Timing may be important for couples experiencing secondary infertility. “Birth spacing” refers to planning the ideal interval between pregnancies. Along with thinking about how far apart you want your kids to be in age, you need to think about hormone balance. It takes time after childbirth for your nutritional status to improve enough to support another pregnancy. It takes time for your body to reestablish hormone balance as well. But if you wait too long, your reproductive hormones may fall out of balance. A recent analysis of 67 studies looking at the outcomes of more than 11 million pregnancies demonstrated that the ideal interval between pregnancies is between 18 months and 6 years. Waiting fewer than 18 months resulted in a much higher chance of preterm birth or having a baby with low birth weight. Women that waited less than 6 months also had a higher risk of miscarriage. Couples, especially those who remarry, might want to keep the 6 year mark in mind when planning to expand their family together.
From PERFECT HORMONE BALANCE FOR FERTILITY[u1] : Book Excerpt: P. 16
Traditionally, bed rest has been recommended for women after any medical procedure. For instance, after delivery of a baby, women were prescribed 6 weeks of bed rest until it was ultimately proven that that inactivity increased their risk of DVT (blood clots in the deep veins). Even though bed rest had been encouraged with good intentions; it did not result in the best outcome. Nonetheless, it is challenging to reverse widely accepted but unhelpful advice. Now that IVF has been around for over 3 decades, it is time to review how we advise patients going through treatment and reconsider whether bed rest is still advisable.
In the early days of IVF, women were restricted to bed rest for 2 weeks after an embryo transfer. In fact, patients were not even allowed to stand up for quite some time after the procedure. Instead they were transported to a hospital gurney and relocated to a hospital bed—even using a bedpan when required instead of going to the toilet. It gradually became apparent that such severe limitation wasn’t needed. Back in 1997, the first study [r1] appeared suggesting that even a 24 hour period of bed rest was unnecessary. Specifically they demonstrated that even when patients were only limited to 20 minutes of activity restriction; pregnancy rates were comparable.
Subsequently, in 2005 a much larger [r2] and well designed study found that when patients were allowed to get up immediately after their embryos were placed; their pregnancy rates were as good as patients that were asked to lie flat for an hour. Finally, a 2011 review [r3] of all of the published research on this subject confirmed that there is no advantage to bed rest and instead that there may be a disadvantage to being totally sedentary. This isn’t surprising since inactivity combined with high levels of estrogen can promote blood clot formation as well as a rise in insulin resistance. By contrast, exercise reduces inflammation, lowers stress hormone levels and promotes healthy blood flow.
During pregnancy there has also been a reversal of the popular myth that exercise should be limited. In 2008, the US Department of Health and Human Services issued comprehensive guidelines that healthy women should begin or continue aerobic exercise of moderate intensity during pregnancy. In fact, it was confirmed in a well designed study [r4] that both mother and baby benefit from aerobic work outs. Despite the research, it is difficult to dispel advice from popular culture. It was even found in one study [r5] that when IVF patients were advised by their doctors to remain active; most still restricted their daily activity. So as we look for ways to further boost our pregnancy rates and improve the health of the pregnancies that result it is important that we constantly re-evaluate how we guide women following IVF.
The greatest healthcare challenge facing us as a society today is related to obesity. It is now estimated that by 2030, 42% of the population in the USA will be obese resulting in a rise in healthcare costs of nearly $149 billion per year. But beyond the financial cost is the impact that obesity has on an individual basis. It is clearly the leading risk factor in the development of heart disease, diabetes and many forms of cancer. Clearly any one of us would like to minimize the impact that this could have upon our own child. New research has confirmed that our efforts to insure a child’s healthy future should begin even before that child has been conceived. Theories were proposed nearly two decades ago that a child’s life-long health risks for problems like diabetes begin shortly after conception. But it is within the last 5 years or so that studies actually began to prove that characteristics like a person’s ability to regulate their body weight can be permanently altered by their mother being overweight or obese during pregnancy. That’s because our ability to regulate our calorie balance (i.e., hunger, satiation, metabolism, etc) has to do with the hormonal and chemical balance that our developing brain was exposed to during fetal development. Although the early studies were done on animals, it hasn’t taken long to establish similar ties in humans as well. For instance, one recent study found that for every 22 lbs that a woman was overweight prior to pregnancy, her baby’s birthweight would predictably be about a half of a pound over the average. Then for each additional 10kg that an overweight woman gains during pregnancy, her child’s birthweight increases by an additional half pound. Along with this higher birth weight is a higher risk of cesarean section and subsequent health problems in childhood. That’s because birthweight is the earliest predictor of how our physiology will respond to our high-calorie and increasingly sedentary lifestyle. Babies either above or below the averages are at highest risk of being overweight or obese before they reach puberty. It has been confirmed that when overweight or obese women become pregnant, their children are at high risk of developing problems with high blood pressure, elevated cholesterol and an increased risk of becoming diabetic before they complete their teenage years. Recently, the Center for Disease Control and Prevention revealed the shocking statistic that nearly one in four adolescents today has diabetes or pre-diabetes. That’s nearly triple the rate of just a decade earlier—an alarming increase. So while we work toward finding more treatment options for overweight children and teens, we should also put greater effort toward identifying and assisting women at risk. Intervention before they become pregnant and during pregnancy can not only improve their health (and fertility), but their child’s entire future. Here are just a few of the strategies that have been shown to work: • Whenever possible, assist patients in losing weight prior to conception • Encourage healthy nutrition during pregnancy • Promote exercise during pregnancy • Identify and treat insulin resistance as early as possible (preferably prior to conception) • Encourage breast feeding—helps mom get back to healthy weight after delivery while reducing rapid weight gain in newborn infants • Avoid hormone disrupting chemicals like bisphenonal A (BPA)—which have been linked with excessive weight gain
A recent study [u1] from the National Institute of Health found lowering dietary fat intake can reduce a woman’s risk of developing gestational diabetes. They were tracking the diet and lifestyle habits of 13,000 women that were between 22 and 45 years of age and enrolled in the US Nurses’ Health Study II. They found about 6% of women developed gestational diabetes. However upon analysis they found that women eating more foods that were high in animal fats had double the risk of developing this problem compared to women on a low fat diet. When they performed a more detailed nutritional analysis, they found that dietary cholesterol and animal fats were the only foods consistently associated with an increased risk of gestational diabetes. So carbohydrates (sugars) did not create any measurable impact. Exercise was found to reduce the risk of diabetes but not enough to offset the effects of a high fat diet. They concluded that reducing the consumption of animal fat by as little as 5% while trying to become pregnant –even if replacing it with plant derived fats—measurably reduces a woman’s risk of diabetes during pregnancy.
There are many hormones that are involved in establishing and maintaining your health so that you can conceive and carry a pregnancy. One of the most important is the hormone called thyroxine which is produced by your thyroid gland. The role of this hormone is to regulate your metabolism much like the computer that regulates the idle speed in your car. If your thyroid hormone production is too low; you may feel sluggish like a car that is trying to stall whereas if your levels are too high you may feel overheated and agitated like a car whose engine is revving inappropriately. Although these examples of the extreme shifts of thyroid hormones are fairly easy to diagnose and treat; there are many subtle imbalances that may still hamper your fertility. An example is the condition called “subclinical hypothyroidism.”
Subclinical hypothyroidism is defined as the state of having an elevated level of TSH (thyroidstimulating hormone) but a normal thyroxine level. In other words, the brain is sending a signal to the thyroid gland to boost production of thyroxine but the thyroid gland isn’t responding fully. This imbalance occurs in about 8% of the general population but it is much more common in women with infertility. If left untreated, several studies suggest that overt hypothyroidism can result; having an adverse effect upon both the mother and her developing baby. New studies are now providing much needed information to settle this debate on when and if this subtle hormone imbalance should be treated.
Earlier this year, a study reviewed the impact that treating subclinical hypothyroidism had upon the outcome of IVF treatment. Since the IVF process allows us to assess egg quality, fertilization, embryo quality and the implantation rate following embryo transfer, it offers us the most precise means to assess the impact of this therapeutic intervention. In this study patients with subclinical hypothyroidism were randomly assigned to treatment with thyroid supplementation or placebo. Those that received the hormone boost had better embryo quality, higher implantation rate and a reduced chance at having a miscarriage–all positive findings for couples trying to have a child.
Another larger study was published last year which was designed to evaluate the pregnancy loss rate as well as the preterm delivery risk in pregnant women with subclinical hypothyroidism. This was a “non intervention study” which means that they were just observing the outcome of the pregnancies without deciding when or who to treat. They found that women with untreated subclinical hypothyroidism had twice the risk of first trimester loss providing strong evidence to support the therapeutic intervention with thyroid supplementation.
Finally, there have been studies suggesting that women with subclinical hypothyroidism may develop low thyroid hormone levels if they consume a diet that is high in products made from soybeans (defined as more than 30g of soy protein per day which includes 16 mg or more of phytoestrogens). That’s because these estrogen-like chemicals produced by soy can reduce the ability of your body to convert thyroid hormone into its active form. In one study that actually looked at the effect of this dietary change, they found that 6 out of 60 patients developed low thyroid hormone levels due to a shift to a high soy diet. So although this healthy change in food choices can increase the risk of hypothyroidism it is not an inevitable change.
My recommendation is that if you have subclinical hypothyroidism that you monitor your condition closely and consult with your doctor as to whether or not you may benefit from supplementation with thyroxine (thyroid hormone) during your fertility treatment and pregnancy.