New Under the Sun:
Volume 5, Issue 4
April is the first full month of spring. Springtime is the season of birth for many animals and of “rebirth” for most plants. Taking this as our clue, this month’s news updates focus on issues related to pregnancy and birth.
Stressing the Point: With around 7 billion humans crowding the world, it would seem that carrying a pregnancy to term must be easy. Once the pregnancy reaches the second trimester, this is pretty much the case. However, during the first critical weeks, particularly the first three weeks after conception, pregnancy loss (termed spontaneous abortion in the first trimester) is actually quite high. Although the exact number is unknown, probably in excess of 50% of all conceptions end in spontaneous abortion. Most women are unaware that they conceived and think they just missed a period.
In order to study first trimester pregnancy loss, women must be enrolled in a research study when they are definitely not pregnant, but plan to become pregnant in the near future. They also cannot be using contraceptives, and must have had at least one previous successful pregnancy. It is difficult to find appropriate study subjects in industrialized nations. But a village in Guatemala provided researchers with just the study population they needed.
There are many causes of spontaneous abortion including chromosomal abnormalities, advanced maternal age, autoimmune diseases, certain infectious diseases, and drug and alcohol abuse, among others. For the Guatemalan study, the factor under consideration was maternal stress levels as measured by the woman’s cortisol levels. It is known from other research that women living under severe stress, such as during wartime or famine, are less likely to have a successful pregnancy outcome than is the case for unstressed women. The hormone cortisol helps maintain homeostasis in the body’s systems. However, under stressful conditions, too much cortisol is released creating negative impacts on the body, including spontaneous abortion.
Cortisol was measured three times each week, on alternate days, from the morning’s first urine sample. Over the course of the one-year study, about one-third (22 of 61) of the women conceived. Of these, 13 (59%) experienced spontaneous abortions, on average within 16 days of conception. When the cortisol levels of these women were analyzed, it was found that 90% of them had highly elevated levels during that first trimester period. Of those women who had normal cortisol levels, only one-third suffered a spontaneous abortion. The conclusion is that women under high stress are significantly less likely to achieve a successful pregnancy than are women who live less stressful lives. Nepomnaschy PA, Welch KB, McConnell DS, Low BS, Strassmann BI, England BG. Cortisol levels and very early pregnancy loss in humans. Proc Natl Acad Sci U S A. 2006 Mar 7;103(10):3938-3942.
Comment: As pointed out by the authors of the study, spontaneous abortion is generally an adaptive response. In the case of abnormalities, the reason is obvious. But spontaneous abortion due to stress is also adaptive. Pregnancy is extremely demanding of a woman’s physical and psychological resources. These demands increase with the newborn infant. It is counterproductive to invest a great deal of time and energy if the infant will die at or soon after birth. Therefore, natural selection has adapted a woman’s body to spontaneously abort if the levels of stress are higher than normal. When conditions improve in her life, she should be able to carry a fetus to term with a higher probability that the infant will survive to adulthood.
The fact that about 50% of all conceptions end in spontaneous abortion in the first trimester should give anyone using an early pregnancy detection kit pause. Yes, the kit can tell that conception occurred, but it cannot tell if it will continue. For this reason, care should be taken in discussing the pregnancy during the first trimester. And, while difficult, if the pregnancy terminates, one should avoid self-blame. It is nature’s way of giving the woman a fresh start for a better outcome.
Breath of Life: Struggling to breathe is obviously a stressor. So it should not be surprising to find that women suffering from asthma have higher rates of adverse pregnancy outcomes than do those who can breathe easily. Two research studies presented at the American Academy of Allergy, Asthma, and Immunology annual meeting this March, 2006 provide information on different aspects of this issue. And, as we will see, these studies tie into a seemingly unconnected third pregnancy-related study. In the first asthma and pregnancy study, researchers working in Manitoba, Canada found that women with a history of asthma, even if the last attack were five years previous to becoming pregnant, had an increased risk of delivering a preterm (<37 weeks gestation) or low-birth-weight (LBW) infant (<2500 gms). These women were about three times as likely as non-asthmatic women to give birth to an infant of less than 32 weeks gestation and/or weighing less than 1500 gms. J.J. Liem, AAAAI 62nd Annual Meeting: Abstract 338. Presented March 4, 2006.
The second asthma and pregnancy study related to fetal growth and development in a different way. Working with a Boston-based population of 1,306 mother/child pairs, the researchers found that mothers who obtained vitamin D through supplementation or diet during pregnancy had a lowered risk of having offspring with asthma. There was a clear inverse association: the higher the maternal intake of vitamin D during pregnancy, the lower the risk of the child wheezing during the first two years of life. Controlling for other dietary factors such intake of fish, fruit, and vegetables did not alter the inverse relationship between vitamin D and asthma. C. Camargo Jr., Advances In Asthma Research. AAAAI 62nd Annual Meeting Presented March 4, 2006.
The third research study does not mention asthma or vitamin D, but as regular readers of AnthroHealth News will quickly grasp, they probably do play a role. A group of researchers located in institutions scattered throughout the United States collaborated to produce the FASTER [First-and Second-Trimester Evaluation of Risk] study. Between 1999 and 2002, 35,529 women were recruited into the study. They all had early access to prenatal care and were followed through to the end of their pregnancy. Despite equal access to comparable prenatal care, the perinatal mortality rate among African Americans was 3.5 times that of European Americans. The African American women experienced higher rates of all causes of fetal/neonatal mortality including: “intrauterine growth restriction, preeclampsia, preterm premature rupture of membranes, gestational diabetes, placenta previa, preterm birth, very-preterm birth, cesarean delivery, light vaginal bleeding, and heavy vaginal bleeding.” The authors seemed at a loss to account for this disparity and called for more research. Healy AJ, Malone FD, Sullivan LM, Porter TF, Luthy DA, Comstock CH, Saade G, Berkowitz R, Klugman S, Dugoff L, Craigo SD, Timor-Tritsch I, Carr SR, Wolfe HM, Bianchi DW, D'Alton ME. Early Access to Prenatal Care: Implications for Racial Disparity in Perinatal Mortality. Obstet Gynecol. 2006 Mar;107(3):625-631.
years ago, I published on the issue of health disparities in general and
LBW infants in particular among African Americans:
It will come as no surprise that I view vitamin D deprivation in this population as a major factor in the higher incidence of LBW infants and infant mortality, and also in the other health conditions and diseases that occur at higher rates among African Americans. In both articles, I stressed the importance of more research on this issue. But, sadly, little has been done in the intervening years, perhaps because funding for this research is deemed as politically charged.
Although I did not
mention asthma in either article, it makes sense that it is related to
vitamin D deprivation since it is an autoimmune problem and several other
autoimmune conditions have been shown to be linked to vitamin D deprivation.
That asthma may be a factor in the higher rate of perinatal mortality
among African Americans is indicated by the fact that this population
has the highest incidence of asthma of any group in the United States.
About 13% of the US population is African American, but 26% of the deaths
from asthma occur in this population.
As noted in the first study in this section, mothers with asthma are more likely to experience poor pregnancy outcomes. The second study points out that asthma is inversely associated with vitamin D supplementation. The third study states that despite early prenatal care, Africans Americans still have extremely high rates of poor pregnancy outcomes. Since a variety of studies have found that African Americans have suboptimal vitamin D levels, it seems obvious that the easiest, cheapest way to improve pregnancy outcomes among this population is to make sure that the mother’s vitamin D levels are optimized well-before pregnancy and that they are maintained throughout pregnancy and beyond. The most recent advice by those who study vitamin D and health is to take a supplement of 2000 IU per day of cholecalciferol (on its own, without calcium or vitamin A). For those who are moderately-to-heavily pigmented, the dosage should probably be double that.
AnthroHealth Tip of the Month: Make sure each pregnancy is planned and that the physical and emotional health of the mother-to-be is in peak condition. For those individuals who won’t be having more children, make sure that any children you do have who are of reproductive age are fully informed about the requirements for achieving an optimal pregnancy outcome. The best diet? An AnthroHealth one, of course! And do not forget to optimize vitamin D levels!!
© 2001-2009 Kathleen E. Fuller, PhD. All rights reserved.