Risk Factors for Ectopic Pregnancy

Report By: Emma Shawkat - 4th Year Medical Student
Institution: Manchester Royal Infirmary
Date Submitted: 17th June 2005
Last Modified: 22nd July 2005
Status: Blue (submitted but not checked)

Three Part Question

In [pregnant women who present with PV bleeding to A&E] what are the [risk factors] for an [ectopic pregnancy]?

Clinical Scenario

A 24 year old woman presents to accident and emergency with vaginal bleeding. She tells you she did a home pregnancy test and it was positive. You want to assess her clinical risk of having an ectopic pregnancy.

Search Strategy

Medline 1966-06/05 using Ovid Interface
Embase 1980-06/05
CINAHL 1982-06/05
The Cochrane Library Issue 2, 2005
({[tubal pregnancy.mp or exp PREGNANCY, TUBAL or ectopic pregnancy.mp exp or PREGNANCY, ECTOPIC or abdominal pregnancy.mp or exp PREGNANCY, ABDOMINAL or extrauterine pregnancy.mp] AND [risk factors.mp or exp Risk Factors or risk assessment.mp. or exp Risk Assessment or risk.mp. or exp RISK]} LIMIT to humans and english)
Cochrane ('ectopic pregnancy' or 'tubal pregnancy') AND 'risk factors'

Search Outcome

997 papers were identified from medline or which 8 were relevant. 3 meta-analyses were found
No additional papers found from the other databases

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Anorlu RI. Oluwole A. Abudu OO. Adebajo S 2005 Feb Denmark	Cases;100 consecutive patients who had laparotomy for ectopic pregnancy in 1 of three hospitals Controls;280 randomly selected consenting women who attended the family planning and gynaecology clinics at the same hospitals as the patients	Case-control study (3b)	Risk factors	Adjusted odds ratio (95% CI): Miscarriage 3.35 (1.93-5.83), Induced abortion 14.71 (5.57-27.96), Complicated induced abortion 4.13 (3.14-7.29), Previous pelvic surgery 2.09 (1.07-3.83), Previous EP 1.2 (0.47-7.2), Infertility treatment 1.69 (0.78-3.56), IUCD 3.76 (2.12-6.69), 15-19 years (sexual debut) 1.93 (1.71-2.93), Multiple sexual partners 3.2 (1.67-5.01) STD 9.06 (4.57-18.59) and PID 5.61 (3.64-10.52)	These risk factors have been found in women from Nigeria.
Bunyavejchevin S. Havanond P. Wisawasukmongchol W 2003 Jun Thailand	208 cases of ectopic pregnancy and 781 controls	Case-control study (3b)	Risk factors	Odds ratio (95% CI): Sexual partners >1 3.02 (1.75-5.23), Hx of PID 3.17 (1.40-7.19), Smoking 2.49 (1.36-4.58), Infertility 2.74 (1.35-5.54)	Population studied was Thai women only
Bouyer J. Coste J. Shojaei T. Pouly JL. Fernandez H. Gerbaud L. Job-Spira N 2003 Feb 1 United States	803 cases of ectopic pregnancy 2 controls; a woman who gave birth at the same centre at which the case was treated and a woman whose delivery occured shortly after treatment of the case.	Case-control study (3b)	Risk factors	Odds ratio (95% CI): Age; 30-34 1.3 (1.0-1.7), 35-39 1.4 (1.0-2.0), >40 2.9 (1.4-6.1), Smoking: Past 1.5 (1.1-2.2), 1-9/day 1.7 (1.2-2.4), 10-19/day 3.1 (2.2-4.3), >20/day 3.9 (2.6-5.9), Prior spontaneous abortion: 1-2 1.2 (0.9-1.6), >2 3.0 (1.3-6.9), Prior induced abortion: Surgical 1.1 (0.8-1.6), Medical (or medical and surgical) 2.8 (1.1-7.2), Appendectomy (ruptured appendix) 1.4 (0.8-2.4), Prior STD: without salpingitis 1.0 (0.8-1.3), with probable PID 2.1 (0.8-5.4), confirmed PID 3.4 (2.4-5.0), Prior tubal surgery 4.0 (2.6-6.1), Previous use of OC 0.7 (0.5-1.0), Previous IUD 1.3 (1.0-1.8), Infertility: <1 year 2.1 (1.2-3.6), 1-2 years 2.6 (1.6-4.2) and >2 years 2.7 (1.8-4.2)	This study was carrid out on french women only
Garrett AM. Vukov LF 1996 Feb United States	Medical records of all patients with ectopic pregnancy who presented from 1986 through 1992 to the emergency department of a large, rural referral hospital with 65,000 annual visits (n=126)	Retrospective case review	Risk factors	Prior tubal surgery 38%, Hx of infertility 35%, PID 17%, Previous EP 16%, Appendectomy/pelvic operation 13%, Fertility drugs 9% & IUD in situ 1%	Data collection was retrospective No odds ratios calculated
				Single risk factor: 17%
				No risk factor: 47%
Ankum WM. Mol BW. Van der Veen F. Bossuyt PM. 1996 Jun Untied States	A total number of 6,718 cases of EP in 27 case control studies and 13,049 exposed women in 9 cohort studies	Meta-analysis	Risk factors (cohort studies)	Common odds ratio (95% CI): Pelvic and/or abdominal surgery 1.5 (1.1-2.6), In utero DES-exposure 5.6 (2.4-13), PID 5.7 (2.5-13), Medical abortion 1.2 (0.78-1.2), Infertility 2.0 (1.2-3.4)	Individual papers do not provide sufficient data to allow multivariate analysis They did not look at contraceptive methods
		Meta-analysis	Risk factors not covered by the cohort studies (case-control, with pregnant controls)	Common odds ratio (95% CI): Previous; Gonorrhoea 2.9 (1.9-4.4), Chlamydia: IgG>1:32 2.8 (2.0-4.0), IgG>1:64 3.7 (2.9-4.7), Ectopic pregnancy 8.3 (6.0-11.5), Tubal surgery 21 (9.3-47), Tubal pathology 3.5, Current smoking 2.3 (2.0-2.8), Ever smoking 2.5 (1.8-3.4), Vaginal douching 1.1, Lifetime no. sexual partners >1 2.1 (1.4-4.8), Age at first sexual intercourse <18 1.6 (1.1-2.5)
Mol BW. Ankum WM. Bossuyt PM. Van der Veen F 1995 UNITED STATES	Case-control and cohort studies published between 1978 and 1994 in English, French, German and Dutch were retrieved by a search in Medline, a hand-search on recent medical journals and cross-references	Meta-analysis	Risk factors (pregnant controls)	Common Odds Ratios (95% CI): Oral contraception: current use 1.8 (0.9-3.4), IUCD: current use 4.2-45, past use 1.6 (1.4-1.8), Sterilization: 9.3 (4.9-18), Condom: 0.97 (0.24-4.0)	No common odds ratio could be calculated for current IUCD use
		Meta-analysis		P values: Oral contraception current use 0.502, IUCD current use 0.001, past use 0.849, sterilization 0.753
Xiong, X. Buekens, P. Wollast, E 1995 UNITED STATES	From 1977 through 1994, 19 publications regarding 16 studies of ectopic pregnancy and IUD use were found by MEDLINE and manual search	Meta-analysis	Current IUD use as a risk for ectopic pregnancy (pregnant controls)	Pooled odds ratio: 10.63, 95% CI: 7.66-14.74 (p<0.01)
Xiong, X. Buekens, P. Wollast, E 1995 UNITED STATES		Meta-analysis	Past IUD use as a risk factor for ectopic pregnancy (pregnant controls)	Pooled odds ratio: 1.33, 95% CI: 1.08-1.63

Comment(s)

Originally only papers that looked at risk factors as a whole, as opposed to papers that looked at individual risk factors were going to be included in this bet. However because the meta-analysis did not report on contraceptive methods as a risk factor, two further meta-analyses had to be included. These reported on the risks associated with contraception as a whole and use of an IUD. When pregnant and non-pregnant controls were used, the odds ratios associated with the pregnant controls are used. This is because an A&E physician has to determine the risk of a pregnant woman having an ectopic gestation.

Clinical Bottom Line

There are numerous risk factors associated with an ectopic pregnancy they are (followed by the range of odds ratios): Pelvic inflammatory disease 3.17-5.7, Infertility 2.0-2.74, In utero DES exposure 5.6, Tubal surgery 4.0-21, Current smoking, 1.7-6.0 Previous ectopic pregnancy 1.2-8.3, Multiple sexual partners 2.1-3.2, Current IUD use 4.2-45, Sterilization 9.3 and Previous abortion 0.95-14.71

References

Anorlu RI. Oluwole A. Abudu OO. Adebajo S Risk factors for ectopic pregnancy in Lagos, Nigeria. Acta Obstetricia et Gynecologica Scandinavica 2005;84(2):184-8
Bunyavejchevin S. Havanond P. Wisawasukmongchol W Risk factors of ectopic pregnancy Journal of the Medical Association of Thailand 2003; 86 Suppl 2:S417-21
Bouyer J. Coste J. Shojaei T. Pouly JL. Fernandez H. Gerbaud L. Job-Spira N Risk factors for ectopic pregnancy: a comprehensive analysis based on a large case-control, population-based study in France American Journal of Epidemiology 2003;157(3):185-94
Anonymous Risk factor for ectopic pregnancy Canadian Family Physician 1999;45:300, 309-10
Garrett AM. Vukov LF Risk factors for ectopic pregnancy in a rural population Family Medicine 1996;28(2):111-3
Ankum WM. Mol BW. Van der Veen F. Bossuyt PM. Risk factors for ectopic pregnancy: a meta-analysis Fertility & Sterility 1996;65(6):1093-9
Mol BW. Ankum WM. Bossuyt PM. Van der Veen F Contraception and the risk of ectopic pregnancy: a meta-analysis Contraception 1995;52(6):337-41
Xiong, X. Buekens, P. Wollast, E IUD use and the risk of ectopic pregnancy: a meta-analysis of case-control studies Contraception 1995;52(1):23-34