The Myths of Breakthrough Ovulation & It’s Purported Abortion

19 Sep

A woman posted a meme on twitter talking about “breakthrough ovulation” and how these eggs fertilized after breakthrough ovulation gets killed by contraceptive pills. I asked her to explain scientifically how does the killing happen, but I never got a reply. My guess was she really did not know what she was talking about and thus the answer (because she just want to instill fear among her readers). How responsible tweet that was huh?

Breakthrough ovulation can happen, especially when the female taking pills is not compliant and does not follow instructions well. According to Dr. Dennis Higginbotham, “failure rates for pregnancy with BCP’s (birth control pills) can be 1% to 5% depending on the particular pill and on the patient compliance. Skipping pills is the usual cause for failure, but ovulation (and pregnancy) can occur even when the pill is taken properly.” (highlight is mine; Reference: Following his statement, it would show that the pills are 95-99% effective in suppressing ovulation.

Pill are composed of synthetic estrogen and/or synthetic progesterone. Some pills are plain progesterone, while some are combined estrogen and progesterone. The hormonal contents of birth control pills are minute as compared to the volume released by the ovary. It mimics the hormone’s action by causing ovary to stop ovulating, thins out the uterine wall, thickens the cervical secretions, all for the purpose of preventing pregnancy.

What are the circumstances surrounding ovulation? When a woman ovulates, there is a high estrogen level in her blood, there is the surge of luteinizing hormone. These two events are important to trigger the eruption of the ovum from the ovary. What are the sequela of elevated levels of estrogen? In the uterus per se, it causes thickening of the walls, increase in blood vessels, as if preparing for a possible pregnancy. That’s what estrogen does to the uterine lining. So, what will happen in cases of breakthrough ovulation, and this egg becomes fertilized? It has a rich uterine lining for implantation. This is contrary to the claim of misinformed anti-reproductive health bill measure that because the woman is taking pills, the uterus is thin and cervical mucus is thick disallowing pregnancy to happen. This is false! Estrogen and progesterone are endocrine hormones. This means that it is secreted by a certain organ, but its effect is transmitted to other organs sensitive to it via the bloodstream. In contrast, paracrine hormones/substances are substances which exert effect to nearby organs by diffusion but not via bloodstream. So in breakthrough ovulation, where the egg gets fertilized, PREGNANCY will take place, NOT ABORTION. As Dr. Higginbotham mentioned, there is 1-5% failure rate.

During the woman’s menstrual cycle, estrogen hormone predominate during the 1st 2 weeks (day 0-14). This hormone prepares the uterus and other reproductive organs for the forthcoming “pregnancy,” assuming that the egg gets fertilized upon its release – uterine lining thickens, there is increase in blood vessels, glycogen, etc. Everything happens in a concerted fashion for the anticipated pregnancy. By around day 14 of the menstrual cycle, the luteinizing hormone surges (released by the pituitary gland) and then triggers the release of the ovum.


Beautiful series of pictures taken by accident by the team of Jacquez Donnez as they were preparing the woman for partial hysterectomy. (source:


Image courtesy of


Image courtesy of

When the ovum is released, the follicle is converted into corpus luteum. Estrogen level now declines dramatically. The corpus luteum now releases progesterone to sustain the ovum. If the ovum gets fertilized, there is rapid proliferation of cells until the fertilized ovum will transform into blastocyst. This happens until about 13 days from fertilization. Up to this point, the corpus luteum provides progesterone for this developing embryo.

By around 13th day post-fertilization, the blastocyst implants. It may cause a minor bleeding in some women (post-implantation bleeding) while others may not. The outer layer of the blastocyst now imbeds itself into the rich vascular uterine wall and forms the placenta. Once implanted, the placenta now assumes the role of producing progesterone for nine months until the baby’s birth, as the corpus luteum has already involuted. This predominance of progesterone over estrogen during the period of pregnancy inhibits the ovary to release ovum for nine months as well.

This effect of progesterone predominance during pregnancy is mimicked by intake of contraceptive pills.  When the woman takes in hormonal pills, the progesterone becomes elevated thereby inhibiting the ovary to release an ovum, the uterine lining not prepared for pregnancy and the cervical mucus viscid, unfriendly to sperm that might swim up to the fallopian tube. Hence pregnancy will become unlikely.

Now it makes me wonder why these anti-rh bill supporters keep on saying that contraceptive pills are abortifacient. How can abortion happen when no ovum is released? And when there is no ovum released, what is there to fertilize? As of now, majority are in acceptance of the fact that fertilization is when human life begins. In cases of breakthrough ovulation which they repeatedly claim, again, if there is ovulation, then the uterus and the cervix is also prepared for a pending pregnancy because the effect of estrogen that lead to ovulation is also echoed in other parts of the female reproductive organ and not on the ovary alone. It does not happen that estrogen causes ovulation, but uterus remains thin and cervical mucus remains viscid. Estrogen and progesterone effects contradicting at the same time? No, dear anti-rh bill supporters, estrogen effect is endocrine. Again, read the meaning of endocrine as I have mentioned above. And if you insist on this premise that an ovum is released but the uterus and cervix is unprepared for a pregnancy, leading to the abortion of that fertilized ovum, then you should be one who is menstruating while pregnant because you think that estrogen and progesterone effects can happen at the same time. I wonder what subspecies of homo sapiens you are, perhaps Homo sapiens mutatis?


Posted by on September 19, 2012 in Pregnancy, RHBill


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16 responses to “The Myths of Breakthrough Ovulation & It’s Purported Abortion

  1. Joyce

    September 19, 2012 at 11:00 am

    I think that was a thorough explanation. I hope they get a better grasp of things after reading this..

  2. Irene Henderson

    September 19, 2012 at 4:14 pm

    I am a proud PRO RH Bill supporter, but I just know now in your blog that a contraceptives pill is not the answer in the increasing rate of abortion. Any ways thanks for sharing the myth!

  3. drclintonb

    December 3, 2012 at 2:01 am

    effect of hormone is universal. it does not target the uterus only. if contraceptive fails, and an ovum is released, remember, what hormone is elevated in a womans body before an ovum is released? ESTROGEN. and what is the role of estrogen to the uterine lining? it prepares the uterus for implantation.

  4. drclintonb

    December 3, 2012 at 2:02 am

    KNOW PHYSIOLOGY FIRST before you start bombarding me with this articles that cannot defend your arguments.

    • drclintonb

      December 3, 2012 at 2:12 am

      you are quoting articles blindly. understand first what i have written in my blog. and correlate it with the barrage of statements you posted in your comment. make it reconcile.

  5. Mrs. Jennilee C. Holman

    February 4, 2013 at 9:19 pm

    Your article was very helpful. I do believe life begins at conception, but I think my God is reasonable. If the pill has a very low rate of ovulation, that does not bother my conscience because the chances of getting pregnant are so low without contraception! I feel you were thorough without being pedantic. Even though I have my religious beliefs, I didn’t like the inflammatory articles I was finding by fundamentalists about “breakthrough ovulation”. I am considering Mirena and ALL I’m looking for is a statistic. Maybe you can help me. I feel you are more interested in truth and science than starting arguments. If the pill has a 2-10% “breakthrough ovulation” rate, what is the rate with Mirena? That is all I want to know so I can make my own choice. All these pro-life websites are filled with so much propaganda and few statistics that I actually find useful.

  6. Melba

    May 7, 2013 at 4:21 am

    Very, very interesting! Eye-opening! As an orthodox, pro-life, Catholic lady I was deeply concerned about the possibility of a fertilized egg not being able to implant in the uterus in the case of breakthrough ovulation. But if I understand correctly, if ovulation does occur- the uterine lining is NOT too thin for implantation. Fascinating! Really fascinating! I’m glad to come across this information. Science is awesome! And what a fantastic photo of the ovary, follicle and ovum! The human body is so beautiful!

    However, one thing is still very disturbing: as the article states, with typical use there’s a possibility of around 5 out of every 100 women becoming pregnant while using OCP. This is one of the significant reasons for concerns with contraception- they don’t always work and so women go to the back-up for “contraceptive failure”- abortion. In which case science proves itself: despite the scientific names of all the different stages, a fertilized egg left on its own to grow in the rich lining of the uterus grows into a miniature human.

    Thank you for the information and the beautiful photo as well!

    • drclintonb

      May 7, 2013 at 5:21 pm

      On the positive note, if mom becomes pregnant, at least no life was lost still. Right?

      • Melba

        May 8, 2013 at 3:52 am

        Oh yes, no life lost is always best! And thank you again for the intriguing information- I will certainly share it.

  7. Mdnd

    July 3, 2013 at 2:43 pm

    Good article, but it leaves some doubts in my mind about the possibility of at least the progesterone-only pill allowing ovulation and fertilization but preventing implantation due to progesterone’s effects on the endometrium. The observation (in the second article quoted below) that most pregnancies that do occur while on this mini-pill are ectopic, suggests that any fertilized eggs which tried to implant in the uterus were unable to do so and were lost.

    I would welcome your explanation or comments on this possibility.

    Below are some explanations of the progesterone-only pill’s mechanism of action, from non-pro-life educational resources.

    1. Birth control pills: The minipill (progestin-only pills)

    “Progestin-only pills suppress ovulation in about half of the menstrual cycles of the women who take them. But they prevent conception primarily by causing changes in the cervical mucus. The mucus thickens, making it difficult for sperm to get through the cervix. So even if you do ovulate, sperm won’t be able to make their way to your fallopian tubes to fertilize the egg. What’s more, progestin may prevent pregnancy by thinning the lining of your uterus, making it less likely that an egg would implant there even if one did get fertilized.”

    Reviewed by the BabyCenter Medical Advisory Board
    Last updated: September 2012

    2. The “Mini-Pill” or Progestin-Only Contraceptive

    How does the progestin-only pill work?
    “POPs may prevent pregnancy in several ways. They thicken the cervical mucus (the substance at the opening of the uterus), making it harder for sperm to reach and fertilize the egg. Like combined pills, they can prevent a woman’s body from releasing an egg during her monthly menstrual cycle. However, ovulation may not be consistently suppressed on POPs. Five percent of women using POPs will have an unintended pregnancy within the first year of typical use. Perfect use rate is 0.5%. The chance of becoming pregnant increases with missed pills. While the overall risk of ectopic (tubal) pregnancy is lowered by this method, any pregnancy that does occur is more likely to be ectopic.”

    McKinley Health Center, University of Illinois at Urbana-Champaign

  8. drclintonb

    December 20, 2013 at 3:23 pm


    PROGESTERONE, is a hormone that antagonizes the effect of estrogen. ESTROGEN is a hormone that prepares the uterus for OVULATION to happen. If ovulation is successful, estrogen declines in amount in the blood and PROGESTERONE starts to rise. The effect of the elevation of progesterone is: 1. suppress the ovary from further ovulation during that whole duration of pregnancy that is why, a pregnant woman does not menstruate during pregnancy, 2. it will sustain the pregnancy until it is completed to term.

    In cases of family planning, and progesterone-only pill is given, the effects as you have mentioned is 1. it suppresses the ovary to release an ova, that’s why they do not menstruate during the time they are taking the pill, the uterus lining is thinned out, and cervical secretion is not permissive for the semen. So since the ovary does not release ova, what is there for the sperm to fertilize? And when there is no ova that gets fertilized, how will an embryo form? So what will be aborted? NONE, according to logic, right?

    In cases of breakthrough ovulation while the woman is taking progesterone-only pill, where the ovary is able to release an ova despite intake of the pill, and it gets fertilized, go back to the first paragraph of my reply to you. The progesterone now, instead of thinning out the uterine lining, iwill promote and protect the pregnancy. Bear in mind that progesterone comes from 2 sources: the corpus luteum (the remains of the ovarian follicle that got released) which is responsible for the progesterone production until the embryo gets implanted, and the 2) placenta – which will secrete progesterone throughout the duration of pregnancy.

    Your logic that progesterone-only pill, when breakthrough ovulation happens and gets fertilized, will be aborted is NONSENSE. Pls employ logic.

    Thank you very much for reading my blog and finding time to react to it.

  9. Jon

    May 12, 2017 at 2:23 am

    I think the concern people have is that when breakthrough happens and a fertilized egg does not implant, a potential human being is lost. But in order to get a balanced view on this, we need to look at what happens in women who are not using birth control. For those women, fully 50% of the eggs that are fertilized either fail to implant, or later end in spontaneous abortion. If your concern is to protect the most future humans possible, it’s clear the pill is the best way to go. According to the most conservative figures, a woman is less likely to expel a fertilized egg on the pill by a factor of 8! Please see Libby Anne’s exhaustive article here:

    • drclintonb

      May 14, 2017 at 1:32 am

      you need to remember this: when a hormone affects one organ, it also affects other organs sensitive to it. During cases of breakthrough ovulation, it means that the progesterone has failed and therefore there is a rise of estrogen. The effect of estrogen in the ovary is to prepare the ova to rupture into the fallopian tube. But then, estrogen also affects the uterus. It prepares the uterus for the incoming implantation/pregnancy. So when there is a breakthrough ovulation, and the ovum released is fertilized, why will it become an abortion when the uterine lining is very well ready to receive the incoming embryo to be implanted? It cannot be that there is ovulation that happens but the uterine lining is thinned out. What is that, selective hormonal effect? That is not how the woman’s body works.

      • Jon

        May 15, 2017 at 3:48 am

        Synthetic progestin also works to make the uterine lining inhospitable to a fertilized egg. Pro-lifers don’t object when the progestin fails to do that and a pregnancy follows. But some of the time these fertilized eggs do not implant. It only happens in about 1 out of 600 women on the pill in any given month. But you are right, Dr. Clinton: about 10 out of 600 women on the pill will become pregnant. That still leaves the 1 woman who the pro-life people object to. But since I posted on May 12, I discovered my math was wrong. Approximately 36 out of 600 women not using birth control will pass a fertilized egg or experience a spontaneous abortion (an event where the egg has implanted and becomes detached) in any given month. So I repeat: If your concern is to protect the most future humans possible, it’s clear the pill is the best way to go. Pro-lifers must support the use of the birth control pill so “save” the most lives—which they generally do not.


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