Do the numbers matter?

By August 14, 2009No Comments

Welcome back to She Worships.  Sharon is still living it up on her honeymoon, but you are sitting by your computer (or snazzy iPhone) reading a blog post from some nerdy medical student.  Sounds like a fair trade huh?  Hey!,  you didn’t have to be so frank.  You could’ve just chuckled.

Baby's Foot

Like Sharon said on Tuesday’s post, my name is David and I have been friends with Sharon for the last 3 years since I came to town for medical school.  She asked me to write some posts for her while she was away on how we as Christians ought to approach and live in light of the often confrontational opinions of the scientific community.  I hope you had the chance to read Tuesday’s post, but today I want to get down to business with a specific topic today.

Just this week I was reading a textbook on the biological basis of AIDS and was amazed by the first sentence in one of the chapters.  It states “Every science has its borderland where the known and visible merge with the unknown and invisible.” The author, rather than opening with some cold hard fact, opened his chapter with an invitation away from the realm of the known virology of HIV and invited the readers to consider the mystery of its complexity.  As believers this is where we often have to live, balancing the tension of understanding the known and longing for the invisible.

It is in that tension that life exists most of the time.  One area where I still don’t have an answer is the question of the ethics of birth control.  I was talking about this issue with my family the other night, and my mom and my sister-in-law where shocked when I told them that there is a possibility that oral contraceptive pills (OCPs) may cause a chemical abortion after fertilization occurs.  This is a topic that is hotly debated and little consensus has been reached within the Christian community.  I care greatly about seeing healthy marriages raise healthy children and doing so to the glory of God.  It is essential that all of us considering parenthood be educated about this topic. Once again I want to arrange the topic in a series of points.  (Spoiler alert: Parents if you don’t want your kids to know that babies don’t come from storks please screen accordingly.)

1. Sin begins in the heart-The way I see it, the driving factor for the overwhelming majority of abortions is idolatry.  “On average, women give at least 3 reasons for choosing abortion: 3/4 say that having a baby would interfere with work, school or other responsibilities; about 3/4 say they cannot afford a child; and 1/2 say they do not want to be a single parent or are having problems with their husband or partner.” (1)  For many in our generation children are seen as an inconvenience, yet free and uninhibited sex is an assumed right.  I believe that there is an inherent difference in the willful cessation of a life and the failure of birth control to prevent ovulation for two parents who are trying to do the best that they know how to prevent pregnancy out of very good intentions.  (I know I am just throwing up comment fodder, but it will be fun.)

2. The Bible does not say that life specifically begins at conception- Like I said in point number 3 in my last post; the Bible is not a scientific textbook.  Before you go getting mad about the statement I just made, I think that this issue is painted with a much more significant brushstroke.  You see, I think it is most clear in the Scriptures that in God’s eyes my life began before the foundation of the world.  (Eph 1:4) Paul goes on to say in Ephesians that we are God’s workmanship, created in Christ Jesus for good works, which God prepared beforehand, that we should walk in them. (2:10) I believe that those good works are carried out through supernatural acts of the Spirit AND by the very natural arrangement of my DNA which God ordained to make me the precise version of a human that he desired.  This arrangement of DNA happens at fertilization.  Most of the time.

3. Becoming pregnant is actually incredible complicated-Why this issue is tough for me is the fact that 70% of fertilizations do not result in a viable pregnancy. (2) Fifteen percent fertilizations are not viable due to a failure to implant into the endometrium which is an issue we will talk about later.  For me as a believer, I have to make a faith statement about what I believe happens to those arrangements of DNA that fail to ever develop into ex utero human beings.  The case for fertilized eggs that fail to appropriately undergo integration of the two parent genomes or fail to survive the treacherous week traveling down the fallopian tubes is that they either are simply conglomerations of DNA that never obtain an existence in the mind of God or they are eternally known and loved souls who are free from the curse of sin (supported in Romans 1) and they dwell eternally with God.  I don’t know what to make of that startling 70%.  God does.

4. The oral contraceptive pill has three mechanisms of action by which it prevents pregnancy- The primary effect is that the progesterone and estrogen derivatives contained in OCPs block the surge in a hormone that tells the body to ovulate and block the development of a dominant egg that is ready to ovulate, respectively.  If this fails due to any one of a number of reasons, the progesterone in the OCP should have also acted to thicken the cervical mucus that theoretically acts as a barrier method to fertilization.  I have read some studies done in rabbits that questioned the effectiveness of this phenomenon, but it is generally accepted that it occurs.  Finally, if steps one and two fail, the third mechanism by which pregnancy is prevented is that the progesterone in the OCP has blocked the proliferation of the endometrium.

5. The endometrium is more important than you think-Many Christian authors (Randy Alcorn et al) use the term “hostile endometrium” when they describe the condition of the endometrial lining for women on OCPs.  My first reaction was “That is a little harsh.  But is it true?” I was very surprised to read in a highly respected Endocrinology textbook (3) that the author actually used the same term.  He goes on to say that “The progestin in the combination pill produces an endometrium that is … exhausted and atrophied…and is therefore not receptive to ovum implantation.

Other studies  “suggest that an endometrial thickness of 8 mm or more is necessary for successful implantation, although not all studies have found such an association. (4) Other researchers have shown that normal OCP use reduced thickness to ~3-4 mm. However the mean value of 3.9 mm had and SD of 3 mm meaning that for some women (top 15%) would retain a possibly thick enough endometrium after a year of OCP use.  This study was conducted using a lower dose progestin OCPs which are most common nowadays.  (5)

Even with all this information I just read this morning in a paper that “exogenous (coming from the outside) progesterone…prevents abortion (spontaneous ones) , further supporting the hypothesis that ovarian progesterone production is essential for the maintenance of early pregnancy” (6)

6. So what does all this mean?-Putting everything together I think the bottom line is that the decision to use OCPs is one that ought to be entered into with sober awareness that there is a risk one may accidentally cause an abortion that they would otherwise be appalled by.  The odds for this occurring are where the tension of science and theology is seen.  From the best I can deduce without finding hard and fast numbers I would say the odds of having a fertilized embryo that would meet a hostile uterus and that be the reason that it fails to survive would be between 1/100 to 1/1000. More clearly, if 1000 women in our church were having sex with their husbands every month and all of them were on the pill, 1 of them would have an abortion that their choice of medical therapy was responsible for.   I know that is a wide window, but there are several factors and conflicting data to consider in that calculation.  I don’t know if those numbers are true or not, no one does.  Keep in mind that 15/100 fertilized eggs fail to do this naturally.  Women get pregnant on the pill all the time, so we know it is not guaranteed to happen just because of the pill.

I believe Sharon has a lot of wisdom and has demonstrated in previous posts that your choice of contraception is tremendously more complicated than simply physiology.  Sharon’s question for me was “Do the numbers matter, or do you just know something is wrong regardless?”  I will ask you the same question.


(1) accessed on 08/12/09

(2)    Blueprints of Obstetrics and Gynecology

(3)    Kronenberg: Williams Textbook of Endocrinology, 11th ed. 2008.  Accessed online through MD Consult. July 2009.

(4)    Gabbe: Obstetrics: Normal and Problem Pregnancies, 5th ed. 2007. Accessed online through MD Consult. July 2009.

(5)    Lüdicke F et al. Effect of a combined oral contraceptive containing 3 mg of drospirenone and 30 microg of ethinyl estradiol on the  human endometrium. Fertil Steril. 2002 Jun;77(6):1308-9

(6)   Norwitz E. UpToDate article: Physiology of Parturition. Updated Nov 19 2008.

Leave a Reply