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Many women of child bearing age are wondering which fish to buy to get those beneficial omega-3 fatty acids without poisoning themselves or eating the last of some endangered species.
Higher intakes of the omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), appear to decrease the risk for hypertension, atherosclerosis, type 2 diabetes, and some inflammatory diseases. DHA decreases the likelihood of premature birth, and is key to normal brain, retinal and possibly testicular development in fetuses.
Mackerel, herring, salmon, halibut and tuna have the greatest amounts of EPA and DHA, but caution is advised.
Some seafood contains significant amounts of methylmercury (meHg), which is toxic to the nervous system and may negate the cardiac benefits of fish. Large scale mercury poisonings 30-40 years ago in Japan and Iraq resulted in infants with cerebral palsy, mental retardation, developmental delay, seizures, blindness, and hearing impairment. While some mothers of affected infants were asymptomatic others showed toxic effects including fatigue, muscle and joint pain, headaches, hair loss, impaired memory and concentration, numbness, loss of peripheral vision, blindness, decreased coordination, difficulty walking, kidney failure, and death.
Research in monkeys has revealed that the reproductive effects of meHg include sperm toxicity, decreased pregnancy rates and increased miscarriages and stillbirths. Human studies describe higher mercury levels in couples experiencing infertility than in fertile couples. In ongoing studies, measurable decreases in intelligence and evidence of learning disabilities have been tied to methylmercury in children of some, but not all fish eating populations.
Toxic amounts of mercury rain down from skies polluted by the burning of coal and leach into waterways from old gold and mercury mines, including one in Marin near Tomales Bay. Bacteria convert the inorganic mercury to meHg, which then increases in concentration in organisms as it moves up the food chain. The human intestine absorbs 95% of ingested meHg, and then the body slowly excretes it over a period of months. Unfortunately, ingested methylmercury can show up in breast milk.
In 2000 the National Academy of Sciences (NAS) set the maximum acceptable daily meHg intake at 0.1 mcg/kg of body weight although some scientists have proposed an even lower threshold. Others have used a weekly or monthly intake guideline, which permits higher intake on any individual day, but limits the amount of fish eaten per week.
The San Francisco Chronicle recently sponsored an analysis of locally purchased fish, which revealed that a 120 lb. person could easily ingest 4 to 40 times her daily allowable intake of meHg by choosing popular fish including swordfish, halibut, Chilean sea bass, and ahi tuna. In separate tests white albacore tuna exceeded the NAS standard by 11 fold and chunk light by 3 to 4 fold.
Consistent with these findings is the report published last year by San Francisco physician Jane Hightower. She found that 66 of her female patients had an average blood meHg level three times the maximum recommended by the National Academy of Sciences (NAS). Many were symptomatic as were some of the children she studied. Agreement on what constitutes "safe" levels of exposure for pregnant women is still pending the outcome of ongoing studies. New data indicate that blood mercury concentrations are higher in the umbilical cord than in the mother and consequently, that 16% of infants are exposed to excessive mercury levels before birth. At an EPA conference in January a new maximum daily meHg intake for pregnant women of 0.07 mcg/kg was proposed.
The FDA has issued a warning that women who might become pregnant should avoid shark, swordfish, king mackerel and tilefish and PFC would add white albacore tuna. By not eating swordfish, shark and tuna, you're not only protecting yourself but also these threatened species (www.montereybayaquarium.org). Also, many fish from Northern California waterways should not be eaten by women of childbearing age because of mercury or PCB contamination (www.oehha.ca.gov/fish.html).
Beth Schriock, MD, a pediatric endocrinologist, is PFC’s Clinical Research Coordinator. She has a keen interest in the environment’s impact on human health.
Our 7 year old daughter sneers when we joke about why she is a fanatic about ice cream: "Because you were a frozen embryo for 9 months." To our 4 year old twin boys, also conceived by ICSI/IVF, we sometimes say, "double trouble - we wanted one more boy, and we got two!" They, along with our adopted Korean son, don’t realize that they are true miracles, particularly since the most recent IVF attempt was given a 2-5% chance of success by Dr. Schriock, because "age was an issue," and to our dismay Emily's FSH level had tripled since our prior successful IVF cycle.
Never as a couple did we predict that we would be challenged with unexplained infertility. Emily took for granted that she would some day have children, having put career and studying as a top priority throughout her second decade. But as a pediatrician and geneticist, we too became part of the Bay Area epidemic of infertility as we struggled to start a family. Each day at work Emily became ever-so-more aware of the challenge as she counseled pregnant women about genetic testing. I myself, a psychiatrist, became concerned about the emotional roller coaster, because Emily seemed obsessed with the goal of having a child.
Despite the lack of control we felt, now that we have completed our quest to be parents, we are truly appreciative of the expertise, wisdom, and compassion of PFC doctors and staff.
We feel blessed by what we have learned:
- We never take our children for granted;
- Each child, no matter how he/she came into the family, is loved equally for the joy each one brings - adoption is just as much of a gift as a pregnancy;
- There are some advantages to raising twins;
- Our lives are enriched from the relationships we formed with health care providers and friends;
- Life is precious - we more deeply cherish our own lives and value friendships, hobbies, nature, family time;
- We have more sensitivity towards others who have similar struggles.
- Don’t hesitate to ask questions or seek multiple consultations;
- It is useful to record all notes in a journal to help think of questions, and to feel more knowledgeable and in control;
- Take advantage of scientific journals on infertility, RESOLVE and their resources;
- Start therapy and counseling if needed;
- Use the internet to research and read the many available books, but also keep in mind that some information is not substantiated by good, sound data;
- The field of infertility advances quickly, and given new choices - there is always hope;
- Look into other options, even though at times it may seem there is no light at the end of the tunnel. Adoption does not have to be a last resort;
--- John and Emily, San Francisco
Q:
I am a 49 year old man considering becoming a father again. Should I be concerned that my age has an impact on sperm quality?
A:
Although there is no strong evidence that sperm suffer the same age related degradation as women's eggs undergo, older sperm do cause their fair share of genetic problems, albeit in a much different way.
In contrast to females, who are born with all their eggs, men have no sperm when they are born. They don’t make any sperm until they reach puberty, when a prolific and persistent production begins. The average man makes about 250 million sperm a day: that’s about 6,000 sperm every time his heart beats. As a man ages, sperm production continues unabated, and there is no strong clinical or scientific evidence that production decreases significantly even in 70 and 80 year old men.
Since sperm production is so high, a man has to keep copying his DNA over and over again to make sperm. All this DNA copying leads to small mistakes, called mutations. If you remember that at its most basic level, DNA is a series of letters that make up recipes called genes. If the recipe is copied millions of times a day, mistakes inevitably happen.
Imagine having a cake recipe that has 3 cups of flour as part of the text. You photocopy the recipe for a friend. She photocopies your photocopy for a friend and so on. After multiple copies, your 3 cups of flour might start to look like 2 cups of flour, and suddenly your cake recipe doesn’t work any more.
These subtle copying defects cause a long list of diseases in the children of older fathers. Lesch Nyhan Syndrome, Polycystic kidney disease and Hemophilia A are among the most well known. For fathers over age 40, the risk of having a child with a disease-causing mutation is similar to the risk the mother has for a child with Down syndrome.
The biology of eggs and the aging of ovarian reserves are relatively well understood phenomena. As people gain a better understanding of how aging sperm can contribute to fertility complications, older couples will have better tools for planning their families.
--- Joe Conaghan, PhD
What might a mindful career-oriented 36-year-old woman have in common with a 22-year-old just diagnosed with an unusual cancer and scheduled for radiation or chemotherapy treatment?
- Both may want to carefully chart their course of family planning.
- Both face the loss of their ovarian egg reserves: one from the damaging chemotherapy, the other from age.
- Both may be considering oocyte (egg) freezing.
What is most important is a patient's absolute understanding of the challenges of egg cryopreservation. To say women's oocytes are much more difficult to freeze than male sperm is an understatement. A good quality female egg is essentially a pin head-sized globule of fluid plus the necessary DNA to carry new life into being. It is this sac of liquid that must be carefully drained and then filled with anti-freeze to help the egg freeze and thaw. Accomplishing this without damaging the microcosm of genetic material, as delicate as a spider web, is the main hurdle. When egg quality is compromised, a myriad of problems ensue: failure to fertilize or implant, miscarriage and birth defects.
The race to offer egg cryopreservation was initially fueled by favorable research results from a study that used subjects in their early 20s, and which resulted in >50% chance of a live birth. Yet with only 7 subjects, that study is not statistically significant. In subsequent studies that used women in their early 30s, the success rate dropped below 25%. Currently, most U.S. clinics pioneering this procedure predict only an 8-10% chance of live birth. Also, a side effect of freezing is the hardening of the egg's outer membrane, known as the zona pellucida, making sperm penetration difficult. However, this is overcome by using ICSI (intracytoplasmic sperm injection).
Those requesting this service need to have all of the facts before making a choice. In particular women in their mid- to late-30s, who tend to be the most enthusiastic candidates, need to weigh other options with higher proven success rates. We at PFC share an understanding with much of the medical community that this procedure may be the right choice for the right person, but only with a full understanding of its limitations. This will be our approach when we start offering egg cryopreservation to our patients later in 2004.
--- Eldon Schriock, MD
A woman trying to get pregnant doesn't need the added stress of wondering if her breast milk carries any toxic synthetic chemical residues from everyday items or environmental pollution.
Besides methylmercury in fish, there are chemical residues found in fire retardants in the foam of that gorgeous new couch, organochlorines in common garden pesticides and anti-wrinkle agents in new clothes. Some residues are benign, and wash through the body; others linger, and through persistent exposure, can show up in blood, fatty tissue and breast milk.
Although the cumulative effects of these so-called bioaccumulators are actively being studied, there are good reasons not to panic. First, not all chemicals that enter a woman's body persist. Many residues are attracted to water rather than fat, and will exit the body through urination.
Second, there is a global movement of activists and scientists working to recognize that women and their children have a fundamental right to clean breast milk. The most problematic pollutants have already been identified, and health activists are determined to stop exposure. In August 2003, they were victorious when California legislators passed a law to ban a class of chemicals used in common fire retardants known as PBDEs that were showing up in large amounts in breast milk.
Finally, some experts concur that the health benefits of breast feeding outweigh the potential negative impacts of low-level lingering chemicals in the breast milk. Some studies have even shown that breast milk can reverse some of the negative effects of low-level fetal exposure to toxic chemicals.
If you are inclined to get more involved in this topic, keep abreast of California State Senator Deborah Ortiz's legislative initiative SB1168 Biomonitoring Program. This pilot program would enable target women to be tested for the presence of harmful chemicals, and it would represent the first statewide initiative of its kind.
--- Philip Chenette, MD
PFC's 2002 success rate data has just been submitted to the Society of Assisted Reproductive Technology (SART) and the Center for Disease Control (CDC). The data could not be compiled until all the 2002 babies were born (late 2003).
As stated every year in the SART-CDC report, there are important factors to consider when using clinic statistics to compare individual clinics’ success rates. For an example, some clinics will accept all patients and other clinics may be less inclined to perform IVF on patients with lower probabilities of success. Some centers may see older patients, on average, or patients with more difficult infertility problems. Furthermore, some clinics will transfer more embryos to achieve a higher success rate, placing a patient at greater risk of high order multiples (triplets or more). For more information on factors to consider and to view published data from 2001, please refer to the CDC website, www.cdc.gov/nccdp/drh/art.htm.
Key points to consider:
- Comparing IVF programs by published statistics requires some insight into why programs may or may not be different. For instance, in 2002 at Pacific Fertility Center, 33% of our patients undergoing IVF had a diagnosis of Decreased Ovarian Reserve, DOR, (a basal FSH level of 10 mIU/mL or higher). This percentage of patients with this diagnosis is one of the highest in the United States. (It is the highest in the nation for centers reporting over 300 IVF cycles per year.) This is a most difficult diagnosis to overcome and therefore PFC is proud that we were able to maintain such high levels of delivered pregnancy with one out of 3 patients undergoing IVF with DOR.
- Our high percentage of DOR patients confirms that we do not restrict the patients who pursue IVF to only those patients most likely to succeed. Despite this fact, PFC’s success rates continue to climb every year. We feel this steady improvement is due to continued innovation and strengthening of all aspects of our program.
PFC performs a substantial volume of IVF and ovum donor cycles. This allows for better statistical accuracy of our data (strength in numbers) and we feel keeps all of us well-attuned to the practice of ART.
PFC’s success rates with frozen embryo transfers approaches that of fresh embryo transfers. We have had a very strong freezing program for many years now and are proud of this. Our patients can avoid high order multiple pregnancies and increase the odds of having more than one child from an IVF cycle.
If you have any questions about this data, please let us know. We’ll be happy to discuss them with you and estimate your individual chances of success.
--- Carolyn Givens, MD