Cervical pregnancy in assisted reproduction: an analysis of risk factors in 91,067 ongoing pregnancies

Published:December 24, 2019DOI:


      Research question

      What is the frequency of cervical pregnancy in women undergoing assisted reproductive technologies (ART) and what are the risk factors?


      Case-control study of women undergoing assisted reproductive technology (ART) at 25 private assisted reproduction clinics run by the same group in Spain. Two control groups (tubal ectopic pregnancies and intrauterine pregnancies) were established. The main outcome measure was frequency of cervical pregnancy. Demographic, clinical factors and IVF parameters were assessed for their influence on cervical pregnancy risk.


      Thirty-two clinical pregnancies were achieved out of 91,067 ongoing pregnancies, yielding a rate of 3.5/10,000. Cervical pregnancies represented 2.02% of all ectopic pregnancies (32/1582). The main risk factors two or more previous pregnancies (OR 2.68; CI 1.18 to 6.07); two or more previous miscarriages (OR 4.21; CI1.7 to 10.43), one or more previous curettages (OR 3.99, CI 1.67 to 9.56), two or more previous curettages (OR 4.71; CI 1.19 to 18.66) and smoking (OR 2.82 CI 1.14 to 6.94). History of caesarean sections and tubal pregnancy was not associated with an elevated cervical pregnancy risk. Infertility conditions and endometrial thickness were similar across the three groups. The proportion of women from whom fewer than 10 oocytes were retrieved was higher in the clinical pregnancy group than in the IUP group.


      In ART, the main risk factors for cervical ectopic pregnancy are a history of at least two pregnancies, miscarriages, at least one curettage and smoking. IVF parameters do not seem to influence the development of clinical pregnancies. Cervical pregnancies are less common in ART than previously reported, attributable to improvements in ART; a publication bias in early IVF reports cannot be ruled out.


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      Roberto Matorras is Professor of Obstetrics and Gynaecology (Basque Country University), Head of the Human Reproduction Unit (Cruces 5 Hospital) and Coordinator of Research and Teaching (IVI Bilbao). He has published 11 books, 120 scientific papers in English and 330 in Spanish. Past President of the Spanish Society of Infertility.
      Key message
      In assisted reproductive technology (ART), the main risk factors for cervical pregnancy are previous pregnancies, miscarriages, curettages and smoking. IVF parameters do not seem to influence cervical pregnancy occurrence. Cervical pregnancy in ART is less common than previously reported, which is probably related to improvements in ART, although a publication bias in early IVF reports cannot be ruled out.