Document Type : Original Article
Authors
1 Akbarabadi Hospital, Department of Obstetrics and Gynocology, Collage of Medical Sciences, Iran University of Medical Sciences, Tehran, Iran
2 Department of Midwifery, Collage of Medical Sciences, Tarbiat Modares University, Tehran, Iran
Abstract
Keywords
An ectopic pregnancy is a complication of pregnancy
in which the blastocyst implants anywhere
outside endometrial cavity of uterine (
Various risk factors for ectopic pregnancy have
been identified (
This case-control study was conducted at Shahid Akbarabady Hospital in Tehran, Iran, from March 2006 to May 2011. The data were collected from a total of 300 pregnant women as controls and of 150 case-patient women whose diagnosis of ectopic pregnancy was confirmed by menstrual history, physical examination, serial beta-human chorionic gonadotropin (βhCG), and abdominal/transvaginal ultrasound. There was a history of delayed or skipped menses in women. Initial symptoms were nonspecific, consisting of a period of amenorrhea and abdominal pain or tenderness, with or without unexpected vaginal bleeding. New onset pain was reported, dull or sharp in nature, which was generalized or localized to one area. Furthermore, they complained about spotty or irregular vaginal bleeding. Early physical examination findings included cervical motion tenderness and abdominal tenderness on abdominal palpation.
All data were collected from the hospital’s medical records, while one woman in case group was compared with two women in the control group at the same time. A questionnaire completed by the corresponding author for the patient in case group involved demographic characteristics, menstrual history, present pregnancy status, diagnostic actions, and management, whereas for women in control group, the last two items, i.e. diagnostic actions and management, were omitted from questionnaire.
Several studies (
We used Statistical Package for Social Science (SPSS; SPSS Inc., Chicago, IL, USA) version 16 for data analysis. Odds ratio (OR) and 95% confidence intervals (CI) obtained after binary logistic regression were used to describe the association between ectopic pregnancy and potential risk factors. Multivariable modeling was employed to determine which factors were associated with ectopic pregnancy, while the association was adjusted for other variables. In this model, we only included variables that were associated with the risk of ectopic pregnancy in univariate analysis.
Our study was a retrospective study including patient files, and we did not directly contact with patient, but our study was confirmed by Ethical Committee of the Shahid Akbarabadi Hospital.
The data for socio-demographic characteristics (age and educational level), parity, and abortion of women in cases and controls are presented in table 1. The average age of women in case and control groups was 28.7 ± 6.0 years (range 16-44 years) and 26.4 ± 5.6 years (range 17-46 years), respectively. The association between ectopic pregnancy and age (
Comparison of age, educational level, parity and abortion of subjects between case and control groups from March 2006 to May 2011
Case(n=150) | Control(n=300) | Crude OR | 95% CI | |
---|---|---|---|---|
N (%) | N (%) | |||
10 (6.7) | 49 (16.3) | 0.36 | 0.18-0.74 | |
35 (23.3) | 102(34.0) | 0.59 | 0.37-0.92 | |
50 (33.3) | 78 (26.0) | 1.42 | 0.92-2.18 | |
31 (20.7) | 51 (17.0) | 1.27 | 0.77-2.09 | |
24 (16.0) | 20 (6.7) | 1 | - | |
79 (52.7) | 172 (57.3) | 0.88 | 0.29-2.71 | |
55 (36.7) | 87 (29.0) | 1.38 | 0.44-4.27 | |
7 (4.7) | 12 (4.0) | 1 | - | |
9 (6.0) | 29 (9.7) | |||
56 (37.3) | 152(50.7) | 1.14 | 0.54-2.4 | |
61 (40.7) | 91 (30.3) | 1.30 | 0.66-2.57 | |
33 (22.0) | 57 (19.0) | 1 | ||
66 (44) | 257 (85.7) | 0.13 | 0.08-0.21 | |
63 (42) | 32 (10.7) | 6.33 | 3.87-10.35 | |
21 (14) | 11(3.7) | 1 | - | |
The comparison of contraceptive methods among the two groups is shown in table 3. A total number of 34 (22.7%) patients in case group and 14 (4.7%) subjects in control group used intrauterine device (IUD) at the time of conception. The oral contraceptive method was recorded in 8 (5.3%) and 24 (8.0%) subjects of case and control groups, respectively. The usage of tubal ligation (TL) was observed in 12 (8%) and 5 (1.7%) women of case and control groups, respectively. Overall, it was revealed that the usage of IUD and TL significantly increased risk of ectopic pregnancy (adjusted OR=4.79, 95% CI:1.61-14.21 and adjusted OR=4.49, 95% CI:1.16-17.28, respectively), whereas oral contraceptives decreased risk of ectopic pregnancy (adjusted OR=0.7, 95% CI:0.23-2.15) (
Table 3 presents the association of three categories of risk factors (high, moderate, and low) with incidence of ectopic pregnancy. It was observed that the risk factors of ectopic pregnancy in women are previous tubal surgery, tubal pathology, assisted reproductive technology (ART), sterilization, previous ectopic pregnancy, IUD usage, infertility, and abdominal/pelvic surgery.
Main risk factors of ectopic pregnancy after final logistic regression analysis (random effects model)
Adjusted OR | 95% CI | P value* | |
---|---|---|---|
2.45 | 0.86-6.97 | 0.09 | |
1.08 | 0.36-3.25 | 0.88 | |
0.45 | 0.05-3.91 | 0.47 | |
0.3 | 0.01-8.04 | 0.47 | |
1.93 | 0.15-23.43 | 0.60 | |
5.24 | 2.04-13.44 | < 0.001 | |
57.93 | 6.79-494.25 | < 0.001 | |
1.92 | 0.4-9.09 | 0.40 | |
0.7 | 0.23-2.15 | 0.54 | |
4.49 | 1.16-17.28 | < 0.001 | |
4.79 | 1.61-14.21 | < 0.001 | |
IUD; Intrauterine device, TL; Tubal ligation, ART; Assisted reproductive technology, CI; Confidence interval and *; For variables with more than two categories, the p value of test for trend is given.
Contraceptive methods and risk factors of ectopic pregnancy compared between subjects of case and control groups
Cases(n=150)No (%) | Control(n=300)No (%) | CrudeOR | 95% CI | |
---|---|---|---|---|
116(77.3) | 286(95.3) | 1 | ||
34 (22.7) | 14 (4.7) | 5. 98 | 3.09-11.57 | |
142 (94.5) | 276 (92) | 1 | ||
8 (5.5) | 24 (8.0) | 0.64 | 0.28-1.47 | |
138 (92) | 295 (98.3) | 1 | ||
12 (8) | 5 (1.7) | 5.13 | 1.77-14.84 | |
100 (96.7) | 296 (98.7) | 1 | ||
/5 (3.3)/ | 4 (1.3) | 2.55 | 0.67-9.64 | |
147 (98) | 297 (99) | 1 | ||
3 (2.0) | 3 (1) | 2.02 | 0.4-10.13 | |
196 (97.3) | 300 (100) | 1 | ||
4 (2.7) | 0 | 2.02 | 0.4-10.13 | |
117 (78) | 299 (99.7) | 1 | 11.4-623.69 | |
33 (22) | 1 (0.3) | 84.33 | ||
136 (90.7) | 293 (97.7) | 1 | ||
14 (9.3) | 7 (2.3) | 1.75 | 0.44-6.96 | |
101 (67.3) | 292 (97.3) | 1 | ||
49 (32.7) | 8 (2.7) | 17.70 | 8.11-38.66 | |
IUD; Intrauterine device, TL; Tubal ligation, ART; Assisted reproductive technology and CI; Confidence interval
The main risk factors of ectopic pregnancy are shown in the table 2. Prior ectopic pregnancy, prior tubal ligation, use of IUD and prior pelvic/abdominal surgery were identified as four main risk factors mentioned in obstetric history. Prior ectopic pregnancy was associated with an increased risk of ectopic pregnancy (crude OR=84.3, 95% CI: 11.4-623.7). Adjustment did not affect this relationship (adjusted OR=57.9, 95% CI: 6.79-494.2; Table 2). There was no significant difference between case and control groups with regard to the prior tubal surgery (adjusted OR=0.45, 95% CI: 0.05-3.91), and tubal pathology (adjusted OR=0.3, 95% CI: 0.01-8.04). There was no statistically significant association between ART (adjusted OR=1.93, 95% CI: 0.15-23.4), infertility (adjusted OR=1.92, 95% CI:0.4-9.09) and ectopic pregnancy (
In the current investigation, we demonstrated that the risk of ectopic pregnancy increases in women over 30 years of age. Similarly, in a case-control study by Karaer et al., they have found that an increase in rate of ectopic pregnancy coincides with an increase in the age of women before reaching age 40 (
The role of age in the incidence of ectopic pregnancy has been suggested by researchers. However, studies have produced conflicting results in this respect (
In this study, we found that there is a relation between use of IUD, oral contraception and TL with risk of ectopic pregnancy. These observations are similar to those previously reported by Chow et al., (1987) (
A Danish study found that 76% of post sterilization pregnancies were ectopic (
The results of the present study showed there is no relation between prior abortion and prior infertility with incidence of ectopic pregnancy. The results obtained about association of prior abortion and incidence of ectopic pregnancy were in agreement with those previously achieved by Ankum et al. in a meta-analysis study, in which they observed no significant association between spontaneous abortion and risk of ectopic pregnancy (OR=0.63-1.5) (
In a follow-up analysis by Tuomivaara and Ronnberg (
Similar to our findings, other studies also found an increased risk of 7-9-fold among women with a history of prior ectopic pregnancy (
We found that there was a significant relationship between risk factors like abdominal/pelvic surgery and incidence of ectopic pregnancy. In a meta-analysis study of Ankum et al. (
We found that there is no significant relationship between risk factors such as prior tubal surgery, tubal pathology, ART and incidence of ectopic pregnancy. Similarity, Karaer et al. (
Tubal pathology referred as prior tubal infection is also found to have a probable causal relation with ectopic pregnancy. In Sweden, a decrease in the rate of chlamydial infection led to a reduction in the incidence of ectopic pregnancy (
Since incidence of ectopic pregnancy is likely to be considered as an important role for future fertility, we designed this study to identify the risk factors of ectopic pregnancy in a sample of Iranian women. In the present study, we found that the main risk factors for incidence of ectopic pregnancy in a sample of Iranian women are prior ectopic pregnancy, prior tubal ligation, usage of IUD, and prior pelvic/abdominal surgery. In addition, ectopic pregnancy was positively related to the previous history of ectopic pregnancy, abortion, caesarean section, and infertility. These findings can be useful for early diagnosis of ectopic pregnancy to pursue proper medical therapy instead of unnecessarily surgical treatment.