How Effective is Plan B? 4

Plan B effectiveness, how effective is plan bThe majority of women have heard of Plan B, however it’s often simply marketed as this thing that you take anytime you’ve had unprotected sex or a contraceptive failure—that is if you don’t want to become pregnant—but how effective is Plan B really? What is Plan B and how does it work? Are there side effects? What are they? Fewer women know the answers to these questions. Luckily, to fully understand how effective Plan B is you need to understand what Plan B is and how it works so you learn the answers to all these questions.

So, let’s start at the beginning…

What is Plan B?

Chances are if you’re looking up Plan B effectiveness, you get that it’s a pill that helps prevent pregnancy, but to be more accurate, Plan B is a large dose of levonorgestrel. Levonorgestrel is a progestin that can prevent pregnancy primarily by preventing ovulation, but it may also prevent implantation.

How does plan B work?

Progesterone is a hormone that’s always present during your menstrual cycle. It maintains your uterine lining after ovulation. If you become pregnant, progesterone rises to cease ovulation and keep you from getting a period. Plan B essentially mimics pregnancy by delivering a large dose of progesterone (levonorgestrel mentioned above) so that the body already “thinks” it’s pregnant, doesn’t ovulate, and instead continues to thicken the uterine lining. As this large dose dissipates, withdraw bleeding occurs which usually resembles a period.

How effective is Plan B?

Plan B effectiveness really hinges on when it’s taken. The manufacture may tout it prevents 7 out 8 pregnancies, but realistically that’s likely only with perfect timing. Yes, Plan B must be taken within 72 hours, but there’s more to that story.

If Plan B is taken early in your cycle, it probably does have the suggested upwards of 89% effectiveness, but closer to mid-cycle, probably not, and after ovulation? It’s nearly a pointless measure. This is because you can’t prevent ovulation if it’s already happened.

After ovulation, all Plan B does is work to thicken the uterine lining more to prevent implantation. This means the later in your cycle it’s taken the less effective it becomes.

So, when should you take Plan B, if at all?

The reason it’s generally recommended to take Plan B at any time if you’ve had unprotected sex and don’t wish to become pregnant is because not all women know when they ovulate. Honestly, if they did they wouldn’t need Plan B, because they would know if the sexual act occurred during a fertile time.

Pregnancy is actually only possible about one week out of the month. You have the viability of sperm at about 5 days and the lifespan of an egg at 48 hours max. You can read more about your chances of pregnancy here, but long story short, in general, sex just before or just after a period is very unlikely to result in pregnancy. Whereas, sex mid-cycle has a higher chance.

Sadly, not all women ovulate mid-cycle. You can’t just assume if the sex is properly timed you won’t become pregnant and don’t need Plan B. It is actually possible to become pregnant from sex just after your period (when Plan B would be most effective), and at mid-cycle when you’re most likely to become pregnant, Plan B will at least hinder implantation by thickening the uterine lining and subsequently causing withdraw bleeding to thin it.

The only situation where we would say you’re probably just suffering side effects for no reason by taking Plan B is when the sex occurred in the final week before your period. Why? First, ovulation has likely already occurred by a long shot. There probably is no chance of pregnancy to begin with. Second, there is very little time to thicken the uterine lining. Additionally, if you are basal body temping and know when you ovulate, there is no reason to take Plan B unless you are in a fertile period.

Speaking of side effects…

Plan B Side Effects:

Side effects of plan B are basically a ramped up version of PMS, but may also mimic pregnancy symptoms. These include nausea, fatigue, feeling hot, discharge changes, bloating, cramping, and gas. This is because, as stated back there on how Plan B works, you’re creating a hormonal situation akin to pregnancy.

However, the most common Plan B side effect is irregular bleeding. Enough so you can read an entire page on this topic here.

I hope this has helped answer your questions about how effective is Plan B, but if not, we welcome comments and questions here at Life with Gremlins.

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4 thoughts on “How Effective is Plan B?

  • Anonymous

    I have done hours of research to try and ease my mind over these last few days but would like some confirmation to see if my girlfriend and I made the right calls. We were dumb and fooling around, and had unprotected penetration for well less than a minute twice on June 30th. Throughout the whole thing I felt in total control and felt nowhere near ejaculation. After I removed myself the first time I wiped everything down, and even after the second time I was only damp around the penis, and we believe it was from her. I did not look hard enough to see if I was leaking at all (dumb move) but I did not go near her vagina anytime after. The last day of her period was June 27th, and according to a tracking app she uses and updates every day or two, her fertile window was set to start around July 2nd and ovulation to occur on July 6th.

    We began to express greater concern as the day went on, and after doing research on the possible dangers of precum if it occurred from me, we decided to get a Plan B pill the next day. She took it around exactly 24 hours after the incident, on July 1st (I wish it was sooner but it was our first available window to obtain it). She has felt no side effects such as vomiting as of the 3rd, so we believe it stayed in her system. With all of that being said, is there anything else we can do but wait for her period, designated to start around the 20th? We did it 6 days before her ovulation is meant to occur, we took the pill within 24 hours for better effectiveness, it had been over two days since my last ejaculation and I had washed my penis and peed numerous times (so lower odds of live sperm in the precum), she had light watery mucus on the 1st to signal the start of her fertile window within a day, and most important of all there absolutely no chance of full ejaculation.

    All of this being considered, what are our odds of pregnancy here? Is there anything more we can do? Even some confirmation that we made the right calls after our mistake would ease our minds. A baby would not end our world but certainly change our life paths quite a bit, and we would prefer to avoid that. Any feedback would be appreciated.

    • Life with Gremlins admin

      Being 6 days before ovulation, the chances of pregnancy were already quite low, she would have had to ovulate a bit early really for there to be any chance at all. On top of that the chances of pregnancy with precum are also very low (less than 4 percent). With plan B use, I’d say her chances are very, very low to none, but no, asides from wait-and-see, there’s nothing else that can be done at this point. Keep in mind she may also see an off-period from the plan B use, try not to worry too much if she’s a bit late/early/sees spotting etc.

  • Juan

    Me and my girlfriend discovered the condom slipped off after we finished Sex. Luckily I pulled out and decided to get her the plan b a hour later. Since I didn’t ejacualte inside her, was it really a good idea to buy her the plan-b pill ?. Does precum still contain some sperm ? I’m still concerned if the plan b is really effective. Thanks

    • Life with Gremlins admin

      Precum can contain sperm, research is still undecided on whether that sperm is just picked up on exit (meaning urination between ejaculation and sex would eliminate it) or actually contained in the precum itself. Either way there’s less than a 4 percent chance of pregnancy with precum, so plan B or not, your chances are low. The plan B should lower that chance further. 🙂