Pregnancy and Birth Control 101

In order for a woman to get pregnant, three things have to happen:

  1. Ovulation
  2. Fertilization
  3. Implantation

Even if all of these steps go perfectly, there is no guarantee that a woman will remain pregnant. But let’s pretend she does remain pregnant and that it’s an unplanned, undesired pregnancy. So she goes to the doctor… like me, for example:

“Hello, I understand you’re pregnant.”
“Yes.”
“How are you feeling about this news?”
“I don’t want to be pregnant.”
“OK, I understand. Please let me take the time to explain all of your options with this pregnancy. You may continue the pregnancy such that you will have a new baby in your family, you may continue the pregnancy and when you give birth place the baby in adoptive care, or you may end the pregnancy by having an abortion.”

This is a simplified version of how I personally counsel all of my patients who are newly pregnant with an unexpected pregnancy about which they are uncertain. (Note: women who answer the first question with “I’m very excited and can’t wait to have my baby!” do not receive counseling on the other options for obvious reasons.)

But, wait a minute! If people use birth control, there should be no such thing as an unplanned pregnancy!

Ah, if only more than just death and taxes were 100% in this world…

BIRTH CONTROL: HOW it works and how WELL it works

Methods that prevent Step #1: Ovulation

  • Nexplanon implant: >99% effective with typical use
  • DepoProvera injection: 94% effective with typical use
  • The Patch, the Ring, and the Pill (AKA combined oral contraceptive pills): 85% effective with typical use
  • Lactational Amenorrhea Method (breast feeding): 98% effective with perfect use in first 6 months postpartum
  • Emergency Contraception (Plan B, ella): the sooner after unprotected intercourse the better! 56-89% effectiveness, though studies are limited. It is ineffective if ovulation has already occurred, thus it is NOT an abortifacient

Methods that prevent Step #2: Fertilization

  • Sterilization (male and female): >99% effective with typical use
  • Mirena IUD (progesterone): >99% effective with typical use
  • ParaGard IUD (copper): >99% effective with typical use
  • Condoms: 80-90% effective with typical use
  • Natural Family Planning methods (withdrawal, calendar, basal body temperature): 75-80% effective with typical use

Methods that prevent (or disrupt) Step #3: Implantation

  • NONE

So, you see, no method works perfectly every time. Human beings are sexual beings and we will have sex. Even when we do everything right to prevent an unplanned pregnancy, our technology is not such that it can be prevented 100% unless one is not sexually active. But what’s the fun in that?


For more info, check out the links on the right under “Knowledge is Power.” Also, the CHOICE Project out of Washington University in St. Louis has a great video on the different methods and how to use them!

Resources: Contraceptive Technology by Hatcher et al, Practice Bulletins by the American College of Obstetricians and Gynecologists

7 Comments on "Pregnancy and Birth Control 101"

  1. Laura Conrad says:

    Thank you doctor about your conversation today on Twitter with us! IUDs are now endorsed by the American Pediatrics’ for teens and I was disturbed by that news.
    Condoms and spermicide is the go to for our society ideally. So to think we may be taking steps back, and not promoting condoms is scary!
    My step brother white male died of AIDS in the 90’s! He got it from his gf who was a drug user, he found out later (post infection).
    IUD’s work two ways not just one. I thought until today they only aborted babies, not fare to not inform woman! Today I read on WebMD that they work two ways, one by preventing some pregnancies and two by messing up the lining of the uterus so implantation doesn’t occur (thus baby starves and dies).
    The part that upsets me, is that us woman are not fully informed! I wasn’t either til now and I thought I was. Information is power!
    Also, let us not lie to our teen girls and say pregnancy is tissue that you can have removed (thus a violent abortion) and grieve at the loss of her baby(s) all her life. This is a child that can grow up to do great things! And bring a lot of love! We need to support woman and families better as a whole! Put some of our selfish plans aside and provide for the lives of children better! I love babies! They are awesome gifts!
    I choose life she is 9 (against anothers wish, who is glad she is alive now), and I am almost 48!
    Best “mistake” ever!!!! Grace is awesome, woman go for it! We can do it, be brave and have your babies! You will never regret choosing to save your babies life!
    God loves you and your baby! 😀 Peace and love to all! Prevention and education is key!

    • Leah Torres says:

      In my practice, whenever discussing safe sex practices, condoms are always emphasized and encouraged for STI prevention. That is an important point, thank you. Being fully informed is best achieved with scientifically accurate information which is what I provide to all of my patients and to anyone that may ask. Regarding terminology, different words should be used in order to show people compassion for the situation they are facing. If I use the term “tissue” to describe a pregnancy, it may be because it is a more delicate way of explaining a miscarriage to someone who is very upset about losing their pregnancy. It may be unkind to say something like “the baby died” if, in fact, there was not an embryo or fetus visualized at that point. While I understand where you are coming from, please recognize that different words can be used in an honest way but also with a delicate nature and compassion that may be required by a health care provider during counseling. Congratulations on being able to choose to continue a pregnancy and parent, which is 1 of the 3 options I offer when discussing pregnancy options. The other two are: 1) continuing the pregnancy and placing the baby for adoption & 2) terminating the pregnancy. I feel an ethical responsibility to explain all of the risks and benefits involved in all 3 options in order for pregnant people to make an informed decision about their pregnancy. Thank you for your comment and for reading the post.

      • Laura Conrad says:

        Thank you again for your response. The compassion and skill set you must have to help families through a miscarriage is incredible. I would stress everyone out and just cry with them. I am a wimp. 😉
        Yes, I too am glad my faith helped me stick to the right choice. Her father is too now! 😉
        The word tissue being used by medical staff in a miscarriage (especially under the conditions you describe) to ease the pain is far different than my concern.
        My concern is young woman have been told by medical staff, their baby is just tissue, and don’t fully understand life, nor understand the baby has a heartbeat. That is difficult to learn later. Very. So the full scoop up front is the best approach. I agree.
        It sounds like you really think about that, each person taking responsibility for themselves is key.
        I can’t judge anyone and try to avoid at all cost. haha Purely for selfish reasons, by the same measure I judge, so I will be. I need Grace and forgiveness, not judgment. 🙂
        I can’t imagine how many you help daily, keep up the positive work. And always speak the truth in love. We need to hear the truth as woman, young and old. We deserve it and our quality of future is dependent on it! Thank you Doctor Torres!

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