Abortion and Preterm Birth — a new study

Sidney Midwife, one of the blogs I read, had this as her most recent post: Study Showing Abortion-Premature Birth Risk Points to Cerebral Palsy. Since this is National Infant Mortality Awareness Month, and since premature birth increases infant mortality, this newest study has implications for this topic.

When I read about the study, I read the article, and then decided to find the abstract. Since the article mentioned that the study was published in the BJOG, and mentioned the study’s lead author, I had a good head-start. So, I went to the BJOG website, did a search for the author’s name, and came up with a pod-cast. Then the abstract. Then — wishful thinking! — I clicked on “fulltext,” fully expecting to go to a login screen, where I would have to pay $38 to view the report. What a pessimist realist! But, lo and behold, the full study is available! [Yeah, I’m a nerd — excited about being able to read a full study. :-)]

Here is the abstract:

Background History of induced termination of pregnancy (I-TOP) is suggested as a precursor for infant being born low birthweight (LBW), preterm (PT) or small for gestational age (SGA). Infection, mechanical trauma to the cervix leading to cervical incompetence and scarred tissue following curettage are suspected mechanisms.

Objective To systematically review the risk of an infant being born LBW/PT/SGA among women with history of I-TOP.

Search strategy Medline, Embase, CINAHL and bibliographies of identified articles were searched for English language studies.

Selection criteria Studies reporting birth outcomes to mothers with or without history of induced abortion were included.

Data collection and analyses Two reviewers independently collected data and assessed the quality of the studies for biases in sample selection, exposure assessment, confounder adjustment, analytical, outcome assessments and attrition. Meta-analyses were performed using random effect model and odds ratio (OR), weighted mean difference and 95% confidence interval (CI) were calculated.

Main results Thirty-seven studies of low–moderate risk of bias were included. A history of one I-TOP was associated with increased unadjusted odds of LBW (OR 1.35, 95% CI 1.20–1.52) and PT (OR 1.36, 95% CI 1.24–1.50), but not SGA (OR 0.87, 95% CI 0.69–1.09). A history of more than one I-TOP was associated with LBW (OR 1.72, 95% CI 1.45–2.04) and PT (OR 1.93, 95% CI 1.28–2.71). Meta-analyses of adjusted risk estimates confirmed these findings.

Conclusions A previous I-TOP is associated with a significantly increased risk of LBW and PT but not SGA. The risk increased as the number of I-TOP increased.

To be honest, the study does not even mention cerebral palsy, nor does it mention infant mortality — those are conclusions drawn by other readers of the study, based on the known facts of the risks of preterm birth and low birthweight. For instance, this cerebral palsy website says, in part,

Extremely low birth weight infants are 100 times more likely to develop CP than a full term infant. In one large overview of 6399 very low birth weight children that survived neonatal intensive care, childen that were evaluated up to age 3, the rate contracting CP was 77 per 1000. 2.5 per 1000 is the normal rate.

The CDC says,

Being born preterm is the greatest risk factor for infant mortality (death within the first year of life). Recent analyses of infant death data by CDC researchers demonstrate that preterm-related deaths accounted for more than 1/3 of all deaths during the first year of life, and more infants died from preterm causes than from any other cause.

Thinking of this sad topic always brings to mind a woman’s blog I read over a year ago. I forget how I even stumbled across it — some word search on Google or WordPress or something. Anyway, she told the story of her pregnancies. Midway through her first pregnancy, she found out that the baby had some defect of some sort — I can’t remember what it was, if it was genetic like Down Syndrome or physical like spina bifida  (probably neither one; it may have even been lethal) — and chose to terminate the pregnancy, rather than to give birth to a deformed child. The abortion took place sometime around 20-24 weeks. Then she got pregnant again; tests showed that everything was fine for this baby, and then a few weeks of gestation after the time of the first abortion, she went into preterm labor that was not (could not be?) stopped, and her baby died. I wondered at the time if her first abortion caused (or at least was a factor in) the early birth of her second baby — that her body having been forced to open too soon for the abortion (an induction abortion, I think, rather than a D&C or D&X), was traumatized by it, and opened too soon during the second pregnancy. This study strengthens that thought. I wonder if women are given true informed consent prior to undergoing abortions, that if they have an abortion, they might later put a wanted child at risk of preterm birth, cerebral palsy, or even death.

Here is a good article that includes more information on preterm birth, including other causes and factors.

5 Responses

  1. This is a classic example of the principle that correlation does not mean causation. The authors present no evidence that abortion causes an increased risk of pre-term birth, merely that the same women who have an abortion are likely to have a pre-term birth.

    As we know, race, economic status, substance abuse, etc. are associated with pre-term birth. These same factors may be present in women who are likely to have an abortion.

  2. I figured you’d respond. Did you see my previous Infant Mortality and abortion post? I really expected you to say something then.

  3. I wonder about women who had a fetal demise and then go on to have a D&E verses induction. I would like to see several studies on this because it would give women a proper plan of action after the demise as to how to handle it…if there was any difference. I know “going natural” with a baby at later stages is an infeciton risk, so moms have to make a decision within a few days to a week.

    • Some time ago, I posted about Cytotec, and some woman wrote a response about how that she had begged the doctor for medicine to complete her miscarriage, and he refused, saying that she needed a D&C. It turns out that the D&C caused her to develop Asherman’s Syndrome (I’d not heard about it before that post) which left her infertile. She is understandably very angry about that. Of course, as you pointed out, a fetal demise may turn into an infection, which itself may cause fertility problems, so there is a risk-benefit to both courses of action.

  4. Whoa, I actually agree with Amy Tuteur about something!

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