SUMMARIES OF 4 STUDIES FROM 2009 AND 2010 CONFIRMING THE ASSOCIATION OF INDUCED ABORTION AND SUBSEQUENT PRETERM BIRTH, AND ONE STUDY SHOWING DEPRESSION ASSOCIATED WITH PRETERM BIRTH. With regard to abortion and preterm birth , 2010 remained a busy year for abortion and preterm birth studies. There were 7 informative studies on preterm birth and induced abortion1-7 Watson et al, 2010 performed a population-based case-control study in Victoria, Australia from April 2002-April 2004 in 73 maternity hospitals.1 The researchers used interviews of patients postpartum to collect complete reproductive histories based on a database of all deliveries of singleton patients delivering 20 to < 32 weeks. They analyzed 603 women with preterm birth and compared them to 796 randomly selected women with birth > 37 weeks. Logistic regression analysis was used to control for sociodemographic factors. From the analysis, estimated unadjusted odds ratios were calculated and adjusted odds ratios were found. Both groups were compared to each other looking at term and preterm deliveries between spontaneous and induced abortions. Watson et al, 2010 found that there was increased risk for preterm birth whether there was a spontaneous or induced abortion. They found the risk of preterm birth increased by (AOR-adjusted odds ratio-adjusted for confounders) of 1.53 [95% CI 1.3-1.8] per abortion WITHOUT a previous preterm birth.1 The risk of preterm birth increased by (AOR-adjusted odds ratio-adjusted for confounders) of 2.79 [95% CI 1.8-4.3] per abortion WITH a previous preterm birth.1 What they did not share was the finding in their data that showed the higher AOR’s for > 2 abortions in their study. The AOR for preterm birth with 2 spontaneous abortions was 2.54 [95% CI 1.3-4.8] and with 2 induced abortions the AOR was 4.93 [95% CI 1.5-17]. The findings with 3 spontaneous abortions was an AOR of 2.88 [95% CI 1.1-7.5] and with 3 induced abortions the AOR was 3.53 [95% CI 1.1-11].1 Watson et al, 2010 performed another study on the same group of patients as the previous study1 to evaluate the effects of a term delivery after an abortion to explore if a term delivery provided a protective effect on preterm birth after an abortion.2 The purpose of this study was to exam if there was a “neutralising effect” of a term birth after an abortion (both spontaneous and induced). The authors, however, did not separate out spontaneous and induced abortions (based on Watson #1 findings) when looking at abortions and preterm birth in the index pregnancy. The analysis also suffered from the effect of a small numbers in both study groups with > parity of 3 in each group (28 cases and 16 controls respectively).2 They found women with parity of >2 with an abortion prior to the index pregnancy, and a previous term pregnancy, had an AOR of 2.71 [95% CI 1.39-5.28] for preterm delivery in spite of the term pregnancy in their first gestation.19 Therefore, they noted that a term delivery does not obviate the effects of an abortion. The authors, as noted previously, did not separate out the type of abortion to be evaluated for the effect so the findings must be taken cautiously. Bhattacharya, et al, 20103 performed a National Health Services Study in Scotland on data from the national data base linked for all women delivering at the Aberdeen Maternity hospital, Aberdeen, Scotland. The study sought to examine the possible inherited predisposition to spontaneous preterm birth. The authors analyzed 22,343 pregnancies in two generations between September, 1948 and March, 2008. The database contained 35,096 pregnancy records of women with daughters available. The authors excluded induced labors (9,521) and cesarean deliveries (1,716) since these do not reflect spontaneous deliveries. There were also 2,103 maternal records lacking gestational age at delivery in the records and 108 daughters with no mode of delivery. This left 13,845 daughters born to 11,576 mothers suitable for analysis. Bhattacharya, et al, 20103 found the interesting risk factor for preterm birth in daughters (adjusted OR) of the daughter herself being born preterm OR 1.49 [95% CI 1.12-1.99].3 Other factors influencing preterm birth were found (adjusted OR’s): < 20 years OR 1.67 [95% CI 1.43-1.94], lower socioeconomic status OR 1.22 [95% CI 1.04-1.44], smoking 10 or more cigarettes per day OR 1.47 [95% CI 1.27-1.71] and body mass index (BMI) less than 20 kg/m2 OR 1.48 [95% CI 1.24-1.77].3 A history of a previous spontaneous birth in the daughter was also associated with an increased risk of preterm birth with and OR of 2.51 [95% CI 1.71-3.66].3 Most interesting of all in the daughters was the finding of an increased risk of preterm delivery in the daughter even if her mother had preterm delivery, not of her daughter, but another pregnancy demonstrating an OR 1.35 [95% CI 1.12-1.63].3 However, perhaps one of the most startling findings in the paper was that spontaneous miscarriage increased the odds of a preterm birth in the mother OR 1.24 [95% CI 1.01-1.52] but, spontaneous miscarriage in the mother, had no effect on the preterm birth rates of the daughters OR 1.04 [95% CI 0.85-1.28].3 Further, the authors did not examine induced abortion in the daughters as a risk for preterm birth. Therefore, before we generalize to a genetic and heritable factor as a cause of spontaneous preterm birth in daughters of women with spontaneous preterm birth, induced abortion must be included as a co-morbidity due to induced abortion’s association with preterm birth. The next study by Voigt, et al 20094 involved 8 German federal states in a retrospective data base linked study from 1998-2000 with reproductive data obtained from 247, 593 patients at first obstetrical visit and verified in the data base4 The authors found, even after controlling for specific occupational comparisons due to possible bias of activity/job for preterm birth, an increased rate of preterm delivery < 36 weeks and early preterm delivery < 31 weeks in women with induced abortions. When specifically analyzing the cohort of women age 28-30 years Voigt, et al 20094 found that 1 induced abortion carried a 7.8% risk of preterm birth and > 2 induced abortions had an 8.5% risk of preterm birth.4 The general population rate of preterm birth without any induced abortions was 6.5% and was statistically significant to (p=0.015).4 Unfortunately, the authors did not calculate any odds ratios for preterm birth associated with induced abortions. The next study came from a single institution in the United Kingdom (UK).5 The study was a case-control study by Yuan, et al 20105. The analysis was done at a National Health Services Hospital in Bristol, UK at a single tertiary hospital from 2002-2004 and used record linkage analysis. The study group was 274 women with preterm singleton deliveries between 22-35 weeks and 559 randomly selected control deliveries from 37-42 weeks during the same time frame. Yuan, et al 20105 found that a previous termination of pregnancy in the study group was higher in the study patients delivering < 35 week when compared to the control group who delivered at term.5 In the study group of patients delivering < 35 weeks, 25.4% (58/228) of the patients had a termination of pregnancy while only 15.9% (88/559) of the control patients delivering at term had terminations of pregnancy. This difference in rate was statistically significant to p<0.007.5 Surprisingly, the authors gave no OR’s for a termination of pregnancy and its associated risk for delivery < 35 weeks, even though the statistical significance was overwhelming. Finally, the authors found the spontaneous miscarriage rates were similar between the groups: >37 weeks 5.4% and < 35 weeks 3.9%.5 The best study from the United States actually discussed cervical insufficiency in the context of abortion.6 Anum et al, 2010 used birth certificate data from US from 2004.6 They utilized only primiparous patients and found 1,115,541 primiparous women to include in the study: 852,296 (76.4%) Caucasian; 166,966 (15.%) Black; 82,965 (7.4%) Asian/Pacific Islander; and remainder Native American.6 Blacks were found to have the highest percentage of 2 or more abortions (4.5%) compared to Caucasians (2.9%), Asians (3.0%), and Native Americans (2.7%).6 Cervical insufficiency was 3.15% in patients >4 abortions compared to 0.15% in those without any abortions:

  • 1 termination 0.46%
  • 2 terminations 0.99%
  • 3 terminations 1.92%6

Using multivariate analysis to control for known risk factors (including abortion) the authors found:

  • Black women had an OR for cervical insufficiency of 2.45 [95% CI 2.22-2.71] compared to Caucasian women
  • Native American women had an OR for cervical insufficiency of 1.62 [95% CI 1.10-2.37] compared to Caucasian women
  • There was no difference between Caucasian women and Asian/Pacific Island women6

Pregnancy termination had a strong association with cervical insufficiency (compared to primaparous women without abortions):

  • 1 termination OR 2.49 [95% CI 2.23-2.77]
  • 2 terminations OR4.66 [95% CI 4.07-5.33]
  • 3 terminations OR 8.07 [95% CI 6.77-9.61]
  • 4 terminations OR 12.36 [95% CI 10.19-15.00]6

Therefore, the horrific effects of abortion are synergistic with the apparent race component of cervical insufficiency and may help explain the increased preterm birth rate amongst Blacks. The final study analyzed was Grote, et al 20107. The authors conducted a meta-analysis of depression’s relationship to: preterm birth, IUGR, and low birth weight.7 They searched: 592 articles on MEDLINE; 27 PsycINFO; 106 CINAHL; 63 Social Work Abstracts; 73 Social Services Abstracts; and 1 Dissertation Abstracts International. In their analysis, 29 studies met the inclusion criteria: 20 for preterm birth (9 significant); 11 low birth weight (5 significant); and 12 IUGR (2 significant). Grote et al, 2010 found depression was increased in preterm birth patients with an of OR 1.39 [95% CI 1.19-1.61].7 However, the authors did not look at the number of terminations of pregnancy that were associated with preterm birth. The paper failed to understand the implications of depression related to abortion and thus the interesting link to BOTH a preterm birth and depression in the “double-effect” of abortion. Conclusions There are over 122 studies demonstrating statistically significant association with preterm birth and induced abortion. (see Appendix A) The data on spontaneous miscarriages is not as clear but the large meta-analyses that control for confounding variables seem to indicate that spontaneous miscarriages are not related to preterm birth.8-9,10 Further, as has been noted earlier in our presentation of the data, the very disease processes and medical problems related to spontaneous miscarriages may also be operative in preterm birth. Lastly, one cannot avoid a spontaneous miscarriage, but, may avoid the tragedy of preterm birth by never undergoing an induced elective abortion. References 1. Watson LF, Rayner J, King J, Jolley D, Forster D, Lumley J. Modelling prior reproductive history to improve prediction of risk for very perterm birth. Paediatric and Perinat Epidem 2010;24: 402-415. 2. Watson LF, Rayner J, King J, Jolley D, Forster D, Lumley J. Modelling sequence of prior pregnancies on subsequent risk of very preterm birth. Paediatric and Perinat Epidem 2010;24: 416-23. 3. Bhattacharya S, Raja EA, Mirazo ER, Campbell DM, Lee AJ, Norman JE, Bhattacharya S. Inherited predisposition to spontaneous preterm delivery. Obstet & Gynecol 2010;115(6): 1124-133. 4. Voigt M, Henrick W, Zygmunt M, Friese K, Straube S, Briese V. Is induced abortion a risk factor in subsequent pregnancy? J Perinat Med 2009;37: 144-149. 5. Yuan W, Duffner AM, Chen L, Hunt LP, Sellers SM, Bernal AL. Analysis of preterm deliveries below 35 weeks’ gestation in a tertiary referral hospital in the UK: A case-control study. BioMed Central 2010;3:119-28. 6. Grote NK, Bridge JA, Gavin AR, Melville JL, Iyengar S, Katon WJ. A meta-analysis of depression during pregnancy and the risk of preterm birth, low birth weight and intrauterine growth restriction. Arch Gen Psychiatry 2010;67(10): 1012-1024 7. Anum EA, Brown HL, Strauss JF. Health disparities in risk for cervical insufficiency. Human Repro 2010 open access. Oxford University Press. Doi:10.1093. vol.0, no. 0 pp 1-7, 2010. 8. Reime B, Schuecking BA, Wenzlaff P. Reproductive Outcomes in Adolescents Who Had a Previous Birth or an Induced Abortion Compared to Adolescents’ First Pregnancies. BMC Pregnancy and Childbirth 2008;8:4. 9. Freak-Poli R, Chan A, Gaeme J, Street J. Previous abortion and risk of preterm birth: a population study. J Maternal-Fetal Med Jan. 2009;22(1):1-7 10. Shah PS, Zao J. Induced termination of pregnancy and low birthweight and preterm birth: a systematic review and meta-analysis. BJOG 2009;116:1425-1442.