Objective
The objective of the study was to characterize women undergoing a termination of pregnancy (TOP) during the second trimester and to evaluate the risk factors and timing of repeat TOP.
Study Design
This nationwide retrospective cohort study investigated 41,750 women who underwent TOP during the first (n = 39,850) or second (n = 1900) trimester in Finland in 2000-2005. The follow-up time was until repeat TOP or until Dec. 31, 2006.
Results
TOP during the second trimester increases the risk of repeat TOP (hazard ratio [HR], 1.4; 95% confidence interval [CI], 1.3–1.6), repeat second-trimester TOP (HR, 3.8; 95% CI, 2.9–5.1), and repeat TOP after 16 weeks of gestation (HR, 5.0; 95% CI, 3.3–7.7). The other risk factor for these is young age (HR, 7.0, 95% CI, 5.3–9.3; and HR, 12.5; 95% CI, 3.1–50.4 for age <20 years).
Conclusion
Second-trimester TOP and young age are risk factors for repeat second-trimester TOP. Special focus on these women might be effective in decreasing repeat abortions.
Termination of an unwanted pregnancy remains a very common gynecological procedure throughout the world despite the improvement in contraceptive choices during the last decades. Thus, induced abortion remains a challenge for health care and family-planning services. In particular, late termination of pregnancy (TOP) is associated with an increased risk of complications.
The risk of abortion-related complications increases with gestational weeks. Major complications during second-trimester abortion occur in less than 1-11% of abortions, depending on the site and type of procedure. The increased morbidity in second-trimester TOP is likely to be due to increased fetal and placental size, increased blood volume, and a distended uterus with decreased resistance. Thus, various guidelines recommend that TOP should be performed as early as possible.
The incidence of TOP varies greatly from country to country, being 9 of 1000 women of fertile age (15-49 years) in Finland, 17 of 1000 in Sweden, 20 of 1000 in the United States, and 18 of 1000 in England and Wales in 2007. The rate of late TOP, performed between gestational weeks 13 and 24 of pregnancy or even later, varies between 5% and 10%. Moreover, the rate of repeat TOP ranges from 30% to 47% in the countries mentioned in the earlier text.
Risk factors associated with repeat TOP have been characterized in several studies. Prior abortion, young age, being parous, smoking, and postponement of initiation of postabortal contraceptive use are related to increased risk. Also, a history of physical or sexual abuse is associated with repeat induced abortion. However, the method of induced abortion (medical vs surgical) in first-trimester TOP is not a risk factor of repeat TOP. However, these data are mainly derived from studies performed on first-trimester TOP. The characteristics and risk factors of repeat later TOP may differ from these.
The aim of this study was to assess the background as well as the risk and timing of a repeat TOP in women undergoing their first TOP during the second trimester (ie, gestational weeks 12 plus 1 to 24 plus 0) in comparison with women undergoing their first TOP during the first trimester of pregnancy (ie, <12 plus 1 gestational weeks).
Materials and Methods
As shown in Figure 1 , the study cohort consisted of 42,955 women who underwent their first termination of pregnancy between Jan. 1, 2000, and Dec. 31, 2005, according to The Finnish Register of Induced Abortions and Sterilizations. Only women not having concurrent sterilization at the time of abortion were included in the study. In addition, women undergoing TOP because of fetal abnormality were excluded because the timing of TOP in these cases is based mainly on fetal diagnosis, thus representing a different entity. This left a total of 41,750 women for further analyses.
The cohort was divided into 2 groups according to the number of gestational weeks at the time of the first TOP. First trimester was defined as duration of gestation 84 days or less (ie, ≤12 plus 0 weeks). Second trimester was defined as duration of gestation between 85 and 168 days (ie, weeks 12 plus 1 to 24 plus 0). This division derives from the Finnish legislation on induced abortion, which divides pregnancies into first and second trimester using the duration of pregnancy of 84 days as a division point.
The follow-up time was until first repeat TOP or until Dec. 31, 2006. All women were followed up for at least 1 year. Deaths (n = 99; 0.002% after first-trimester primary TOP and n = 12; 0.004% after second-trimester primary TOP) in the cohort were not taken into account in calculations of the follow-up time, nor was possible emigration to other countries.
To be considered as a repeat TOP, the time interval between the index TOP and the repeat TOP was compared with the reported gestational weeks at the time of repeat TOP. This was done because the Finnish legislation requires a new application and a new announcement for a TOP if the first attempted TOP is unsuccessful and the pregnancy continues into the second trimester. Therefore, ongoing pregnancies after a failed first-trimester abortion were not mistakenly considered as repeat abortions.
The effects of background factors such as socioeconomic status (SES) and type of residence were also evaluated. The former was defined by using the stated occupation or the highest educational level found in the Abortion Register. Coding was based on national standards published by Statistics Finland.
SES was divided into 5 categories: upper white-collar workers, lower white-collar workers, blue-collar workers, students (level of education not defined), and others. The type of residence was defined by using data on the municipality of residence, available in the Abortion Register. The municipalities were divided into 3 categories: urban, densely populated, or rural areas, according to national standards.
According to the current law on induced abortions in Finland, TOP can be allowed up to 20 plus 0 weeks of gestation (24 plus 0 weeks in cases of a medical condition of the fetus). An approval with a legal indication for termination of pregnancy is needed, although the legislation is interpreted liberally.
Legal indications for the TOP include social, ethical, and medical reasons. Medical reasons include maternal health issues (ie, a pregnancy being a risk to the woman’s health or life, woman’s sickness, or physical defect or infirmity etc) or other reasons that neither the mother nor the father are able to take care of the child. Medical reasons also include proven or suspected fetal issues (ie, mental deficiency, severe illness, or handicap of the fetus).
Ethical and social reasons are the pregnancy or child care being a considerable stress on living or other conditions; age below 17 or 40 years or older at the time of conception; or 4 or more previous deliveries; or rape, incest, or other reasons mentioned in the penal law. Finnish legislation on induced abortion can be found at www.finlex.fi .
This study had an approval of the Finnish Ministry of Social Affairs and Health (STM/1690/2006).
Statistical analysis
Statistical analyses were performed using PASW 18.0 for Mac (SPSS Inc, Chicago, IL). Confidence intervals for the differences between independent proportions were calculated by using interval estimation for differences. Time to repeat TOP was analyzed with survival methods (Kaplan-Meier) and their statistical significance with log rank tests (Mantel-Cox). Risk factors of repeat TOP were analyzed by using Cox regression models. Estimated risks were presented as hazard ratios (HRs) with 95% confidence intervals (CIs). Variables that showed a statistically significant association ( P < .05) with repeat TOP in univariable analysis were entered in multivariable analysis. Forward conditional Cox regression model was used.
Results
First terminations of pregnancy were performed less often during the second trimester (7% vs 93%). In this cohort first-trimester TOP was performed either medically or surgically, but the majority (86.3%) of second-trimester TOP was performed medically, using a combination of mifepristone and misoprostol. Only 12.5% of second-trimester terminations were performed surgically.
The durations of pregnancy (mean ± SD) at the time of TOP were 8.2 (±1.7) and 15.7 (±2.1) gestational weeks in the cohorts of first- and second-trimester primary TOP, respectively. The annual frequency of second-trimester first TOP in this cohort varied from 6.7% to 7.5% during 2000-2005. The follow-up times (mean ± SD) were 47.8 ± 20.8 and 47.0 ± 20.7 months following first- and second-trimester index TOP, respectively.
The characteristics of the 2 cohorts are shown in Table 1 . The mean (±SD) ages of the women undergoing first TOP during the first and second trimesters were 24.7 (±7.3) and 22.2 (±7.0) years, respectively ( P < .001).
| Characteristic | First trimester (n = 39,850) | Second trimester (n = 1900) | Difference percent (95% CI) | P value |
|---|---|---|---|---|
| Age, y | ||||
| <20 | 12076 (30.3) | 880 (46.3) | –16.0 (–18.3 to –13.7) | < .001 |
| 20-24 | 10934 (27.4) | 499 (26.3) | 1.2 (–0.9 to 3.2) | .26 |
| 25-29 | 6694 (16.8) | 190 (10.0) | 6.8 (5.3–8.1) | < .001 |
| 30-34 | 4920 (12.3) | 155 (8.2) | 4.2 (2.8–5.4) | < .001 |
| 35-39 | 3644 (9.1) | 120 (6.3) | 2.8 (1.6–3.9) | < .001 |
| ≥40 | 1582 (4.0) | 56 (2.9) | 1.0 (0.1–1.7) | .02 |
| Deliveries | ||||
| 0 | 25239 (63.3) | 1399 (73.6) | –10.3 (–12.3 to –8.2) | < .001 |
| 1 | 5901 (14.8) | 244 (12.8) | 2.0 (0.3–3.4) | .02 |
| ≥2 | 8710 (21.9) | 257 (13.5) | 8.3 (6.7–9.9) | < .001 |
| History of miscarriage | ||||
| 0 | 35722 (89.6) | 1743 (91.7) | –2.1 (–3.3 to –0.7) | .003 |
| 1 | 3281 (8.2) | 126 (6.6) | 1.6 (0.4–2.7) | .01 |
| ≥2 | 847 (2.1) | 31 (1.6) | 0.5 (–0.2 to 1.0) | .14 |
| Type of residence | ||||
| Urban | 29048 (72.9) | 1298 (68.3) | 4.6 (2.5–6.7) | < .001 |
| Densely populated | 5446 (13.7) | 295 (15.5) | –1.9 (–3.6 to –0.3) | < .001 |
| Rural | 5356 (13.4) | 307 (16.2) | –2.7 (–4.5 to –1.1) | < .001 |
| Marital status | ||||
| Single | 26955 (67.6) | 1431 (75.3) | –7.7 (–9.6 to –5.6) | < .001 |
| Cohabiting | 6155 (15.4) | 298 (15.7) | –0.2 (–2.0 to 1.4) | .78 |
| Married | 6740 (16.9) | 171 (9.0) | –2.8 (–4.2 to 1.6) | < .001 |
| Socioeconomic status | ||||
| Upper white-collar | 2469 (6.2) | 51 (2.7) | 3.5 (2.7–4.2) | < .001 |
| Lower white-collar | 7572 (19.0) | 224 (11.8) | 7.2 (5.6–8.6) | < .001 |
| Blue-collar workers | 5240 (13.1) | 253 (13.3) | –0.2 (–1.8 to 1.3) | .83 |
| Students | 15629 (39.2) | 762 (40.1) | –0.9 (–3.2 to 1.3) | .44 |
| Others | 2699 (6.8) | 117 (6.2) | 0.6 (–0.6 to 1.6) | .30 |
| Not known | 6241 (15.7) | 493 (25.9) | –10.3 (–12.3 to –8.3) | < .001 |
| Indication | ||||
| Considerable stress | 34762 (87.2) | 1456 (76.6) | 10.6 (8.7–12.6) | < .001 |
| Age <17 years | 3670 (9.2) | 353 (18.6) | –9.4 (–11.2 to –7.7) | < .001 |
| Rape | 20 (<0.1) | 1 (<0.1) | 0 (–0.2 to 0) | .96 |
| Age ≥40 years | 923 (2.3) | 33 (1.7) | 0.6 (–0.1 to 1.1) | .10 |
| ≥4 deliveries | 355 (0.9) | 19 (1.0) | –0.1 (–0.7 to 1.1) | .62 |
| Maternal health | 120 (0.3) | 38 (2.0) | –1.7 (–2.4 to –1.2) | < .001 |
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