The Impact of Birth Control Pills on Female Fertility | Dr. Natalie Crawford & Dr. Andrew Huberman
00:00:00.000 | I get a lot of questions about birth control,
00:00:05.000 | but on my social media handles.
00:00:07.180 | - Don't we all, don't we all?
00:00:08.980 | - To be clear.
00:00:09.820 | It's a vast topic for exploration,
00:00:14.180 | but along the lines of what we're talking about now,
00:00:17.700 | I've heard, and I suspect it may not be true,
00:00:20.660 | but tell me, is there any evidence that taking birth control
00:00:25.660 | can disrupt the process that you just described?
00:00:28.740 | And when we talk about birth control,
00:00:29.900 | we should probably define what we're talking about.
00:00:31.460 | So there are hormone-based birth controls, AKA the pill.
00:00:35.860 | There are also hormone-based birth controls
00:00:37.340 | that are not in pill form.
00:00:38.640 | There are IUDs that are copper IUDs.
00:00:42.620 | There are other IUDs.
00:00:43.580 | Let's just talk about hormone-based contraception
00:00:47.340 | in females, which many of them, as I understand,
00:00:52.340 | are estrogen mimics or estrogen themselves
00:00:55.640 | that suppress ovulation.
00:00:57.220 | Do they diminish or increase the number of eggs
00:01:00.620 | that are taken from the vault?
00:01:01.960 | - Fantastic question.
00:01:03.200 | Let's talk about what people say is the pill.
00:01:06.200 | So let's specifically talk about
00:01:07.720 | combined oral contraception,
00:01:09.700 | the pill which has ethanol estradiol
00:01:11.940 | and some type of progestin.
00:01:13.940 | No, contraception does not change
00:01:16.800 | the release of eggs out of the vault.
00:01:18.520 | They are occurring at the same process and the same pathway.
00:01:22.180 | You're not ovulating because that estrogen does prevent FSH
00:01:25.820 | from coming from the brain.
00:01:27.260 | So you have the group of eggs still come out of the vault.
00:01:29.820 | There's no FSH.
00:01:30.980 | They just all die.
00:01:32.200 | The next group comes out.
00:01:34.300 | So when you are saying,
00:01:36.640 | are you gonna run out of eggs faster?
00:01:38.120 | Is it gonna harm your fertility?
00:01:39.700 | Does birth control impair the process?
00:01:42.120 | The answer is no.
00:01:43.380 | But there's a couple important caveats.
00:01:45.560 | One is that the birth control pills,
00:01:47.340 | especially if you take them continuously
00:01:49.940 | or for a prolonged period of time,
00:01:52.460 | the body's smart and the ovaries start to say,
00:01:55.260 | well, we're not really doing anything.
00:01:57.100 | And one of those markers of ovarian reserve we have is AMH
00:02:00.380 | and that's anti-mullerian hormone.
00:02:02.460 | And AMH is made from the granulosa cells
00:02:04.720 | or the cells that surround every follicle.
00:02:07.340 | So in the shortest way possible,
00:02:09.640 | more eggs in the vault, more come out every month,
00:02:12.120 | higher AMH.
00:02:13.300 | Fewer eggs in the vault, fewer come out, lower AMH.
00:02:16.820 | If your AMH is being suppressed
00:02:19.220 | because of the birth control pill,
00:02:20.860 | because it's decreasing the activity
00:02:22.460 | of those granulosa cells,
00:02:24.380 | you might get a low AMH value
00:02:27.380 | when you've been on the birth control pill for a long time.
00:02:30.100 | That is completely reversible.
00:02:32.580 | But it can be significant.
00:02:34.100 | So if somebody is wanting to get an AMH level,
00:02:37.720 | let's say somebody comes to my clinic,
00:02:39.280 | they're not trying to get pregnant and they're on the pill
00:02:41.400 | and they're considering freezing their eggs
00:02:43.660 | so we're going to check their ovarian reserve.
00:02:46.220 | If we draw it, I always say this,
00:02:49.900 | AMH may be up to 30% lower
00:02:51.980 | than somebody who is on the birth control pill.
00:02:54.500 | So we can still draw it.
00:02:55.980 | And if it comes back in the normal range, we feel good.
00:02:59.460 | But if it does come back low,
00:03:00.900 | we're going to have to make a decision.
00:03:02.800 | Are we going to stop the birth control pill
00:03:04.900 | for a period of some months,
00:03:06.720 | use alternative contraception
00:03:08.180 | if you don't want to be pregnant,
00:03:09.300 | and then repeat this test to see if this is a true low
00:03:13.460 | because we do see that young women
00:03:15.500 | do have low ovarian reserve sometimes,
00:03:18.100 | or was this just suppressed
00:03:19.440 | because you were on the birth control pill?
00:03:22.140 | So we see it impact some of the hormone testing
00:03:25.300 | that we can do.
00:03:26.380 | And I think that's an important distinction.
00:03:28.820 | And we can see that the longer you take it,
00:03:31.360 | that potentially it might actually improve your fertility
00:03:35.300 | if you had underlying endometriosis
00:03:37.500 | or some medical conditions
00:03:39.500 | that we see associated with infertility.
00:03:41.820 | So prolonged pill users
00:03:44.100 | can potentially improve their fertility
00:03:47.360 | versus people who are trying to get pregnant that same age
00:03:50.100 | who were not on the pill.
00:03:52.020 | Those studies are complicated, right?
00:03:54.300 | Because of selection bias.
00:03:55.420 | Because if you've been on the pill for 10 years,
00:03:57.300 | you're a little bit older.
00:03:58.900 | So is it that they were preventing pregnancy
00:04:01.100 | and the other group potentially had some exposures
00:04:03.420 | so they were inherently more infertile
00:04:05.560 | than the group that was on the pill?
00:04:07.780 | But we do know that the pill doesn't cause infertility.
00:04:10.700 | And I use it all the time.
00:04:12.040 | All the time in IVF cycles,
00:04:13.620 | we put people on the birth control pill
00:04:15.900 | because we can actually synchronize that group of eggs
00:04:18.820 | that comes out of the vault to grow together.
00:04:21.580 | Because your body doesn't want to have
00:04:23.660 | 20 babies at one time, right?
00:04:25.540 | And what we're trying to do with IVF,
00:04:26.860 | get 20 eggs to grow if that's what's out of the vault,
00:04:29.640 | really goes against the check and balance of the human body
00:04:33.880 | to not have 20 babies at once.
00:04:36.860 | - Why is it that males who take testosterone,
00:04:40.240 | synthetic testosterone,
00:04:41.740 | it shuts down their own testosterone production
00:04:43.900 | and sperm production,
00:04:44.900 | but females who take estrogen
00:04:46.380 | in the form of birth control pills,
00:04:47.620 | it doesn't shut down estrogen production by the ovaries?
00:04:50.500 | - So I love this question.
00:04:52.160 | You know the answer,
00:04:53.000 | so I like it extra because I know you're asking.
00:04:55.300 | Spermatogenesis is a constant and ongoing process, right?
00:04:59.140 | So in women,
00:05:00.140 | you're born with all the eggs you're ever going to have.
00:05:02.340 | And what we're talking about is if we stop FSH
00:05:06.260 | at that moment,
00:05:07.260 | we're just impacting the ability to ovulate at that time.
00:05:09.980 | But we're not changing this constant loss
00:05:11.780 | throughout the vault.
00:05:12.900 | Spermatogenesis, right?
00:05:14.260 | The sperm is made every single day,
00:05:16.100 | you're making brand new sperm.
00:05:17.440 | So 72 days for the sperm to be created in the testes
00:05:20.560 | and 18 days to find their way out the ejaculatory system.
00:05:24.620 | And so exposures that you have
00:05:27.700 | that stop the production of FSH and LH
00:05:30.480 | inhibit the development,
00:05:32.460 | the creation of new sperm.
00:05:34.300 | So somebody who's been on testosterone
00:05:37.460 | will tell the brain,
00:05:39.540 | the brain doesn't know it's from your taking it.
00:05:41.260 | It says, "Hey, we have plenty of sperm, we're good.
00:05:43.540 | We don't need any more."
00:05:44.820 | So the brain then gets suppressed
00:05:46.480 | and doesn't make that FSH and LH,
00:05:49.020 | therefore not stimulating both
00:05:51.620 | for their testosterone production,
00:05:53.120 | 'cause you don't need that.
00:05:54.640 | But testosterone production and sperm production
00:05:56.460 | go hand in hand.
00:05:57.300 | So therefore you're no longer making new sperm.
00:06:00.300 | And in fact, the longer you're on testosterone,
00:06:04.060 | the harder it may be to get sperm production to come back.
00:06:06.500 | And in 25% of people, they may not get it back
00:06:09.340 | if they've been on prolonged testosterone exposure.
00:06:12.260 | So it's really because of what
00:06:15.060 | women will sometimes say is unfair,
00:06:16.640 | which is the fact that you're born with all these eggs
00:06:18.920 | and you run out of them.
00:06:20.100 | They accumulate the wear and tear of your life, right?
00:06:23.020 | We see egg quality being a huge issue
00:06:25.400 | and female reproduction,
00:06:27.160 | yet men get to have new sperm every 90 days.
00:06:30.700 | They get to wash away whatever bad deeds they did
00:06:33.160 | and can change their lifestyle and their exposures
00:06:35.420 | and have very different sperm.
00:06:37.500 | But because of that same process,
00:06:39.460 | things that shut off the production of FSH, LH
00:06:41.840 | really impact sperm quite significantly.
00:06:44.420 | Is there any evidence that birth control,
00:06:47.620 | oral estrogen progestin-based birth control,
00:06:50.780 | just to keep it specific,
00:06:52.140 | can increase rates of cancers,
00:06:53.820 | can decrease rates of cancers,
00:06:55.700 | can lead to any sorts of disruptions
00:06:58.620 | in bodily function or health
00:07:02.260 | that's really like a rock solid result
00:07:04.600 | that's been seen by multiple studies, clinical trials,
00:07:07.600 | or are we still just in the dark about a lot of this stuff?
00:07:12.180 | - Okay, so nothing is without risk.
00:07:14.280 | Getting pregnant's not without risk.
00:07:15.800 | Taking the birth control pill is not without risk.
00:07:18.400 | We do see that there's been a lot of not informed consent
00:07:23.400 | in people who are taking the birth control pill,
00:07:25.800 | meaning maybe they weren't educated
00:07:27.920 | about what all of their options were,
00:07:30.380 | the positives and the negatives about each one of them.
00:07:33.460 | If we're gonna reference the convo to the pill,
00:07:35.840 | estrogen progesterone pill,
00:07:37.360 | important to understand that neither the estrogen
00:07:39.380 | nor the progesterone are the same estrogen progesterone
00:07:41.980 | that your ovaries make, right?
00:07:43.700 | It's ethanol estradiol,
00:07:45.120 | which your brain interprets as an estrogen,
00:07:47.700 | but other parts of your body may not.
00:07:49.980 | And then it's various types of progestins,
00:07:52.740 | some of which have even androgenic
00:07:54.700 | or male hormone-like properties,
00:07:56.660 | and some of which do not.
00:07:58.420 | So there's a ton of variation,
00:08:00.220 | even the amount of ethanol estradiol that each pill has
00:08:03.580 | with your low low and your low pills having less,
00:08:07.380 | and even with the modern day average pill
00:08:09.600 | having a lot less estrogen than it used to.
00:08:13.260 | When you're on the birth control pill,
00:08:15.340 | your ovaries aren't making estradiol.
00:08:18.620 | And that estradiol is important
00:08:21.400 | in growing the uterine lining,
00:08:23.620 | but also for the genital structures.
00:08:26.060 | And so we think about vaginal health and vulvar health,
00:08:29.180 | we certainly see that especially with continuous use.
00:08:32.540 | So if we distinguish, you take the pill for 21 days
00:08:36.740 | and you have a seven day break where you might bleed
00:08:39.020 | or you take sugar pills and then you take them again,
00:08:41.680 | a lot of people now are taking continuously
00:08:44.420 | where you have exposure to these compounds every single day.
00:08:48.580 | - So in like the wheel, the little pouch with the wheel
00:08:53.580 | of different colored pills,
00:08:55.400 | may have seen these on the countertop
00:08:58.100 | in previous relationships.
00:08:59.900 | And then there's the ones that sometimes people
00:09:01.820 | just opt not to take because those are the,
00:09:03.820 | not the placebo, they're the sugar pills.
00:09:05.980 | There's no need to take estrogen during that phase.
00:09:08.420 | And then they repeat.
00:09:09.700 | - Exactly.
00:09:10.540 | - Okay, but some people are taking estrogen
00:09:12.380 | all the way around the dial. - Continuously,
00:09:13.220 | it's very common right now.
00:09:14.580 | So people, and they're not wrong, they say,
00:09:16.960 | oh, well, why have a period in these little breaks?
00:09:20.340 | It's not really a reflection of my hormone status,
00:09:22.380 | which is accurate.
00:09:23.460 | And so they're taking them continuously.
00:09:25.660 | You also have less pill failure pregnancies.
00:09:28.200 | So if you're using the pill for contraception,
00:09:30.140 | that can be a great strategy.
00:09:31.820 | But the longer you take them,
00:09:32.780 | we do see some vaginal and vulvar changes, right?
00:09:36.100 | And so atrophic vaginitis,
00:09:38.260 | people who notice increased sensitivity,
00:09:40.500 | decreased elasticity, increase discomfort with intercourse,
00:09:45.380 | increase in yeast infections,
00:09:47.340 | that can sometimes be seen
00:09:48.420 | because that environment is different.
00:09:51.020 | Now, that's just one thing that can come from the pill.
00:09:55.000 | We also see the pill be lifesaving for other people.
00:09:58.280 | They have terrible PMS or premenstrual dysphoric syndrome
00:10:03.060 | where their mental health,
00:10:04.180 | when they change from high to low estrogen,
00:10:07.420 | it's always the change in estrogen that interferes,
00:10:10.260 | can cause some people to really have mental health issues
00:10:13.260 | that are so severe
00:10:14.660 | that having that stable hormone level is helpful.
00:10:17.980 | And so the pill can be extremely beneficial for some people
00:10:20.860 | when it comes to mental health.
00:10:22.260 | It can be beneficial for people who have issues
00:10:25.600 | with very heavy periods and anemia.
00:10:27.540 | Instead of getting blood transfusions,
00:10:29.420 | taking the birth control pill might prevent the lining
00:10:32.120 | of the uterus from growing so much that they bleed so much.
00:10:34.940 | Same thing with fibroids.
00:10:37.100 | People with PCOS.
00:10:38.500 | PCOS is polycystic ovarian syndrome.
00:10:41.220 | If we wanna put it very simply,
00:10:43.120 | you have a lot of eggs in your vault,
00:10:44.440 | so you release a lot of eggs every month.
00:10:46.560 | And what this does is the FSH signal gets diluted
00:10:50.060 | and so you're not responding to the normal signal
00:10:53.040 | and you don't ovulate.
00:10:54.540 | And because the ovary is a hormone-making factory,
00:10:57.060 | it gets really bored when it can't make estrogen
00:11:00.020 | 'cause that egg's not growing,
00:11:01.340 | so it starts to make testosterone.
00:11:03.180 | So you start to see this androgen-dominant environment
00:11:05.860 | associated with lack of ovulation
00:11:08.240 | and having a lot of follicles inside the ovary
00:11:11.540 | that are not really responding.
00:11:13.020 | - Androgenization, excuse me, androgenization
00:11:16.520 | of other tissues like body hair,
00:11:19.000 | deepening of voice. - Yeah, body hair.
00:11:21.020 | Typically the level of testosterone made in PCOS
00:11:23.940 | isn't truly deepening voice.
00:11:26.380 | It can if there is an ovarian tumor making testosterone
00:11:30.140 | or certain other conditions.
00:11:31.240 | But typically with PCOS, you see increase in body hair,
00:11:34.260 | increase in acne, and you can see some
00:11:36.460 | even like male pattern balding,
00:11:38.340 | some temporal balding of women, so some hair loss.
00:11:41.700 | - Temporal balding, so like the widow's peaking?
00:11:43.700 | - Yeah, the widow peaking and then thinning out
00:11:45.620 | in these two areas.
00:11:47.340 | And then we see an increase in body composition
00:11:50.860 | towards the male level.
00:11:51.800 | So if we think about a male body holding your fat
00:11:55.260 | in your abdominal region,
00:11:57.220 | and if we think about the traditional female body
00:11:59.540 | holding more fat in the hips and thighs area,
00:12:02.540 | we see that when this hormone shifts in PCOS,
00:12:05.220 | you tend to get more abdominal fat distribution,
00:12:07.840 | which then leads to further insulin resistance
00:12:10.440 | and metabolic syndrome.
00:12:11.880 | But in PCOS, because you're not ovulating,
00:12:15.060 | and those ovaries, each little follicle
00:12:19.340 | makes a tiny amount of estrogen.
00:12:21.360 | We'll say each little follicle, when it's not responding,
00:12:23.700 | will make one to two picograms of estrogen.
00:12:26.680 | But if you have 50 of them each month,
00:12:28.620 | you're having some constant estrogen exposure.
00:12:31.900 | So that lining of the uterus
00:12:33.220 | is being constantly stimulated to grow,
00:12:35.340 | and you're never getting the progesterone to stabilize
00:12:38.280 | or the progesterone withdrawal to bleed.
00:12:40.580 | So endometrial cancer is much higher
00:12:42.440 | in people with PCOS who don't ovulate,
00:12:44.260 | and the birth control pill can prevent that.
00:12:47.000 | Any unopposed estrogen situation,
00:12:49.460 | because the body is made to have
00:12:51.220 | both estrogen and progesterone.
00:12:53.820 | So we see an immense decrease in endometrial cancer,
00:12:56.820 | an immense drop in ovarian cancer.
00:12:58.860 | Ovarian cancer comes from the remodeling of the ovary.
00:13:01.740 | So every time you have a follicle grow, and it ruptures,
00:13:04.740 | and it makes the corpus luteum, and then it heals up,
00:13:07.780 | those are opportunities for those cancer cells
00:13:11.780 | to go away in that remodeling process
00:13:14.180 | and lead to ovarian cancer.
00:13:16.500 | And because you're not ovulating on the pill,
00:13:19.940 | your incidence of ovarian cancer drops dramatically.
00:13:23.420 | 10 years of pill use has dropped the chance
00:13:25.500 | you get ovarian cancer by more than 90%.
00:13:28.300 | And of course, ovarian cancer is super hard to diagnose
00:13:31.780 | because the innervation to the peritoneal system is poor,
00:13:35.780 | and you don't have any outward signs
00:13:37.300 | often till late-stage disease.
00:13:39.640 | That being said,
00:13:40.760 | could you potentially have an increase in breast cancer
00:13:45.060 | in some people?
00:13:46.180 | - By taking the pill?
00:13:47.020 | - By taking the pill.
00:13:48.180 | That's a concern, especially in people
00:13:50.380 | who might be predisposed to this for some other reason.
00:13:52.940 | - They might have BRCA mutations or something like that.
00:13:55.900 | And then is there a situation where the pill
00:13:59.260 | certainly masks what's going on with your menstrual cycle?
00:14:02.740 | And I really think this is where women's health
00:14:05.780 | has a huge history in paternalism,
00:14:08.100 | meaning doctors will just tell people,
00:14:11.180 | this is what you're going to do.
00:14:12.620 | So your periods are irregular,
00:14:14.380 | here is the birth control pill.
00:14:16.180 | And they're not explaining why or the pros and cons to it.
00:14:18.980 | And what happens is people are not being taught
00:14:21.740 | how their bodies work, and now they are
00:14:23.500 | because of your podcast amongst others.
00:14:26.380 | And now they're able to know that my period's a vital sign
00:14:29.860 | and I don't know what it is,
00:14:31.020 | because the pill is producing a different environment.
00:14:34.900 | The pill's also been associated with
00:14:36.740 | potentially development of things like leaky gut or IBS.
00:14:40.320 | And so there is a definite change in your environment
00:14:44.700 | when you're on the birth control pill.
00:14:46.040 | Increased risk of blood clots
00:14:47.620 | because of how it's processed in the liver,
00:14:49.900 | increasing your clotting factors.
00:14:51.460 | - Can I just interrupt there?
00:14:53.260 | You know, I'm aware that a fairly high percentage of people
00:14:58.260 | have mutations in Factor V Leiden, a clotting factor.
00:15:04.580 | Fewer people are, as we say, homozygous,
00:15:06.980 | have two deficient copies, mutant copies, I should say.
00:15:10.940 | But there are many people out there
00:15:11.940 | that have one mutant copy of Factor V Leiden.
00:15:13.900 | And my understanding is that oral contraception in females
00:15:16.700 | can really exacerbate the Factor V Leiden mutation.
00:15:20.580 | Do you suggest that people get their Factor V Leiden
00:15:25.580 | genetics analyzed?
00:15:27.440 | I mean, it's pretty inexpensive to do, right?
00:15:29.160 | I think on a standard blood test,
00:15:30.420 | you can just ask for the Factor V analysis.
00:15:33.680 | And it's not like a really in-depth thing.
00:15:35.820 | You don't have to fly to somebody that's a-
00:15:36.660 | - Yeah, it's a blood test.
00:15:37.500 | - Yeah, you don't have to fly to another country,
00:15:39.660 | you know, like you do for many things.
00:15:41.820 | - It's important to say that's not the norm, right?
00:15:43.540 | Like that's not the recommendation.
00:15:45.020 | When you're talking about putting somebody
00:15:46.140 | on the birth control pill,
00:15:47.600 | you want to make sure they don't have high blood pressure
00:15:49.460 | 'cause it can increase their blood pressure.
00:15:51.060 | You want to make sure they don't smoke cigarettes
00:15:52.700 | because the combination of the pill and cigarette smoking
00:15:55.620 | can increase the risk of a stroke.
00:15:57.540 | But the recommendation is not to screen them
00:15:59.340 | to see if they have any inherited clotting disorders.
00:16:02.140 | That said, if you ever have a blood clot
00:16:04.540 | on the birth control pill,
00:16:05.940 | 'cause you're traveling on a plane
00:16:07.220 | or you're just on the pill or you're living your life,
00:16:10.020 | you're now gonna get this extensive workup
00:16:12.160 | to find out if you do have that.
00:16:14.100 | It's by no means wrong, and specifically you should,
00:16:17.020 | if anybody in your family has ever had a DVT,
00:16:20.460 | so a deep vein thrombosis, so a blood clot in their leg,
00:16:23.420 | or a pulmonary embolism or a PE,
00:16:25.780 | so anybody in your family has had one of those,
00:16:28.180 | you should 100% get worked up for clotting disorders.
00:16:31.740 | And if you have something, like you carry Factor V,
00:16:34.660 | you should no longer take the birth control pill.
00:16:36.860 | And specifically the pill, because it's an oral pill
00:16:39.940 | and how it's metabolized in the liver
00:16:42.300 | is actually what is causing the change
00:16:45.820 | in those clotting factors
00:16:46.900 | because that's where they're made as well.
00:16:48.820 | So it doesn't mean you can't take any form of contraception,
00:16:51.900 | but we do wanna make sure
00:16:53.300 | that we counsel you appropriately.
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