Week 3: Conception

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This is your Pea in the Podcast for week three of your pregnancy. I'm Bonnie Petrie, joined by Dr. Laurie Swaim, an obstetrician with Houston Women's Care Associates in Houston, Texas.

Well this is it, the big week when sperm and egg meet and become one. You have conceived. "It actually happens in the fallopian tube and that's the one thing that a lot of people don't really get. And it happens you know either at ovulation or you know within a short period of time after ovulation. And then what happens is the sperm and the egg together after fertilization hang out in the tube and don't really implant in the uterus until about day tenish. And so the hormone you know a lot of women come in before they've missed their period, they want a pregnancy test you know they're four days after ovulation, well it's never going to be positive even if you are pregnant because zygote if you will hasn't implanted in the uterus yet, unless it's implanted in the tube which is a bad thing, that would be an ectopic pregnancy but even then it would be undetectable at for example what we would call three week gestation which would really be one week of actual pregnancy."

And during week three your baby will grow to consist of a ball of cells that can fit onto a head of a needle or if you're going to have fraternal twins, two balls of cells that can fit onto the heads of two needles. Fraternal twins happen when two eggs are released and are fertilized by two different sperms. Identical twins occur when a single sperm and egg join then divide into what will become genetically identical people. Now if they are in your future the split may also happen this week or early next week. A multiple pregnancy is more likely than it ever was. The March of Dimes says between the years 1980 and 2000 the number of twin births has increased 74 percent. Now that may be because twins are more likely for older women and more older women are having babies these days. More women are also using fertility medication, some of which may increase the chances of a multiple pregnancy. Now if you are carrying high order multiples, those are triplets or more, some of those may be identical while others may be fraternal.

Now if you're having a singleton or twins or more the big moment is happening right around this time. Now if you've been thinking about pregnancy and you're taking medications you need to talk to your doctor because Dr. Laurie Swaim says there are some things that you cannot safely ingest while pregnant. These things are called teratogens, "A teratogen is an agent like a drug or a chemical or some matter that could be ingested that could cause deformity in the developing embryo fetus." Or a teratogen could end a pregnancy, "There's a commonly used drug for rheumatoid arthritis, there aren't many women with rheumatoid arthritis who are reproductive age but nevertheless that drug will likely abort the pregnancy. There are some drugs, there's a drug that's a drug thinner called Cuminin which causes very severe embryopathy, the baby has a lot of deformities. There are certain drugs we know that are more likely to be associated with spine bifida neural tube defects, those are certain seizure medications. But there's a huge wide range of alcohol, for example, in high, high doses could be considered a teratogen."

There is an acne medication that is so dangerous to a developing baby doctors are very careful about prescribing it, "Acutane absolutely is a teratogen and most dermatologists won't give it to a woman without reliable forms of birth control. And that's because acutane and high doses of vitamin A are known to be dangerous to the resulting fetus and even the topical vitamin A we have women stay away from." So once again if you are taking any kind of medication at all, please talk to your doctor, find out if it's safe.

Now for people who are actively trying to conceive, this week is torture because there is no way to tell if you have done it. Hopeful moms looking for pregnancy symptoms are unlikely to find any, although some moms to be do report a tiny amount of bleeding, spotting actually that they attribute to the implanting of the embryo to the uterine wall toward the end of the week. Your hopes may be dashed by the onset of typical premenstrual symptoms which can mimic very early pregnancy symptoms so you may feel some breast tenderness or you may feel the need to pee a little more or you may be a little bit more tired as this week comes to a close there's no going back now, a baby is coming. You are three weeks pregnant; there are only 37 weeks to go until the big week, week 40.

That's your Pea in the Podcast for week three of your pregnancy. Dr. Swaim and I look forward to talking with you again next week. I'm Bonnie Petrie, thanks for listening.