNANCY TRIMESTER, FIRST to search PREGNANCY, FIRST TRIMESTER 1975
History Note: 76; was PREGNANCY, FIRST TRIMESTER 1975
Date Introduced: 1975/01/01
Last Updated: 2018/07/01

Allowable Qualifiers: blood (BL)

cerebrospinal fluid (CF)

drug effects (DE)

ethnology (EH)

genetics (GE)

immunology (IM)

metabolism (ME)

physiology (PH)

psychology (PX)

radiation effects (RE)

urine (UR)

Concept UI: M0017488
Scope Note: The beginning third of a human PREGNANCY, from the first day of the last normal menstrual period (MENSTRUATION) through the completion of 14 weeks (98 days) of gestation.
Terms: Pregnancy Trimester, First Preferred Term
Term UI T033182
Date01/01/1999
LexicalTag NON
ThesaurusID NLM (1975); Pregnancy, First Trimester
Term UI T033181
Date07/25/1975
LexicalTag NON
ThesaurusID NLM (1976); Trimester, First
Term UI T033183
Date07/25/1975
LexicalTag NON
ThesaurusID UNK (19XX); Early Placental Phase
Term UI T033180
Date05/01/1989
LexicalTag NON
ThesaurusID NLM (1990)

Pregnancy Trimester, First MeSH Descriptor Data 2026