title: A home calendar and recall method of last menstrual period for estimating gestational age in rural Bangladesh: a validation study.
abstract: The best method of gestational age assessment is by ultrasound in the first trimester; however, this method is impractical in large field trials in rural areas. Our objective was to assess the validity of gestational age estimated from prospectively collected date of last menstrual period (LMP) using crown-rump length (CRL) measured in early pregnancy by ultrasound.
  
  
  
  As part of a large, cluster-randomized, controlled trial in rural Bangladesh, we collected dates of LMP by recall and as marked on a calendar every 5 weeks in women likely to become pregnant. Among those with a urine-test confirmed pregnancy, a subset with gestational age of <15 weeks (n = 353) were enrolled for ultrasound follow-up to measure CRL. We compared interview-assessed LMP with CRL gestational age estimates and classification of preterm, term, and post-term births.
  
  
  
  LMP-based gestational age was higher than CRL by a mean (SD) of 2.8 (10.7) days; differences varied by maternal education and preterm birth (P < 0.05). Lin's concordance correlation coefficient was good at ultrasound [0.63 (95 % CI 0.56, 0.69)] and at birth [0.77 (95 % CI 0.73, 0.81)]. Validity of classifying preterm birth was high but post-term was lower, with specificity of 96 and 89 % and sensitivity of 86 and 67 %, respectively. Results were similar by parity.
  
  
  
  Prospectively collected LMP provided a valid estimate of gestational age and preterm birth in a rural, low-income setting and may be a suitable alternative to ultrasound in programmatic settings and large field trials.
  
  
  
  ClinicalTrials.gov NCT00860470.
authors: Department of Nutritional Sciences, The Pennsylvania State University, 110 Chandlee Laboratory, University Park, PA, 16802, USA. adg14@psu.edu.|Department of International Health, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD, 21205, USA. adg14@psu.edu.
authors: Alison D
authors: AD
authors: Gernand
authors: The JiVitA Maternal and Child Health and Nutrition Research Project, Godown Road, Gaibandha, Bangladesh.
authors: Rina Rani
authors: RR
authors: Paul
authors: The JiVitA Maternal and Child Health and Nutrition Research Project, Godown Road, Gaibandha, Bangladesh.
authors: Barkat
authors: B
authors: Ullah
authors: Centre for Nuclear Medicine & Ultrasound, Rangpur Medical College Hospital Campus, G.P.O. Box No. 16, Rangpur, Bangladesh.
authors: Muhammad A
authors: MA
authors: Taher
authors: Division of Maternal-Fetal Medicine, The Johns Hopkins Hospital, 1800 Orleans St, Baltimore, MD, 21287, USA.
authors: Frank R
authors: FR
authors: Witter
authors: Department of International Health, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD, 21205, USA.
authors: Lee
authors: L
authors: Wu
authors: Department of International Health, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD, 21205, USA.
authors: Alain B
authors: AB
authors: Labrique
authors: Department of International Health, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD, 21205, USA.
authors: Keith P
authors: KP
authors: West
authors: Department of International Health, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD, 21205, USA.
authors: Parul
authors: P
authors: Christian
mesh_terms: D000293:Adolescent; D000328:Adult; D001459:Bangladesh; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D008598:Menstruation; D011939:Mental Recall; D011203:Poverty; D011247:Pregnancy; D011258:Pregnancy Tests; D011295:Prenatal Care; D012424:Rural Population; D013995:Time; D016216:Ultrasonography, Prenatal; D055815:Young Adult
keywords: Bangladesh; Crown-rump length; Gestational age; Last menstrual period; Ultrasound; Validation