Writing an abstract, and language and grammar – day 2: structuring an abstract

Writing an abstract, and language and grammar – day 2: structuring an abstract

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The advice below applies to writing an abstract for a research article rather than an abstract presentation at a conference. The Journal has approached this part of writing a research paper last as normally it would be best to write the abstract after you have written all of the other sections of the paper. Indeed, as a short summary of the paper it will be difficult to write the abstract until you have written the rest of the paper.

Typically an abstract should cover and mirror the main sections of your research paper, so normally:

  • Introduction
  • Methods
  • Results
  • Discussion/conclusion

Some journals may require that you write a structured abstract with certain sections, which are in any case unlikely to be that dissimilar from those above. You may choose yourself to write it as a structured abstract with the above headings, but even if you don’t do that, following this structure through your abstract will make it easier to write.

Most journals will give you a word limit of around 300 words which means being succinct in your approach to writing is key. We will write more about being succinct in other journal entries in the future.


The two tenses normally used in an abstract are either the present simple or present perfect.

The present simple

We show in this study that…

The results of this study indicate that…

The present perfect

We have shown in this study that…            

Our new method has been developed to…

 Passive or active voice

Please refer to week 1 where we covered writing in the passive or active voice. Generally it is easier to write in the active voice, i.e. ‘we did this’. But you should be consistent throughout your paper and follow the precedent for your area. If you have a choice the advice of this journal is that it is easier to write in active form. It is also easier to keep the sentences shorter and with only 300 words in an abstract, brevity is key.

Other tips for writing a clear and concise abstract

Avoid long sentences – try to use shorter sentences and single words instead of longer expresions, e.g. use ‘therefore’ instead of ‘therefore, it is considered that’.

Avoid jargon and unknown abbreviations – even though abbreviations are shorter, it is important that people can easily understand the abstract.

Avoid repetition and words that aren’t needed – replace nouns with pronouns, e.g. he, she, they, her, it, them; and delete words that aren’t necessary.

Avoid too many details – background information and other details about your study can go in other parts of your study.

Abstract extract

Read the example below as an example of a useful structure to an article with concise text.

Cancer in children born after frozen-thawed embryo transfer: A cohort study



The aim was to investigate whether children born after assisted reproduction technology (ART), particularly after frozen-thawed embryo transfer (FET), are at higher risk of childhood cancer than children born after fresh embryo transfer and spontaneous conception.

Methods and findings

We performed a registry-based cohort study using data from the 4 Nordic countries: Denmark, Finland, Norway, and Sweden. The study included 7,944,248 children, out of whom 171,774 children were born after use of ART (2.2%) and 7,772,474 children were born after spontaneous conception, representing all children born between the years 1994 to 2014 in Denmark, 1990 to 2014 in Finland, 1984 to 2015 in Norway, and 1985 to 2015 in Sweden. Rates for any cancer and specific cancer groups in children born after each conception method were determined by cross-linking national ART registry data with national cancer and health data registries and population registries. We used Cox proportional hazards models to estimate the risk of any cancer, with age as the time scale.

After a mean follow-up of 9.9 and 12.5 years, the incidence rate (IR) of cancer before age 18 years was 19.3/100,000 person-years for children born after ART (329 cases) and 16.7/100,000 person-years for children born after spontaneous conception (16,184 cases). Adjusted hazard ratio (aHR) was 1.08, 95% confidence interval (CI) 0.96 to 1.21, p = 0.18. Adjustment was performed for sex, plurality, year of birth, country of birth, maternal age at birth, and parity. Children born after FET had a higher risk of cancer (48 cases; IR 30.1/100,000 person-years) compared to both fresh embryo transfer (IR 18.8/100,000 person-years), aHR 1.59, 95% CI 1.15 to 2.20, p = 0.005, and spontaneous conception, aHR 1.65, 95% CI 1.24 to 2.19, p = 0.001. Adjustment either for macrosomia, birth weight, or major birth defects attenuated the association marginally. Higher risks of epithelial tumors and melanoma after any assisted reproductive method and of leukemia after FET were observed.

The main limitation of this study is the small number of children with cancer in the FET group.


Children born after FET had a higher risk of childhood cancer than children born after fresh embryo transfer and spontaneous conception. The results should be interpreted cautiously based on the small number of children with cancer, but the findings raise concerns considering the increasing use of FET, in particular freeze-all strategies without clear medical indications.

This extract is taken from: Sargisian N, Lannering B, Petzold M, Opdahl S, Gissler M, et al. (2022) Cancer in children born after frozen-thawed embryo transfer: A cohort study. PLOS Medicine 19(9): e1004078. https://doi.org/10.1371/journal.pmed.1004078

There is no multiple choice quiz with today’s lesson.

Lesson tags: English for scientists, Structuring an abstract, Writing an abstract
Back to: English for Scientists