Over the last few months, the concept of birth control has been under great scrutiny in the American eye. Many politicians have been discussing it’s “moral” implications, and whether institutions or organizations should have the right to deny insurance coverage for hormonal contraception if it does not fall within the confines of their belief systems. And while American women have narrowly escaped legislation that would impede their reproductive health and freedom, politicians, mostly men, feel it necessary to make misinformed or even completely false statements about birth control.
For some strange reason, there is this erroneous idea that birth control is not a matter of health, but rather a means by which a woman can engage in careless and frequent sexual activity, with a man, and without the consequences of pregnancy. It’s clear that the picture these politicians are trying to paint is that of debauchery and immorality, which, of course, is a departure from the puritanical integrity they embody. But, rather than focus on this utter nonsense, I would prefer to highlight the significant impact birth control will have on the future of our civilization and our planet.
The human population has grown steadily since the beginning of our species. However, the rate of growth began to skyrocket after the industrial revolution, and our population has actually doubled over the last 50 years, reaching 7 the billion mark in March of this year. This is an astounding statistic since it took until 1804 – around 50,000 years – to reach our first billion.
World Population: 1800 – 2100 (Wikimedia Commons)
What makes these numbers really scary is the concept of carrying capacity, which is an ecological term used to describe the maximum number of individual members of a species that a certain habitat can support. In this case, the species is human and that certain habitat is planet earth.
Here’s the thing: the availability of our resources will not match the rate of population growth. Given our current technologies, there is only so much food we can grow, only so much water we can drink, only so much space we can inhabit, only so much waste we can safely rid, only so much energy we can harness. There will be a point that the human population will hit its carrying capacity on earth, and when it does, the chances of widespread famine will be great, and the delineation between the developing world and the developed world will be no longer.
Given this very serious issue, Britain’s Royal Society has recently convened to discuss the future of the human population and on April 26th, 2012, and published their findings in the People and the Planet Report [PDF]. For me, key findingnumber three struck a cord:
Reproductive health and voluntary family planning programmes urgently require political leadership and financial commitment, both nationally and internationally. This is needed to continue the downward trajectory of fertility rates, especially in countries where the unmet need for contraception is high. (emphasis theirs)
Political leadership and financial commitment – Did you see that, American politicians?? For those of you who are unnecessarily waging war on women’s reproductive rights, its time to get your giant heads out of your collective asses and realize the implications of legislation that would go against ensuring both the continued success of our species and the health of our planet. It is time to stop spending money on these regressive and oppressive campaigns guised under the false pretense of “religious freedom” and start making a financial commitment to the women (and by association, men) who live in our nation.
To drive this point even further, here is another excerpt from the People and the Planet Report (my favorite bit, found in Box 2.5 on page 33):
Women bear the main physical burden of reproduction: pregnancy, breastfeeding and childcare. They also bear the main responsibility for contraception as most methods are designed for their use. Men, it may be argued, reap the benefits of children without incurring an equal share of the cost. It follows that women may be more favourable to the idea of small families and family planning than their partners but unable to express their inclinations in male-dominated systems. Such views received international endorsement in the Program of Action resulting from the UN conference on population in 1994. Paragraph 4.1 states that “improving the status of women is essential for the long-term success of population programs”.
We currently live in a nation where 99% of women who are of reproductive age have used some form of birth control at least once. And when it comes to hormonal contraception, over 80% of sexually active women aged 15-44 have relied on “the pill” as a means to prevent unwanted pregnancies. This has contributed to an average of two births per American woman, which is considered to be the replacement rate for a population. Compare this number to countries where birth control and reproductive education is scarce – countries like Niger (7.52 births per woman) or Afghanistan (5.64 births per woman) – and one can see the impact of family planning through contraception. Furthermore, it has been well documented that women in developed worlds who are provided with the means to control their fertility are more empowered and their families are healthier.
While our situation in the US is significantly better compared to underdeveloped nations where rape and the cultural devaluing of women is commonplace, we still have a responsibility to uphold – a responsibility that would undoubtedly increase the quality of life for women (and men), as well as contribute to the overall health of the human population. Why would we want to go backwards and remove the ability of a woman to decide when, if ever, she would like to reproduce?
Having access to birth control empowers women and allows them to make greater contributions to society. And because contraception is primarily the responsibility of a woman, our society needs to ensure that birth control, reproductive education, and family planning resources are readily available to EVERYONE.
The United Nations predicts that the ten-billionth person will be born around 2050. Will we continue to fight this ridiculous fight against women’s rights or will we redirect our collective energy to developing technologies that will help our species and planet better cope with the increasing demands associated with a steadily rising population? Let’s stop allowing stupidity to prevail and let’s start doing the right thing: making sure that birth control is readily available to any woman who wishes to use it. Because, now more than ever, it is clear that birth control will save the world.
Note: In my readings for this article, I came across a wonderful resource for anyone interested in learning more about human fertility and population growth. Through the wonders of the internet, Academic Earth is offering a free (!) online course called Global Population Growth, given by Yale University professor Robert Wyman.
These views are the opinion of the author and do not necessarily either reflect or disagree with those of the DXS editorial team.
Politics often interferes where it has no natural business, and one of those places is the discussion among a teenager, her parents, and her doctor or between a woman and her doctor about the best choices for health. The hottest button politics is pushing right now takes the form of a tiny hormone-containing pill known popularly as the birth control pill or, simply, The Pill. This hormonal medication, when taken correctly (same time every day, every day), does indeed prevent pregnancy. But like just about any other medication, this one has multiple uses, the majority of them unrelated to pregnancy prevention.
But let’s start with pregnancy prevention first and get it out of the way. When I used to ask my students how these hormone pills work, they almost invariably answered, “By making your body think it is pregnant.” That’s not correct. We take advantage of our understanding of how our bodies regulate hormones not to mimic pregnancy, exactly, but instead to flatten out what we usually talk about as a hormone cycle.
The Menstrual Cycle
In a hormonally cycling girl or woman, the brain talks to the ovaries and the ovaries send messages to the uterus and back to the brain. All this chat takes place via chemicals called hormones. In human females, the ovarian hormones are progesterone and estradiol, a type of estrogen, and the brain hormones are luteinizing hormoneand follicle-stimulating hormone. The levels of these four hormones drive what we think of as the menstrual cycle, which exists to prepare an egg for fertilization and to make the uterine lining ready to receive a fertilized egg, should it arrive.
In the theoretical 28-day cycle, fertilization (fusion of sperm and egg), if it occurs, will happen about 14 days in, timed with ovulation, or release of the egg from the ovary into the Fallopian tube or oviduct (see video–watch for the tiny egg–and Figure 1). The fertilized egg will immediately start dividing, and a ball of cells (called a blastocyst) that ultimately develops is expected to arrive at the uterus a few days later.
If the ball of cells shows up and implants in the uterine wall, the ovary continues producing progesterone to keep that fluffy, welcoming uterine lining in place. If nothing shows up, the ovaries drop output of estradiol and progesterone so that the uterus releases its lining of cells (which girls and women recognize as their “period”), and the cycle starts all over again.
A typical cycle
The typical cycle (which almost no girl or woman seems to have) begins on day 1 when a girl or woman starts her “period.” This bleeding is the shedding of the uterine lining, a letting go of tissue because the ovaries have bottomed out production of the hormones that keep the tissue intact. During this time, the brain and ovaries are in communication. In the first two weeks of the cycle, called the “follicular phase” (see Figure 2), an ovary has the job of promoting an egg to mature. The egg is protected inside a follicle that spends about 14 days reaching maturity. During this time, the ovary produces estrogen at increasing levels, which causes thickening of the uterine lining, until the estradiol hits a peak about midway through the cycle. This spike sends a hormone signal to the brain, which responds with a hormone spike of its own.
Fig. 2. Top: Day of cycle and phases. Second row: Body temperature (at waking) through cycle. Third row: Hormones and their levels. Fourth row: What the ovaries are doing. Fifth row: What the uterus is doing. Via Wikimedia Commons.
In the figure, you can see this spike as the red line indicating luteinizing hormone. A smaller spike of follicle-stimulating hormone (blue line), also from the brain, occurs simultaneously. These two hormones along with the estradiol peak result in the follicle expelling the egg from the ovary into the Fallopian tube, or oviduct (Figure 3, step 4). That’s ovulation.
Fun fact: Right when the estrogen spikes, a woman’s body temperature will typically drop a bit (see “Basal body temperature” in the figure), so many women have used temperature monitoring to know that ovulation is happening. Some women also may experience a phenomenon called mittelschmerz, a pain sensation on the side where ovulation is occurring; ovaries trade off follicle duties with each cycle.
The window of time for a sperm to meet the egg is usually very short, about a day. Meanwhile, as the purple line in the “hormone level” section of Figure 2 shows, the ovary in question immediately begins pumping out progesterone, which maintains that proliferated uterine lining should a ball of dividing cells show up.
Fig. 3. Follicle cycle in the ovary. Steps 1-3, follicular phase, during which the follicle matures with the egg inside. Step 4: Ovulation, followed by the luteal phase. Step 5: Corpus luteum (yellow body) releases progesterone. Step 6: corpus luteum degrades if no implantation in uterus occurs. Via Wikimedia Commons.
The structure in the ovary responsible for this phase, the luteal phase, is the corpus luteum (“yellow body”; see Figure 3, step 5), which puts out progesterone for a couple of weeks after ovulation to keep the uterine lining in place. If nothing implants, the corpus luteum degenerates (Figure 3, step 6). If implantation takes place, this structure will (should) instead continue producing progesterone through the early weeks of pregnancy to ensure that the lining doesn’t shed.
How do hormones in a pill stop all of this?
The hormones from the brain–luteinizing hormone and follicle-stimulating hormone– spike because the brain gets signals from the ovarian hormones. When a girl or woman takes the pills, which contain synthetics of ovarian hormones, the hormone dose doesn’t peak that way. Instead, the pills expose the girl or woman to a flat daily dose of hormones (synthetic estradiol and synthetic progesterone) or hormone (synthetic progesterone only). Without these peaks (and valleys), the brain doesn’t release the hormones that trigger follicle maturation or ovulation. Without follicle maturation and ovulation, no egg will be present for fertilization.
Most prescriptions of hormone pills are for packets of 28 pills. Typically, seven of these pills–sometimes fewer–are “dummy pills.” During the time a woman takes these dummy pills, her body shows the signs of withdrawal from the hormones, usually as a fairly light bleeding for those days, known as “withdrawal bleeding.” With the lowest-dose pills, the uterine lining may proliferate very little, so that this bleeding can be quite light compared to what a woman might experience under natural hormone influences.
How important are hormonal interventions for birth control?
Every woman has a story to tell, and the stories about the importance of hormonal birth control are legion. My personal story is this: I have three children. With our last son, I had two transient ischemic attacks at the end of the pregnancy, tiny strokes resulting from high blood pressure in the pregnancy. I had to undergo an immediate induction. This was the second time I’d had this condition, called pre-eclampsia, having also had this with our first son. My OB-GYN told me under no uncertain terms that I could not–should not–get pregnant again, as a pregnancy could be life threatening.
But I’m married, happily. As my sister puts it, my husband and I “like each other.” We had to have a failsafe method of ensuring that I wouldn’t become pregnant and endanger my life. For several years, hormonal medication made that possible. After I began having cluster headaches and high blood pressure on this medication in my forties, my OB-GYN and I talked about options, and we ultimately turned to surgery to prevent pregnancy.
But surgery is almost always not reversible. For a younger woman, it’s not the temporary option that hormonal pills provide. Hormonal interventions also are available in other forms, including as a vaginal ring, intrauterine device (some are hormonal), and implants, all reversible.
One of the most important things a society can do for its own health is to ensure that women in that society have as much control as possible over their reproduction. Thanks to hormonal interventions, although I’ve been capable of childbearing for 30 years, I’ve had only three children in that time. The ability to control my childbearing has meant I’ve been able to focus on being the best woman, mother, friend, and partner I can be, not only for myself and my family, but as a contributor to society, as well.
What are other uses of hormonal interventions?
Heavy, painful, or irregular periods. Did you read that part about how flat hormone inputs can mean less build up of the uterine lining and thus less bleeding and a shorter period? Many girls and women who lack hormonal interventions experience bleeding so heavy that they become anemic. This kind of bleeding can take a girl or woman out of commission for days at a time, in addition to threatening her health. Pain and irregular bleeding also are disabling and negatively affect quality of life on a frequent basis. Taking a single pill each day can make it all better.
Unfortunately, the current political climate can take this situation–especially for teenage girls–and cast it as a personal moral failing with implications that a girl who takes hormonal medications is a “slut,” rather than the real fact that this hormonal intervention is literally maintaining the regularity of her health.
For some context, imagine that a whenever a boy or man produced sperm, it was painful or caused extensive blood loss that resulted in anemia. Would there be any issues raised with providing a medication that successfully addressed this problem?
Polycystic ovarian syndrome. This syndrome is, at its core, an imbalance of the ovarian hormones that is associated with all kinds of problems, from acne to infertility to overweight touterine cancer. Guess what balances those hormones back out? Yes. Hormonal medication, otherwise known as The Pill.
Again, for some context, imagine that this syndrome affected testes instead of ovaries, and caused boys and men to become infertile, experience extreme pain in the testes, gain weight, be at risk for diabetes, and lose their hair. Would there be an issue with providing appropriate hormonal medication to address this problem?
Acne. I had a friend in high school who was on hormonal medication, not because she was sexually active (she was not) but because she struggled for years with acne. This is an FDA-approved use of this medication.
Are there health benefits of hormonal interventions?
In a word, yes. They can protect against certain cancers, including ovarian and endometrial, or uterine, cancer. Women die from these cancers, and this protection is not negligible. They may also help protect against osteoporosis, or bone loss. In cases like mine, they protect against a potentially life-threatening pregnancy.
Are there health risks with hormonal interventions?
Yes. No medical intervention is without risk. In the case of hormonal interventions, lifestyle habits such as smoking can enhance risk for high blood pressure and blood clots. Age can be a factor, although–as I can attest–women no longer have to stop taking hormonal interventions after age 35 as long as they are nonsmokers and blood pressure is normal. These interventions have been associated with a decrease in some cancers, as I’ve noted, but also with an increase in others, such as liver cancer, over the long term. The effect on breast cancer risk is mixed and may have to do with how long taking the medication delays childbearing. ETA: PLoS Medicine just published a paper (open access) addressing the effects of hormonal interventions on cancer risk.
[Editor's note: We are pleased to be able to run this post by Dr. Kate Clancy that first appeared at Clancy's Scientific American blog, the wonderful Context and Variation. Clancy is an Assistant Professor of Anthropology at the University of Illinois. She studies the evolutionary medicine of women’s reproductive physiology, and blogs about her field, the evolution of human behavior and issues for women in science. You can follow her on Twitter--which we strongly recommend, particularly if you're interested in human behavior, evolutionary medicine, and ladybusiness--@KateClancy.]
Over the course of my training to become a biological anthropologist with a specialty in women’s reproductive ecology and life history theory, or ladybusiness expert, I have learned a lot about miscarriage. Only it wasn’t miscarriage, it was spontaneous abortion. Except that some didn’t like the term spontaneous abortion and used intrauterine mortality (Wood, 1994). Or fetal loss. Fetal loss is probably the most common.
There is also pregnancy loss (Holman and Wood, 2001). You can use that term, too. Oh, or aContinue reading →
Prenatal care and treatment access are big factors.
By Laura Newman
Last week, the media got all excited about the possibility of a cure for HIV perinatal transmission. What was lacking was the recognition that the public remains largely ignorant about HIV in pregnant women. Yet with good wellness care, prevention, HIV testing, and medication,HIV transmission from mother to child can be close to zero. The public needs to know that women who are pregnant and HIV positive can also live good-quality lives, as can their children.
Thanks to Dr. Judy Levison, an obstetrician/gynecologist whose career centers on caring for HIV-pregnant women, I began to learn how scientific advancements in HIV-care make it possible for pregnant women with HIV and HIV-positive men to have children and not transmit the virus to their newborns. In the midst of this learning experience, I found out that a young woman I know, “Angela*,” was HIV positive and wanted to plan a pregnancy. I was shocked; I knew plenty of gay men with HIV, but rarely had I met a woman who had contracted the virus. Planning a pregnancy while being infected with HIV was something that I couldn’t imagine.
“Angela” is married and has lived with HIV for some years, with a low viral load by taking good care of herself and taking recommended antiretroviral therapy, when needed. She sought artificial insemination, one of several options available to HIV-affected couples. It worked. When she was planning her pregnancy, her parents were resistant. They worried that even though she is healthy now, that might change. They couldn’t imagine being saddled with taking care of a young child. Her parents’ resistance reminded me of the old coming-out stories we used to hear and how parents adapted to learning their child is gay. To their credit, both parents soon rose to the occasion. Angela and her spouse have a healthy toddler, and the grandparents love spending time with him.
Angela’s story isn’t everyone’s story. The hubbub at the recent 20th Conference on Retroviruses and Opportunistic Infections was not on the “functional cure” of the baby born to a pregnant woman with HIV, but on why, in this day and age, the mother doesn’t seem to have received the recommended prenatal care and antiretroviral therapy herself. Under what circumstances did she deliver? How did mom and baby get lost in the healthcare system? It’s far too easy to be captivated by a potential breakthrough and forget that plenty of people don’t get access to basic science-backed care that prevents HIV transmission in the first place.
As I describe below and as Angela’s experience illustrates, a lot of evidence shows that it is very safe for women with HIV to get pregnant, have healthy babies, and not transmit HIV to their children. Unfortunately, for many pregnant women with HIV, harsh judgments and inaccurate assumptions often carry the day. Let’s just say that HIV-positive moms and their kids have not earned the acceptance allotted to, say, a Magic Johnson, who has had HIV for decades, and with good HIV and wellness care, lives a good-quality life.
These inroads in science-based HIV prevention and care that have helped Johnson so much lag behind in poor and minority communities in the United States and low-resource countries around the world. HIV disproportionally affects African-Americans in the United States, and access to care, Medicaid cuts, and poverty reduce the chance that many people in need will receive good state-of-the-art prevention (regular testing, practicing safe sex, not sharing drug needles) and wellness care. Perinatal transmission could well rise in these communities.
Facing down ignorance
At first, being pregnant was not easy for Angela — not because her pregnancy was hard (it was not) — but because of the uneasiness some of her coworkers expressed about her becoming pregnant as an HIV-positive woman. Even though Angela worked in healthcare, some of her coworkers thought she had no business being pregnant. When she complained to her supervisor, the manager urged Angela to take it upon herself to educate staff about scientifically proven treatments for pregnant women with HIV that help moms stay well and prevent transmission to the baby. Angela asked instead for an in-service training, which was scheduled. Her colleagues’ attitudes turned around after the in-service.
It meant a lot to her to change the culture.
Angela had a normal term delivery, gave birth to a healthy baby, who is now a toddler, with no sign of HIV infection. Angela’s viral load remains undetectable. They are living healthy, high-quality lives like many other families, moms, and children.
The parents and prenatal planning
The ideal in the setting of HIV infection is that both partners are involved in preconception planning. Prevention of transmission of HIV from an HIV-positive father to an HIV-negative mom and fetus is now possible. The door is now open to HIV-positive men and women who want families but have HIV. Any plans they had to become parents have not simply vanished.
HIV research has advanced to the point that we now know that if HIV-positive individuals work with knowledgeable medical providers and have good access to proven practices, parents and children do quite well. Essential practices include:
Before trying to conceive, people should take antiretroviral drugs and have their infection under control, shown by a low viral load or undetectable levels of the virus (“undetectable” levels vary, depending on the lab) in their blood;
Couples are instructed to have unprotected sex only when the woman is ovulating. Current guidelines recommend using an ovulation prediction kit, which you can purchase at most drugstores.
Artificial insemination is another option that HIV-affected couples are using, as Angela did.
HIV testing is recommended routinely for all pregnant women, as well as for all non-pregnant adults and teens.
If a woman learns during her pregnancy for the first time that she is HIV infected, she can work with her healthcare provider to stay healthy, prevent mother-to-child transmission, and prevent passing HIV to her partner.
In general, people infected with HIV who are not pregnant begin taking anti-HIV medications when their CD4 counts fall below 500 cells/mm3 (HIV targets these immune cells and destroys them, compromising a person’s immunity). The medication regimen during pregnancy depends on whether or not you are taking medication to improve your own health or just your baby’s. In many cases, healthy women delay starting antiretroviral medication until the second trimester, which is when all women should be on HIV medication. However, HIV medication and interactions with other drugs and the fetus are complicated and require consultation with a physician. If women are diagnosed later in a pregnancy, they should start HIV drugs then. You can find detailed recommendations here.
During childbirth, women whose viral loads are still undetectable can have normal vaginal deliveries. However, according to the National Institutes of Health and other authorities, scheduled cesarean delivery at 38 weeks of gestation is recommended to reduce perinatal transmission of HIV for women with HIV-RNA levels >1,000 copies/mL or unknown HIV levels near the time of delivery, regardless of whether they were taking recommended antiretroviral drugs during pregnancy. The guidelines state that when there is a low rate of transmission (viral loads lower than 1000 copies/mL), the benefits of a scheduled c-section are unclear. Dr. Levison, an obstetrician/gynecologist at Baylor College of Medicine, Houston, TX, says that in her practice, women rarely need a cesarean section.
The newborn child
In the United States, breastfeeding is discouraged because HIV can be transmitted in breast milk. According to the Centers for Disease Control and Prevention (CDC), the risk for HIV transmission goes up as much as 45%. However, the topic of breastfeeding remains controversial. In healthy women with no HIV history, the broad consensus is that breastfeeding is best, giving babies excellent nutrition and helping the infant bond with mom. And many parts of the world have problems with sanitation and dirty water, making breastfeeding preferable to mixing formula. Outside of the US, according to Levison, in the UK, breastfeeding guidelines are more liberal. Furthermore, in some cultures, women are afraid not to breastfeed for fear that they will be outed as having an HIV infection, according to Levison, so many treating physicians adapt practice to the culture, preferences of the mom. Internationally, for example, in Africa, women often breastfeed and remain on antiretroviral drugs during that time. Formula is also costly. In the US, poor moms are eligible for formula through the federal Women’s Infants and Children’s nutritional support program.
Besides breastfeeding, HIV-positive moms need to know that pre-chewing of food before feeding baby is a transmission risk.
As soon as a woman goes into labor and during childbirth, the infantmust begin a six-week course of the antiretroviral medication zidovudine (AZT). Current guidelines also state that the baby should be tested for HIV at 14 to 21 days, at 1 to 2 months, and again at 4 to 6 months. If the viral load remains undetectable after two tests, the baby is considered to not have gotten HIV.
Resolving resource disparities
The moms, dads, and kids with HIV have enormous potential to live healthy lives for decades on proven antiretroviral drugs.
In fact, a December 2012 CDC Fact Sheet states that the number of women with HIV giving birth in the United States increased approximately 30% from 6,000 to 7,000 in 2000 to 8700 in 2006. During that same time frame, the estimated number of perinatal infections per year in all 50 states and 5 dependent areas continued to decline.
It’s not all good news, though, because of marked disparities in resource allocation and pre- and perinatal care. According to CDC data, 63% of perinatal infections were in blacks/African-Americans; 22% were in Hispanics/Latinos, and 13% were in whites. That leaves a lot of work to be done in enhancing targeted prevention programs.
Another recent milestone is that the US Preventive Services Task Force is finally about to endorse universal HIV testing, long after the CDC backed such a move in 2006. This milestone is important to because it is also linked to health reform. All public and private health plans are required to provide coverage for U.S. Preventive Services Task Force-recommended preventive services without patient copayments.
With this availability, perhaps women might learn about an HIV infection before they become pregnant, giving them time to have their own treatment in place before it is too late to protect the baby. The case report of the baby cured of HIV gives a lot of hope, but even more preferable would be preventing HIV infection in the first place, through safe sex and not exchanging needles. Once people become infected, for whatever reason, their lives should no longer be viewed as if they are at in a holding pattern until death.
The world needs to know that just like every other mom, dads and pregnant women with HIV can parent children, stay healthy, and not transmit the virus to their babies. Paramount in this is universal HIV testing for adults and teens, prevention programs, and ensuring scientifically proven treatment of the mother before, during, and after her pregnancy.
An historic view interpretation of the placenta (source).
She gave me a few minutes to meet my daughter before she reeled me back into a state that was my new reality. “You’re not finished Jeanne. You still need to birth your placenta.” What?!?! More pushing? But I was lucky and the efforts required to bring my placenta ex vivo were minimal.
This is the second placenta my body helped make. OK, so it doesn’t EXACTLY look like meatloaf…
The idea of a placenta, which is the only human organ to completely and temporarily develop after birth, was fascinating. That thing sitting in a rectangular periwinkle bucket was what allowed me to grow another human.. inside of my body! There was no way I was not going to check it out, as well as create a permanent record of its relatively short-lived existence.
My first impression was that it looked like “meatloaf.” Not necessarily a well made meatloaf, but perhaps one that is made by my mother (sorry mom). But, alas, chaos reigned and I wasn’t able to really take a good look. However, for my second birth and hence second placenta, my midwife indulged me with a more detailed look and a mini-lesson.
Baby’s eye view: Where geekling deux spent 39 weeks and 4 days.
Her gloved hands, still wet with my blood and amniotic fluid, slid into the opening that was artificially created with a tool resembling a crocheting needle. She opened the amniotic sac wide so I could get a baby’s eye view of the crimson organ that served as a nutritional trading post between me and my new bundle of joy.
She explained that the word “placenta” comes from from the Greek word plakoeis, which translates to “flat cake” (however, I’m sure if my mom’s meatloaf was more common in ancient Greece, the placenta would be named differently). “It’s one of the defining features of being a mammal,” she explained as I was working on another mammalian trait – getting my baby to nurse for the first time.
That was about all I could mentally digest at the time, but still, more than three years later, the placenta continues to fascinate me, mostly due to the fact that it is responsible for growing new life. It’s a natural topic for this long overdue Pregnancy101post, so let’s dive in!
Development of the placenta
It all starts when a fertilized egg implants itself into the wall of the uterus. But, in order to fully understand how it works, we should start with an overview of the newly formed embryo.
The very early stages of us (and many other things that are alive).
The trophoblast invades the uterus, leading to implantation of the blastocyst.
As soon as a male sperm cell fuses with a female egg cell, fertilization occurs and the cells begin to multiply. But, they remain contained within a tiny sphere. As the cells continue to divide, they are given precise instructions depending on their location within that sphere, and begin to transform into specific cell types. This process, which is called cellular differentiation, actually seals the fate every cell in our body, sort of like how we all have different jobs – some of us are transport things, some of us are involved in policing the neighborhoods, some of us build structures, some of us communicate information, some of us deal with food, some of us get rid of waste, etc. Every cell gets a job (it’s the only example of 100% employment rates!).
Now back to the cells in the fertilized egg. As they start to learn what their specific job will be, the cells within the sphere will start to organize themselves. After about 5 days after fertilization, the sphere of cells becomes something called a blastocyst, which readies itself for implantationinto the wall of the uterus.
The act of implantation is largely due to the cells found on the perimeter of the blastocyst sphere. These cells, collectively known as the trophoblast, release a very important hormone – human chorionic gonadotropin (hCG) – that tells the uterus to prepare for it’s new tenant. (If you recall, hCG is the hormone picked up by pregnancy tests.) Around day 7, the trophoblast cells start to invade the lining of the uterus, and begin to form the placenta. It is at this point that pregnancy officially begins. (Here is a cool video, created by the UNSW Embryology Department, showing the process of implantation.)
Structure of the placenta
Eventually the trophoblast becomes the recognizable organ that is the placenta. Consider the “flat cake” analogy, with the top of the cake being the fetal side (the side that is in contact with the baby), and the bottom of the cake being the maternal side (the side that is in contact with the mother).
Cross section of the placenta: Blood vessels originating from the fetus sit in a pool of maternal blood, which is constantly replenished my maternal arteries and veins. The red represents oxygenated blood, and the blue represents de-oxygenated blood.
Projecting from the center of the fetal side of the placenta are two arteries and one vein, coiled together in a long, rubbery rope, often bluish-grey in color. This umbilical cord serves as the tunnel through which nutrients and waste are shuttled, and essentially serves to plug the baby into the mother’s metabolic processes. At the umbilical cord-placenta nexus, the umbilical cord arteries and vein branch out into a network of blood vessels, which further divide into a tree-like mass of vessels within the placenta.
These tree-like masses originating from the umbilical cord (and thus fetus) sit in a cavity called the intervillous space, and are bathed in nutrient-rich maternal blood. This maternal blood, which provides the fetus with a means for both nutrient delivery and waste elimination, is continually replenished via a network of maternal arteries and veins that feed into the intervillous space. Furthermore, these arteries and veins help to anchor the placenta into the uterine wall. One of the most interesting aspects about the mother-feus relationship is that the blood vessel connection is indirect. This helps to prevent a detrimental immune response, which could lead to immunological rejection of the fetus (sort of like how a transplanted organ can become rejected by the recipient).
Functions of the placenta
Just like a plant needs sunlight, oxygen, and water to grow, a baby needs all sorts of nutrients to develop. And since a baby also produces waste, by nature of it being alive and all, there is an absolute requirement for waste removal. However, because we can’t just give a developing fetus food or a bottle, nor are we able to change diapers in utero, the onus lies completely on the biological mother.
This is where the placenta comes in. Because the fetus is plugged into the circulatory system of the mother via the umbilical cord and placenta, the fetus is provided with necessary nutrients and a mechanism to get rid of all the byproducts of metabolism. Essentially, the placenta acts as a waitress of sorts – providing the food, and cleaning it all up when the fetus is done eating.
But it’s not just about nutrition and waste. The placenta also serves as a hormone factory, making and secreting biological chemicals to help sustain the pregnancy. I mentioned above that the placenta produces hCG, which pretty much serves as a master regulator for pregnancy in that it helps control the production of maternally produced hormones, estrogen and progesterone. It also helps to suppress the mother’s immunological response to the placenta (along with other factors), which cloaks the growing baby, thereby hiding it from being viewed as a “foreign” invader (like a virus or bacteria).
Another hormone produced by the placenta is human placental lactogen (hPL), which tells the mother to increase her mammary tissue. This helps mom prepare for nursing her baby once it’s born, and is the primary reason why our boobs tend to get bigger when we are pregnant. (Yay for big boobies, but my question is, what the hell transforms our rear ends into giant double cheeseburgers, and what biological purpose does that serve?? But I digress…)
Despite the fact that the mother’s circulatory system remains separate from the baby’s circulatory system, there are a clear mixing of metabolic products (nutrients, waste, hormones, etc). In essence, if it is in mom’s blood stream, it will very likely pass into baby’s blood stream. This is the very reason that pregnant mothers are strongly advised to stay away from cigarettes, drugs, alcohol, and other toxic chemicals, all of which can easily pass through the placental barrier lying between mother and fetus. When moms do not heed this warning, the consequences can be devastating to the developing fetus, potentially leading to birth defects or even miscarriage.
There are also situations that could compromise the functions of the placenta – restriction of blood supply, loss of placental tissue, muted placental growth, just to name a few – reducing the chances of getting and/or staying pregnant. This placental insufficiency is generally accompanied by slow growth of the uterus, low rate of weight gain, and most importantly, reduced fetal growth.
And it’s not just the growth of the placenta that is important – where the placenta attaches to the uterus is also very important. When the placenta grows on top of the opening of the birth canal, the chances for a normal, vaginal birth are obliterated. This condition, known as placenta previa, is actually quite dangerous and can cuase severe bleeding in the third trimester. 0.5% of all women experience this, and it is one of the true medical conditions that absolutely requires a C-section.
Then, there is the issue of attachment. If the placenta doesn’t attach well to the uterus, it could end up peeling away from the uterine wall, which can cause vaginal bleeding, as well as deprive the baby from nutrient delivery and waste disposal. This abruption of the placenta is complicated by the use of drugs, smoking, blood clotting disorders, high blood pressure, or if the mother has diabetes or a history of placental abruption.
Conversely, there are times when the blood vessels originating from the placenta implant too deeply into the uterus, which can lead to a placenta accreta. If this occurs, the mother generally delivers via C-section, followed by a complete hysterectomy.
Cultural norms and the placenta
There are many instances where the placenta plays a huge role in the culture of a society. For instance, both the Maori people of New Zealand and the Navajopeople of Southwestern US will bury the placenta. There is also some folklore associated with the placenta, and several societies believe that it is alive, pehaps serving as a friend for the baby. But the tradition that seems to be making it’s way into the granola culture of the US is one that can be traced back to traditional Chinese practices: eating the placenta.
Placentophagy, or eating one’s own placenta, is very common among a variety of mammalian species. Biologically speaking, it is thought that animals that eat their own placenta do so to hide fresh births from predators, thereby increasing the chances of their babies’ survival. Others have suggested that eating the nutrient-rich placenta helps mothers to recover after giving birth.
However, these days, a growing number of new mothers are opting to ingest that which left their own body (likely) through their own vaginas. And they are doing so though a very expensive process involving dehydrating and encapsulating placental tissue.
Why would one go through this process? The claims are that placentophagy will help ward of post partum depression, increase the supply of milk in a lactating mother, and even slow down the ageing process. But, alas, these are some pretty bold claims that are substantiated only by anecdata, and not actual science (see this).
So, even though my placentas looked like meatloaf, there was no way I was eating them. If you are considering this, I’d approach the issue with great skepticism. There are many a people who will take advantage of maternal vulnerabilities in the name of cold hard cash. And, always remember, if the claims sound to good to be true, they probably are!
Thanks for tuning into this issue of Pregnancy101, and enjoy this hat, and a video!
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