International Journal of
Nursing and Midwifery

  • Abbreviation: Int. J. Nurs. Midwifery
  • Language: English
  • ISSN: 2141-2456
  • DOI: 10.5897/IJNM
  • Start Year: 2009
  • Published Articles: 193

Full Length Research Paper

Agreement between estimated date of delivery determined by last menstrual period and ultrasound: A prospective cohort of Tanzanian women

Pernille N. Nielsen
  • Pernille N. Nielsen
  • University of Southern Denmark, Odense, Denmark.
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Chunsen Wu
  • Chunsen Wu
  • University of Southern Denmark, Odense, Denmark.
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Jane J. Rogathi
  • Jane J. Rogathi
  • Kilimanjaro Christian Medical University College, Moshi, Tanzania.
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Geofrey N. Sigalla
  • Geofrey N. Sigalla
  • Kilimanjaro Christian Medical University College, Moshi, Tanzania.
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Lene Sperling
  • Lene Sperling
  • Odense University Hospital, Odense, Denmark.
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Rachel Manongi
  • Rachel Manongi
  • Kilimanjaro Christian Medical University College, Moshi, Tanzania.
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Dan W. Meyrowitsch
  • Dan W. Meyrowitsch
  • University of Copenhagen, Copenhagen, Denmark.
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Tine Gammeltoft, Mag Art
  • Tine Gammeltoft, Mag Art
  • University of Copenhagen, Copenhagen, Denmark.
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Vibeke Rasch
  • Vibeke Rasch
  • University of Southern Denmark, Odense, Denmark. 2Odense University Hospital, Odense, Denmark.
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  •  Received: 07 January 2021
  •  Accepted: 03 August 2021
  •  Published: 31 August 2021

Abstract

In Tanzania, the estimated delivery date (EDD) is mainly determined by the last menstrual period (LMP), presumably leading to inaccurate estimates with a falsely high proportion of post-term and preterm deliveries. The study aimed to compare EDD determination by LMP and ultrasound in pregnant Tanzanian women and examine how the dating method affects the proportions born preterm, at term, and post-term and assess how maternal characteristics relate to wrongly EDD determination by LMP. 1123 women attending antenatal care in Moshi, Tanzania were included. Gestational age (GA) at birth was calculated according to LMP and ultrasound separately. The distribution of preterm (GA<259 days), term (GA 259-294 days), and post-term (GA >294 days) births was examined separately for LMP and ultrasound. According to LMP, 17.0% of deliveries were preterm and 17.6% post-term. According to ultrasound, 7.7% of deliveries were preterm and 3.4% post-term. Unplanned pregnancy was associated with an increased odds ratio of 3.06 (95% CI: 1.91-4.91) for preterm delivery when LMP was used for EDD determination instead of ultrasound. Parity 3+ was associated with an increased odds ratio of 2.12 (95%CI: 1.16-3.89) for post-term delivery when EDD was assessed by LMP.  LMP based EDD increased the preterm birth rate two times and the post-term birth rate five times compared to ultrasound-based EDD. 

Key words: Gestational age, pregnancy length, last menstrual period (LMP), dating methods, preterm, post term, Africa.