The association between endometriosis, adenomyosis and preterm delivery

The association between endometriosis, adenomyosis and preterm delivery

Endometriosis and adenomyosis are associated with adverse obstetric outcomes.

Key Points


  • This review emphasizes that there is a higher risk for preterm delivery and SGA in women with endometriosis and adenomyosis.
  • A careful follow-up is very important for these women to prevent obstetric adverse outcomes.


  • Preterm delivery and SGA are associated with short-term and long-term neonatal and perinatal complications. Thus prevention of these conditions is very probable with closer monitorization of women with endometriosis and/or adenomyosis.

 What’s done here?

  • This systematic review and meta-analysis include all published epidemiological observational studies from 1950 to October 2017 investigating the association between endometriosis and/or adenomyosis and the preterm delivery and /or SGA in the databases PubMed and Embase. 
  • Two independent authors evaluated all included 21 studies which are scored as high quality according to the Newcastle-Ottawa Quality Assessment Scale.

 Key results:

  • Endometriosis and adenomyosis, both of which is defined as the presence of endometrial tissue outside the uterus, are two diseases with many common features.
  • Infertility may be encountered in women with both disorders, although it is less common in women with adenomyosis.
  • It has been found that poor obstetric outcomes such as miscarriages, preterm delivery, having a child that is SGA and late pregnancy complications are more frequent in women with adenomyosis as the junctional zone is more affected in this disease.
  • This publication reviews 21 studies and a total of 2,517,516 women and states that women with endometriosis and/or adenomyosis are at risk for preterm delivery and having an SGA child.
  • Based on limited studies, adenomyosis seemed to increase the risk of preterm delivery and SGA much more than only endometriosis.


  • This review has strengths because it represents a large and comprehensive meta-analysis including 21 studies with a focus on adenomyosis and singleton pregnancies.
  • Furthermore, singleton pregnancies were also sub-analyzed separately considering the close association between twinning and preterm delivery and SGA. 

Lay Summary

Endometriosis and adenomyosis are diseases of the same spectrum which have common features and coexist in some but not all patients. Both diseases are characterized by endometrial implants outside of the uterine cavity. Endometriosis is defined as the localization of endometrium outside the uterus, whereas adenomyosis is recognized by in-growth of the endometrium into the myometrium. The spectrum of symptoms includes dysmenorrhea, chronic pelvic pain, dyspareunia, and infertility. Bruun and Arendt et al, a group of scientists from Aarhus University in Denmark, published a review titles as “Endometriosis and adenomyosis are associated with increased risk of preterm delivery and a small-for-gestational-age child: a systematic review and meta-analysis” in the Acta Obstetricia et Gynecologica Scandinavica. These authors investigated whether there is an association between the presence of endometriosis and/or adenomyosis and preterm delivery and/or having an SGA child as poor obstetric outcomes.

In the past publications, it was concluded that women with endometriosis were at risk for preterm delivery and SGA; however, adenomyosis has not yet been sufficiently evaluated. In this review, 21 studies and a total of 2,517,516 women were analyzed by two independent authors. Women with endometriosis were at risk for preterm delivery (OR 1.47, 95% CI 1.28-1.69) and for having an SGA child (OR 1.26, 95% CI 1.04-1.54). The association between adenomyosis and poor obstetric outcomes were analyzed in a limited number of studies. If the pregnant women had adenomyosis, there was a higher risk for preterm delivery (OR 3.09, 95% CI 1.88-5.09) and for having an SGA child (OR 3.23, 95% CI 1.71-6.09). Unlike previous systematic reviews and meta-analyses, in this review, the focus was on the association between adenomyosis and preterm delivery and SGA and also singleton pregnancies were sub-analyzed excluding multiple pregnancies from the study. Association between endometriosis and SGA was attenuated slightly based on studies with only singleton pregnancies. Despite the limited number of related publications, adenomyosis is more closely associated with preterm delivery and SGA due to the more pronounced junctional zone changes.

“This study may suggest a closer prenatal monitoring of pregnant women with endometriosis and adenomyosis to prevent adverse birth outcomes” they added.

Research Source:

endometriosis adenomyosis preterm delivery small-for-gestational-age (SGA)


EndoNews highlights the latest peer-reviewed scientific research and medical literature that focuses on endometriosis. We are unbiased in our summaries of recently-published endometriosis research. EndoNews does not provide medical advice or opinions on the best form of treatment. We highly stress the importance of not using EndoNews as a substitute for seeking an experienced physician.