It’s being said that if you want a baby born on 11-11-11, you should “get ready to get on it this weekend.” So…
By Allen J. Wilcox
You already know where babies come from – the business about sperm and eggs, and getting them together. You also know something about birth control – after all, people spend most of their reproductive years trying NOT to get pregnant.
But there comes a time for many women when they ready to have a baby. That’s when some interesting questions arise.
- Once you stop using birth control, how long does it take to get pregnant?
- Is there something women should do to increase their chances of getting pregnant?
- What can a woman do to help make sure her baby will be healthy?
Let’s start with the last question first. The most important thing a woman can do before getting pregnant is to start taking daily multivitamins with folic acid. Folic acid helps prevent serious birth defects of the brain and spine (neural tube defects) and probably other defects as well. These defects happen very early in the baby’s development – waiting until you think you are pregnant can be too late.
Another thing you can do, if you are a smoker, is to quit smoking. Smoking puts a damper on women’s fertility (although apparently not on the fertility of men – life is not fair). Smoking also increases the small chance of fetal death later in pregnancy. Do yourself (and your baby) a favor, and give up the cigarettes.
Besides that, what should you do (besides the obvious)?
Nothing.
Really, nothing. You already have a lot going for you. Consider the benefits of your family history – not a single one of your ancestors was infertile. If you are a reasonably healthy person with no history of reproductive problems, and if you are having unprotected sex at least weekly, biology is on your side.
Some useful facts
There is a spectrum of fertility, ranging from very low to very high. You won’t know where you are on that spectrum until you actually try to conceive. On average, your chance of getting pregnant in the first month is 25%. For a few unlucky couples, the chances are zero – they are sterile. Other couples may have a 50% or 75% chance of getting pregnant in their very first month of trying. For couples as a whole, about half will be pregnant after three months. That goes up to two-thirds of couples after six months, and more than 90% after a year. Even if you don’t conceive in the first year, you still have a 50% chance in the next year or so. Only about 5% or so of couples are unable to conceive at all by natural means.
Probably the biggest predictor of fertility is woman’s age. Women are at their reproductive peak during their twenties. As they move through their thirties, their fertility begins to decline. This is relevant because many women (for lots of good reasons) delay their childbearing until they are in their 30s or even older. If a woman is not so fertile to start with, this delay can cause problems. Unfortunately, there is no medical test to tell women in advance how fertile they are.
The fertility window
Let’s get down to the biology. Pregnancy happens when couples have sex during the five days before ovulation and the day of ovulation itself. (In other words, sperm can survive up to five days in the woman’s reproductive tract.) This six-day fertility window gives you a fairly wide span of days in each cycle for intercourse that can produce pregnancy.
But there is a catch. Most women don’t know
Julio Torres, Intern.
Ancient Bodies, Modern Lives: How Evolution Has Shaped Women’s Health written by Wenda Trevathan, Ph.D., a Regents Professor of Anthropology at New Mexico State University, we learn about a range of women’s health issues. Trevathan’s hypothesis is that many of the health challenges faced by women today result from a mismatch between how our bodies have evolved and the contemporary environments in which we live. In the following excerpt, Trevethan draws from Jane Goodall’s observations of primates to illuminate how grandmothers, by virtue of being present in the family, contribute to the growth of prosperity of the grandchildren and the family unit as a whole.
Grandmothers and Reproductive Success
Most long-lived, group-living mammals have in their social groups as many as three generations present at any one time. Examples include elephants, whales and many primates. For primates who live in matrilocal groups, that usually means three generations of females: Infants, their mothers, and their grandmothers. A famous example comes from Jane Goodall’s studies of a Tanzanian chimpanzee social group in which Flo, her adult sons Faben and Figan, and her daughter Fifi lived together. Flo was a high-ranking female and her presence had a number of positive effects on her offspring. For example, Fifi was able to stay in the troop into which she was born, whereas the more typical pattern among chimpanzees appears to be for young females to leave their birth troops at maturity. By staying with her mother, Fifi was also able to rise to a high status. She began reproducing much earlier than most chimpanzee females and not only set the record for reproductive success at Gombe, but one of her sons became the largest male ever recorded at Gombe. Two of Fifi’s sons rose to high status in the dominance hierarchy and her daughter began reproducing much earlier than Fifi did. There is little doubt that grandmother Flo’s status had an effect on her daughter’s (and thus her own) reproductive success. There is no evidence, however, that Flo contributed directly to the care and feeding of her grandchildren, although it is true that she was not in good health at the time Fifi’s first infant was born in 1971.
Anthropologist Sarah Hrdy notes that despite her reproductive success, Flo serves as a good example of why having offspring at later ages may not be a good way to achieve this success or why “stopping early” might be selectively advantageous. Flo reproduced for the last time when she was very old and in poor health, but that infant did not live long. Goodall proposes that this last pregnancy was so draining for her that she was unable to mother her other young offspring, Flint, and when Flo died, Flint died also, even though he as at an age when he should have been able to survive on his own. In fact, if Flo had stopped reproducing after Flint, he probably would have lived, perhaps going on to sire another offspring and increasing Flo’s reproductive fitness through her grandchildren.
Similar evidence that the presence of grandmothers has positive effects on reproductive success comes from observations of a number of other primate species. Again, it is not usually resources and direct care that older female grandmothers provide; rather, they help to defend the infants from other troop members (including infanticidal males) whose behaviors endanger them. In fact, observers report that grandmothers will often act even more vigorously in defense of infants than younger kin. Grandmother Japanese macaques make a significant difference in survival of their grandchildren through the first year of life. Furthermore, females have much greater reproductive success if they have living mothers, even when those older females are still r
