Pregnancy

My best friend finally succeeded in his efforts to stop smoking when he experienced a highly motivating life change: Fatherhood. Likewise, many women discover that wanting to have a safe and healthy pregnancy gives them unprecedented desire to kick their tobacco habit. Knowing the research and clinical evidence may be useful to parents-to-be who have some questions about smoking:

1. Quitting smoking is very hard – does it really make enough difference to be worth it? Yes. To get one sense of the impact of smoking on fetal development, recall the widespread panic in the 1980s about “crack cocaine babies.” Subsequent research has shown that the damage to fetuses of cigarette smoking is in fact worse than that of crack cocaine use. Even if it didn’t benefit the fetus (and later, the infant) for a mother to quit smoking, it would still be worth using the extra motivation to quit that pregnancy provides for the sake of the mother’s long term health.
2. When is the best time to try to quit? Early. In an excellent lecture I saw last week, Professor Zachary Stowe, MD, with the University of Arkansas for Medical Sciences, pointed out that the soonest a woman can know she is pregnant is 4-6 weeks after conception, at which point fetal organogenesis is well underway. Further, Stowe and other researchers have conducted research identifying nicotine and its metabolites in the fetal compartment even after the mother has stopped smoking. Dr. Stowe therefore suggests that rather than waiting to quit until after stopping birth control or after pregnancy has been confirmed by a test, a mother-to-be should wait two weeks after quitting smoking before going off birth control. Note: Even if you didn’t do this, quitting smoking at any point later in the pregnancy is still good for the fetus (and for you too).
3. I smoke, but I’m not carrying the baby, so why does it matter whether I quit? This isn’t just about mom. Passively absorbed smoke contributes to nicotine in the fetal compartment, meaning that even if the mother quits, smoking by her partner may affect the fetus. Also, an added benefit to a couple of quitting together is suggested by research and clinical experience in addiction treatment: Relapse is more likely when the visible, auditory and olfactory cues of substance use remain in the environment. Hence, a mom-to-be is going to have a much harder time quitting cigarettes if her partner remains a smoker. More positively, if two people quit together they can remove those cues from the environment and also have built-in social support for resisting the cravings they both may experience.
4. Where can we get help with smoking cessation? Free resources are just a click away here. If you need extra support, consult your physician, who can help you both with smoking cessation and with other conditions you may have (e.g., depression) that make it hard to quit.

Addiction expert Keith Humphreys, PhD, is a professor of psychiatry and behavioral sciences at Stanford and a career research scientist at the Palo Alto VA. He recently completed a one-year stint as a senior advisor in the Office of National Drug Control Policy in Washington.

Previously: Craving a cigarette but trying to quit? A supportive text message might help, Exercise may help smokers kick the nicotine habit and remain smoke-free, Kicking the smoking habit for good and Can daily texts help smokers kick their nicotine addiction?
Photo by YOUscription

Near the end of a woman’s pregnancy, obstetricians use ultrasound to check that the baby is poised to be born head-first. Since breech vaginal deliveries (with the feet or rear end first) are risky for both mom and child, many physicians opt to schedule a c-section if the baby isn’t head-down at the end of pregnancy.

However, before they take that step, doctors can perform a procedure called an external cephalic version (or simply “version”) to try to turn the baby. To do this, they push on the mother’s pregnant abdomen while carefully monitoring the baby with ultrasound. In the past, women were not given anesthesia during this procedure, but recent research has shown that administering anesthesia can make versions more successful, perhaps because the medications help to relax the women’s abdominal muscles and allow the physician to use less pressure. Unsurprisingly, moms who receive pain relief are also happier with the process than those who don’t.

But there’s a wrinkle: Some physicians have worried about the additional expense of using anesthesia for versions, since the anesthesiologist’s time and the drugs used come with costs. Researchers from Stanford and Lucile Packard Children’s Hospital decided to address this conundrum by analyzing whether the additional cost of anesthesia was offset by the savings from enabling more vaginal deliveries and avoiding some cesareans.

In our press release, Brendan Carvalho, MD, the lead author of the new research, explained the findings:

“[O]ur work shows that it doesn’t add significant costs, and most likely reduces overall costs because more women can avoid cesareans.”

…

The study found that using anesthesia increased average success rates of version procedures from 38 percent to 60 percent. Because it led to fewer cesareans, use of anesthesia also decreased the total cost of delivery by an average of $276; the range of cost differences estimated by the model extended from a $720 savings to a $112 additional cost.

Looking at the question of cost-effectiveness in a different way, the success rates of versions had to be improved at least 11 percent with anesthesia for the cost of the anesthesia to be negated, the researchers calculated.

So far, Carvalho said, Packard Children’s is one of only a few Bay Area hospitals offering anesthesia for versions. But he hopes his team’s findings will encourage more physicians to consider the practice, since it’s good for both mothers’ well-being and hospitals’ bottom lines.

Previously: Should midwives take on risky deliveries?
Photo by Trevor Bair

Here’s a new reason to dislike smog: Air pollution from traffic has been linked to birth defects in a large new Stanford study of women who lived in California’s smoggy San Joaquin valley during the early weeks of their pregnancies.

From our press release on the study:

“We found an association between specific traffic-related air pollutants and neural tube defects, which are malformations of the brain and spine,” said the study’s lead author, Amy Padula, PhD, a postdoctoral scholar in pediatrics. The research appears online today in the American Journal of Epidemiology.

“Birth defects affect one in every 33 babies, and about two-thirds of these defects are due to unknown causes,” said the paper’s senior author, Gary Shaw, PhD, professor of neonatal and developmental medicine. “When these babies are born, they bring into a family’s life an amazing number of questions, many of which we can’t answer.”

The new research focused on five structural birth defects thought to be potentially affected by the mother’s environment during pregnancy, as well as seven pollutants measured during the EPA‘s federally mandated monitoring of air quality. The researchers compared more than 800 women who had a pregnancy affected by a birth defect between 1997 and 2006 to a similar number of women who had healthy babies during the same period. All of the women lived in the San Joaquin valley during their first eight weeks of pregnancy, and each gave the researcher her home address so that her pollution exposure could be estimated using data from nearby EPA air-quality monitoring stations.

The study is just the beginning of researchers’ efforts to understand the effects of traffic pollution on fetal development. Although a few prior studies have suggested a possible link, they have focused on different geographic regions, have produced conflicting results and have had various flaws in their methods. The new study is the first, for instance, to evaluate women’s pollution exposure in early pregnancy, when birth defects are likely to be developing, rather than at birth.

Much work is still needed in this area, the scientists say, including widening the scope of birth defects studied and examining the effects of combinations of pollutants. If future studies support the new findings, they could offer a route for preventing some devastating birth defects.

Previously: Better diet in pregnancy shown to protect against birth defects, NIH study supports screening pregnant women for toxoplasmosis and Federal government tests potential health risks of 10,000 chemicals using high-speed robot
Photo by Lynn Friedman

A large body of scientific research supports the safety and effectiveness of intrauterine devices and other forms of long-acting, reversible contraception (LARC) for adolescents, and physicians should offer these birth control methods to young women in their care. That’s the message behind a series of review articles published this week in a special supplemental issue of the Journal of Adolescent Health.

Stanford ob/gyn expert Paula Hillard, MD, who edited the supplement, explained to me that doctors are missing a great opportunity to prevent unwanted pregnancies by not offering young women the LARC birth control methods, which include IUDs and hormonal implants. Not only are the LARC methods very safe, the rate of unintended pregnancy with typical use of these techniques is 20 times lower than for alternate methods such as the Pill or a hormone patch.

But a design flaw in one specific IUD used in the 1970s - the Dalkon Shield - increased women’s risk for pelvic infections and gave all IUDs a bad rap. Use of IUDs among adult American women has been low ever since; it’s even lower in teens.

“Long after it was proven that the Dalkon Shield was particularly bad and newer IUDs were much safer, women were just scared,” Hillard said. “Not only did women stop asking for for them, many doctors also stopped using IUDs.”

The new review articles that Hillard edited are targeted at physicians but contain some interesting tidbits for general readers as well. The article titled “Myths and Misperceptions about Long Acting Reversible Contraception (LARC)” provides scientific evidence to refute several common myths, concluding, for instance, that IUDs don’t cause abortions or infertility, don’t increase women’s rates of ectopic pregnancy above the rates seen in the general population, and can be used by women and teens who have never had children.

And, as Hillard put it for me during our conversation, “These birth control methods are very safe and as effective as sterilization but completely reversible. They work better than anything else, and they’re so easy to use.”

Previously: Will more women begin opting for an IUD?, Promoting the use of IUDs in the developing world, and Study shows women may overestimate the effectiveness of common contraceptives
Photo, by ATIS547, shows a public sculpture on the campus of the University of California, Santa Cruz that is affectionately known as the “Flying IUD”

By combining scans of healthy fetuses in the womb, including that of a woman who agreed to weekly electrocardiography scans starting at 18 weeks gestation until just prior to delivery, a team of UK-based researchers have created a 3D computerized model of the activity and architecture of human heart development. Their findings were published Thursday in the Journal of the Royal Society Interface Focus. According to a University of Leeds release:

Although [researchers] saw four clearly defined chambers in the foetal heart from the eighth week of pregnancy, they did not find organised muscle tissue until the 20th week, much later than expected.

Developing an accurate, computerised simulation of the foetal heart is critical to understanding normal heart development in the womb and, eventually, to opening new ways of detecting and dealing with some functional abnormalities early in pregnancy.

The above image shows an MRI scan of the heart of a 139-day-old fetus as seen from the top, with the muscle cells highlighted in red. An accompanying video illustrates fetal hearts at different stages of gestation.

Via Futurity
Photo by University of Leeds

I’ve been fascinated by the placenta ever since I wrote about Lucile Packard Children’s Hospital neonataologist Anna Penn, MD, PhD, and her quest to find out more about this ‘most mysterious organ.’ The recent work of Penn and others have shown that the placenta is much more than a mere housekeeper moderating the ongoing biological conversation between mother and fetus. It also differs markedly among species, which suggests a history of rapid evolution.

Now, geneticist Julie Baker, PhD, and graduate student Edward Chuong have published an intriguing article (.pdf) in Nature Genetics suggesting that species-specific differences are due to the activity of viral sequences that have been incorporated into the mammalian genome over time. (My colleague, Bruce Goldman, has written an elegant description of how these sequences, called endogenous retroviruses, are constantly accumulating in our DNA.) As Chuong explained in an e-mail to me:

Endogenous retroviruses, or ERVs, are genomic “parasites” that occupy 8 to 10 percent of mammalian genomes. They must be aggressively silenced for the embryo to develop properly. In contrast, ERVs are highly active in the placenta, although their functional role - if any - has largely remained a mystery. In this study, we show that these ERVs function as a genome-wide source of enhancers in the placenta. Our findings point to ERV enhancer activity as a potentially significant evolutionary mechanism driving the rapid evolution of the placenta.

Why might the placenta need to evolve so quickly? Well, as any pregnant woman will tell you, with pregnancy comes many indignities. Some are purely physical in nature, others are less obvious. Specifically, the maternal immune system has to be kept from recognizing the fetal cells as foreign and mounting a fatal attack. The placenta protects the fetus by, among other things, secreting molecules to dampen the mother’s immune response; the immune system, conversely, tries to evade this suppression. Says Chuong:

Intriguingly, the fact that the placenta is remarkably different across species may reflect an ongoing co-evolutionary arms races between parent and offspring.

Previously: The placenta sacrifices itself to keep baby healthy in case of starvation, research shows, Program focuses on the treatment of placental disorders and Viruses can cause warts on your DNA

Over on Motherlode, there’s a beautiful and heartbreaking piece on stillbirth, written by a woman who lost her daughter during her 36th week of pregnancy. Noting that stillbirth is far more common than one might think, Sarah Muthler writes:

I’ve read at least a dozen articles about SIDS, and can tick off a handful of risk factors, but until last year, I knew nothing about stillbirth. All of that talk about SIDS has saved lives. Research and awareness have helped cut the death rate in half in the past 20 years. Meanwhile, the United States stillbirth rate has barely budged in the past 15 years.

This silence around stillbirth, this fear of causing fear, leaves families blindly groping as they make the hardest decisions of their lives. If I had known anything at all about stillbirth, I could have made better decisions regarding my daughter’s death. I wish that I had been told to bring some of her clothes to the hospital so she could wear them. I wish that my husband and I had been strong enough to choose to have an autopsy even though our doctor didn’t encourage it. I wish I had known that grant money might be available to cover the several thousand dollars that the autopsy would have cost.

Muthler argues we need to find a way to talk about and educate people on the issue. “If those conversations inspire even a little more research and awareness,” she writes, “then maybe people will see that our lost babies aren’t just a horror story. They’re part of a love story, too.”

Previously: Pregnancy loss puts parents’ relationship at risk

There’s an interesting guest post today on the TED blog about efforts to use human-centered design to reduce mortality rates in the southeast African country of Malawi.

The effort is being driven by Malawi President Joyce Banda. A key part of the proposal is to construct 150 “maternal waiting homes” near clinics where rural women can stay as their due date approaches. By providing housing to expectant moms, Banda and health officials hope more women will give birth at facilities staffed with health providers and equipped to handle complications, instead of in their homes with less-experienced birth attendants. Courtney Martin and John Cary write:

Blueprints for these brick and concrete structures were developed by the Ministry of Health, taking two forms — a 24-bed version and a slightly larger 32-bed structure. Each is projected to cost between $70,000-$80,000, and will be funded by Malawi’s private sector and outside philanthropic support. These waiting homes have the opportunity to become beacons of hope in a country caught between natural beauty and devastating poverty.

But it’s not just bricks-and-mortar that Banda is using to change women’s lives; it’s also a human-centered design for the healthcare system — too long understaffed and disproportionately urban. The Presidential Initiative on Maternal Health & Safe Motherhood, for example, is already training tribal chiefs in the importance of clinic birth for rural women, recognizing that their influence will largely determine what kinds of healthcare options women feel compelled to access. Once the chiefs have encouraged women to get to clinics, they will be met by new community midwives (Banda aims to train over 1,000 by 2014) and training opportunities at the “waiting homes.” Indeed, the Malawian women we interviewed expressed that they would love to gain new skills and knowledge while they wait for their babies to arrive.

Resource-limited settings, like the rural villages of Malawi, seem like unusual places to find this kind of systemic and environmental design. But there are important precedents. For example, the breathtaking Butaro Hospital in Rwanda, designed by MASS Design Group and operated in January 2011 by Partners in Health (PIH).

The post continues with an explanation of how the Butaro Hospital was designed to enhance healing and how such projects, and potentially those in Malawi, could teach the developed world about dignifying design. It’s worth reading.

Previously: Stanford alums develop way to review maternal and child health products used in developing nations, How Embrace infant warmers are saving lives in developing nations, A low-cost way to keep premature babies warm and well, Anti-overkill: Low-cost, life-saving medical inventions and Reducing infant mortality rates in developing countries
Photo by DFID - UK Department for International Development

Can’t blame us if our feet hurt. We humans have been walking erect for well over 3 million years.

That new style of locomotion necessitated “considerable anatomical changes that altered the size and shape of the human female pelvis and the dimensions of the birth canal,” write Stanford and evolutionary theorist Peter Parham, PhD, and pathologist Ashley Moffitt, MD, of the University of Cambridge, in a just-released review article in Nature Reviews Immunology.

Walking upright, along with the development of our bigger brains, allowed us to head out out of Africa into Eurasia. Successive migration events of this nature have occurred a number of times since - leading to the emergence of Neanderthals in Europe around 600,000 years ago and the arrival there of anatomically modern humans (that’s us) a scant 67,000 years ago, give or take a few weeks.

But those bigger brains caused problems, too, the authors write:

The size of the human baby’s head increased until it reached the limit defined by the birth canal… [A]t full term, a modern human baby’s head just fits into the birth canal… [I]n the course of human evolution, birthing became a difficult, dangerous and frequently fatal process…

Bigger brains need more nourishment in utero, putting greater demands on the blood supply to the placenta. Plus, insufficient blood supply to the placenta can lead to pre-eclampsia, stillbirth or low birth weight. But if an emerging baby’s head is too big, it could kill both mother and child on the way out of the womb. It’s a delicate balancing act.

To the rescue come specialized immune cells called natural killer (or NK) cells, which play an important role in our front-line defense against infectious pathogens. NK cells play a key role in reproduction, too, by carefully regulating the development of placental blood vessels. This keeps fetal growth in bounds.

NK cells feature a particular surface molecule that comes in two versions. One of these versions turns out to be somewhat better suited for the task of managing fetal growth, the other for fighting infectious pathogens. Both of these versions are found in every human population ever studied, suggesting that a group’s survival over evolutionary time is favored by some optimal balance between the two.

Parham and Moffett conjure up a vision of just how such a compromise between these two versions might arise:

When an epidemic infection passed through a population, causing disease, death (particularly of the young) and social disruption, selection favored [one version]. When the epidemic subsided, the surviving and now smaller population was immune to further infection and enriched for [that version]. At this juncture, survival of the current generation was no longer the issue, and the priority became production of the next generation. [This favored the evolutionary selection of] factors that enhance the generation of larger and more robust progeny… [H]uman history has always involved successive cycles of [this] type…

Thus, all human populations maintain a mix of both surface-molecule versions. Any distinction between safe, efficient reproduction and vulnerability to infectious disease may seem nonexistent to people who consider babies to be invading organisms - which I suppose they are, in a way. (But cute, too.)

Previously: Our species’ twisted family tree, Humans owe important disease-fighting genes to trysts with cavemen and Humans share history - and a fair amount of genetic material - with Neanderthals
Photo by Lord Jim

Scope will be on a limited publishing schedule in honor of Martin Luther King, Jr. Day. We’ll resume our normal schedule tomorrow.

Updated 12-6-12: In the video above, Shawn Chavez, PhD, first author of the study, describes the work and its significance.

***

12-4-12: Couples who turn to in vitro fertilization, or IVF, are desperate to have a family. But, despite many advances, the odds of a successful pregnancy from each round of costly, emotionally demanding embryo transfer are only about 30 percent. The problem stems from the fact that many human embryos are faulty from the earliest stages and will never develop successfully.

Stanford researchers Renee Reijo Pera, PhD, and Barry Behr, PhD, have been working to find out why - and to develop ways to increase the odds of a successful pregnancy through IVF. They report findings from some of their work in today’s Nature Communications, which I describe in a release:

The research suggests that fragmentation — a common but not well-understood occurrence in the early stages of human development in which some of the cells in an embryo appear to break down into smaller particles — is often associated with a lethal loss or gain of genetic material in an embryo’s cells. Coupling a dynamic analysis of fragmentation with an analysis of the timing of the major steps of embryonic development can significantly increase the chances of selecting an embryo with the correct number of chromosomes, the researchers found.

…

“It is amazing to me that 70 to 80 percent of all human embryos have the wrong number of chromosomes,” said [Reijo Pera], professor of obstetrics and gynecology. “But less than 1 percent of all mouse embryos are similarly affected. We’re trying to figure out what causes all these abnormalities.”

Reijo Pera and Behr started a company called Auxogyn to investigate ways to bring these findings into the clinic. The company, which is now privately held, is currently conducting clinical trials of an earlier version of the technique. Reijo Pera and Behr hold stock in the company.

Continue Reading »