AP Biology class blog for discussing current research in Biology

Tag: pregnancy

Maternal Stress During Pregnancy

According to researchers at the University of Cincinnati, maternal stress during pregnancy has a harmful effect on the neurodevelopment of babies. A methyl group gets added to DNA, which is called DNA methylation. This likely plays a role in it. The findings could provide new insight into how the fetal environment potentially influences neurodevelopment, metabolism, and immunologic functions. 

DNA methylation

More than 5,500 people took part in this study, which broke down into 12 different groups. The research examines financial stress, conflict with a partner, conflict with a family member or friend, abuse, and death of a friend or relative. Plus, there is a cumulative score that combines all these categories. 

Two young people demonstrating combat

They found that mothers experienced a great amount of stress during pregnancy. There was an association with DNA methylation in the umbilical cord blood, which is an epigenetic modification in the baby’s development. They found five specific locations of DNA methylation with three different maternal stressors. The three different maternal stressors were conflict with a friend or family, abuse, and death of a close friend or relative.  

Epigenetics modifications

In AP Biology, we have learned that DNA methylation causes nucleosomes to pack tightly together, which prevents transcription factors from binding to the DNA. Gene expression is the process of turning on a gene to produce protein and RNA. 

The researchers plan to further investigate and do some functional analyses to see how the genes work and how the DNA methylation affects their expression. 


How Chewing Gum(If You’re a Pregnant Woman) Might Just Prevent You From Having Preterm Birth

In the United States alone, 1 out of every 10 infants is born prematurely. While this might not initially seem to be very significant, this statistic entails hundreds of thousands of infants born prematurely every year. Premature infant birth can cause a myriad of problems – ranging from mild consequences, like small body size, to more severe ones, respiratory distress. Even further, babies born prematurely are more likely to die in their first year alive than babies born according to term. 

If you are a pregnant woman, these facts may scare you. However, there may be a simple fix – the next time someone offers you a stick of sugar-free gum, accept their offer. 

More specifically, xylitol gum, in a large study in Malawi, has been shown to reduce preterm births. In the study, 36.6% of women who did not receive the gum birthed their babies preterm, while only 12.6% of women who regularly chewed xylitol gum birthed their babies preterm, displaying a 24% decrease in preterm births. 

Despite it being a simple solution, the mechanism for xylitol as a saver of infant life is more complex. Oral bacteria is one of the largest hubs for bacteria life in your body; second only to gut flora. However, harmful bacteria growth poses the risk of infected gum tissue, which leads to bacterial infection of the bloodstream and internal organs, including the placenta in pregnant mothers. Although the scientific reasoning is still shaky, certain bacterial infections of the placenta originating from oral flora may cause complications leading to premature childbirth.

Even more technically, xylitol affects the energy-production processes of oral bacteria, such as Streptococcus mutans (MS). When xylitol is consumed by MS bacteria, MS transports the xylitol sugar into the cell using facilitated diffusion, and transports it via the same processes that happen to control growth inhibition. Xylitol is converted to xylitol-5-phosphate, which MS then dephosphorylates. After, the bacteria expels this dephosphorylated molecule out of the cell actively, requiring energy. However, the metabolism of xylitol by MS does not provide it with any significant energy as a product. Thus, MS repeats this process until it starves to death due to lack of energy, as MS is not taking in enough energy to meet its energy demands from xylitol metabolism. 

In conclusion, chewing xylitol gum as a treatment for premature childbirth has yielded promising results thus far. And due to its high efficacy to cost ratio and high availability, chewing xylitol gum seems to be an effective treatment for premature childbirth in poorer nations like Malawi. Xylitol chewing gums

Pregnancy vs The Vaccine

Getting COVID as one person is already a risky and life-threatening experience, but imagine obtaining COVID while carrying another human inside of you! Though there are risks of getting the vaccine shots while pregnant, there are far more risks for the baby to be born unhealthy if the mother is unvaccinated. Why risk your baby’s life when there is an easily preventable way of avoiding the possibility of losing your child? 

The risks from developing COVID-19 when pregnant and unvaccinated were demonstrated in a recent study from Scotland. From December 2020 until the end of October 2021, a period when vaccines were available, there were 4,950 confirmed coronavirus infections among pregnant women. 77% percent occurred in those unvaccinated, along with 91 percent of the 823 hospital stays and all but two of the 104 intensive care admissions, researchers report January 13 in Nature Medicine.


Babies suffered too. The death rate for babies born within 28 days of their mother’s COVID-19 diagnosis was 22.6 deaths per 1,000 births, much higher than the rate for all newborns during the pandemic, 5.6 per 1,000. All of the babies who died over the course of the study were born to women who weren’t vaccinated when they got COVID-19, the researchers found. Scientists are still unraveling what’s happening behind the scenes during a SARS-CoV-2 infection in pregnancy, and why the delta variant was especially deadly for those expecting. The highest numbers of U.S. deaths for pregnant individuals, 40 in August and 35 in September, occurred during the delta surge. There aren’t details yet on how pregnant people fare after becoming ill with the now-dominant omicron variant. But experts don’t advise a wait-and-see approach. And the vaccines continue to offer protection against severe disease and death.

Pregnancy can be a risky time to get an infection in general. Influenza and malaria, for example, can be more severe in people who are pregnant than in those who aren’t. That risk is tied to changes in the immune system. “Pregnancy is a very complicated immune state,” says Andrea Edlow, a maternal-fetal medicine specialist at Massachusetts General Hospital and Harvard Medical School in Boston. The immune system needs to defend pregnant individuals and their fetuses against pathogens. If COVID is contracted by the mother while pregnant, then the baby in the womb will have to fight off COVID just as the mother has to. Learned in AP Biology, the mother has an advantage over the baby because the mother’s immune system has been exposed to more pathogens including bacteria, viruses, toxins, or other foreign substances that the baby hasn’t. In other words, the mother has adaptive immunity or acquired immunity, so after the first line of defense, known as innate immunity, is insufficient to control the infection, the adaptive response kicks into gear to try and fight off COVID. This puts the baby at severe risk of dying because its immune system is not fully developed yet, and hasn’t been exposed to any other pathogen before.  

There have been 169,407 cases of COVID-19 among pregnant individuals in the United States since the pandemic’s start, with a spike in late December of 2021 due to omicron. The counts for January 2022 are not yet complete. When the delta variant took over in the summer and fall of 2021, the risk of stillbirth grew, the study found. From March 2020 to June 2021, before delta, the risk was 1.5 times higher for pregnant women with COVID-19. From July to September of 2021, when delta reigned, there were 3,559 deliveries among women with COVID-19, of which 96, or 2.7 percent, were stillbirths. Of the 169,330 deliveries among those without the disease, 1,075, or 0.6 percent, were stillbirths. That’s four times the risk.

The first inklings that COVID-19 was especially dangerous for pregnant people came in the first year of the pandemic. Year two brought vaccines and plenty of research found COVID-19 vaccination was safe during pregnancy. More than 194,000 pregnant people in the United States have gotten COVID-19 vaccines as of January 31, according to the CDC. There have been no reported safety concerns. A study of close to 2,500 participants in a CDC COVID-19 pregnancy registry found no increased risk of miscarriage after vaccination, researchers reported in October of 2021 in the New England Journal of Medicine. Nor is there a risk of the baby coming too soon or too small, researchers report January 7 in Morbidity and Mortality Weekly Report. The U.S. study of over 40,000 pregnant women found no link between COVID-19 vaccination and preterm birth.

COVID-19 vaccines (2021) A

Even with the reassuring data on COVID-19 vaccination during pregnancy, it’s been hard to stamp out the uncertainty some feel about the shots. Other vaccines are routinely recommended in pregnancy, such as the influenza shot. But the COVID-19 vaccines were new, and pregnant people, as is standard practice, were excluded from the clinical trials that assessed the shots’ safety and efficacy. Excluding pregnant women from the trials can make it seem like “something must be wrong, this must be dangerous,” Edlow says. There were no safety issues among individuals who became pregnant during the trials, nor were there safety concerns in animal studies. Medical organizations said that COVID-19 vaccines shouldn’t be withheld due to pregnancy, but a forceful recommendation for vaccination didn’t come until July 2021.  

Though there has been hesitation from amounts of pregnant women about receiving the vaccine, at the end of the day they are just trying to protect their children from this very harmful and deadly virus, and the more knowledge they get from their doctors the more they understand that the best way for their child to be protected and healthy is if they get the vaccine.


How America is Failing Black Women During Pregnancy and Childbirth

In the United States, about 700 women die each year due to pregnancy related causes and about 65,000 women come close to death. The U.S. has the highest maternal mortality rate compared to developed nations. Maternal mortality is when a person dies during pregnancy, at delivery or shortly after childbirth. While this is a shocking statistic, an even more surprising one is that in the United States, Black women are three to four times more likely to die because of a pregnancy-related issue than white women. This disproportionate ratio is one of the reasons that the United States Mortality rate is much higher than other developed countries. But, the death of many of these Black mothers are preventable. 

In the past, healthcare professionals and researchers have attributed this high rate of mortality due to pre existing conditions because Black women are more likely to be obese or hypertensive. More recently, in the scientific community there has been an agreement that the blame should not be placed on the women but instead on systemic racism. This is not only in healthcare but also because of other social inequities such as access to food, good schools, jobs, and safe drinking water, just to name a few. When understanding health inequities it is important to look at these social determinants of health, as well as access to prenatal care. While the blame is put on a number of complex issues, unconscious bias of healthcare providers play an important role. This is shown clearly through Serena Williams childbirth complications. Williams is at the top of her field, and a well respected woman. Despite being such an affluent figure, she was dismissed when she told nurses that her breath was shortening during childbirth. The nurses wasted crucial time even though they were informed of Williams’ medical history. Serena William’s story does not stand alone, well off Black women are more likely to die than white women due to pregnancy related issues. In general, one in four Black women report feeling disrespected by medical professionals. There are so many stories, such as, a new mother whose doctors didn’t believe her when she said she was having a heart attack until she had a second one, a mother whose obesity was blamed when she had trouble breathing when in the end it was her heart failing.

Recognizing the issue is only part of it, the next step is to implement policy and change to ensure that Black mothers do not die due to systemic racism and bias in the healthcare system. One way to potentially decrease the high rates in mortality is to recognize race as a factor during prenatal screenings, this way pre-existing conditions and health complications are less likely to be blamed. Hospitals should implement training on unconscious bias because if healthcare providers are not aware of the issue, they may not notice their own bias. There should also be a push for more standardized healthcare, an increased awareness around maternal health and ensuring that mothers make decisions about their own care. Realistically, there is not one answer to this issue as it goes beyond the healthcare system and instead is just one outcome of systemic racism in the United States. So, what do you think is the best solution to decrease the disproportion mortalities in maternal medicine?

Can Stress Affect Pregnancies in Later Generations?

We all know stress isn’t always a good thing, but it could be important to especially avoid it at certain points in one’s life. Recently researchers from the University of Lethbridge in Canada investigated the effects of stress on pregnancies and how it can influence pre-term births. It is already known that pre-term births them selves lead to health issues later in life, but there were some new discoveries involving epigenetics.




These researchers studied the length pregnancies of rats, due to the generally small amounts of variation between them, and found something intriguing. They carried out the experiment by first splitting the first generation of rats into “stressed” and “not stressed” groups. What they found was that the daughters of stressed rats had a shorter pregnancy than the daughters of not stressed rats.

This trend continued into the granddaughters of the rats. They also displayed high levels of glucose than the control group, and they weighed less. The stress also compounded, or increased, through generations.

This can all translate into human pregnancies. The researchers believe that the epigenetic changes in the rats is due to microRNA (miRNA) – non-coding RNA molecules that play a role in regulating gene expression. They bind to complementary mRNAs and prevent them from being translated. This is different than what is usual belief with epigenetics which is that epigenomes are affected by DNA methylation of the nucleotide base pairs. Metz, a scientist working on this research states that microRNAs “are important biomarkers of human disease, can be generated by experiences and inherited across generations. We have now shown that maternal stress can generate miRNA modifications with effects across several generations.”

It is very similar to the information found with the generational epigenetic effects of famine in the “Ghost in Our Genes” video that we watched in class.

This research can help determine pre-term births and the causalities that can come along with them. While the research is still not the whole picture, it is another step towards understanding our genetics.


Are the teens on teen mom the only ones?

Many people talk about the teens on 16 and Pregnant and how we as a nation have increased our teen pregnancy rates, but according to News Day teen pregnancies are at an all time low. “There has been a phenomenal drop [of 9 percent] in the last two years,” said Brady Hamilton. Many people frown upon the the fact that now more than ever we have been hearing about teen pregnancies but according to this article there has been a 44% drop in teenage pregnancies since 1991.

copyright: Gabrielle A.copyright: Gabrielle Aaron

“The U.S. teen birthrate is still among the highest for industrialized countries, however.” This makes me wonder because we may have the most teenage mothers recorded but what about all of the other industrialized countries that don’t always record every teenage birth. Also in the US we consider 19 year olds teenagers but in many other countries any age above 18 is considered an adult.

The largest concern that I have with this article is that many teenage pregnancies are not considered pregnancies if they are aborted. While I do think that the rates have dropped due to education in schools I still believe that our rates of pregnancies are very high but we just have ways to invalidate it, thus causing less teenage moms. What do you think? Do you think this article is wrong or right?

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