The effect of induced abortion on subsequent pregnancy outcome

Induced abortion and ectopic pregnancy: A systematic review and meta-analysis

OBJECTIVE

Existing evidence of the relationship between induced abortion and ectopic pregnancy has not been assessed rigorously. This systematic review provides a comprehensive evaluation to examine whether induced abortion (IA) can increase the rate of ectopic pregnancy (EP).

METHODS

We searched PubMed, EMBASE, Web of Science, Cochrane, CNKI, WanFang, and Sinomed databases since their inception until February 2023. Eligibility criteria included case-control studies and cohort studies that analyzed induced abortion associated with ectopic pregnancy. Data analyses were conducted by using R-studio Version 1.1.383 software.

RESULTS

A total of 33 case-control studies and 7 cohort studies involving 132,926 participants were included. In case-control studies, there was a significant association between induced abortion and ectopic pregnancy by using single-factor analysis data (OR = 2.32, 95% CI = 1.81-2.98). Subgroup analysis by region suggested no statistical significance in the Americas (OR = 1.15, 95% CI = 0.92-1.43) and Eastern Mediterranean (OR = 3.64, 95% CI = 0.88-15.18). The relationship was significant by using multiple regression analysis data (OR = 1.97, 95% CI = 1.38-2.80). In cohort studies, statistical significance was found (OR = 1.42, 95% CI = 1.001-2.018) after omitting one study in sensitivity analysis. The combined results of the two types of studies suggested that induced abortion would increase the risk of ectopic pregnancy to some degree, but the conclusion needs to be considered with caution.

CONCLUSION

This study indicated that IA could increase the risk of EP to some degree and the times of IA had a negative impact on the risk. Safe abortion and avoiding repeat abortion due to unintended pregnancy could protect women's fertility.

Is a pregnancy following a second trimester uterine evacuation associated with increased adverse maternal and neonatal outcomes?

OBJECTIVE

To evaluate maternal and neonatal outcomes of pregnancies following a uterine evacuation in the second trimester, in comparison to a first trimester spontaneous pregnancy loss.

STUDY DESIGN

A retrospective analysis of data of women who conceived ≤6 months following a uterine evacuation due to a spontaneous pregnancy loss and subsequently delivered in a single tertiary medical center between 2016 and 2021. Maternal and neonatal outcomes were compared between women with second trimester (14-23 weeks) and first trimester (<14 weeks) pregnancy loss. The primary outcome of this study was the preterm delivery (<37 weeks) rate. Secondary outcomes were adverse maternal and neonatal outcomes. Univariate analysis was followed by multiple logistic regression models; adjusted odds ratios (aORs) and 95 % confidence intervals (CIs) were calculated.

RESULTS

During the study period, 1365 women met the inclusion criteria. Of those, 272 (19.9 %) women gave birth following a second trimester uterine evacuation and 1093 (80.1 %) women following a first trimester uterine evacuation. There were no demographic differences between the two groups. No difference was found in the preterm delivery rate in the subsequent pregnancy (5.1 % vs. 5.3 %, p = 0.91), further confirmed in the multivariate analysis [aOR 1.02 (0.53-1.94), p = 0.96]. No differences were identified with respect to other maternal and neonatal parameters examined, including hypertension disorders of pregnancy, third stage placental complications, mode of delivery and neonatal birth weight.

CONCLUSION

Pregnancy conceived shortly after second trimester uterine evacuation as compared to first trimester, confers no additional risk for preterm delivery or other adverse perinatal outcomes. Further studies to strengthen these findings are needed.

Definition and Multiple Factors of Recurrent Spontaneous Abortion

Recurrent spontaneous abortion (RSA) is usually defined as three or more spontaneous abortions prior to 20-28 weeks gestation. RSA affects approximately 2-5% of all women of childbearing age, and it brings tremendous psychological and psychiatric trauma to the women and also results in economic burden. The causes could be female age, anatomical and chromosomal abnormalities, genetic, endocrinological, placental anomalies, infection, smoking and alcohol consumption, psychological factor, exposure to environmental factors such as heavy metal, environment pollution, and radiation.

No. 360-Induced Abortion: Surgical Abortion and Second Trimester Medical Methods

OBJECTIVE

This guideline reviews evidence relating to the provision of surgical induced abortion (IA) and second trimester medical abortion, including pre- and post-procedural care.

INTENDED USERS

Gynaecologists, family physicians, nurses, midwives, residents, and other health care providers who currently or intend to provide and/or teach IAs.

TARGET POPULATION

Women with an unintended or abnormal first or second trimester pregnancy.

EVIDENCE

PubMed, Medline, and the Cochrane Database were searched using the key words: first-trimester surgical abortion, second-trimester surgical abortion, second-trimester medical abortion, dilation and evacuation, induction abortion, feticide, cervical preparation, cervical dilation, abortion complications. Results were restricted to English or French systematic reviews, randomized controlled trials, clinical trials, and observational studies published from 1979 to July 2017. National and international clinical practice guidelines were consulted for review. Grey literature was not searched.

VALUES

The quality of evidence in this document was rated using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology framework. The summary of findings is available upon request.

BENEFITS, HARMS, AND/OR COSTS

IA is safe and effective. The benefits of IA outweigh the potential harms or costs. No new direct harms or costs identified with these guidelines.

Association of induced abortion with preterm birth risk in first-time mothers

Women who have previously had an induced abortion (IA) before their first birth have been associated with preterm birth (PTB). However, previous studies on the PTB are inconsistent. Therefore, the aim of this study was to clarify the association between IA and PTB and low birth weight (LBW) for first-time mothers. A total of 3,684 Southern Chinese women who gave birth for the first time to a live singleton infants were recruited between January 2015 and December 2015 in the province of Guangdong, China. Univariable and multivariable analyses were conducted to determine whether IA was associated with PTB and LBW. Previous IA was not associated with increased risks of PTB or LBW, adjusted odds ratios were 0.80 (95% CI = 0.53 to 1.20) and 0.86 (95% CI = 0.57 to 1.31), respectively. Additionally, no significant associations were observed for infants born at before 37, before 32, and before 28 gestational weeks. And no significant associations were also observed for LBW measuring lower than 2500 grams and also measuring lower than 1500 grams. Our study suggested that a previous IA, as compared with women who reported no previous IA, does not increase the risk of PTB or LBW in subsequent pregnancy for the first-time mothers among Southern Chinese women.

Perinatal outcomes after induced termination of pregnancy by methods: A nationwide register-based study of first births in Finland 1996-2013

Background

Women with previous terminations of pregnancy (TOPs) before their first birth have been associated with poorer perinatal outcomes. However, previous studies on the perinatal outcomes by the method in previous TOPs are inconsistent.

Objective

To examine the perinatal outcomes of the first-time mothers with singleton births, by the method of previous TOP (medical and surgical vs no TOP, and surgical vs medical).

Method

This is a nationwide register-based study including 419,879 first-time Finnish mothers with singleton birth during the time period 1996–2013. Mothers having their first birth were identified from the Medical Birth Register and linked to the Abortion Register by their identification numbers. Multinomial logistic regression analysis was performed to examine the risk for preterm birth, low birth weight, small for gestational age and perinatal death by the method in previous TOPs.

Results

Among the first-time mothers, 87.0% had no history of TOPs, 3.2% had a history of medical TOP(s), 9.2% had a history of surgical TOP(s) and 0.6% had a history of both (medical and surgical) TOP(s). No significant differences in perinatal outcomes were found among the women with surgical TOPs, compared to the women with no TOPs. In unadjusted analysis, increased odds for preterm birth and low birth weight were found when comparing women having previous surgical TOPs with medical TOPs. Even after the adjustment of potential confounders, odds for preterm birth < 37 weeks (OR = 1.19, 95% CI = 1.04–1.36) and low birth weight < 2500 g (OR = 1.16, 95% CI = 1.00–1.35) remained significant. After restricting data to the single TOP, the results were similar; OR for both preterm birth and low birth weight was 1.18 (95% CIs = 1.02–1.36 and 1.01–1.38).

Conclusion

Perinatal outcomes did not differ among the mothers with surgical TOPs compared to the mothers with no TOPs, while the outcomes were poorer after surgical TOP(s) than after medical TOP(s).

"I was close to death!": abortion and medical risk on American television, 2005-2016

OBJECTIVES

To examine the portrayal of complications and long-term health consequences associated with abortion on television, recognizing the impact that fictional stories can have on public beliefs about abortion's safety.

STUDY DESIGN

Using a systematic online search, we identified all instances of abortion on US television from 2005 to 2016. We qualitatively coded these plotlines to identify any occurrences of complications, interventions or long-term health consequences associated with abortion care, with 95% intercoder reliability. We calculated the frequencies and rates of these occurrences in Microsoft Excel.

RESULTS

Our search identified 80 abortion plot lines. A percentage of 37.5 of characters who obtained an abortion experienced complications, interventions and/or negative health consequences. This rate contrasts with the 2.1% of real patients who experience complications or require intervention as a result of their abortions. Most onscreen complications were major events (e.g., hemorrhage), as opposed to real women, whose complications are mostly minor. Major medical interventions (e.g., hysterectomy) were similarly overportrayed, while the most commonly used interventions for real patients (e.g., medication) were not depicted at all. Finally, 22.5% of characters faced a long-term adverse health consequence, including mental illness, infertility or death. The onscreen abortion mortality rate was 5%, about 7000 times the actual mortality rate.

CONCLUSIONS

Overall, television dramatically exaggerates the risk associated with abortion procedures, overportraying medical complications - particularly major and life-threatening complications - and long-term adverse health consequences. This pattern of misrepresentation may be partially attributable to the occurrence of stories about illegal abortions or abortions taking place outside of modern medical contexts.

IMPLICATIONS

Onscreen abortion portrayals may contribute to inaccurate beliefs about abortion's risk that are common among the public, broadly, and abortion patients, specifically. Abortion advocates and providers will be more equipped to respond misinformation if they understand how and to what extent our popular culture portrays abortion as unsafe.

[Risk factors associated with spontaneous preterm deliveries before 30 weeks in Martinique F.W.I.: a case-control study]

OBJECTIVES

Early premature delivery is more prevalent in overseas territories than in continental France. Many differences are observed between pregnant women in France and in Martinique which may explain the higher preterm birth rate in the latter territory. The study compares prevalence of possible risk factors in preterm and term deliveries in Martinique.

PATIENTS AND METHODS

A retrospective study was conducted during two years (2010-2011). All deliveries before 30 weeks were included and several characteristics were compared with a group of term deliveries during the same period. All premature deliveries before 30 weeks were collected but only spontaneous ones were analysed.

RESULTS

Fifty deliveries before 30 weeks were recorded, among which 38 were spontaneous. Only a significantly higher prevalence of previous preterm delivery (OR=4.1 [1.3-13]) and twin pregnancies (OR=26.6 [3.19-219.6]) was found in the study group. Gram negative bacterial species were also more prevalent in vaginal sampling of preterm deliveries (OR=23.3 [2.7-204.6]).

CONCLUSION

Factors linked to prematurity before 30 weeks in Martinique are classical. Several features are different between pregnant women in France and in Martinique but do not appear as risk factors for prematurity in the latter territory.

Mifepristone-induced abortion and duration of third stage labour in a subsequent pregnancy

To evaluate the impact of mifepristone-induced abortion (MA) on the duration of third stage labour in a subsequent pregnancy, an observational cohort study was conducted from 1998 to 2001 at antenatal clinics in Shanghai, Beijing and Chengdu, China. A total of 4925 pregnant women with no history of induced abortion (NA) and 4931 pregnant women with one previous MA were enrolled and followed until delivery. Of these, 5139 women who delivered singletons vaginally were used in the present analyses, including 2614 with NA and 2525 with a history of MA. Maternal characteristics, labour duration and other obstetric and gynaecological information were obtained. The incidence rates of prolonged third stage of labour were 1.55% and 1.49% in NA and MA, respectively. After adjusting for age at delivery, maternal education, maternal occupation, area of residence, duration of gestational, type of delivery and pregnancy-induced hypertension, MA was not associated with the risk of prolonged third stage of labour (odds ratios = 0.92, 95% confidence interval 0.58, 1.44). Subgroup analysis of women with MA showed similar results regardless of gestational age at abortion, woman's age at abortion, subsequent curettage/complications and the interpregnancy interval. In conclusion, the data did not provide evidence that one MA was associated with the risk of prolonged third stage of labour in a subsequent pregnancy in primiparae.

Risk of spontaneous abortion following induced abortion is only increased with short interpregnancy interval

We set out to study the risk of spontaneous abortion following a first trimester induced abortion as a function of the interpregnancy interval between two pregnancies. The cohort study is based on the following databases: Danish national registries: the Medical Birth Registry (MBR), the Hospital Discharge Registry (HDR), and the induced Abortion Registry (IAR). All primigravid women in the time period from 1980 to 1982 were identified in the MBR, the HDR and the IAR. A total of 15 727 women who terminated the pregnancy with a first trimester induced abortion were selected as the induced abortion cohort, and 46 026 women who did not terminate the pregnancy with an induced abortion constituted the control cohort. By register linkage all subsequent pregnancies which were not terminated by induced abortion were identified from 1980 to 1994. Only women who had a non-terminated pregnancy following the index pregnancy were selected. Women whose first pregnancy was terminated following a first trimester induced abortion had a risk of spontaneous abortion of 11.0% vs. 9.4% in the control cohort. This relative difference of 1.17 was not statistically significant in logistic regression analyses. An increased risk was only found for women who had an interpregnancy interval of less than 3 months (OR=4.06, 95% C.I.=1.98-8.31). The abortion method, vacuum aspiration with dilatation or evacuation with dilatation did not modify this elevated risk. Overall the study did not show an increased risk of spontaneous abortion following one or more induced abortions, except for women with a short interpregnancy interval between an induced abortion and a subsequent pregnancy. We recommend women who have a first trimester induced abortion be advised to wait at least 3-6 months before trying to become pregnant again.

Medical abortion and the risk of subsequent adverse pregnancy outcomes

BACKGROUND

The long-term safety of surgical abortion in the first trimester is well established. Despite the increasing use of medical abortion (abortion by means of medication), limited information is available regarding the effects of this procedure on subsequent pregnancies.

METHODS

We identified all women living in Denmark who had undergone an abortion for nonmedical reasons between 1999 and 2004 and obtained information regarding subsequent pregnancies from national registries. Risks of ectopic pregnancy, spontaneous abortion, preterm birth (at <37 weeks of gestation), and low birth weight (<2500 g) in the first subsequent pregnancy in women who had had a first-trimester medical abortion were compared with risks in women who had had a first-trimester surgical abortion.

RESULTS

Among 11,814 pregnancies in women who had had a previous first-trimester medical abortion (2710 women) or surgical abortion (9104 women), there were 274 ectopic pregnancies (respective incidence rates, 2.4% and 2.3%), 1426 spontaneous abortions (12.2% and 12.7%), 552 preterm births (5.4% and 6.7%), and 478 births with low birth weight (4.0% and 5.1%). After adjustment for maternal age, interval between pregnancies, gestational age at abortion, parity, cohabitation status, and urban or nonurban residence, medical abortion was not associated with a significantly increased risk of ectopic pregnancy (relative risk, 1.04; 95% confidence interval [CI], 0.76 to 1.41), spontaneous abortion (relative risk, 0.87; 95% CI, 0.72 to 1.05), preterm birth (relative risk, 0.88; 95% CI, 0.66 to 1.18), or low birth weight (relative risk, 0.82; 95% CI, 0.61 to 1.11). Gestational age at medical abortion was not significantly associated with any of these adverse outcomes.

CONCLUSIONS

We found no evidence that a previous medical abortion, as compared with a previous surgical abortion, increases the risk of spontaneous abortion, ectopic pregnancy, preterm birth, or low birth weight.

Cervical dilation before first-trimester surgical abortion (<14 weeks' gestation). SFP Guideline 20071

First-trimester surgical abortion is a common, safe procedure with a major complication rate of less than 1%. Cervical dilation before suction aspiration is usually accomplished using tapered mechanical dilators. Risk factors for major complications in the first trimester are increasing gestational age and provider inexperience. Use of laminaria for cervical priming reduces the risk of cervical laceration and, to a lesser extent, uterine perforation. While pharmacological priming agents may potentially have the same effects, no published studies to date have been large enough to assess these outcomes. Given an experienced provider, the risk of these injuries during suction aspiration is very small. Cervical priming can be achieved with osmotic dilators or pharmacological agents. The advantages of osmotic dilators such as laminaria, Dilapan-S and Lamicel are their ability to produce wide cervical dilation, and for the synthetic types, their advantages include predictable effects and rapid onset of action. A disadvantage of osmotic dilators is that they require a speculum examination and a trained clinician to perform the insertion. When cervical priming is performed, misoprostol is the prostaglandin analogue most commonly used worldwide. Compared to laminaria, vaginal misoprostol requires a shorter period of time to achieve the same dilatation, is associated with less discomfort and is preferred by women. The sublingual route appears as effective as vaginal administration and requires less time for priming (2 h), but it is associated with more side effects. Oral administration can produce equivalent dilation to vaginal or sublingual administration, but higher doses and longer treatment periods (8 to 12 h) are required. Buccal administration of misoprostol appears to have a pharmacokinetic and physiologic profile similar to vaginal administration; however, there are no published studies of buccal misoprostol prior to first-trimester suction abortion. While extensive data demonstrate that a variety of agents are safe and effective at causing cervical softening and dilation preoperatively, there are not enough data to conclude that routine cervical priming is necessary to reduce complications of first-trimester surgical abortion. Cervical priming increases preoperative cervical dilation, making the procedure easier and quicker for the physician. However, in order to preoperatively dilate the cervix, the woman must receive the agent at least 3 to 4 h prior to her procedure. Besides the additional waiting, the woman might experience bleeding and cramping prior to the procedure. There are insufficient data evaluating how cervical priming affects women's quality of life in relation to abortion. Based on existing evidence, the Society of Family Planning does not recommend routine cervical priming for suction aspiration procedures. The Society of Family Planning further recommends that providers consider cervical priming only for women who may be at increased risk of complications from cervical dilation, including those late in the first trimester, adolescents and women in whom cervical dilation is expected to be difficult due to either patient factors or provider experience.

Impact of midtrimester dilation and evacuation on subsequent pregnancy outcome

OBJECTIVE

This study was undertaken to evaluate the impact of second-trimester dilation and evacuation (D&E) on subsequent pregnancy outcome.

STUDY DESIGN

Medical record review of 600 patients undergoing midtrimester (14-24 weeks) D&E from 1996 to 2000 and evaluation of subsequent pregnancy outcome. Mann Whitney U, Spearman rho, and chi(2) tests were used in statistical analysis with a P value <.05 considered significant.

RESULTS

Ninety-six subsequent pregnancies were identified, including 12 first-trimester spontaneous abortions, 1 second-trimester fetal death, 1 ectopic pregnancy, and 5 elective terminations. Seventy-seven pregnancies resulted in the delivery of a live-born infant at a median gestational age of 39.0 weeks. Five pregnancies (6.5%) were complicated by spontaneous preterm birth. Patients delivered preterm had an earlier gestational age at D&E (18.0 vs 20.0 weeks, P =.02) and a trend toward less preoperative cervical dilation (2.0 vs 3.0 cm, P =.09) than patients delivered at term.

CONCLUSION

Second-trimester D&E is not a risk factor for midtrimester pregnancy loss or spontaneous preterm birth. Preterm delivery in future gestations appears less likely when greater preoperative cervical dilation is achieved with laminaria, possibly because of a decrease in cervical trauma.

The contribution of cohort studies to prescribing research

This paper highlights the main issues in the design, analysis and interpretation of cohort studies used in prescribing research.

Induced abortion in the first trimester of pregnancy and risk of miscarriage

OBJECTIVE

To analyse the relation between induced abortion and risk of subsequent miscarriage.

DESIGN

Case-control study conducted between February 1990 and May 1995.

PARTICIPANTS

Case group included 782 women (median age 32 years, range 14-46) admitted for spontaneous abortion (within the 12th week of gestation) to a network of obstetric departments in the greater Milan area. The control group was recruited among women who gave birth at term (> 37 weeks of gestation) to healthy infants on randomly selected days at the hospitals where cases had been identified. A total of 1543 controls (median age 30 years, range 14-45) were interviewed.

RESULTS

A total of 102 cases (13%) and 181 controls (12%) reported one or more induced abortions. No clear relation emerged between miscarriage and induced abortions. In comparison with women reporting no induced abortion the odds ratio (OR) for miscarriage were 1.1 (95% CI 0.8-1.4) in women reporting one induced abortion and 0.9 (95% CI 0.4-1.8) in women reporting two or more. Likewise, there was no association between time since last and age at first induced abortion and risk of miscarriage.

CONCLUSIONS

This study did not find any strong association between induced and spontaneous abortion.

The effect of induced abortion on subsequent fertility

OBJECTIVE

To investigate the effect of induced abortion on subsequent fertility.

DESIGN

1. Prospective cohort study of women who had an unplanned pregnancy at recruitment. 2. Retrospective study of women who had a planned pregnancy at recruitment.

SETTING

Joint Royal College of General Practitioners/Royal College of Obstetricians and Gynaecologists study based in general practice in England, Scotland and Wales, between 1976 and 1987.

SUBJECTS

1. Prospective study: Four hundred and thirty-three women with a recruitment unplanned pregnancy ending in induced abortion (abortion group) and 1035 women with a recruitment unplanned pregnancy which ended naturally (nonabortion group). All subsequently had a planned pregnancy, or were known to be trying to conceive at some point during the follow-up. 2. Retrospective study: Nine thousand two hundred and ninety-nine women who presented at recruitment with a planned pregnancy.

MAIN OUTCOME MEASURE

The women's estimated length of planning time, expressed as a fertility rate ratio.

RESULTS

Induced abortion was not related to future fertility. In the prospective study, the fertility rate ratio (FRR) of the abortion group relative to the nonabortion group was 0.94 (95% CI 0.83 to 1.07, P = 0.37). This result was supported by the retrospective study, which again showed no important difference between the two groups.

CONCLUSION

Induced abortion does not appear to have an important effect on future fertility.