Audio podcast launched: Termination of pregnancy and the risk of subsequent preterm birth – what is the evidence?

A meta-analysis published in BJOG has suggested that women with a history of termination of pregnancy (TOP) may have an increased risk of low birth weight and preterm birth in subsequent pregnancies. The study found that the risk increased as the number of terminations increased. The podcast is a series of interviews inspired by this paper.

Visit the podcast page for details.

In this meta-analysis, researchers from the Knowledge Synthesis Group of Determinants of preterm/LBW births in Toronto, Canada reviewed 37 studies of low to moderate risk of bias. Data from 1965 to 2001 was included in the studies. The studies took place in a range of international locations.

The results found that a history of TOP was associated with an increased risk of low birth weight (OR 1.35) and preterm birth (OR 1.36), but not small for gestational age. A history of more than one TOP was associated with an increased risk of low birth weight (OR 1.72) and preterm birth (OR 1.93).

The authors stress that further studies are needed to assess the impact of newer techniques, and to identify the safest method of pregnancy termination in the first and second trimester. Recent changes such as access to early medical abortion, and the use of medications such as misoprostol prior to surgical intervention, may minimise trauma to the cervix. Outcomes in subsequent pregnancies thus need to be assessed and compared to those observed in older studies.

Lead author, Dr. Prakesh Shah, from the Department of Pediatrics at Mount Sinai Hospital in Toronto, said “several biomedical, social, environmental, lifestyle-related, genetic and other factors contribute to preterm and low birth weight births, and this needs to be kept in mind when interpreting our results. We caution against causal interpretation of these results as the confounding effects of socioeconomic factors, which are important, were considered in very few studies.

“Any discussion regarding the downsides of TOP is incomplete without discussing the downside of unwanted pregnancies, as they are also at risk of adverse outcomes.”

Prof. Philip Steer, BJOG editor-in-chief, said “This study highlights the need to assess and improve techniques in order to make termination of pregnancy safer for women”.

“There is no question that TOP remains an essential part of women’s healthcare. However, it is important to evaluate the risks and benefits of different techniques in order to ensure safe procedures and healthy future pregnancies for women.”

Shah P, Zao J on behalf of Knowledge Synthesis Group of Determinants of Preterm/LBW Births. Induced termination of pregnancy and low birthweight and preterm birth: a systematic review and meta-analyses. BJOG 2009; 116:1425–1442. DOI: 10.1111/j.1471-0528.2009.02278.x.